SPE 80945

Ratings Standardization for Production Packers John Fothergill, SPE, Baker Oil Tools

Copyright 2002, Society of Petroleum Engineers Inc. This paper was prepared for presentation at the SPE Production Operations Symposium, held in Oklahoma City, Oklahoma, 22-25 March 2003. This paper was selected for presentation by an SPE Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Papers presented at SPE meetings are subject to publication review by Editorial Committees of the Society of Petroleum Engineers. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of where and by whom the paper was presented. Write Librarian, SPE, P.O. Box 833836, Richardson, TX 75083-3836, U.S.A., fax 01-972-952-9435.

Abstract Longstanding ambiguity surrounding performance ratings for production packers continues to be a topic of concern, as increasingly demanding completion environments drive more critical product selection processes. Inconsistencies in manufacturer testing methodologies and design validation procedures have previously not supported a quality selection process. Completion engineers, not equipped with a thorough understanding of the nuances of packer performance characteristics under various load conditions, have been dependent upon the technical expertise and good faith of the manufacturer. This paper gives the completion engineer a working understanding of applied packer performance ratings. The evolution of qualifying testing procedures is discussed, as well as the most recent advancements in the standardization process. Ratings standardization set forth in ISO 14310, establishing both quality control and design validation grades, is described. Completion engineers and other decision makers, as well as salesmen need this information for informed product comparisons and proper matching of product to application. Introduction This paper is to provide the information necessary for critical evaluation of only one component in the completion system. Although beyond the scope of this paper, it is important to recognize how the entire system must also be critically evaluated. If the value of accurate well data is not self evident, it should become so through the discussion of how that criteria effects the packer. The near infinite variety of oil and gas completion scenarios makes detailed discussion of applications impractical, but good completion planning practices will ensure that some specific information is

consistently available in the completion planning process, including:

• Casing/Liner and tubing data • Dogleg severity and well bore deviation • Initial bottomhole pressure • Bottomhole temperature • Wellbore preparation • Perforating • Completion fluids • Specific hostile conditions / CRA requirements • Anticipated life of the completion • Production media and rates • Anticipated stimulation conditions over the life of the

completion • Multi-zone flow control requirements • ID compatibility • Minimum bottomhole pressure • Landing conditions • Packer setting requirements and limitations • Well intervention With the requirements and limitations of the applications clearly defined, cost comparisons and the economic benefit of any proposed value enhancing features in the system can be fairly evaluated. This statement is true only if the completion engineer can trust in the validity of claims made by the manufacturer and there is a standard in place supporting those claims. The implications of product liability have historically guided manufacturers to limit their recommendations to a product perceived adequate for the application. Fringe applications that stretch product limitations increasingly drive the need for standardization in today’s environments. Ratings in Perspective Historically, misconceptions surrounding ratings have persisted more from a lack of understanding, rather than any attempt to be misleading.

Example: The manufacturer was asked to develop a packer capable of sustaining a differential pressure of 6,000 psi. The packer was developed and tested in the casing sizes and weights specified. Pressure was applied below the packer to the specified limit, and some subjective pressure value would be applied for a safety factor. When successful, the manufacturer offered the product rated

2 SPE 80945

to 6,000 psi. Temperature might or might not have been considered, depending on the manufacturer.

Evolution toward improving sophistication of design and testing from that reference point has varied dramatically among manufacturers. Improvements in testing procedures in support of ratings can be attributed to the lessons learned in application, as much as any initiative on the part of manufacturers. Those faced with the most demanding application requirements were forced to develop both quality programs and design validation processes to meet those requirements. The basic test of applying maximum pressure expectations evolved into more extensive tests. Testing began to incorporate attempts to simulate more, if not all, of the anticipated conditions to which the tool would be subjected in application. Issues of practicality still imposed limitations on the manufacturer to fully test the anticipated conditions. Time to market and development costs continued to constrain the technical verification process for any new product development. The need for some compromise of technical verification and economic justification became apparent in establishing valid and broadly applied ratings standards. A clear understanding of the design and application issues would first have to be in place to move forward. How Packers Work and How Packers Fail Before a packer’s rating can have value, it is necessary to understand its function and how various loading conditions and environmental factors influence its ability to perform. By simplest definition, the packer’s function is to grip and seal. It must remain anchored stationary within the casing, and it must maintain pressure sealing integrity with differential pressures, either below or above the tool. Initial setting forces apply loads, wedging the slips into the casing wall through movement of the cones. These same forces supply energy for the packing element system, generating rubber pressure sufficient to produce the sealing effect. Conditions after setting can act to enhance the initial sealing and anchoring effect, but when increased sufficiently, will ultimately produce failure. The area(s) of failure can be predicted by the combination of the applied loads. Variations in design will influence load carrying characteristics, but all have failure modes associated with extremes of the same conditions. The basic load matrix (Table 1) provides the basis for evaluating the simultaneous effects of both differential pressures and applied axial loads. Temperatures and other environmental conditions, as well as the packer’s component materials, will influence the packer’s ability to carry combined loads.

Table 1 – Rating Envelope Quadrants Tension Applied with

Pressure Above the Packer

Tension Applied with Pressure Below the

Packer Compression Applied with

Pressure Above the Packer

Compression Applied with Pressure Below the

Packer

s 1

6

7

3

4

5

2

Fig. 1 Basic Permanent Product The seven most common areas production packer are enumeratcollapse (3), packing element sycollapse at the body/lower guidguide connection failure (2), anbody lock ring failure (7), and b

Anchor Thread

r Bearing Shoulde Body Lock Ring

p

Upper Sli

Upper Cone

Packing Element

e

Lower Con

Body

Lower Slip

Guide-to–body connection

Lower guide

ion Packer Configuration

of failure on a permanent ed, including body stem failure (4), pin

e connection (5), bchor attachment failure (1), earing failure (6)

ody-to-

.

SPE 80945 3

Packer Performance Envelopes Development of the performance envelope represents a major step forward in bringing practical meaning to packer ratings. With an understanding of the interaction of combined loading conditions, it is possible to produce a representation of a predictable safe operating zone (performance envelope) for a packer. The performance envelope concept has made it possible to evaluate the packer’s design, calculating the envelope parameters, based on dimensional and material specifications. Worst case conditions of the application can then be overlaid to the envelope.

Tens

ion

Com

pres

sion

Above BelowDifferential Pressure

Forc

e

4

3

7

6

5

4

3

21

It is important to realize this envelope does not define points of failure. Rather, it only illustrates limits that can be calculated to provide predictably reliable performance. Where conditions of actual application define a condition outside the envelope, risks are introduced. The level of risk might or might not be deemed acceptable, following careful evaluation. When using performance envelopes as a comparative tool between competing manufacturers, it also important to recognize the influence of variations in acceptable safety factors, and how they might be calculated. For instance, manufacturer A sets standards defining any calculated bearing damage to components as beyond acceptable. Manufacturer B considers that same calculation’s degree of bearing failure not significant enough to interfere with the performance of the system. Taking this latitude wherever possible affords Manufacturer B the opportunity to enhance the perception of performance, despite having no real performance advantage. For this reason, performance envelope representations are most appropriately used as tool in evaluating each manufacturer’s tool to a given application. Incorporating the performance envelope in the completion planning process provides the opportunity to make necessary modifications in the completion design, material changes, and/or procedural changes to ensure reliable performance. If the performance envelope is to be used in a manufacturer-to-

manufacturer comparison for performance value to price, close scrutiny as to calculated values is necessary for a fair comparison. Using the Performance Envelope Familiarization with the four quadrants of loading conditions and the associated failure modes provides understanding of the failure implications. With this knowledge, the completion engineer can reasonably evaluate the implied risks when all best efforts still point to some conditions beyond the envelope boundaries. Each of the failure modes are examined here. Distinction is made concerning what conditions constitute potential damage to the tool, and what conditions can result in catastrophic failure. This discussion is limited to permanent production packers, but the same considerations apply to retrievable production packers or service packers. Although the differences in configuration of retrievables will apply loads to components different from those in the permanent packers, loading implications can be similar. Body Collapse This failure mode is defined by collapse of the packer body onto the outside diameter (OD) of the seal assembly. This condition results from excessive stress generated in the body. The excessive stress can be produced by differential pressures from above or below the packer, packer to tubing forces, or the combined effects of these forces. These forces act on both the cross-sectional area of the body and that of the packing element system. Any compressive or tensile forces applied to the body are permanently trapped between the slips.

Fig. 2. Areas outside the envelope are beyond the calculated safe operating zone. The numbers represent a failure mode, called out in Fig. 1, resulting from axial loading and differential pressure.

Consequences: Although body collapse can have serious implications, it does not imply a catastrophic failure. This situation might result in enough friction force on the OD of the seal assembly to prevent free movement of a floating seal assembly, or the ability to remove an anchor seal assembly, but it will not cause the packer to leak or move. This effect is represented in region 3 of the rating envelope. Packing Element System Failure This system is comprised of the packing element and supporting back-up rings. Failure of the system can occur with the packing element extruding through the back-up system, or by degradation of the packing element due to temperature or chemical effect, or failure of the back-up system. Extrusion of packing element through small gaps in the back-up system or anomalies in the casing ID can result when the temperature rating of the packing element material is exceeded, particularly in combination with differential pressures and packer-to-tubing forces that exceed the tool’s rating. Degradation of the packing element resulting from excessive temperature or chemical effect is an application design issue that must be considered in the completion system plan. It is

4 SPE 80945

not expressed as part of the pressure and axial load limits represented in the rating envelope. Failure of the packing element back-up system is the bending or shearing of the back-up rings. The back-up system is designed to expand to the casing ID, filling the extrusion gap between the packer’s OD and casing ID. Excessive pressure can produce this failure, so it follows for a given size packer, support for the back-up system is reduced, relative to increased casing ID. Consequences: Failure of the packing element system is catastrophic. Once the sealing integrity is compromised, well pressure can no longer be controlled, failing the completion system. This limitation is illustrated in region 4 of the rating envelope. Pin Collapse at the Body/Guide Connection This failure mode is possible in applications with a plug set in a nipple below the packer, or where a seal bore extension is fitted to the bottom of the packer. Similar to body collapse, exposure of thread connection to pressure can cause deflection of the pin connection of the packer. This has the same implications as body collapse, resulting in sticking the sealing assembly. Consequences: As with body collapse, stuck seals can cause high tubing stresses, but is considered non-catastrophic. Unlike body collapse, deflection of the pin connection to point of interference with seal assembly is not a locked in force, and equalization of the pressure will normally allow the pin connection to return to its original dimension. Region 5 of the rating envelope illustrates this limitation. Body-To-Guide Connection Failure Failure of the body-to-guide connection is defined as one of two variations. It can occur as a failure of the material at the thread relief when tensile forces exceed the body material’s yield strength. A failure of the thread itself can occur when tensile loads exceed the bearing strength of the threads. This connection is affected by both differential pressure from below the packer and packer-to-tubing tensile forces. This condition will normally occur as a result of the additive forces of both differential pressure and tensile load, and is typically at issue during stimulation procedures.

Tens

ion

Com

pres

sion

Above BelowDifferential Pressure

Forc

e

Stimulation

Production

Fig. 3. The point within the envelope referencing the production condition is safely within the performance range of the packer. However, the combination of forces associated with ballooning and contraction of the tubing during stimulation, indicate tensile forces at the packer, possibly causing failure.

The importance of considering the impact of anticipated stimulation procedures is illustrated in Figure 3. Plotting of both producing and stimulating conditions would imply other options should be considered. Although it is acceptable for the producing condition, it would likely be necessary to consider changing to a higher yield strength material in the packer, or allowing the seal assembly to float in order to manage the stresses of stimulation. Consequences: Failure of the body-to-guide connection is a catastrophic failure. The connection’s failure would free the body to move up through the packer. The guide, with its attachments, would fall downhole. The rating limit of the connection is represented in region 2 in the rating envelope. Anchor Attachment Failure This failure can occur only when the tubing is anchored to the packer, which is normally accomplished with a left hand square thread or jay lug / jay slot type anchor. Both configurations are similar in load considerations of material strength versus contact area. Failure can occur in the thread relief if tensile loads exceed the body’s material yield strength. Failure of the thread itself can occur when the thread’s shear or bearing strength is exceeded. The same would apply to the jay lug / jay slot. Swelling of the body can also be seen as a failure, or as a contributing factor in the failure of the thread or jay lug. This would occur when the elastic burst limit of the wall is exceeded. Consequences: Failure of the anchor connection is catastrophic. The seal assembly is freed from the packer seal bore, resulting in loss of the completion system’s pressure integrity. Limits of the anchoring device are represented in region 1 of the rating envelope.

SPE 80945 5

Body Lock Ring System Failure Failure of the body lock ring system can result with stresses exceeding the material’s shear or bearing strength. This applies to ring itself or its supporting components. Consequences: With failure of the body lock ring system, the body is allowed to float as pressure reversals are experienced. Although the slips have locked in packing element force, movement of the body will cause wear on the ID of the packing element. This can eventually cause a leak, but in the absence of pressure reversals, there are no serious consequences associated with the body lock ring failure. Limits of the body lock ring system are represented in region 7 of the rating envelope. Bearing Failure This failure mode is associated with both anchor and locator type seal assemblies. Bearing failure can occur when compressive packer-to-tubing force exceeds the bearing strength of the material at the contact point between the anchor or locator and the packer. Another criterion of failure is the stress generated by the radial component of the contact force. Consequences: There is potential, with extremely high compressive loads, to swage the seal assembly into the body when the seal assembly’s top shoulder angle is shallow. Minor bearing failure that only causes slight deformation of the mating surfaces will not compromise the completion system. The bearing load limitation is represented in region 6 of the rating envelope. Factors Influencing the Rating Envelope In addition to the design characteristics and configuration of a packer, there are other variables that can significantly move the performance boundaries. Aside from the availability of cross-sectional area in the packer’s construction, two other areas warrant discussion, due to their influence on performance. The influence of both material selection and the packer size, relative to the casing ID, have been referenced in the evaluation of failure modes. The effect of material selection is illustrated in Figure 4. It is important to understand the dynamics of material selection to achieve the optimum completion design. History has shown the waste of thousands of dollars spent in material selection criteria that was unwarranted for the application. Likewise, lack of attention to characteristics of the materials and how conditions will affect them can contribute to catastrophic failure or shortened life of the completion. Ideally, the flexibility, reliability and economy of the completion system are all optimized in planning the completion design.

Tens

ionCo

mpr

essio

n

Above BelowDifferential Pressure

Forc

e

110,000 psiMYS

80,000 psiMYS

Fig. 4. The change in material selection from 80,000 psi MYS to 110,000 psi MYS can provide a proportional increase in performance.

Sizing of the packer relative to casing ID will enhance or restrict performance, as referred to in the discussion of limitations of the packing element and back-up systems. Figure 5 illustrates the effect of changing casing ID for a given size packer. Flexibility in packer size selection is not only limited by the manufacturer’s product offering, but is also affected by the casing string design. Casing string design can be particularly problematic where heavy weight casing is set above the packer setting depth in lighter weight casing, while also requiring high differential pressure control.

Tens

ionCo

mpr

essio

n

Above BelowDifferential Pressure

Forc

e

38 ppf

23 ppf

Fig. 5. The example shows the performance envelope change in pressure rating limits for 7-in. casing, comparing the inside area for 23 ppf casing with the extended area available with 38 ppf casing.

While considering alternative manufacturers for the completion system design, there will often appear to be more

6 SPE 80945

flexibility in casing weight range coverage with one manufacturer’s product versus another’s. These differences can be attributed to how a manufacture approaches the design requirement. One manufacturer might design for target pressure ratings, while the other emphasizes the broadest possible coverage of casing weights. It is important in evaluating options to recognize the effect of packer OD to casing ID, most importantly where high pressure, high temperature, or both are anticipated. Importance of Understanding the Rating Envelope The performance envelope concept is an excellent tool in bringing understanding and predictability to how a tool should perform and how it might fail in application. With that said, there remain serious questions that need to answered before committing what can today be millions of dollars into high risk completions. The decision maker for any completion should be able to make that decision with full confidence that what is represented in a rating envelope can be validated by the manufacture. Only in recent years has a concerted effort been made in the industry to give the decision maker better tools to evaluate the claims made by manufacturers. Historically, a completion engineer would not only need to know what questions to ask, but also how to ask them, to ensure the product was accurately represented. The broad use of 10,000 psi rated retrievable packers, available from several manufacturers, can serve to illustrate how the validity of claims can be distorted. Hypothetical Example: A well is to be completed, anticipating stimulation soon after completing. The completion engineer has run tubing movement calculations to confirm loads on the packer. It appears the packer will be exposed to a maximum treating pressure differential of 9,800 psi. The initial bottom-hole temperature is 340°F, being cooled to 120°F during treatment. Tubing movement will apply 80,000# packer-to-tubing tensile stress. The completion engineer asks the following questions of a packer manufacturer’s sales representative: Q: Do you have a retrievable packer rated to 10,000 psi? A: Yes Q: Is it rated for the 340°F? A: Yes, it is rated to 350°F. Q: Will it withstand 80,000# tensile load? A: Yes, it is rated to 90,000# The completion engineer ordered the packer, only to see it fail late in the stimulation job, which had been proceeding according to plan. The completion engineer accuses the sales representative of misrepresenting his product. The sales representative responds that he was not given enough information. He did not realize his customer expected the packer to be subjected to those conditions described to occur in combination. Why did the packer fail? Technically, it failed because the combined loads added boost force into the packing element,

applied to both the cross-sectional areas of the packer body and the packing element system. The packing element integrity was already partially compromised by the temperature. Proper design validation testing would have shown this packer should have been rated to 6,000 psi, when subjected to the additional tensile load and temperature conditions. The failure could have been avoided by reviewing the requirements with a properly developed and validated performance envelope for the packer. Design Validation Testing It is important to emphasize the performance envelope concept is a relatively new tool. Regardless of manufacturer, many of the packers they offer will not have a performance envelope to document their ratings. Typically, only packers developed in recent years will be supported by a ratings envelope. Regardless of whether an envelope has been created, the testing regime that qualifies a packer’s rating is of utmost importance. Prior to the recent efforts to standardize design validation testing, there was no standard to support claims made by any manufacturer. Several considerations that should have been accounted for in testing were subject to compromise, either out of ignorance or cost and time to market considerations. Among them are the following:

• Combined loading • Pressure reversals • API casing tolerances • Temperature

o Maximum setting temperature o Minimum setting temperature o Cool down

• Gas or fluid environment The previous hypothetical example of an application scenario indicates just how the lack of a representative design validation testing procedure can be misleading. A valid testing regime should attempt to replicate the conditions expected in application. Combined Loading – The necessity of subjecting the packer to the combined loads of pressure differentials, with applied tensile and compressive loads has been discussed in the ratings envelope and failure mode discussion. The inter-dependent relationships of the packer’s components dictate that combined loading is essential to design validation. Pressure Reversals – While applying combined loads, the packer should be subjected to pressure reversals. Every packer design will be expected to withstand some cycling of pressure differentials from below to above, and again from below. Testing often exposes a packing element system failure only after pressure reversal, where a single pressure build up would not expose the failure. API Casing Tolerances – The variations in casing ID for any given casing weight can be viewed as building a safety factor into the rating of a packer. Historically, packers were

SPE 80945 7

tested only in the nominal ID for the specified casing weights. Upgraded testing programs, in recent years, have demonstrated the inadequacy of that testing. It left no margin for casing variances, due either to corrosion, wear, or mill variations. Not only does this impact sealing integrity, but also the reliability of proper slip setting, or slip release in case of retrievable packers. Some packers on the market today are also still plagued by problems associated with stroke length issues related to casing ID variations. The API tolerances were established as an allowable range in weight per foot for API certified tubulars. ID tolerances are extrapolated values according to casing weight, derived as follows: Calculation for Min/Max OD OD = Nominal OD of Tubing OD Tolerance, For OD ≤ 4”, TOL = ± .031 For OD ≥ 4-1/2”, TOL = .010 X OD, - .005 X OD For OD ≤ 4” ODmin = OD - .031 ODmax = OD + .031 For OD ≥ 4-1/2” ODmin = OD – (.005 X OD) = 0.005 X OD ODmax = OD + (.010 X OD) = 1.010 X OD Calculation for Min/Max ID ID = Nominal ID of Tubing WPE = Plain-End Weight of Tubing WPEmax = WPE + (.065 X WPE) = 1.065 X WPE, lbs. WPEmin = WPE – (.035 X WPE) = 0.965 X WPE, lbs. WPE = π/4 (OD2 - ID2) in2 X 12/ft X .283lb/in3

WPE = π/4 (OD2 - ID2) X 3.396, lbs. WPE – 2.670 (OD2 - ID2), lbs. (OD2 - ID2) = WPE/2.670 = .3745 X WPE OD2 - ID2 – (.3745 X WPE)

o ID = SQRT [OD2 – (.3745 WPEmax)]

IDmin = SQRT[ODmin2 – (.3745 WPEmax)] IDmin = SQRT[ODmin2 – (.3745 X 1.065 X WPE)]

o IDmin = SQRT[ODmin2 – (.3988 X WPE)] The resulting tolerance ranges for a sampling of some of the common casing sizes are illustrated, as well as the comparative tolerance range of each. OD PPF Min ID Nominal ID Max ID 4-1/2” 11.60# 3.940” 4.000” 4.069” 5-1/2” 20.00# 4.696” 4.778” 4.868” 7” 29# 6.088” 6.184” 6.293” 7-5/8” 33.7# 6.662” 6.765” 6.882”

OD PPF Tolerance Range 4-1/2” 11.60# .129” 5-1/2” 20.00# .172” 7” 29# .205” 7-5/8” 33.7# .220” The implications of the API tolerance in casing ID’s are significant, not only related to packer performance, but also to development costs. Packers capable of performing to the rating envelope in nominal ID’s will often fail when tested in the minimum or maximum ID extremes. The problems of meeting satisfactory test results are further complicated with retrievable packers. Retrievable packers that must set in the max ID tolerance must also set and retrieve at the min ID tolerance. Achieving a reliable balance, both in packing element systems and slip systems can drive testing costs to hundreds of thousands of dollars over that required if only testing in nominal ID’s. In the absence of a uniform standard for design validation testing, the incentive for compromise is obvious. Temperature – The effect of temperature on the sealing system of a packer should require qualification in developing the rating envelope. Any temperature rating should be qualified as related to applied differential pressures. A temperature rating, independent of pressure, is in effect an empty claim. Likewise, stating a temperature rating at a given differential pressure rating without validating that rating at API casing ID tolerances, can also be misleading. This relates to the packing element’s failure mode associated with the size of the extrusion gap between the packer OD and casing ID. Qualification of the packing element system should include verification of the seal at the stated maximum setting temperature and a minimum setting temperature. An effective minimum cool down temperature should also be verified through the qualifying tests. Each combination in variations of durometers to meet the rated temperature range should be individually qualified at the rated differential pressures. Gas or Fluid Environment Qualification – It not necessary that every packer design be capable of maintaining a gas tight seal, as some designs will only be exposed to fluid environments in actual application. In such cases, attempting to verify a gas tight seal would only drive up development costs, with no offsetting benefit in application. Packers to be exposed to setting in gas environment must be qualified accordingly. Typically, this applies to packers developed for wireline deployment, anticipating running in a pressurized well environment. In either case, the validation of pressure differentials, temperatures, and casing ID tolerances are still at issue. Moving Toward Standardized Ratings As the knowledge of potential problems in packer applications has developed, coupled with the increased risks of failure, most manufacturers have attempted to upgrade testing procedures. Existing products have generally been in use long enough to have developed a loosely defined envelope of their own, proven out through empirical run data. Cost constraints

8 SPE 80945

have generally dictated that improved testing standards have been limited to new product development programs. However, in the absence of a uniform standard, the improvements have not necessarily been consistent between manufacturers. The lack of uniform standards for quality and design validation testing would continue to leave any decision maker in the completion planning process with much uncertainty. The decision maker has had no consistent measure for comparison of competing claims made by manufacturers. In addition, the array of variables associated with packer ratings demonstrate how the reliability of performance can be affected. Any compromise on even one of the qualifying factors can lead to failure. This concern has driven many decision makers to resort to costly third party inspections, where the risks and costs of failure are extreme. It is clear that a practical, yet comprehensive set of standards has been needed. The need includes the realization that the requalifying of every packer product offering of each manufacturer is simply cost prohibitive. Some graduated standard would be required to address proven products in low risk application, while ensuring incremental standards would meet the requirements of increasingly demanding applications. This initiative has now resulted in the development of a uniform process to qualify both quality levels and design validation testing procedures. Development of ISO/FDIS 14310 The concerns expressed have been recognized by the International Standards Organization (ISO). Work of the ISO is carried out through technical committees. A technical committee was formed to address theses issues, as pertaining to packers and bridge plugs. The work was done under the ISO Technical Committee ISO/TC 67, responsible for materials, equipment and offshore structures for the petroleum and natural gas industries, through Subcommittee SC 4, for drilling and production equipment. From the work of Subcommittee SC 4, the International Standard ISO 14310 was prepared, addressing both quality and design validation testing standards. Preparation of the standard was a collaborative effort of purchasers and manufacturers. The standard is intended to provide requirements and information to both parties in the selection, manufacture, testing and use of packers and bridge plugs. It is not intended to address the installation and maintenance of these products. Graduated Levels of Standards The International Standard has been developed in incremental levels both in quality and design validation to meet increased demands of performance. Quality levels are graduated in three levels (Q1-Q3). Design validation testing has been graduated in six levels (V1–V6), with one special design validation grade (V0) to provide the purchaser the choice of requirements to meet their preference or application.

The standard for quality control increases as the number decreases, such that Q3 is the minimum quality standard offered by the product standard. The Q2 rating provides additional inspection and verification steps, and Q1 rating is the highest, although additional upgrades can be specified by the purchaser. Quality Control Grades Requirements for the three quality control grades are outlined in Table 2. The following abbreviations and terms are used in the table: COC – Certificate of Conformance MTR – Material Test Record NDE – Non Destructive Examination Type 1 components or welds – isolates pressure or subject to tensile load Type 2 components or welds – not subject to Type 1 criteria Table 2 – Quality Control Grades Q3 Q2 Q1

Material COC or MTR COC or MTR

Verify MTR for Type 1 Components COC or MTR for other components

Castings COC COC COC

Heat Treatment

COC (subcontractor) Job lot verify (supplier/mftr)

COC (subcontractor) Job lot verify (supplier/mftr)

Heat treat certificate for Type 1 components

Component Traceability

Job lot traceable for Type 1 components

Job lot traceable for Type 1 components

Heat traceable for Type 1 components

Component dimensional Sampling plan Sampling plan 100% for Type 1

components Welding

Type 1 welds Visual Surface NDE per sampling plan & visual

Surface NDE 100% & visual

Type 2 welds Visual Visual Visual

Hardness

Type 1 components None Sampling plan 100%

Type 2 components None None None

Component NDE

Type 1 components None

Surface NDE per sampling plan

Surface NDE 100%

Type 2 components None None Visual

Shear devices Heat Lot verification

Heat Lot verification

Heat Lot verification

Assembly verification None Functional test

ID drift

Functional test ID drift OD dimensional Torque documentation

Assembly traceability None None

Serialization for Type 1 components

QC documentation

Supplier/mftr retained

Supplier/mftr retained

Supplier/mftr retained

SPE 80945 9

The ISO standard also includes detailed instructions for the documentation for each of the criteria outlined in the table. This documentation is to be maintained for a period of 5 years, and it is available for audit by the purchaser. Design Validation Testing per ISO/FDIS 14310 Design validation grade V6 is the minimum grade and represents equipment for which the manufacturer has defined the validation method. This is applied to many of the existing industry products, proven by previous testing methods and past performance in application. The complexity and severity of the validation testing increase to the V0 grade. These standards do not preclude manufacturers from offering, or purchasers from accepting, alternative equipment or engineering solutions. This can be particularly applicable for innovative or developing technologies. Standard validation grades:

V6: Supplier/manufacturer defined V5: Liquid test V4: Liquid test + axial loads V3: Liquid test + axial loads + temperature cycling V2: Gas test + axial loads V1: Gas test + axial loads + temperature cycling

Special validation grade: V0: Gas test + axial loads + temperature cycling + special acceptance criteria (V1 + zero bubble acceptance criteria) Bridge plugs may be run and tested without axial load; however, all validation grades are applicable. Packers or bridge plugs verified to grade V5 through V1 shall not be rated for casing or tubing sizes and weights that can have a maximum ID larger than the ID used in the validation test. Tolerances on casing/tubing ID are governed in accordance with ISO 11960. In addition to the general specifications for design validation testing outlined here, the ISO standard specifies detailed criteria and instructions concerning how the validation testing is to be conducted for each grade. It also addresses the management of minor and substantive design changes. Other Efforts In Standards and Improved Reliability It is important to emphasize that most packers on the market today have not been subjected to the ISO standard. Some manufacturers are attempting to validate some previously produced products in accordance to the ISO standard, or at least revisit their quality standards and design validation procedures. Increasing application demands and product liability issues have forced manufacturers to review their existing products for more stringent standards. The API has also recognized the need for uniform product standards. The API specification 11D1 has been developed in close concert with the ISO 14310 standard. Effective January 1, 2003, manufacturers have been provided the opportunity to qualify products per the API 11D1 specification. Those

products meeting the API criteria can now carry an API monogram, in effect being API certified. Enhanced design validation testing is also conducted by some manufacturers, which goes beyond the ISO standard. This testing not only validates the rating envelope, but attempts to simulate the anticipated worst case application scenario for the tool. This might include additional pressure reversal cycling, fluid exposures, flow loop testing, or other criteria for customer special requests. Summary The expectation for reliable performance for packers must be supported by thorough planning of the completion, including all anticipated conditions beyond the initial completion. The responsibility for the proper selection of equipment is shared by both purchaser and manufacturer. This requires an understanding how the equipment should be expected to perform, and what conditions will contribute to failure. Historically, the industry was limited in its ability to assess and verify a product’s suitability for a given application. The ratings envelope concept has provided an excellent tool for comparing packer performance capabilities with its application. The introduction of the ISO standard (ISO/FDIS 14310) and the API 11D1 specification will enhance the benefit of rating envelopes by ensuring uniform measures. To the extent these new standards proliferate through the industry, either through manufacturer initiative or purchaser demand, performance reliability should improve. Acknowledgements The author wishes to thank the management of Baker Oil Tools for their encouragement and support in developing this paper. References

1. ISO, “Petroleum and Natural Gas Industries – Downhole Equipment – Packer and Bridge Plugs”, ISO Standard 14310, Latest Edition

2. Hoppman, Mark; Walker, Tim: Petroleum Engineering International, Harts Publications, Inc. “Predict Permanent Packer Performance”

3. McCasland, Mark; Luce, Tom: “A Systematic Approach to Development and Deployment of Downhole Completion Equipment for High Profile HP/HT Projects” SPE 77822 Presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition in Melbourne, Australia, 8 – 10 October 2002.

4. Dyson, William Q.; Coludrovich, Earl; Creech, Rachael; Weldy, John C.; Fruge, Michael; Guidry, Marton: “Best Completion Practices” SPE/AIDC 52810 Presented at the SPE/AIDC Drilling Conference in Amsterdam, Holland, 9 – 11 March 1999.

5. Turner, Will: “Methods to Assess the Reliability of Downhole Completions: The Need for Industry Standards” OTC 12168 Presented at the Offshore Technology Conference in Houston, TX, 1 – 4 May 2000.

10 SPE 80945

6. Watson, Graeme; Hibberd, Roger; Turner, Will; Hidding, Gert Jan: “Cost Reduction in Downhole Completion Equipment Supply: A Case History” SPE 53914 Presented at the SPE Latin American and Carribean Petroleum Engineering Conference in Caracas, Venezuala, 21 – 23 April 1999.

7. Williford, James; Rice, Pat; Ray, Thomas: “Selection of Metallugy and Elastomers Used in Completion Products to Achieve Predicted Product Integrity for the HP/HT Oil and Gas Fields of Indonesia” SPE 54291 Presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition in Jakara, Indonesia, 20 – 22 April 1999.

8. API “Petroleum and Natural Gas Industries – Downhole Equipment – Packer and Bridge Plugs”, API Specification 11D1, First Edition, July 2002