1. Introduction (626)

8/9/2019 1. Introduction (626)

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Pemex Short CourseOffshore Drilling

Lesson 1

Introduction


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Lesson 1 - Introduction

Floating Drilling Outline

Floating Drilling Vessels

Types of Motion

Types of Waves

When is Drilling Possible (WOW)

Vessel Capacities

Movement of Liquids


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Instructor: Jerome J. Schubert

Phone: 979/862-1195E-mail: [email protected]

Introduction - contd


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Drilling Lessons:

Can be found on the web at:

http://pumpjack.tamu.edu/~schubert/

Introduction - contd


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1. Floating Drilling: Equipment and its Use,

Practical Drilling Technology, Vol.2, by Riley

Sheffield, Gulf Publishing Company, Houston,

TX, 1980.

2. Applied Drilling Engineering, by Adam T.

Bourgoyne Jr., Martin E. Chenevert. Keith K.

Millheim and F.S. Young. SPE Textbook Series,Vol. 2, Society of Petroleum Engineers,

Richardson, TX, 1991.

References


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1. IADC Deepwater Well Control Guidelines,

Published by the International Association of

Drilling Contractors, Houston, TX, 1998.281-578-7171

2. Design for Reliability in Deepwater

Drilling Operations, by L. M. Harris.ThePetroleum Publishing Company, Tulsa, OK,

1979.

References


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3. An Introduction to Marine Drilling, by

Malcolm Maclachlan. Daytons Oilfield

Publications Limited, P. O. Box 11, Ledbury,Herefordshire HR8 1BN, England, 1987.

4. Drilling Engineering, A complete Well

Planning Approach, by Neal Adams andTommie Carrier. PennWell Publishing

Company, Tulsa, OK, 1985.

References - contd


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5. Practical Well Planning and Drilling

Manual, by Steve Devereux. PennWell

Publishing Company, Tulsa, OK, 1998.

6. Oilwell Drilling Engineering, Principles

and Practice, by H. Rabia. Graham &Trotman. Printed byThe Alden Press,

Oxford, UK, 1985.

References - contd


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Schedule

Introduction to Class,

Deepwater Platforms

Floating Vessels,

Types of Motion, Station Keeping

Wellheads and BOPs in Floating DrillingDrilling Risers, High Pressure Riser

Motion Compensation


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Schedule Pore Pressure and Prediction

Fracture Gradients

LWD and Formation Test

Special Problems in Floating Drilling

Shallow water Flows; Hydrates

Dual Gradient Drilling


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Schedule

Special Applications

Well Control


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Drilling Rigs

Drilling Systems

Drilling Rigs


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Drilling Team

Drilling Rigs

Rig Power System

Hoisting System

Circulating System ...

Rotary Drilling


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The Rotary System

The Well Control System

Well-Monitoring System

Special Marine Equipment

Drilling Cost Analysis

Examples

Rotary Drilling - contd


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NobleDrillings

Cecil

Forbes

A Jack-Up

Rig


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Sonats

George

Washington

A Semi-

Submersible

Rig


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Zapatas

Trader

A Drillship


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TENSION LEG PLATFORM


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Shells

Bullwinkle

Worlds tallest

offshore structure

1,353 water

depth

Productionbegan in 198945,000 b/d

80MM scf/d


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Fig. 1.5

Classification of

rotary drilling rigs


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Drilling Operations

Field Engineers, Drilling ForemenA. Well planning prior to SPUD

B. Monitor drilling operations

C. After drilling, review drilling results andrecommend future improvements

- prepare report.

D. General duties.

What are the well requirements?

Objectives, safety, cost


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Criteria for determining

depth limitation

Derrick

Drawworks

Mud Pumps

Drillstring

Mud System

Blowout Preventer

Power Plant


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A Rotary RigHoisting System


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Projection ofDrilling Lines

on Rig Floor

TOTAL

E = efficiency = Ph/Pi = W/(n Ff) or Ff= W/(nE) (1.7)


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Load on Derrick

(considering friction in sheaves)

Derrick Load = Hook Load

+ Fast Line Load+ Dead Line Load

Fd = W+ Ff+ Fs

F WW

E n

W

n

E E n

E nW

d ! = 1

E = overall efficiency: E = en

e.g., if individual sheave efficiency = 0.98 and n = 8, then E = 0.851


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Example 1.2A rig must hoist a load of300,000 lbf.The

drawworks can provide an input power to the

block and tackle system as high as 500 hp.Eight lines are strung between the crown block

and traveling block. Calculate

1.The static tension in the fast line

when upward motion is impending,

2. the maximum hook horsepower

available,


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Example 1.2, cont.3. the maximum hoisting speed,

4. the actual derrick load,

5. the maximum equivalent derrick

load, and,

6. the derrick efficiency factor.

Assume that the rig floor is arranged as

shown in Fig. 1.17.


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Solution1. The power efficiency forn = 8 is

given as 0.841 in Table 1.2.The tension

in the fast line is given by Eq. 1.7.

lbnE

W

F 590,448*841.0

000,300

!!!

( alternatively, E = 0.988 = 0.851 )


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Solution2. The maximum hook horsepower

available is

Ph= Eypi = 0.841(500) = 420.5 hp.

yyy


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Solution3. The maximum hoisting speed is given by

v P

Wb

h!

!

hpft-lbf/ mi

hp300,000 lbf

46.3 ft / mi

420 533 000

.,


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Solution to 3., cont.To pull a 90-ft stand would require

t ! !90

1 9ft

46 .3 ft / m in. m in .


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Solution4.The actual derrick load is given by

Eq.1.8b:

F E En

EnW

d!

1

= 1 + 0.841 + 0.841(8)0.841(8)

(300,000)

= 382,090 l f.


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Solution5.The maximum equivalent load is given

by Eq.1.9:

lbf

Wn

n

de

de

000,450

000,300*8

484

!

!

!


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Solution6.The derrick efficiency factor is:

,4

,3

de

dd !!

84.9%r849.0E !


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Drillshi

- moored


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Heave

SurgeSway

Roll

PitchYaw


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Motions restricted to the horizontal planeSURGE: Translation fore and aft (X-axis)

SWAY: Translation port and starboard (Y-axis)

YAW: Rotation about the Z-axis (rotation aboutthe moonpool)

Motions that operate in vertical planesHEAVE: Translation up and down (Z-axis)ROLL: Rotation about the X-axis

PITCH: Rotation about the Y-axis

Vessel Motions


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Wave Direction

Beam Waves

Quartering Waves

Head

Waves


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Significant Wave Height, ft

Roll vs. Significant Wave Height


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Significant wave height is the average height

of the 1/3 highest waves in a sample.

EXAMPLE The significant wave height in thefollowing sample is 24 ft.

7, 21, 19, 11, 18, 26, 13, 17, 25

[ Sign. WH = (21 + 26 + 25) / 3 = 24 ft ]

Avg. WH = (7, 21, 19, 11, 18, 26, 13, 17, 25) / 3 = 17.4 ft

What is Significant Wave Height?


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Significant Wave Height, ft

Heave vs. Significant Wave Height


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Heave vs. Wave Approach Angle

BOW BEAM


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Roll & Pitch vs. Wave Approach Angle

BOW BEAM


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Typical Vessel Motion Limits - Criteria

Operation Wave Height Heave

ft ft

Drilling Ahead 30 10

Running and

Setting Casing 22 6

Landing BOP and Riser 15 3Transferring Equipment 15 -


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What is lt ?


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Some Definitions

Freeboard

Draft

Width


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G = center of gravity. B = center of buoyancy

G is

above B!


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U

NOTE:

B has moved!

GZ =righting

arm


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Dynamic Stability - for certification


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Dynamic Stability

For adequate stability, the area under the

righting moment curve to the second

intercept or to the down-flooding angle,

whichever is less, must be a given amountin excess of the area under the wind

heeling moment curve to the same limiting

angle. The excess of this area must be atleast 40% for shiplike vessels and 30% for

column-stabilized units (see Fig. above).


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Free Surface Effects

CG moves!


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Tall, narrow tank is more stable ...


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Effect of Fluid Level in Tank


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Effect of Partitions in Tank


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The Vessel - Classification

Three classification societies are particularly

important to offshore drilling. These societies are:

1. Introduction (626)

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