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DRILLING & MEASUREMENTS

SUGAR LAND

LEARNING CENTER

Drill Bits

SELF - LEARNING PACKAGE

USEFUL PRE-REQUISITES

Knowledge of the Drilling Process.

Knowledge of the Rotary Rig and its Components.


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Drill Bit Self-Learning Package December 2001

Sugar Land Learning Center Page 2

DRILLING & MEASUREMENTSSUGAR LAND LEARNING CENTER

DRILL BITS SELF-LEARNING PACAKAGE

Welcome to Drill Bit Self-Learning Package. This package is design togive you an introductory understanding of Drill Bits.

Introduction to Self-Learning

Self-Learning enables you to learn at your pace, in your time, and in yourway. This course book provides the content, structure, and organization ofyour learning, which would otherwise be managed by an instructor in aclass. It also gives you some review questions to help you to confirm yourunderstanding. Below is some information to help you get started.

How To Use This Self-Learning Package

- Try to do the course in a maximum of 2 sessions, close together:(For example: Work session - - Break - - Work session)

- Set yourself up in a suitable learning environment: no noise, nointerruptions, and no distractions.

- Use the review questions to confirm that you have understood.They are for your benefit. They are not assessed or marked. Ifyou get an answer wrong, just go back through the material.

- It is useful, but not essential for you to have met the pre-courserequirements stated on the course book cover.

Everything you need to complete the Drill Bit Self-Learning Package iscontained in these notes. To get started turn to the next page.


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Table of Contents

OBJECTIVES.........................................................................................4

INTRODUCTION...................................................................................5

DRILL BIT INDUSRTRY OVERVIEW................................................ 6

- Drill Bit Competitors........10- Drill Bit Market Past & Present...........12- Drill Bit Competitors: Strengths & Weaknesses... . .13

- Hughes Christensen........13- Smith Geodiamond.....14

- Schlumberger Drill Bits......... 15- Security DBS.... .........16- Drill Bit Industry Summary.................17

ROLLER CONE BITS .........................................................................19

- Component Parts...19- Exterior Parts....20- Interior Parts..... 23

- Bearings......23- Seals....26

- Grease System........29- Assembled Components... .. ...30

- Cutting Structure...31- Insert Bits...... .31- Tooth Bits.... ..34

- Hydraulic Configurations.........36- Nozzles.....38- IADC Code...40- Schlumberger Nomenclature....43- Schlumberger Features... .45- Schlumberger Product Lines.54

FIXED CUTTER BITS.........................................................................55

- PDC..... .55- Natural Diamond & TSP.... ..56- Impregnated Diamonds.....57


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FIXED CUTTER BITS.........................................................................58

- PDC Components....... .58- PDC Nozzles ....... 67

- PDC Designs.....68- PDC Cutters .........69- Schlumberger PDC Cutter Technology....71- NPI PDC Cutters .........75- TReX Cutters........76- Schlumberger Fixed Cutter Product Lines. ..79- Schlumberger Fixed Cutter Nomenclature... ...82- Schlumberger Fixed Cutter Features... ....83

DRILL BIT LINKS ON THE SCHLUMBERGER HUB..................... 88

Objectives

Upon completion of this Drill Bit Self-Learning Package, you should be ableto do the following things:

?? Describe the Drill Bit industry

?? List the 4 major Drill Bit competitors and their strengths & weaknesses

?? Identify the interior components of a roller cone bit

?? Identify the exterior components of a roller cone bit?? Identify the component parts of a roller cone bit?? Describe the different roller cone hydraulic configurations

?? Describe the roller cone IADC Code

?? Demonstrate an understanding of Schlumbergers roller conenomenclature

?? List and describe Schlumbergers roller cone features

?? List Schlumbergers roller cone product lines

?? Identify the major types of fixed cutter bits

?? Identify the major components of PDC bits?? Describe Schlumbergers PDC cutter technology

?? List Schlumbergers fixed cutter product lines

?? Demonstrate an understanding of Schlumbergers fixed cutternomenclature

?? List and describe Schlumbergers fixed cutter features


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Introduction

Reed-Hycalog (Schlumberger Drill Bits) is the combination of two strong,

technologically advanced leaders in the supply of drill bits and expertise tothe petroleum drilling industry. The union of the two companies provides atotally integrated, full-service company dedicated to implementing drill bitsolutions on a worldwide basis.

The history behind the two companies is as diverse as the product lines theycollectively distribute. Reed Tool Company was formed in 1915 whenClarence E. Reed formed a partnership with J.H. Giesey to manufacturedrilling tools. Throughout the years, Reed has designed, manufactured, andsold thousands of different products to make drilling around the world more

efficient. Today, Reed focuses its technical resources on developingpremium roller cone drill bits with over 400 different sizes and types of bitsin its product line.

J.R. Frenchie Mayeaux and Dan Grady in Shreveport, Louisiana formedHycalog (HYdroCArbon-LOGging) in 1946. This company was latercombined with the US operations of Drilling and Service and the Ruckercompanies. Originally operating as a core bit company, Hycalog has nowgrown into the leading supplier of PDC and natural diamond drill bitsworldwide with the number one market position in most drilling areas.

The most recent chapter in this history was the acquisition of Reed-Hycalog(via Camco International) by Schlumberger. Reed-Hycalog is now anintegral part of Drilling & Measurements, which is part of SchlumbergersReservoir Development Group. In 2001, Reed-Hycalog began the transitionof changing the companys name to Schlumberger Drill Bits.

Schlumberger Drill Bits has four strategically located ISO 9001 certifiedmanufacturing facilities with the most modern CNC manufacturingequipment in order to meet customers requirements. Roller Cone

manufacturing plants are located in Houston, TX and in Singapore. TheFixed Cutter manufacturing plants are located in Houston, TX and inStonehouse, England. The safety record within these facilities, and in thefield, surpasses the industry standard defined by Drill Bits and bySchlumberger. In addition to ISO 9001, Schlumberger Drill Bits meets theAPI Q1 standard and the Schlumberger QHSE standards.


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Within the fixed cutters there are two types of bits: PDC bits(Polycrystalline Diamond Compact) and Natural Diamond/Impreg.

PDC Bit Natural Diamond / Impreg Bit

Customers Expectations

In order to sell drill bits, specific customers expectations must be met.

There are several things that the customer might expect from a drill bit whenthey buy it:

- they may expect the bit to drill an entire interval

- they may expect the bit to drill the interval faster than onprevious wells

- they may want the bit to drill it at the lowest cost-per-foot

- they may want a good dull condition from the drill bit onceit comes out of the hole

- they may be interested in directional accuracy

- they may have some other criteria that they are interested in


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Which one of these customers expectations are the most important?

From a drill bit aspect, bit cost-per-foot is going to be the best measure of

performance. But, the customer is not always interested in cost-per-foot.Sometimes they are interested in making sure they can drill the interval in aspecific amount of time irregardless of how much it costs them. Sometimesthey have to drill the interval at a certain ROP (Rate Of Penetration) in orderto meet the criteria that they have for a specific well. Another situation thatcustomers might need is to have a good dull condition. This is importantbecause sometimes customers rerun bits on multiple wells. Sometimesdirectional accuracy is the most important for a customer. This is extremelyimportant if you are drilling horizontal or directional wells anywhere in theworld. The directional accuracy could be far more important than how much

it cost for the bit, or how much it cost to drill a specific interval of the well.If the customer cannot hit their targets, then they are not going to get thereservoir development that they expect. There could be some other thingsthat customers expect out of bits; for example, hours. There are somecustomers in parts of the United States that if the bit does not drill a certainamount of hours then their expectations have not been met.

So which one is most important? The answer is it depends. It depends onwhat that specific customer's expectations are out of the drill bit. It is the

responsibility of the Drill Bit Engineers and Specialist to find out what arethe customers' expectations. Once the customers expectations areidentified, the proper bit to meet the proper application can be selected.

Drill Bit Sales

Drill bits are sold in a variety of different ways.One of the ways drill bits are sold is at the rig site.In this situation bits are loaded up in the back of apickup truck and an Engineer or Specialist, in a

geographically assigned area, will go out into thefield and sell the bits at the drilling rigs. Contact ismade with the people that are buying the bits. Thena decision is made on what bits are going to meetthat customer's expectations on that specificlocation.


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Another way drill bits are sold is in the office. They are sold to operatingcompanies, to drilling engineers, and to purchasing departments. Typicallyit is better not to sell bits to purchasing departments because they are only

interested in price. Drill bits are not a commodity. They are a performancetool.

Drill bits are also sold directly to directional drillers and drilling contractors.There are a lot of wells that are drilled, especially in the US and Canada, ona footage basis. Footage means that a drilling contractor has agreed with anoil company that they will drill a specific depth of a well for a certain price.In this case the contractors are responsible for purchasing the bits. The drillbits will be sold directly to the drilling contractor as opposed to the oilcompany. There are some situations where directional drillers are

responsible for buying the bits. Directional companies will turnkey adirectional well, or a section of a well. Being part of Drilling &Measurements, Schlumberger Drill Bits will need to take advantage of thissituation when D & M has the directional job and is buying the bits.

Drill bits are also sold by tender to national oil companies. Basically whatthis means is that a national oil company will put out a bid for bits.Sometimes this is for a 6-month supply, a year supply, or some other periodof time that they will designate. All of the major drill bit companies get to

bid on the tender. The bits are typically bought from whomever providesthem with the lowest price.

Another way drill bits are sold is by supply contracts to major oil companies.This is typically driven by management consultants and purchasingmanagers. When this happens the companies are trying to reduce their costsover a period of time by buying bits in bulk from one or more of the majordrill bit suppliers. Many of the major oil companies do have some kind ofsupply contracts with one or more of the drill bit companies.


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Drill Bit Competitors

There are 4 major drill bit competitors that control approximately 92% of the

$1 billion dollar worldwide drill bit market.

First is Hughes Christensen. Hughes Christensen is owned by Baker HughesInternational. They are the #1 drill bit company in the world withapproximately 30% market share. Hughes is the roller cone portion of thebusiness and Christensen is the fixed cutter portion of the business.

Second is Smith Geodiamond. Smith GeoDiamond is owned by SmithInternational. They are the #2 drill bit company in the world withapproximately 27% market share. Smith is the roller cone portion of the

business and Geodiamond is the fixed cutter portion of the business.

Third is Reed-Hycalog which in 2001 were changing the name toSchlumberger Drill Bits. Reed-Hycalog is owned by Schlumberger and ispart of Drilling & Measurements. They are the #3 drill bit company in theworld with approximately 20% market share. Reed is the roller cone portionof the business and Hycalog is the fixed cutter portion of the business.

Fourth is Security DBS. Security DBS is owned by Halliburton. They arethe #4 drill bit company in the world with approximately 15% market share.Security is the roller cone portion of the business and DBS is the fixed cutterportion of the business.

There are several other drill bit competitors around the world thatcollectively have approximately 8% market share. There are RBI, Varel,Walker-Macdonald and TSK which are all roller cone companies. There arealso many regional and local PDC companies located around the world.

The drill bit market is basically split out into the 2 major bit types - roller

cone and fixed cutter. The roller cone is approximately 60% or $600million, and the fixed cutter is about 40% or $400 million.


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Drill Bit Market Past and Present

To understand the drill bit market, it is necessary to look at the market in the

past and then where it is today.

Past Drill Bit Market

On the vertical axis is penetration rate, and on the horizontal axis isformation compressive strength.

The chart shows the PDC, the tooth, the insert, and the impreg / naturaldiamond bits. As indicated, there is very little overlap between the PDC, thetooth bits, the insert bits, and the diamond / impreg. If a customer wanted to

drill in a specific area it would be pretty easy to identify what type of bitthey were going to need to run for the particular formation. Based on howfast they wanted to drill it, and the compressive strength of the rock, it woulddictate which one of the four bit types would actually be used in thatparticular application.

Formation Compressive Strength

Penetration

Rate

PDC

Tooth

Insert

Impreg

& N.D.


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Today the bit market has changed quite a bit.

Present Drill Bit Market

On the vertical axis is penetration rate, and on the horizontal axis isformation compressive strength.

With the evolution of PDC cutter technology, the evolution of tooth bits andof insert bits, and the improvements to the impreg and natural diamond bits,there is now quite a bit of overlap in the present bit market. If a customerwanted to drill in a specific formation, a decision would have to be made onwhich drill bit type would be the best to use. This was one of the majorreasons why all 4 of the major roller cone drill bit companies and the major

fixed cutter drill bit companies combined as one instead of operating as twoseparate companies.

Formation Compressive Strength

PenetrationRate

PDC

ToothInsert

Impreg

& N.D.


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Drill Bit Competitors Strength & Weaknesses

Hughes Christensen

The first strength of Hughes Christensen is that they were the first in BitOptimization Service. Basically they were the first ones to put a drill bitengineer in a customers office, at no charge, to do all of the analytical andbusiness requirements for the customers drill bit needs. In some cases theywere given a bit contract to provide a certain number of bits. Hughes wasfirst in this Bit Optimization service. Smith and Security quickly followedand Schlumberger Drill Bits were the last ones to offer that service.

The second strength of Hughes Christensen is volume economics. They

build twice as many bits as Schlumberger Drill Bits. Their volumeeconomics allow them to have a lower cost per bit because they can absorbthe overhead from their factories over a greater number of products.

The third strength of Hughes Christensen is market strategy. They havedone an excellent job over the years of marketing their product. Everyinnovation, every new feature, and every good performance are published inmany of the oil & gas publications.

The final major strength of Hughes Christensen is name recognition.Hughes was the first roller cone drill bit company. They are very wellknown throughout the industry. They have good competitive products.

Hughes Christensen does have several weaknesses. First, they have anarrogant sales staff. This attitude has cost them some business in the past.

Their second major weakness is sometimes they are slow to respond. Sincethey have such large volumes of product they cannot always get their bitsout to the market in as a timely manner as they would like to. Also the

actual drill bit market is not predictable. So if activity increases faster thanplanned, sometimes Hughes Christensen can be a little slow to get theirproducts out to the market place.


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Smith Geodiamond

The first strength of Smith Geodiamond is they have autonomy, which

allows them to focus. Since they are not owned by one of the major oilservice companies, they can spend more of their time focused specifically onthe drill bit segment.

The second strength of Smith Geodiamond is that they were second in themarket with Bit Optimization Service. Soon after Hughes Christensen, theystarted putting their engineers in the offices to help make bit selections.

The third strength of Smith Geodiamond is that they market new technologyvery well. Any time they come up with what new products or features, they

have brochures coming out, they have covers on the major oil publications,and they do an excellent job of marketing their product.

The third strength of Smith Geodiamond is the fact they acquiredexperienced personnel. A few years ago, Smith decided that they wanted togo full force into building fixed cutter bits and becoming a dominant force inthe fixed cutter market. They decided to go after the #1 fixed cuttercompany in the world at that time - Hycalog. They hired HycalogsPresident, their Vice- Presidents, their design engineers, and they selected

and hired the specific Hycalog salesmen that they wanted for specificgeographical areas. Instead of developing their company and theirpersonnel, they went out and bought them from Hycalog. This is one of thethings that contributed to Hycalog falling from the #1 fixed cutter companyin the world to #3, and has allowed Smith Geodiamond to become a viablefixed cutter competitor.

The final major strength for Smith Geodiamond is customer relations. Theyspend a lot of money, time, and resources on making sure they take care oftheir customers. They give away jackets, shirts, cups, hats, etc. They also

take their customers on expensive trips. They are the drill bit company thatare the most committed to spending money on customer relations.

Smith Geodiamond does have several weaknesses. The first weakness is alack of corporate structure. They are not owned by of one of the majordrilling service companies. This limits the amount of corporate support,financial & technical resources, and personnel resources.


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Smith Geodiamond

The second weakness of Smith Geodiamond is the lack of access to related

drilling technologies. Schlumberger Drill Bits has Drilling & Measurementswith the PowerDrive and PowerPak systems. Hughes Christensen has BakerInteq with the AutoTrack system. Security DBS has Sperry Sun with theGeoPilot system. The lack of access to related drilling technologies doesput Smith Geodiamond at a disadvantage.

The final weakness of Smith Geodiamond is that they have limitedpackaging opportunities. If you are not owned by one of the major servicecompanies, it is very difficult to package all the services in order to providethe drilling solutions that the customers may need.

Schlumberger Drill Bits (Reed-Hycalog)

The first strength of Schlumberger Drill Bits is the differentiatedtechnologies. There are many developments that have been patented thatdifferentiates Schlumberger from their competitors.

The second strength of Schlumberger Drill Bits is fixed cutter market

recognition. A few years ago Hycalog was the #1 fixed cutter company inthe world. They are still recognized in several markets as being the #1 fixedcutter company.

The third major strength of Schlumberger Drill Bits is the Schlumbergerresources. Financial, technical, and personnel resources are now available.

Schlumberger Drill Bits also have several weaknesses. First was thecompanys focus on margin. While this may not be a bad strategy, if you are

going to try to gain market share, margins may not be the primary focus.Currently under D & M, the focus is on market share first.

The second weakness of Schlumberger Drill Bits is late to service delivery.It sometimes takes a lot longer to get products to the market place than it didfor the competitors.


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To become the #1 drill bit company in the world, it will require bettercustomer response and getting products on time to the market as quickly aspossible.

The last major weakness of Schlumberger Drill Bits is struggling toreorganize. There have been 3 reorganizations in the last 4 years. First,Schlumberger acquired Camco International. This made Reed and Hycalogpart of Schlumberger. Second, was the reorganization of Reed ToolCompany and Hycalog to combine to form one company, Reed-Hycalog.Finally, in January 2001, Reed-Hycalog reorganized into Drilling &Measurements. Almost any company would have had difficulty survivingthree reorganizations in four years.

Security DBS

The first strength of Security DBS is their synergy with Sperry Sun. Thisgives them access to related drilling technologies and packagingopportunities.

The second strength of Security DBS is the modernization of theirmanufacturing plant. Within the last two years they renovated their roller

cone manufacturing plant. They put in new machinery and new technologyto improve the speed and efficiency of building their roller cone bits.

The third strength of Security DBS is that they were right behind Hughesand Smith with Bit Optimization Service.

The last strength of Security DBS is their fixed cutter technology. In theirfixed cutter bits, they have some excellent products and some excellentcutter technology.

Security DBS also has several weaknesses. The first weakness is their rollercone technology. Most of their roller cone bits are not competitive withHughes, Smith, and Schlumberger. However, they do make a few goodproducts, especially in their bigger bits that have performed well in the Gulfof Mexico and in other offshore applications.


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The final weakness of Security DBS is that they tend to operate as 2 separatecompanies. Since they have such a strong fixed cutter side and such a weakroller cone side, most of the focus is on fixed cutter bits. Even though they

are one company, they tend to operate as two. This prevents them frombeing a fully unified company.

Drill Bit Industry Summary

Drill bits have unique technologies. There are different drilling demands.Almost anywhere in the world that drilling is done the drill bit applicationwill be different. For example, in multiple places in the United States therewill be different formations and different drilling applications.

Drill bits have unique design concepts. There is a lot of design work thatgoes into fixed cutter and roller cone bits. There are materials issues,bearings, elastomers, grease, moving parts, and cutter development.

Drill bits have manufacturing issues. One of the reasons why there are only4 major drill bit companies that control approximately 92% of the worldwidemarket, is because roller cone manufacturing is a very capital-intense andcomplicated business. Not everybody can easily get into the roller conemanufacturing business. That is one of the reasons for the major oilfieldservice companies such as Schlumberger, Baker, and Halliburton aligningthemselves with an established drill bit company. It would be very difficultfor someone to start up a new roller cone company.

Finally, patents are what are unique to drill bit technologies. There are manypatents that are filed on drill bits that never get into bits. It is a verycompetitive market with only 4 major competitors in the market place. Allof the drill bit companies are actively trying to patent everything they can toprevent the competitors from copying their designs or taking advantage of

some of the concepts and innovations that have been developed.


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Drill Bit IndustryDrill Bit Industry

Review QuestionsReview Questions List the major Drill Bit types

List the 4 major Drill Bit competitors and their

market shares

List Schlumberger Drill Bits strengths & weaknesses

Describe the Schlumberger Drill Bit plan for market sharegrowth

List 4 Schlumberger Drill Bit Roller Cone differentiations

List 4 Schlumberger Drill Bit Fixed Cutter differentiations

List 6 things that are new for Schlumberger Drill Bits


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Roller Cone Bits Component Parts

There are two types of roller cone bits. There are tooth bits and there are

insert bits. Sometimes roller cone bits are referred to as rock bits. Undertooth bits, these bits are sometimes referred to as steel tooth bits or mill toothbits. On the insert side, these bits are sometimes referred to as carbide bitsor button bits.

The roller cone bits are basically made up of the 3 major things. There are:1) lugs, 2) cutters, and 3) component parts.

To make a roller cone bit there will be 3 lugs per bit. All 3 lugs will be

exactly the same. There will also be 3 cutters per bit. All 3 cutters will havedifferent cutting structures. Finally there will be a variety of componentparts.

Lugs Cutters Component Parts

To make 1 roller cone bit, it takes:- 3 lugs- 3 cutters- 3 sets of component parts.

The cutters are attached to thelugs. Then the 3 lug and cutterassemblies are welded togetherto make a drill bit.


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Roller Cone Exterior Parts

In this diagram, the first area to identify is the API pin. The purpose of thepin is to connect the bit to the drill string and to allow fluid to get through

into the body of the bit and out through the nozzles.

Next is the bit body. This is all the exterior part of the bit that is not thecutter. So it includes all 3 of the lugs, the nozzle pods, and the areas thatare on the shirttail.

The next area is the lug. As mentioned before, it takes 3 lugs to make up 1bit. So the lug is the area of the bit where the shirttail is located and the bitbody that goes down to the pin. It is the part of the bit that holds on thecutter.

There are 3 cutters on each bit. There is Cutter #1, Cutter #2, and Cutter #3.Each one of these 3 cutters will have a different cutting structure design.The way to identify the 3 cutters is Cutter # 1 will have the insert or tooththat is the closest to the centerline of the middle of the bit.

Pin

Nozzle, Pod & Socket

Cutter #3

Shirttail

Heel Row

Gage Row

Cutter #1

Cutter #2

Inner Row

Lug

Bit Body

Bit Bowl

Nose


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Once the Cutter #1 is identified, count the cutters in a clockwise manner tofind Cutter #2 and Cutter #3. The reason these cutter numbers are importantis when dull grading the bits, the location of the dulling characteristics willbe identified by the cutter numbers. When identifying whether the

bearings/seals are effective or have failed, the cutter numbers are used if all3 of the cutters do not have the same grading.

The nose of the bit is the area of inserts or teeth that is the closest to thecenter of the middle of the bit. The inner row would be all of the rows thatare not the gauge. The gauge row is the row of inserts that are the furtheston the outside of the cutting structure. The heel row are small, tungstencarbide or diamond inserts that are put on the back face of the cutter.

The shirttail is the area of the lug where the grease reservoir cap, the hard

metal that is applied to protect the shirttail, the cone retention loading hole,and the grease-loading hole is located. This is an important part of the bitbecause it will identify some of the areas that will need to be protected.Shirttail protection features that are added to the bits will be discussed later.

Pin


Cutter #3

Shirttail

Heel Row

Gage Row

Cutter #1

Cutter #2

Inner Row

Lug

Bit Body

Bit Bowl

Nose


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Then there is the nozzle pod and socket. This is the where the nozzles islocated. There is an O-ring and a snap ring that holds the nozzles in. Thiswhole assembly area where the nozzle goes in is called the nozzle pod andnozzle socket.

Finally there is the bit bowl. This is all of the blank space, the void spacethat is inside, the interior of the bit beneath the cutters, and inside of thenozzle pod and nozzle sockets. In the bit bowl is where there may be drilledcuttings. A lot of flow has to get through there in order to keep the bit clean.This is also where your center jet would be installed if a center jet were to beadded to any bit.

Now that the external parts of the roller cone drill bit have been reviewed, itis time to take a look at what is on the inside. The focus will be on the

bearings and seals. These are one of the most critical parts of a roller conedrill bit. If the bearings and seals fail prematurely, your bit life will belimited.

Pin


Cutter #3

Shirttail

Heel Row

Gage Row

Cutter #1

Cutter #2

Inner Row

Lug

Bit Body

Bit Bowl

Nose


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Roller Cone Interior Parts

Bearings

In roller cone bits, there are generally 4 major bearings.

There is the main bearing, the retention bearing, the thrust bearing, and thepin bearing.

The main bearing, the thrust bearing, and the pin bearing are all load-bearingsurfaces. The function of the retention bearing is to attach the cutter to thelug. However, through testing, and looking at the bits that have been cutdown for dull analysis, the retention bearings also do take some load.

Retention Bearing

Thrust Bearing

Pin Bearing

Main Bearing


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There are 2 major types of main bearings in a roller cone bit. There are rollerbearings and there are friction/journal bearings.

Roller bearings are long cylinders that roll in tracks or grooves that havebeen cut in the lug. Typically roller bearing bits will have two rows of rollerbearings, or three rows for the larger bits. They roll freely between the cutterand the journal.

The friction or journal bearing bits have a bushing that rotates between thelug and cutter. Schlumberger Drill Bits have a floating bushing that rotatesfreely between the cutter and the lug. In the past these bearings were calledfriction bearing. Today, most people in the drill bit industry call themjournal bearings.

Roller Friction / Journal


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There are two types of retention bearings. There are ball bearings and thereare threaded rings.

On most all drill bits, the cones or cutters are held onto the lug using ballbearings. This is not a unique feature to Schlumberger. Ball bearings areused by all 4 major drill bit competitors as their cone retention bearings.Ball bearings roll in the track and keep the cutter from falling off of the lug.

The threaded ring, however, is a unique and patented feature that can only beused by Schlumberger Drill Bits. It is attached by the threads in the cuttershell and the corresponding threads located on the threaded ring. Thethreaded ring rides in a groove on the lug, and allows the cutter to beattached to the lug. A retention tool holds the threaded ring in place whilethe cutter is screwed on. Once the cutter is on, the retention tool is takenout, and a peening tool is inserted. The peening tool will peen or deface the

threads on the cutter to prevent the cutter from backing off. The advantagesof having a threaded ring retention bearing over a ball bearing is:

- the threaded ring will help reduce the lost cone rate by two-thirds- it becomes an integral part of the cutter, so it allows the cutter to

have more freedom and be better tolerant of cutter movement- it has surface contact as opposed to point loading of the balls

bearings

Balls Threaded Ring


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With ball bearings there is point loading that can cause spalling,Spalling is little particles of metal that have flaked off of the lug surface.This makes the surface uneven and no longer will run smoothly. This

affects the bearing performance. As soon as the bearing performance isnegatively affected, then the bit life will be limited.

Seals

At Schlumberger there are 4 major types of seals that are used. The first isan O-ring seal. Years ago the O-ring seal was patented by Hughes and wasnot allowed to be used by any of the other major bit companies. WhatHughes actually patented was the amount of squeeze on the O-ring to sealthe bit to keep the drilling fluids out and keep the bearing grease in.

Reed-Hycalog decided to use a HNBR radial seal to counteract the patentHughes had on the O-ring. The HNBR radial seal is a patented feature that

only Schlumberger uses. Smith and Security decided that they would goahead and use the O-ring even though Hughes had a patent. Then severalyears later there were lawsuits. Hughes was paid hundreds of millions ofdollars by Smith and Security for violation of their patent. The O-ringpatent has expired and is now used by Schlumberger Drill Bits.

O-Ring

and

HNBR Radial

HNBR

Texturized

HNBR

Ribbed

Texturized


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The O-ring seal is used in Schlumbergers 4-3/4" and smaller inch diameterbits. All of the bits larger than 4 3/4, use the HNBR radial seal. The radialseal provides several advantages. It runs cooler, it is recessed and is better

protected, and it is more tolerant of cutter movement. A radial seal is flatand has more surface contact.

The next seal used by Schlumberger is a HNBR texturized seal. HNBRstands for Hydrogenated Nitrile Butadiene Rubber. It is obvious why thisseal is just called HNBR. The HNBR texturized seal was the seal that wasdeveloped for Schlumbergers motor bit product line. This seal has a seriesof Xs cut into the inside surface of the seal. The purpose of these Xs is totrap grease in all of the little small pockets, as shown in this picture.

By trapping the grease into these little pockets, it allows the seal to runcooler. Typically motor bits are running at higher RPM (Revolutions PerMinute) so running cooler is important to extending bit life.

The HNBR ribbed textured seal is a brand new sealthat was recently developed to be put intoSchlumbergers new Titan bits. It is an upgrade

from the HNBR texturized seal in that it has a rib inthe middle that helps keep the grease on both sides ofthe seal. As shown in this picture, once the grease getsinto the little pockets, it gets trapped and allows theseal to run cooler. A cool running seal is critical whenrunning at high rotary speeds on motor bits.

HNBR

Texturized

Seal


29/89



From this diagram, the bearing terms can be identified. Starting on the right-hand side of the picture an insert bit cutter is shown. The ball race is wherethe ball bearings roll and allow the cutter to move around the lug. Movingfrom the right side of the diagram into the middle of the cutter is the cutterbore. The cutter bore has the internal bearing surfaces that match up withthe corresponding parts on the lug. There is also a groove in which the sealis recessed. Moving on into the center part of the diagram is the thrustwasher. The thrust washer is a washer that is silver-plated. The silver isused as a dry lubricant so as the thrust washer heats up, takes loads, becomeshot, and develops friction; the silver will melt and form a lubricant. Nextthere is the floating bushing. This is a copper beryllium bushing that is alsosilver-plated for dry lubricant. Next is the HNBR radial seal. This could bea texturized radial seal, a ribbed texturized radial seal, or an O-ring. Thisshows the order in which component parts and the cutter fit on the lug.

Moving over to the journal part of the lug is the thrust pin bearing and thepilot/friction pin bearing. Next there is the main bearing surface, the ball

bearing groove, the seal land, and the back face of the cutter. The ballretention plug is used to secure the cutter once it is connected to the lug.The ball bearings are loaded through this ball-loading hole on the backsideof the journal. After the proper number of balls are loaded, the retainingplug is inserted and is welded with what is called a frogeye weld.

Insert Cutter

Cutter Bore

Floating Bushing

Radial Seal

Ball BearingBall

RetainingPlug

Thrust Washer

Seal Land

Snag

Main Bearing Pilot Pin(Friction Pin)

Shirttail

Seal Groove

Ball Race(Bearing Race)


30/89



Grease System

On sealed bearing roller cone bits there is a grease system. This diagram

shows Schlumberger Drill Bits greasing system. The grease reservoir iswhere the extra grease for the bearings is located. The grease is pumpedfrom the grease reservoir through a grease passage holes into all of thebearing surfaces. To ensure that grease gets to all the bearing surfaces,grease is painted on every bearing surface before the bit is assembled. Agrease-compensating diaphragm is used. If too much pressure builds up inthe reservoir or bearing system, the grease can vent or release through thediaphragm so it does not burst the seal. Once the seal is damaged or fails,the drilling fluid will flow in, compromise the bearing system, and will limitthe bearing life. On top of the diaphragm is a reservoir cap that is held inplace with a snap ring. A hex nut is screwed in with an Allen wrench thatcloses off the grease-loading hole.

Grease Reservoir

Grease Loading

Hole Plug

Snap Ring

Reservoir Cap

GreasePassage

Holes

Diaphragm

Threaded Ring

Access Hole Plug


31/89



Assembled Interior Components

Earlier the ball-loading hole for a ball bearing retention system was

discussed. If the bit has a threaded ring, the threaded ring access hole iswhere the tool to hold the threaded ring still is located. It also serves as theaccess hole for the peening tool used to deface the threads on the cutter sideof the threaded ring assembly. A threaded ring access hole plug is theninserted and sealed off with a frogeye weld.

This diagram shows a view of the cutter assembled to the journal on the lug.Starting on the left side is the borehole wall. Moving inward from the leftside of the picture are the heel row inserts that are in contact with theborehole wall. Next are gauge row inserts. This diagram shows how much

of the insert is actually in the cutter and how much of the insert is protrudingout from the cutter shell. On the top of the picture is the radial seal and thegroove where the radial seal is recessed. Next is the main bearing - in thiscase a journal bearing. On the bottom of the picture are the inner rowinserts. Finally there is the thrust bearing, thrust washer, and the pinbearing.

Hole Wall

Gauge

Row

Radial

Seal

Thrust

Bearing

Retention

Bearing

Heel

Row

Inner

Row

Cutter

Lug

Main

Bearing

Pin

Bearing

Hole Wall

Gauge

Row

Radial

Seal

Thrust

Bearing

Retention

Bearing

Heel

Row

Inner

Row

Cutter

Lug

Main

Bearing

Pin

Bearing


32/89



Cutting Structure Insert Bits

The cutting structure is also important for the life of a drill bit. If the cutting

structure fails the bit is finished. If the cutting structure wears out, theinserts break, or the cutting structure gets damaged, the bit will have to bepulled out of the hole because it will no longer be able drill the formationseconomically. Sometimes the cutting structure of a bit is called the coneor the cutter. These two terms can be used interchangeably.

Starting on the right side of this diagram is the cone profile. The coneprofile identifies how aggressive the bit is going to be in terms of cuttingformation. A more rounded cone profile would be for a more aggressive bit.A flatter cone profile will be used for a slower drilling, more durable cuttingstructure type bit, typically used in harder formations. Beginning on the

right side of the picture and moving inward, the first insert is the spear pointor the spade. This is also the nose insert. When identifying the nose inserton the cutter, this is the insert that is closest to the center of the middle of thebit.

Spear Point(Spade)

Heel Face

(Gage Face)l

Heel Row Coneor

Cutter

Cone Shell

Gage Row Interlock Row

Cone Groove

Inner RowsOuter Rows

Back Face

Insert Pad

Cone Profile

Seal Flange

Teeth


33/89



Next are the insert pads. The insert pads are created as a result of thedesigned cone grooves. Since the bit has 3 cutters, each with a differentcutting structure, the cutting elements have to intermesh with each other.The cone grooves are machined into the cutter to allow the inserts tointermesh. Another reason for the insert pad is to support the insert. If theinsert is not protected, and the proper amount of the insert is not in the cuttershell, the insert will not be properly supported and will break.

Next are the inner row inserts. These are all the inserts that are not the gaugerow inserts and not the nose row inserts. The remaining row of inserts arecalled the interlock row. An interlock row means that part of the interlockinsert is intersecting the line of the gauge row inserts. This does not meanthat these inserts are on top of each other. It just means that they intersectthe line of the gauge row inserts. Finally there is the heel row. The heel row

inserts are on the back face of the cutter.

Spear Point(Spade)

Heel Face(Gage Face)l

Heel Row Cone

or

Cutter

Cone Shell

Gage Row Interlock Row

Cone Groove

Inner RowsOuter Rows

Back Face

Insert Pad

Cone Profile

Seal Flange

Teeth


34/89



This picture gives a few examples of insert shapes by formation.Schlumberger has over 100 different insert shapes and types that are used ontheir roller cone drill bits. As illustrated, the inserts get shorter and morerounded when going from soft formations to harder formations. The firstinsert on the chart has a sharp tip and a lot of protrusion. The straight lines

that go across the picture indicate the protrusion. Everything below that linerepresents the part of the insert that is buried in the cutter shell. Everythingabove that line represents the part of the insert that is protruding from thecutter shell and makes contact with the formation. The first insert has quitea long protrusion and the insert shape is quite sharp. Looking at the very lastinsert in this picture, that insert is much shorter and has a much roundershape. Selecting the right insert for the right bit is most important to provideyou the best bit performance in any given application.


35/89



Cutting Structure Tooth Bits

Mill tooth bits have their tooth shape milled out of steel. Once the teeth are

milled, a hard metal is welded to each tooth to make the tooth more durable.There are 4 basic types of hard metal that are used on Schlumbergers milltooth bits.

Duraclad Hardmetal Armorclad Hardmetal

First there is the standard Duraclad hard metal. This is a tungsten carbidematrix composite. The hard metal is welded onto the teeth in a manualprocess. Duraclad has a lot of porosity. It is a durable product but istypically use this in Schlumbergers non-premium tooth bits.

The next type of hard metal is called Armorclad. This is much more denseand much less porous type of material. It has a much higher concentrated

mix of tungsten carbide pellets. Armorclad is typically use this in thepremium mill tooth bits such as EHT, MHT, and the SL - Slim Line bits.Armorclad II is a new hardmetal that has just been introduced. This is apremium hard metal that is an upgrade from Armorclad. This hardmetal willbe used on the new Titan tooth bit products.


36/89



Finally there is the built-in hard metal PMC (Powdered Metal Cutter).Schlumberger has as patented process of using powdered metal to make atooth cutter. Because of the patent protection, Schlumberger is the only drill

bit company that can use this built-in hard metal. The PMC producttechnology has been in development for more than 12 years. In 2001 thefirst PMC products will be going standard. The first product lines will beFMJ (Full Metal Jacket) and CMC (Composite Matrix Cutter).

PMC Built-In Hardmetal

PMC is a built-in hardmetal that is built using a mold. This hard metal ismore durable, more abrasive-resistant, and provides a lot longer life for thetooth. PMC will also allow more flexibility in designing tooth shapes. ForSchlumberger Drill Bits, the PMC process for making tooth bits maybecome the way tooth bits are made in the future. It will be moreeconomical to manufacture once the process is fully developed. All ofSchlumbergers competitors use welded hard metal on their tooth bits.


37/89



Hydraulic Configurations

Hydraulics are very important for a drill bit. The primary purposes of

hydraulics for the drill bit are to keep the bit cool and to get the cuttings offthe bottom of the hole and up the annulus. There are 3 basic Schlumbergerhydraulics configurations: Conventional, Mudpick, and Mudpick II.

First is conventional hydraulics. This means that the drilling fluid comes outof the nozzle and goes straight to the bottom of the hole. There is no toothcleaning and the fluid cleans the rock between the cutting zones. There isstagnant flow at the cutting zone where the inserts or teeth are in contactwith the bottom of the hole. There is no cleaning where the cutters areactually in contact with the formation. All of the competitors use some form

of conventional hydraulics.

In the late 1970s, early 1980s, Reed started developing improved hydraulics.The objective was to find a way, given the same set of hydraulic conditions,that ROP could be improve by changing the direction of the hydraulic flow.In the early 1980s, Reed introduced the patented Mudpick hydraulics.

Mudpick IIMudpick IIMudpickMudpickConventionalConventional


38/89



With Mudpick hydraulics, as you can see in this picture, the position of thenozzle is re-directed so that now the flow is cleaning the gauge row andinterlock row inserts. The rock is being cleaned at the leading edge of thecutting zone. The stagnant flow has been shifted to the trailing side of thecutter. Now there is better cleaning on the bottom of the hole. WithMudpick there was an increase in rate of penetration given the same set ofhydraulic conditions. Without changing nozzle diameter, the flow rates, and

any of the variables for hydraulics, ROP was improved by changing toMudpick hydraulics. We use Mudpick hydraulics on all of theSchlumberger product lines, except those that use the Mudpick II hydraulics.

In the early 1990s, almost ten years after the development of Mudpick,Mudpick II hydraulics was introduced. Mudpick II cleans the gauge rowand inner row of teeth. It cleans the rock at the cutting zone right at thecorner as the inserts are coming around to make contact with the formation.It cleans the cuttings from the bottom of the hole and removes the stagnantflow completely from the cutting zone. The stagnant flow is shifted outsidethe area where the inserts are in contact with the formation. Mudpick II hasshown that ROP was increases an average of 20% - 22% over the offset bitruns. Mudpick and Mudpick II hydraulics are patented features ofSchlumberger. None of the other drill bit companies can use these hydraulicconfigurations.

Mudpick IIMudpick IIMudpickMudpickConventionalConventional


39/89



Competition has developed various types of hydraulic configurations tocombat Mudpick and Mudpick II hydraulics. Because of the improvementsin ROP, the competitors will continue to try to meet or exceed

Schlumbergers performance.

Schlumberger builds bits with both Mudpick and Mudpick II hydraulics.The reason for this is because there are both advantages and disadvantagesto Mudpick II. Mudpick II will increase ROP, but it is limited to only thesoft and soft-to-medium formations. The harder the formations become, theless effective the Mudpick II hydraulics. Also, because of the angle of thenozzle and the flow, there have been some cases of abnormal erosion in thegauge and interlock row insert where the fluid is hitting the cutting structureat high rates of speed. There has also been some backwash on the shirttail asa result of the Mudpick II configuration. Whether Mudpick or Mudpick II isthe right hydraulic configuration for a specific bit will be determined by theapplication, the hydraulic conditions, and satisfying the customer's needs.

Schlumbergers Roller Cone Nozzles

Schlumberger has a variety of different types of roller cone nozzles. Thechart bellows shows the 2 basic types of Schlumberger nozzles: shroudednozzle and standard nozzle.

STANDARD

TYPE

SHROUDED

TYPE

STANDARD

TYPE

SHROUDED

TYPE

BIT SIZE

RANGE

3-3/4 5-1/25-7/8 6-3/47-7/8 99-1/2 18-1/2 20 26

STANDARD

TYPE

AAKAKCKDKEK

SHROUDED

TYPE

AACKACKCCKDCKECK

NOZZLESAVAILABILITY

SIZE (32ND)TFA in

80.049

90.062

100.077

110.093

120.110

130.130

140.150

150.173

160.196

180.249

200.307

220.371

240.442

280.601

STANDARD TYPE

AAK ? ? ? ? ? ? ? ? ? ? ?

AK ? ? ? ? ? ? ? ? ? ? ?

CK ? ? ? ? ? ? ? ? ? ? ? ? ?

DK ? ? ? ? ? ? ? ? ? ? ? ? ? ?EK ? ? ? ? ? ? ? ? ? ? ? ? ? ?

SHROUDED TYPE

AACK ? ? ? ? ? ?

ACK ? ? ? ? ? ? ? ?

CCK ? ? ? ? ? ? ? ? ? ? ?

DCK ? ? ? ? ? ? ? ? ? ? ?

ECK ? ? ? ? ? ? ? ? ? ? ?

NOZZLE

TYPE

AAKAACK

AKACK

CKCCK

DKDCK

EKECK

NOZZLE OUTSIDE DIAMETER IN 0.811 0.926 1.173 1.297 1.609TFA WITHOUT NOZZLE IN 0.517 0.673 1.081 1.321 2.033

STANDARDTYPE

SHROUDEDTYPE

NOZZLES AVAILABILTY

BIT SIZE

RANGE

3-3/4 5-1/25-7/8 6-3/47-7/8 99-1/2 18-1/2 20 26

STANDARD

TYPE

AAKAKCKDKEK

SHROUDED

TYPE

AACKACKCCKDCKECK

NOZZLESAVAILABILITY

SIZE (32ND)TFA in

80.049

90.062

100.077

110.093

120.110

130.130

140.150

150.173

160.196

180.249

200.307

220.371

240.442

280.601

STANDARD TYPE

AAK ? ? ? ? ? ? ? ? ? ? ?

AK ? ? ? ? ? ? ? ? ? ? ?

CK ? ? ? ? ? ? ? ? ? ? ? ? ?

DK ? ? ? ? ? ? ? ? ? ? ? ? ? ?EK ? ? ? ? ? ? ? ? ? ? ? ? ? ?

SHROUDED TYPE

AACK ? ? ? ? ? ?

ACK ? ? ? ? ? ? ? ?

CCK ? ? ? ? ? ? ? ? ? ? ?

DCK ? ? ? ? ? ? ? ? ? ? ?

ECK ? ? ? ? ? ? ? ? ? ? ?

NOZZLE

TYPE

AAKAACK

AKACK

CKCCK

DKDCK

EKECK


STANDARDTYPE

SHROUDEDTYPE

BIT SIZE

RANGE

3-3/4 5-1/25-7/8 6-3/47-7/8 99-1/2 18-1/2 20 26

STANDARD

TYPE

AAKAKCKDKEK

SHROUDED

TYPE

AACKACKCCKDCKECK

NOZZLESAVAILABILITY

SIZE (32ND)TFA in

80.049

90.062

100.077

110.093

120.110

130.130

140.150

150.173

160.196

180.249

200.307

220.371

240.442

280.601

STANDARD TYPE

AAK ? ? ? ? ? ? ? ? ? ? ?

AK ? ? ? ? ? ? ? ? ? ? ?

CK ? ? ? ? ? ? ? ? ? ? ? ? ?

DK ? ? ? ? ? ? ? ? ? ? ? ? ? ?EK ? ? ? ? ? ? ? ? ? ? ? ? ? ?

SHROUDED TYPE

AACK ? ? ? ? ? ?

ACK ? ? ? ? ? ? ? ?

CCK ? ? ? ? ? ? ? ? ? ? ?

DCK ? ? ? ? ? ? ? ? ? ? ?

ECK ? ? ? ? ? ? ? ? ? ? ?

NOZZLE

TYPE

AAKAACK

AKACK

CKCCK

DKDCK

EKECK


STANDARDTYPE

SHROUDEDTYPE

NOZZLES AVAILABILTY


40/89



The standard type nozzle has got a flat surface on the top and the snap ring,which is what holds the nozzle in the bit. On the shrouded type nozzle, thesnap ring is covered by a recessed groove. The purpose for shrouded

nozzles is for use with highly abrasive fluids or if there are highly abrasiveformations. The shroud protects the snap ring. All nozzles are measured in32nds of an inch in terms of the diameter. In the picture on the previouspage there is a 14 stenciled on top of the nozzle above the center hole. Thismeans that this nozzle is a 14/32nd nozzle.

Hughes Christensen also used the same types of roller cone nozzles asSchlumberger. In fact the nozzles are interchangeable. Smith Geodiamonduses a screw type nozzle. Security DBS uses a nozzle that is held in by anail. The Smith and Security roller cone nozzles are not interchangeablewith Schlumberger.

Roller Cone ComponentsRoller Cone Components

Review QuestionsReview Questions

Identify the exterior components of a roller cone bit

Identify all of the interior components of a roller cone bit

List the 2 Schlumberger Drill Bit main bearing types

List the 2 Schlumberger Drill Bit cone retention bearings

List the 3 Schlumberger Drill Bit seals

List the 3 Schlumberger Drill Bit hydraulic configurations

URNAL &

LLER

BALLS

THREATED

CONVENTIONAL

MUDPICK

MUDPICK II


41/89



Roller Cone IADC Code

The IADC code, which stands for International Association of DrillingContractors, was developed for roller cone bits in 1992. There is an IADC /SPE Paper 23937, that details this IADC roller cone bit classification

system. In the IADC roller cone classification system the numbers aredivided up into formation, series / types, and cutting elements. Within softor hard formations, there will be a series and type. If the first two numbersof the IADC code are 11 through 34 the cutting element will be mill tooth.If the first two numbers of the IADC code are 41 to 84 the cutting elementwill be a tungsten carbide insert bit.

The second digit of the IADC code tells the hardness of the bit within theseries. So a 11 would be the softest of the mill tooth bits. A 12 would bethe next hardest, and 13 would be the hardest. On inserts, for example, there

may be a 41, 42, 43, 44, 45, etc. So within the series, the harder the bit, thehigher the second number will be.

IADC Cutting Structure CodeIADC Cutting Structure Code

11-

to

34-

Soft

toHard

Mill

Tooth

Formation Series / Type

Soft

to

Hard

41-

to

84-

Tungsten

Carbide

Insert

Cutting

Element


42/89


43/89



There are several letters used in IADC to represent these special features.They are not used very often. Most of the time the bit manufacturer willchoose to identify the special feature in their nomenclature as opposed to the

IADC code. Below is a list of these special features:A = air applicationB = special bearing /sealC = center jetD = deviation controlE = extended jetsG = gauge or body protectionH = horizontal or steering applicationJ = jet deflectionL = lug padsM = motor applicationS = standard steel tooth modelT = a two-cone bitW = enhanced cutting structureX = predominantly chisel tooth insertsY = conical tooth insertZ = other shaped insert

The M letter is used most often to designate a bit is designed for motor

application.

The IADC code for roller cone bits has several uses. It is a good startingplace when trying to compare roller cone bits on offset bit records. In orderto determine what bit is going to be run in a specific application, bitperformance has to be evaluated. By looking at offset bit records, the IADCcode of the offset bits can be identified. Why would the IADC code be onlya starting place? If a customer says, I need a 12-1/4 IADC code 517,sure, which one do they want? Within the industry there are probably 60+12 517 type bits. The IADC code gives a general indication of what kindof cutting structure is needed. The features, or combination of features, willthen be selected for the specific application.


44/89



Schlumberger Drill Bits Roller Cone Nomenclature

Below is an example of two of Schlumbergers roller cone bits:

a 12-1/4 EHP51HDLK and a 17-1/2 EMS13GC.

The first set of numbers, the 12-1/4 and the 17-1/2, represent the size ininches. The size is also indicated in metric on Schlumbergers box labelsfor those that work in the metric system.

The next set of prefixes in Schlumbergers nomenclature represent theproduct line. In this case, EHP, Enhanced High Performance, and EMS,

Enhanced Motor Series, are the product lines for these particular bits. TheSchlumberger product lines will be discussed later.

The next two numbers are the first two numbers of the bits IADC code.Schlumberger Drill Bits is the only company that uses the first two numbersof the IADC code, to identify their cutting structure. All the rest of thecompetitors use different sets of nomenclature and different sets of numbersto identify their bit types. In the top example, the 12-1/4" EHP51, the 51indicates that the first two numbers of the IADC code for this bit is a 517.In the bottom example, the 17-1/2" EMS13, the IADC code for this bit is135. So the first two numbers of the IADC code is represented in ournomenclature as 13. In 2001, Schlumberger launched three product lineswhich do not use the first 2 numbers of the IADC code in its nomenclature.The numbers used in the FMJ, DJ, and DR product lines are not associatedwith the IADC code.

12 EHP 51 H DLK

SizeSize

17 EMS 13 G C

ProductProduct

LineLine

IADCIADC

CuttingCutting

StructureStructure

AddedAdded

FeaturesFeatures

DesignDesign

VariantVariant


45/89



The next letter, if there is one, would represent the design variant. There arethree different design variants frequently used by Schlumberger. They aredesignated by A, H, and X. Below are the design variants:

A = Chisel-Shaped Inserts. The application for this would be an aggressiveinsert shape typically for soft to medium formations. The downside to usingthe A variant is that an insert shape that is sharp chisel may not be durableenough. If the insert is not durable enough, the bit life could be limited.

H = Chisel-Shaped Inserts in IADC code 41 to 51 with 3 cutter skew.Typically insert bits in 41 to 51 range have 5 cutter skew. The applicationfor the H designate is that it is a durable skew angle for any applicationwhere you need more durability. A 5 skew is for a more aggressive bit butit is less durable. A 3 skew is a little less aggressive but it is more durable.Durability could be needed in situations like running high RPM(Revolutions Per Minute), a directional situation, motor bit runs, or any timethere are streaky formations. The downside is that the more durable the bit,the slower the ROP. So a little bit of ROP is sacrificed in order to getdurability. Schlumberger also builds bits that have faster ROP. So itdepends on the customer's expectations, the application, and the objectivefor that bit run.

X = is a special cutting structure that might vary from type to type.When an X is in the suffix of Schlumbergers nomenclature, the specialcutting structure will be different from a normal bit. The applications forthis type bit are formations such as medium-hard carbonates that suit anaggressive gauge design but does not lead to gauge breakage. The downsideis that if you put a little longer gauge row inserts in for aggressive gaugedesign, there could be a tendency for the inserts to break.

Schlumberger Drill Bits has several options for added features.With the example of the 12-1/4", DLK stands for diamond lug pad and Kshirttail protection, and in the case of the 17-1/2" EMS13, G stands for gageprotection on the bit and C stands for center jet.


46/89



Schlumberger Drill Bits Roller Cone Features

Below are the Schlumberger Drill Bits roller cone features:

C= Center Jets. There are 2 types of center jets. There is a single-portcenter jet that is installed in the center of the bit to provide hydraulic fluid tothe inner row and nose area. There is also a three-port center jet. The three-port center jet is fixed and is installed in the factory. For the single-portcenter jet, it is interchangeable and can be installed or changedin the field.

There are several benefits to running center jets. They reduce bit balling andhelp keep the nose and inner rows of the cutting structure clean. The majordisadvantage of center jets is that they can reduce the outer cutter cleaning.If a bit has three nozzles, and then a center jet is added, there will be lessfluid exiting out of the 3 outside nozzles.

C - Center JetF - Flame Spray cutter shell coatingG - Heel Row Inserts on tooth bitsJA - Jet Air DrillingK - Shirttail InsertsKP - Shirttail Inserts - Premium CoverageKPR - Shirttail Inserts Raised - Premium CoverageL - Lug Stabilizing PadM - Mudpick II Hydraulics on HP Bits

T - GageGuard - shorter inserts in between the gauge row Inserts

Single Port Three Port


47/89



Another disadvantage is the center jet can aggravate the nose area. Withhigh flow rates through your center jet, there can be nose cone erosion in thecenter of the bit. The applications for center jets are basically in bits 12-1/4"

and larger. It is available in 7-7/8" and larger, and on occasion, a center jethas been installed in a bit smaller than 7-7/8". Typically center jets are usedin medium to very soft, very sticky, gumbo type formations, or wherecleaning around the center of the bit is most important. Generally, no morethan 18% of the TFA (Total Flow Area) should be going through the centerjet. If the center jet is more than 18% TFA, the outside nozzles could bestarved for fluid and will not keep the gauge row of inserts cleaned.

D= Diamond PDC-coated inserts. PDC stands for Polycrystalline DiamondCompact. The purpose of using PDC-coated inserts is to eliminate thermalfatigue and to eliminate abrasive wear. Almost any of the cutting structureor shirttail inserts can be replaced with the diamond PDC-coated inserts.In the Schlumberger nomenclature, it is very simple to identify what featureshave diamond PDC-coated inserts and which ones do not. When looking atthe suffixes of Schlumberger nomenclature, everything to the right side ofthe D represents diamond PDC-coated inserts. Everything to the left side ofthe D represents non-diamond PDC-coated inserts. The competition uses theD repetitive when they indicate their diamond coated inserts.

The benefits of PDC-coated inserts, the D feature, are that it does eliminate

abrasive wear and thermal fatigue. There are some downsides, however. Itis costly. Some of the PDC-coated inserts could cost $25, $50, or $100 perinsert. The application must be right for using these inserts because it doesincrease the cost of the bit. Another downside is it will not solve fracturedue to overload. If the inserts are breaking due to overload, using diamondPDC-coated will not solve the problem. It will only help if the bit isexperiencing abrasive wear and thermal fatigue.


48/89



The applications for the D feature would be any application where abrasivecutting structure wear or thermal fatigue limits bit life. It can also be used indirectional applications where there would be excessive wear on the gauge

row inserts. The diamond PDC-coated insert would be a good solution tothat gauge wear problem.

F= Flame Spray. This is a tungsten carbide coating that is applied to thefinished cutter in a high-velocity oxygen-fuel environment. After the insertsare pressed into the cutter, the cutters are sent to an outside vendor for theFlame Spray to be applied. For Flame Spray, the steel cutter shell surface isbombarded with tungsten carbide pellets at high velocity and they areembedded into the cutter shell.

The benefits of Flame Spray are that it reduces cutter shell erosion andeliminates cone wear. The downside is that the coating may flake due todifferences in modulus of elasticity between the tungsten carbide pellets andthe steel. The best applications for flame spray is directional, or anyapplication where there is off-center rotation, gyration, or cutter wear limitsbit life due to erosion. Sometimes this happens with poor solids control orhigh solids in the mud. Flame spraying has to be done in the before the bit

is assembled. It is not something that can be done in the field. It has to berequested while the bits are being built. If there is a very abrasive formation,the abrasive formation will erode the steel. The problem with cutter shellerosion is that when the cutter shell is eroded, there is no longer support forthe inserts. Once the inserts fall out, the bit will not drill at an adequateROP. The bit will have to pull out of the hole and be replaced.

Flame

Spray

Cutter


49/89



G= heel row inserts on a tooth bit. Not all of tooth bits come with heel rowinserts. Typically it is included on the directional tooth bits and on themotor tooth bits. The G feature is standard on all insert bits, so it is not

included as a part of the insert bit nomenclature.

The benefit of the G feature is that it helps maintain gauge. It is in contactwith the borehole wall and it does help protect the gauge teeth on a milltooth bit. It does have side cutting ability and it is diamond-compatible.

The downside is that in some designs, it can reduce the total carbide ongauge. If the gauge row carbide were compromised in order toaccommodate the hole for the G feature, it probably would not be added.The applications would be any application where gauge rounding results inan under gauged hole or premature bearing failure. This feature will be usedin bits that are for directional applications, or any tooth bits that are run in amotor application.

The next feature is TuffGage. There is no nomenclature for this feature atthe present time. It is a different configuration of the heel pack inserts.

Typically there is one row of large heel pack inserts going around the backface of the cutter. The TuffGage feature basically is two rows of inserts.Sometimes they line up one on top of each other. Sometimes they arestaggered between each other. Sometimes they have skip spacing betweenthe two rows of inserts. Generally these inserts are smaller.

G Feature


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TuffGage in this heel pack configuration, give somewhere in the range of

20% to 40% more carbide on the back face of the cutter. That increaseimproves durability. It helps protect the gauge row inserts and helpsincrease the bit life.

The next features are shirttail and lug protection. There are 3 configurationsof shirttail and lug protection used by Schlumberger Drill Bits:

- K, KP, DK, and DKP- KPR and DKPR- L and DL

K, KP,

DK, & DKP KPR & DKPRL & DL


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K, KP, DK, and DKP are holes that are drilled into the shirttail where flattoptungsten carbide inserts are pressed into the drilled holes. There are standardpatterns that are use for the K and KP shirttail protection. However, there is

the flexibility to install any kind of design pattern as long as the pattern doesnot violate the specs in terms of the relationship of the inserts to each other,to the grease-loading hole, to the grease reservoir cap, and to the hard metal.This is an add-on feature. It can be done after the bit is built, either in thefactory or at a machine shop that has been certified at a field location.

The second type of protection is L, or DL, which stands for lug stabilizerpad. This is a piece of steel that is welded onto the shirttail and thenmachined. Once the piece of steel is machined to the proper diameter,holes are drilled and tungsten carbide inserts or diamond-coated inserts arepressed into the lug pad. The benefits of the lug pad are they stabilize thebit, they help to maintain gauge by reducing side loads, and they also reducebit body wear. The downside is that sometimes the lug pads extend thegauge length of the bit. This can be a possible problem in a directional wellwith the overall length and steerability of the bit. So if the lug pads extendthe gauge length and affect directional steerability, they will not be installedon the bit.

The third type of shirttail protection is KPR and DKPR. This is shirttail

protection that is premium. The R stands for raised inserts that are roundedand protruding from the shirttail. This feature was introduced in 2000 andhas become a very effective shirttail feature. This feature can also beinstalled in both the factory and in the field. There is a new KPR insert thatis just being introduced. It is called Mega KPR. This is an insert that isgoing to be used on the Titan product line. The difference between MegaKPR and the standard KPR, is that the standard KPR insert is 5/8" diameterand the Mega KPR inserts are 3/4" diameter. The applications for this isdirectional or any application where: 1) off-center wear or bit rotation isencountered, 2) bit stability could be a problem or be a limiting factor, or 3)in any application where a little more insurance is wanted. They can also beused in situations where a customer just wants to make sure that they do nothave any shirttail damage or they just want a little extra protection.


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These shirttail features do not cost very much and is a very effective tool tohelp ensure that you have a longer bit life. In a directional or off-centerwear application, these features are very important because they do help

protect the shirttail and protect the gauge row. In a directional situation, thebit is laying on the low side of the hole the majority of the time. Theshirttail and gauge row inserts are taking an abnormal amount of wear.Also, in a directional application, there are more opportunities for downholevibrations, off-center wear, and gyrations. This shirttail protection, gives thebit added bit life when running in a directional application.

T = GageGuard. This is the insert that is located in between the gauge rowinserts as shown in the picture below.

This insert is typically a shorter, rounder protruding insert. It makes contactwith the borehole wall which helps to protect the gauge inserts. This helpsbecause it gives 3 points of contact with the borehole wall. There are thegauge row inserts, the GageGuard inserts, and the heel pack inserts, all incontact with the borehole at the same time. This transfers the load betweenthe 3 inserts and helps protect the gauge row, which is the most vulnerable

part of the bit. The benefits of the GageGuard feature are better gaugedurability and better material selection. Diamond PDC-coated inserts canalso be used with GageGuard. The downside is that there may be areduction in gauge count on some designs.

GageGuard


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In order to make the space to drill the hole and press in the GageGuardinsert, some of the gauge row inserts would have to be moved or eliminated.In some designs, it is not worth sacrificing the gauge row inserts for the

GageGuard feature. If the gauge row inserts are spread out too far, or theconfiguration is changed, the gauge row could be weakened. It is notbeneficial to weaken the gauge row by adding GageGuard. If it does cause areduction in the gauge count for some designs, GageGuard would not beadded. GageGuard is a factory-installed feature. It is not an add-on feature.The bit has to be designed with GageGuard on it from the beginning.GageGuard does come standard on some Schlumberger products but is notavailable on all of the product lines. Most applications will see benefits ofGageGuard unless there is a reduction in the gage count that limits the run.

JA= Jet Air. It is design differences that are used for durable bit geometryfor under-balanced drilling. It typically has a low offset, an open cuttingstructure, and has special nozzle ports. There are only two areas in theworld that typically use jet air bits. They are used in the Northeast and inWest Texas, U.S.A. The bit is only built in two sizes, 7-7/8" and 8-3/4".The applications are for under-balanced drilling using air, foam, or mist.

M= in the suffix represents Mudpick II hydraulics on HP bits. Normally ifa bit had Mudpick II hydraulics, it would be called EHP. In order for a bit to

be an EHP, it had to have three things: 1) threaded ring, 2) Mudpick IIhydraulics, and 3) enhanced shirttail protection. In the 7-7/8" product lineball bearing are used instead of threaded rings. Since these bits do not havethreaded ring, they cannot be called EHP. The way the Mudpick IIhydraulics are designated on the 7-7/8" product line is by the M. Thebenefits of Mudpick II hydraulics on HP bits are a faster ROP (Rate OfPenetration) and better cutter and bottom hole cleaning. Most importantly, itmakes more efficient use of the available hydraulic energy. There are somedownsides to using Mudpick II hydraulics. There may be some cutter shellerosion due to the high-energy zone directly at the corner. There have alsobeen some cases of backwash on the shirttail. Mudpick II cannot be usedeffectively in all situations. It works well in most soft and mediumformations, especially where there is a tendency for bit balling. Any timethere is low hydraulic energy or more efficient use of the hydraulic energy isneeded, Mudpick II hydraulics is an effective tool.


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Diamond Features

With Schlumbergers roller cone cutting structure and shirttail features, there

is the opportunity to use diamond PDC-coated inserts. If a bit has diamondPDC-coated inserts, the following designations are used:

DA - Diamond Coating on All Inserts

DN - Diamond Coating on Nose Row Inserts

DI - Diamond Coating on Inner Row Inserts

DG - Diamond Coating on Gage Row Inserts

DT - Diamond Coating on GageGuard Inserts

DH - Diamond Coating on Heel Row Inserts

DK - Diamond Coating on Shirttail Inserts

DKP - Diamond Coating on Premium Shirttail Inserts

DKPR - Diamond Coating on Premium Shirttail Raised Inserts

DL - Diamond Coating on Lug Pad Inserts

Nomenclature & FeaturesNomenclature & Features

Review QuestionsReview QuestionsDescribe the features in the suffixes on each

of the following roller cone bits:

- 07 7/8 HP51X-MKP

- 12 1/4 EHT11GK

- 08 1/2 EHP51ACDLK- 17 1/2 EMS11DHKPR

- 05 7/8 SL51HFDGH

- 08 1/2 DJ44HTKPRDH

- 07 7/8 HP62JA


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Schlumbergers Roller Cone Product Lines

In Schlumberger Drill Bits there are 3 major roller cone product lines:

1) Roller Bearing Non-Sealed, 2) Journal Bearing Sealed, and 3) RollerBearing Sealed. Below is a list of all the current Schlumberger roller coneproduct lines (red indicates new products Schlumberger launched in 2001):

Y Non-sealed roller bearingHP High PerformanceEHP Enhanced High PerformanceMHP Motor High PerformanceEHT Enhanced Hardmetal ToothMHT Motor Hardmetal ToothJA Jet AirSL Slim Line (Marketed as Sabre)DJ Driver Journal (directional product line)

FMJ Full Metal Jacket (PMC product line)CMC Composite Matrix Cutter (PMC product line)MS Motor SeriesETS Enhanced Turbine SeriesEMS Enhanced Motor SeriesT TitanDR Driver Roller (directional product line)

Journal

Bearing

Sealed

HP

EHP

MHP EHT

MHT

JA

SL

DJ

FMJ

CMC

RollerBearingNon-Sealed

Y

RollerBearingSealed

MS

ETS

EMS

T

DR


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Fixed Cutter Bits

The 3 types of fixed cutter bits are 1) PDC bits, 2) Natural Diamond and

TSP bits, and 3) Impregnated Diamond bits.

PDC(Polycrystalline Diamond Compact) bits have PDC cutters as theprimary cutting structure. The PDC bits are built with either a steel body ora matrix body. The polycrystalline diamond compact consists of a diamondlayer attached to a tungsten carbide substrate to form the complete cutter.Shown in this picture are the diamond table and polycrystalline diamondcompact mounted onto the carbide substrate.

There are 5 basic cutter sizes that are used in the oilfield to make PDC drillbits. These PDC cutters range in size from 19 millimeter down to 8

millimeter.

DiamondTable

TungstenCarbideSupport

Polycrystalline

DiamondCompact

Increase theallowable RPM, ROP.

Decrease the abrasiveness of the rock.


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The PDC cutters are inserted into the bit body at an angle away from normal.This is called the backrake angle. Depending the on this angle of orientationof the cutters, it determines how aggressive the bit's cutting structure will be.

The lower the backrake angle, the more aggressive the bit. Typically thebackrake angle of PDC bits will be between 18% and 40%.

When finally assembled the soft formation PDC bit looks something like thepicture below. Shown are the cutters, the blades, and the pin.

PDC CUTTER

BLADE

?

PDC CUTTER

BLADE

?

Cutters

Pin

Blade

BackrakeAngle


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General PDC Terms

Natural diamondand TSP(Thermally Stable Polycrystalline) bits useexposed surface-set diamonds as the primary cutting structure. Thesegenerally range from 5 to 8 stones per carat up to 1 stone per carat. Ina natural diamond bit, the diamonds are set on the blades very closelyspaced, as shown below.

BLADE

NOZZLE

JUNK SLOT AREA

Natural Diamond Bit


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TSPbits use thermally stable polycrystalline diamonds as the cuttingstructure. Once again, these are quite small pieces, ranging from about 1 to2 millimeters in size. These are set so that they actually shear the formation

rather than the grinding mechanism used by the natural diamond bits.Shown below is the orientation of the TSP cutters along the blades or ribs.

Impregnated diamondbits use an even smaller diamond, basically a grit-sized diamond, which is set into a matrix in the blades. This then wearsaway, continually exposing new diamond to do the cutting. By using verysmall grit size, obviously the potential for high rates of penetration is

limited. These bits tend to drill in the range of 1 to 5 feet per hour onaverage. Pictured below is an impregnated diamond bit with grit that isso fine that the cutting structure on the blades of the bit cannot be seen.

TSP Bit

Impregnated Diamond Bit


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The failure methods of the 3 fixed cutter bits are shown below:

The impregnated diamond bits predominately drills by grinding when in ahard formation, although it may convert to shearing in a softer format

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