By Dr. Khaled El-shreef

Transcription

1 King Saud University Petroleum and natural Gas Engineering Department PGE 475: 3 (3, 1, 0) Special Topics in Drilling Engineering Second Semester ( ) Prerequisite: PGE 472 By Dr. Khaled El-shreef 1 PGE 475 Special Topics in Drilling Engineering First Semester ( ) Textbooks: 1. Advanced Oilwell Drilling Engineering Handbook, Dr. Bill Mitchell, Golden, USA, 10th Edition, referred to the Society of Petroleum Engineers, Advanced Well Control, Textbook, David Watson, Terry Brittenham, and Preston L. Moore, SPE, Vol. 10,

2 Description Directional and horizontal drilling. Directional and horizontal well planning. Survey tools and practices, measurement while drilling (MWD). Types of horizontal wells. Kick off tools and equipment. Bottom hole assembly in horizontal drilling. Survey calculation methods. Well control in vertical wells. Hydrostatic pressure vs. formation pressure. Types of kick and kick causes. Kick indications. Shut-in procedures. Kill methods and kill procedures. Well-control equipment. 3 Objectives The course is designed to provide the techniques and practical applications of horizontal drilling and represents a practical approach to well control and emphasizes the equipment. 4 2

3 Topics 1. Introduction to directional drilling. (2 classes). 2. Steps in designing well profile, kick-off point and buildup rate. (3 classes). 3. Directional planning, purpose, considerations and calculations (5 classes). 4. Kick-off tools, purposes and functions (2 classes). 5. Horizontal drilling, design of BHA, max. Dog-leg severity and preventing unscheduled events (fatigue, pipe sticking, miss target, etc.) (5 classes). 6. Survey tools (MWD) and practices, well profile calculations. (4 classes). 5 Topics 7. Well control, introduction and definitions of related terms (3 classes). 8. Hydrostatic pressure vs. formation pressure, formation integrity test, and causes of underbalance situations (4 classes). 9. Kick causes, detection and warning signs, shut- In procedures and collection of data (5 classes). 10. Calculating drillstring and annular volume, kill methods, circulating pressure losses (6 classes). 11. Well control equipment, Ram-type blowout preventers. (3 classes) 12. Test (2 classes) 6 3

4 Evaluation 10 % for attendance, participation, quizzes and home works and 40% for two mid-term exam and 50% for the final examination. 7 Office Hours Officially: Saturday, 10:00-12:00 am Monday, 10:00-12:00 am Wednesday, 10:00-12:00 am 8 4

5 DIRECTIONAL AND HORIZONTAL DRILLING COURSE CONTENT Introduction to directional drilling a directional well Tools used to deflect a wellbore Survey instruments Survey calculations Horizontal drilling 9 Introduction Directional drilling is the art and science involving the intentional deflection of a wellbore in a specific direction in order to reach a predetermined objective below the surface of the earth 5

6 Introduction At one time it was thought that all wells were vertical The petroleum industry did not become fully aware of deviated well problems until the development of the Seminole, Oklahoma field. The wells in this field were drilled very close together. As a result of the deviation tendencies, wells were drilled into other drilling wells and wells which were already producing. 11 Introduction Methods to measure deviation were developed in the 1920 s Directional drilling developed after 1929 when new survey instruments were available (inclination and direction) 12 6

7 Introduction The first controlled directionally drilled well was drilled in the Hunting town Beach Field in 1930 to tap offshore reserves from land locations Directional drilling became more widely accepted after a relief well was drilled near Conroe, Texas in Introduction Today, directional drilling is an integral part of the petroleum industry It enables oil companies to produce reserves that would not be possible without directional drilling 14 7

8 Introduction Applications The most common applications of directional drilling, 15 Introduction One of the primary uses of directional drilling was to sidetrack a well even if it was to go around a stuck BHA 16 8

9 Introduction Sometimes multiple sidetracks are used to better understand geology or to place the wellbore in a more favorable portion of the reservoir 17 Introduction Straight hole drilling is a special application of directional drilling To keep from crossing lease lines To stay within the specifications of a drilling contract To stay within the well spacing requirements of a developed field 18 9

10 Introduction Drilling multiple wells from a single structure or pad Most offshore development would not be possible without directional drilling 19 Introduction Inaccessible surface location Drilling in towns, from land to offshore and under production facilities 20 10

11 Introduction Drilling around salt domes Salt can cause significant drilling problems and directional drilling can be used to drill under the overhanging cap 21 Introduction Steeply dipping sands can be drilled with a single wellbore 22 11

12 Introduction Fault drilling In hard rock, deviation can be a problem Sometimes the bit can track a fault Drilling at a higher incident angle minimizes the potential for deflection of the bit 23 Introduction Relief well drilling Directional drilling into the blowout when the surface location is no longer accessible Very small target and takes specialized equipment 24 12

13 Introduction Horizontal drilling Increasing exposure of the reservoir to increase productivity 25 Introduction Multilateral drilling Drilling more than one wellbore from a single parent wellbore 26 13

14 Introduction Extended reach drilling wells are characterized by high inclinations and large departures in the horizontal plane 27 Introduction Extended reach wells are wellbores where the horizontal departure HD is significantly higher than the true vertical depth of the well TVD. Extended reach wells have been drilled with HD/TVD ratios greater the 6/

15 Introduction BP drilled a well at Wytch Farm with a measured depth of 34,967 (10,658 m), a TVD of 5,266 (1,605 m) and horizontal departure of 33,181 (10,114 m) 29 Introduction There are four basic hole patterns Not all wells conform to the basic hole patterns and may be a combination of patterns For simplicity, the basic hole patterns are defined as: 30 15

16 Introduction Type I is a build and hold Drilled to a relatively shallow KOP Deflected to a maximum inclination The inclination is held relatively constant to TD 31 Type II is a build, hold and drop often termed an S curve Multiple targets Around salt domes More torque and drag for the same departure Introduction 32 16

17 Introduction Type III is a continuous build to target Deeper kickoff point Small horizontal departure Less expensive 33 Introduction Type IV is a horizontal wellbore Build rates may be high Hold inclination is near 90 degrees 34 17

18 TVD, ft RKB Common terminology for a directional profile KOP Build Section EOB Tangent or Hold Drop Section Departure, ft 35 Three items required for any directional well Build rate Hold inclination Kick off point (KOP) Assume two and calculate the third 36 18

19 The paper method is still one of the simplest methods for calculating the hold inclination 37 D is used to indicate TVD X is used to indicate DEP 38 19

20 r r B r 180 B r R r 1 r 2 (3) (3) (10) sin 1 DR 2 R XL 2 L (8) D D 4 D 1 (9) Single Equation X X 4 r1 r2 (11) L D X R 2 (12) 39 Example 1 in the book shows how to determine the hold angle when the build rate and kickoff point has already been selected Kickoff point is 2000 feet Build rate is 2 o /100 feet Target TVD is 9800 feet Target DEP is 2926 feet Total depth is 10,000 feet TVD 40 20

21 The equations can be used to determine the hold inclination in Example 1 D 1 = KOP = 2000 D 4 = Target TVD = 9800 X 4 = Target DEP = r ' eqn 3 B (2 /100) r r 2 0 D D4 D eqn 9 R r1 r eqn 10 X X 4 r1 r eqn 11 L D X R L eqn

22 sin sin sin O DR XL eqn R L (7800)( ) (61.21)( ) The hold inclination needs to be 22 o 43 Example 2 shows drilling the same directional well using a Type II or S curve KOP = 2000 Build rate = 2.5 o /100 Drop rate = 1.5 o /100 Target TVD = 9800 Target DEP = 2926 Total depth = 10,000 TVD Calculate the hold angle with the single equation in the paper 44 22

23 Calculate r 1 and r r ' eqn B (2.5/100) r r ' eqn B (1.5/100) r 3 45 Calculate D from equation 9 D D4 D Calculate R from equation 10 R r1 r

24 Calculate X with equation 11 X X 4 r1 r Calculate L with equation 12 L D X R 1 ( ) L Calculate the hold angle with equation 8 sin sin DR XL 2 2 R L (7800)( ) ( )( ) O 48 24

25 Example 1 in the book shows how to determine the hold angle when the build rate and kickoff point has already been selected Kickoff point is 2000 feet Build rate is 2 o /100 feet Target TVD is 9800 feet Target DEP is 2926 feet Total depth is 10,000 feet TVD 49 Determine the hold inclination and the detailed MD, TVD and DEP for the well The hole can be divided up into sections Vertical to KOP Build Hold or tangent to target Hold or tangent to TD 50 25

26 Determine the MD, TVD and DEP for the vertical to KOP section Section MD TVD DEP Vertical to KOP Build Hold to Target Hold to TD 51 Determine the hold inclination from the chart Inclination is 22 o 22 o 52 26

27 Determine the MD, TVD and DEP of the build section MD I I 2 1 B r 22 0 MD 1100 feet 2/ TVD TVD 180MDSinI 2 SinI1 I I Sin 22 Sin MDCosI CosI I I DEP DEP Cos 0 Cos

28 For the build section Section MD TVD DEP Vertical to KOP Build Hold to Target Hold to TD You can also use the build up tables in the Appendix 55 BUILD RATE DEG/100 FEET = 2 RADIUS OF CURVATURE = FEET INC MD TVD DEP INC MD TVD DEP INC MD TVD DEP

29 Calculate the MD, TVD and DEP for the hold section TVD remaining = TVD remaining = DEP remaining = DEP remaining = MD of the hold section

30 MD DEP Sin I MD Sin 22 Section MD TVD DEP Vertical to KOP Build Hold to Target Hold to TD 59 Calculate the MD, TVD and DEP of the hold to TD 60 30

31 The TVD is feet from 9800 feet to 10,000 feet MD TVD Cos I 200 MD Cos 22 DEP TVD xtani DEP 200 xtan Section MD TVD DEP Vertical to KOP Build Hold to Target Hold to TD Total 10, ,

32 63 The next step is to determine The closure distance and direction, The North coordinate, and the East coordinate. The closure direction is given as N20 E. The closure distance is the horizontal departure at any point in the well

33 At Target Depth, North Coordinate b = C (closure)* Cos (A) = 2926*cos(20)= East Coordinate a = C (closure)* Sin (A) = 2926*sin(20)=

34 Horizontal Plan View of the well 67 Class Problem Given the target data in example 1 Calculate the kickoff point if the build rate will be 2 o /100 and the hold inclination will be 35 o 68 34

35 69 There are many ways to drill a directional well Example 2 shows drilling the same directional well using a Type II or S curve 70 35

36 Example 2 KOP = 2000 Build rate = 2.5 o /100 Drop rate = 1.5 o /100 Target TVD = 9800 Target DEP = 2926 Total depth = 10,000 TVD 71 Determine hold inclination from the chart Hold inclination is 24 o 24o 72 36

37 Determine the MD, TVD and Dep. Section MD TVD DEP Vertical to KOP Build Hold Drop Vertical to TD 73 Determine the MD, TVD and DEP for the build and drop sections Can be calculated using the radius of curvature calculations or can use the buildup charts Dropping from 24 o to 0 o will give the same TVD and DEP as building from 0 o to 24 o 74 37

38 BUILD RATE DEG/100 FEET = 2.5 RADIUS OF CURVATURE = FEET INC MD TVD DEP INC MD TVD DEP INC MD TVD DEP BUILD RATE DEG/100 FEET = 1.5 RADIUS OF CURVATURE = FEET INC MD TVD DEP INC MD TVD DEP INC MD TVD DEP

39 Build and drop sections Section MD TVD DEP Vertical to KOP Build Hold Drop Vertical to TD 77 Calculate the TVD and DEP of the hold section TVD remaining = = DEP remaining = = Calculate the MD of the hold section 78 39

40 MD MD ( ' 2 2 ( TVD DEP 2 ) ) The hold section can be entered into the table Section MD TVD DEP Vertical to KOP Build Hold Drop Vertical to TD 80 40

41 Add the vertical to total depth Section MD TVD DEP Vertical to KOP Build Hold Drop Vertical to TD Total 10, ,

42 The next step is to determine The closure distance and direction, The North coordinate, and the East coordinate. The closure direction is given as S 40 W. 83 At Target Depth, North Coordinate b = C (closure)* Cos (A) = 2926*cos(220)= East Coordinate a = C (closure)* Sin (A) = 2926*sin(220)=

43 85 Horizontal Plan View of the well 86 43