Directional Well Planning Directional Well Planning

© 2007 PetroSkills LLC, All Rights Reserved

Directional Well PlanningDirectional Well Planning

2 © 2007 PetroSkills LLC, All Rights Reserved

PlanningPlanning

Three items required for any Three items required for any directional welldirectional well

Build rateHold inclinationKick off point (KOP)

Assume two and calculate the Assume two and calculate the thirdthird


PlanningPlanning

The build rate can be chosen for any number of reasons−

To minimize the possibility of fatigue in the drill pipe

−

Run an assembly that remains steerable, rotary or motor

−

Minimize the possibility of a keyseat−

Minimize torque and drag


PlanningPlanningThe hold inclination may be selected−

Less than 10o, it is difficult to maintain the direction of the wellbore

−

Greater than 30o, it becomes increasingly hard to clean the cuttings from the hole

−

Hole cleaning is the most difficult between 45o

and 60o

−

Above 60o, wireline tools may not fall in an open hole

−

Above 70o, wireline tools may not fall in cased hole


PlanningPlanning

The kickoff point can be selected based on hole conditions−

The kickoff point may be selected so that the build section will be cased at the end (selected based on casing seat)

−

It may be advantageous to drill a troublesome portion of the well vertically and get it cased

−

Directional drilling usually takes longer


PlanningPlanning

−

If the troublesome zone has lost circulation, LCM in the mud is hard on MWD tools

−

A zone that sloughs substantially may slough faster if sloughing is due to stress and the well is drilled at an appreciable inclination

−

It may be better to finish the build curve and start drilling the hold section before drilling a troublesome formation


PlanningPlanning

Example 4Example 4--1 (on page 41 (on page 4--2) 2) shows how to determine the hold shows how to determine the hold angle when the build rate and angle when the build rate and kickoff point have already been kickoff point have already been selectedselected

Kickoff point is 2000 feetBuild rate is 2o/100 feetTarget TVD is 9800 feetTarget DEP is 2926 feetTotal depth is 10,000 feet TVD


PlanningPlanning

Determine the hold inclination Determine the hold inclination and the detailed and the detailed MDMD, , TVDTVD and and DEPDEP for the wellfor the well


PlanningPlanning

The hole can be divided up into The hole can be divided up into sectionssections

Vertical to KOPBuildHold or tangent to targetHold or tangent to TD


PlanningPlanning

Determine the MD, TVD and DEP Determine the MD, TVD and DEP for the vertical to KOP sectionfor the vertical to KOP section

SectionSection MDMD TVDTVD DEPDEPVertical to Vertical to KOPKOP

2000.002000.00 2000.002000.00 0.000.00

BuildBuild

Hold to Hold to TargetTarget

Hold to TDHold to TD


PlanningPlanning

Determine Determine the hold the hold inclination inclination from the from the chartchartInclination Inclination is 22is 22oo

22o


PlanningPlanning

Determine the MD, TVD and DEP Determine the MD, TVD and DEP of the build sectionof the build section

rBIIMD 12 −=Δ

feet 1100100/2

022=

−=ΔMD


PlanningPlanning

( )( )( )( ) 17.1073

0220sin22sin1100180

=−

−=Δ

πTVD

( )( )( )12

21 coscos180II

IIMDDEP−

−Δ=Δ

π

( )( )( ) 60.208

02222cos0cos1100180

=−

−=Δ

πDEP

( )( )( )( )12

12 sinsin180II

IIMDTVD−

−Δ=Δ

π


PlanningPlanning

For the build sectionFor the build section


2000.002000.00 2000.002000.00 0.000.00

BuildBuild 1100.001100.00 1073.171073.17 208.60208.60




PlanningPlanning

You can also use the build up You can also use the build up tables in the Appendixtables in the Appendix


PlanningPlanningBUILD RATE DEG/100 FEET = 2 RADIUS OF CURVATURE = 2864.79 FEET

INC MD TVD DEP INC MD TVD DEP INC MD TVD DEP0.00 0.00 0.00 0.00 30.00 1500.00 1432.39 383.81 60.00 3000.00 2480.98 1432.391.00 50.00 50.00 0.44 31.00 1550.00 1475.48 409.19 61.00 3050.00 2505.60 1475.912.00 100.00 99.98 1.75 32.00 1600.00 1518.11 435.31 62.00 3100.00 2529.46 1519.853.00 150.00 149.93 3.93 33.00 1650.00 1560.28 462.17 63.00 3150.00 2552.55 1564.204.00 200.00 199.84 6.98 34.00 1700.00 1601.97 489.77 64.00 3200.00 2574.86 1608.955.00 250.00 249.68 10.90 35.00 1750.00 1643.18 518.09 65.00 3250.00 2596.38 1654.086.00 300.00 299.45 15.69 36.00 1800.00 1683.88 547.13 66.00 3300.00 2617.11 1699.577.00 350.00 349.13 21.35 37.00 1850.00 1724.07 576.87 67.00 3350.00 2637.05 1745.438.00 400.00 398.70 27.88 38.00 1900.00 1763.74 607.30 68.00 3400.00 2656.19 1791.629.00 450.00 448.15 35.27 39.00 1950.00 1802.87 638.43 69.00 3450.00 2674.51 1838.14

10.00 500.00 497.47 43.52 40.00 2000.00 1841.45 670.23 70.00 3500.00 2692.02 1884.9711.00 550.00 546.63 52.63 41.00 2050.00 1879.47 702.71 71.00 3550.00 2708.71 1932.1012.00 600.00 595.62 62.60 42.00 2100.00 1916.92 735.84 72.00 3600.00 2724.58 1979.5213.00 650.00 644.44 73.42 43.00 2150.00 1953.78 769.61 73.00 3650.00 2739.61 2027.2114.00 700.00 693.06 85.10 44.00 2200.00 1990.05 804.03 74.00 3700.00 2753.81 2075.1515.00 750.00 741.46 97.62 45.00 2250.00 2025.71 839.08 75.00 3750.00 2767.17 2123.3316.00 800.00 789.64 110.98 46.00 2300.00 2060.76 874.74 76.00 3800.00 2779.69 2171.7317.00 850.00 837.58 125.18 47.00 2350.00 2095.17 911.01 77.00 3850.00 2791.36 2220.3518.00 900.00 885.27 140.21 48.00 2400.00 2128.95 947.87 78.00 3900.00 2802.19 2269.1719.00 950.00 932.68 156.08 49.00 2450.00 2162.08 985.32 79.00 3950.00 2812.15 2318.1620.00 1000.00 979.82 172.77 50.00 2500.00 2194.56 1023.34 80.00 4000.00 2821.27 2367.3221.00 1050.00 1026.65 190.28 51.00 2550.00 2226.36 1061.92 81.00 4050.00 2829.52 2416.6422.00 1100.00 1073.17 208.60 52.00 2600.00 2257.48 1101.05 82.00 4100.00 2836.91 2466.0923.00 1150.00 1119.36 227.74 53.00 2650.00 2287.92 1140.72 83.00 4150.00 2843.44 2515.6624.00 1200.00 1165.21 247.67 54.00 2700.00 2317.66 1180.91 84.00 4200.00 2849.10 2565.34


PlanningPlanning

Calculate the MD, TVD and DEP Calculate the MD, TVD and DEP for the hold sectionfor the hold section

TVD rem = 9800 – 2000 – 1073.17TVD rem = 6726.83DEP rem = 2926 – 0 – 208.60DEP rem = 2717.40MD of the hold section


PlanningPlanning

IDEPMDsinΔ

=Δ

01.725422sin

40.2717==ΔMD


2000.002000.00 2000.002000.00 0.000.00

BuildBuild 1100.001100.00 1073.171073.17 208.60208.60


7254.017254.01 6726.836726.83 2717.402717.40



PlanningPlanning

Calculate the MD, TVD and DEP Calculate the MD, TVD and DEP of the hold to TDof the hold to TDThe TVD is 200.00 feet from 9800 The TVD is 200.00 feet from 9800 feet to 10,000 feetfeet to 10,000 feet

ITVDMD

cosΔ

=Δ

71.21522cos

200==ΔMD


PlanningPlanning

ITVDDEP tan×Δ=Δ

81.8022tan200 =×=ΔDEP


2000.002000.00 2000.002000.00 0.000.00

BuildBuild 1100.001100.00 1073.171073.17 208.60208.60


7254.017254.01 6726.836726.83 2717.402717.40

Hold to TDHold to TD 215.71215.71 200.00200.00 80.8180.81

TotalTotal 10,570.7210,570.72 10,000.0010,000.00 3006.813006.81


PlanningPlanning


PlanningPlanning

Class Problem Class Problem ––

Problem 1 on Problem 1 on page 4page 4--3939

Given the target data in Example 1Target TVD is 9800 feetTarget DEP is 2926 feetBuild rate is 2o/100’Hold inclination is 35o

Calculate the KOP


PlanningPlanning

SolutionSolutionDraw a picture to determine what information you have, what can be calculated and what is needed


PlanningPlanning

9800’

2926’

Inclination = 35º

ΔTVD of build section

ΔDEP of build section

ΔTVD of hold section

ΔDEP of hold section

Can calculate the change in TVD and DEP for the build curve


PlanningPlanning

Determine the ΔMD to get to 35° at a build rate of 2°/100 feet

rBIIMD 12 −=Δ

feet 1750100/2

035=

−=ΔMD


PlanningPlanning

( )( )( )( ) 18.1643

0350sin35sin1750180

=−

−=Δ

πTVD

( )( )( )12

21 coscos180II

IIMDDEP−

−Δ=Δ

π

( )( )( ) 09.518

03535cos0cos1750180

=−

−=Δ

πDEP

( )( )( )( )12

12 sinsin180II

IIMDTVD−

−Δ=Δ

π


PlanningPlanningBUILD RATE DEG/100 FEET = 2 RADIUS OF CURVATURE = 2864.79 FEET


10.00 500.00 497.47 43.52 40.00 2000.00 1841.45 670.23 70.00 3500.00 2692.02 1884.9711.00 550.00 546.63 52.63 41.00 2050.00 1879.47 702.71 71.00 3550.00 2708.71 1932.1012.00 600.00 595.62 62.60 42.00 2100.00 1916.92 735.84 72.00 3600.00 2724.58 1979.5213.00 650.00 644.44 73.42 43.00 2150.00 1953.78 769.61 73.00 3650.00 2739.61 2027.2114.00 700.00 693.06 85.10 44.00 2200.00 1990.05 804.03 74.00 3700.00 2753.81 2075.1515.00 750.00 741.46 97.62 45.00 2250.00 2025.71 839.08 75.00 3750.00 2767.17 2123.3316.00 800.00 789.64 110.98 46.00 2300.00 2060.76 874.74 76.00 3800.00 2779.69 2171.7317.00 850.00 837.58 125.18 47.00 2350.00 2095.17 911.01 77.00 3850.00 2791.36 2220.3518.00 900.00 885.27 140.21 48.00 2400.00 2128.95 947.87 78.00 3900.00 2802.19 2269.1719.00 950.00 932.68 156.08 49.00 2450.00 2162.08 985.32 79.00 3950.00 2812.15 2318.1620.00 1000.00 979.82 172.77 50.00 2500.00 2194.56 1023.34 80.00 4000.00 2821.27 2367.3221.00 1050.00 1026.65 190.28 51.00 2550.00 2226.36 1061.92 81.00 4050.00 2829.52 2416.6422.00 1100.00 1073.17 208.60 52.00 2600.00 2257.48 1101.05 82.00 4100.00 2836.91 2466.0923.00 1150.00 1119.36 227.74 53.00 2650.00 2287.92 1140.72 83.00 4150.00 2843.44 2515.6624.00 1200.00 1165.21 247.67 54.00 2700.00 2317.66 1180.91 84.00 4200.00 2849.10 2565.34


PlanningPlanning

You have the departure of the build section and total departure so you can calculate the departure of the hold sectionDEPhold = 2926 – 518.09 = 2407.91From the right triangle in the hold section, the TVD of the hold section can be calculated


PlanningPlanning

You have the departure of the build section and total departure so you can calculate the departure of the hold sectionDEPhold = 2926 – 518.09 = 2407.91From the right triangle in the hold section, the TVD of the hold section can be calculated

9800’

2926’

Inclination = 35º






PlanningPlanning

The kickoff point can be calculated from the target TVD less the hold TVD and the build TVDKOP = 9800 – 3438.85 – 1643.18KOP = 4717.97 feet

( )hold

hold

TVDDEPI =tan

( ) ( ) 85.343835tan

91.2407tan

===I

DEPTVD holdhold


PlanningPlanning

The kickoff point can be calculated from the target TVD less the hold TVD and the build TVDKOP = 9800 – 3438.85 – 1643.18KOP = 4717.97 feet

( )hold

hold

TVDDEPI =tan

( ) ( ) 85.343835tan

91.2407tan

===I

DEPTVD holdhold

9800’

2926’

Inclination = 35º






PlanningPlanning

There are many ways to drill a There are many ways to drill a directional welldirectional wellExample 4Example 4--2 (page 42 (page 4--13) shows 13) shows drilling the same directional well drilling the same directional well using a Type II directional well or using a Type II directional well or ““SS””

curvecurve


PlanningPlanning

Example 4Example 4--22KOP = 2000’Build rate = 2.5o/100’Drop rate = 1.5o/100’Target TVD = 9800’Target DEP = 2926’Total depth = 10,000’ TVD


PlanningPlanning

Determine Determine hold hold inclination inclination from the from the chartchartHold Hold inclination is inclination is 2424oo

24o


PlanningPlanning

Determine the MD, TVD and DEP Determine the MD, TVD and DEP


2000.002000.00 2000.002000.00 0.000.00

BuildBuild

Hold Hold

DropDrop

Vertical to TDVertical to TD


PlanningPlanning

Determine the Determine the MDMD, , TVDTVD and and DEPDEP for the build and drop sectionsfor the build and drop sectionsCan be calculated using the Can be calculated using the radius of curvature calculations radius of curvature calculations or can use the buildup chartsor can use the buildup chartsDropping from 24Dropping from 24oo

to 0to 0oo

will give will give

the same the same TVDTVD and and DEPDEP as as building from 0building from 0oo

to 24to 24oo


PlanningPlanningBUILD RATE DEG/100 FEET = 2.5 RADIUS OF CURVATURE = 2291.83 FEET


10.00 400.00 397.97 34.82 40.00 1600.00 1473.16 536.19 70.00 2800.00 2153.62 1507.9811.00 440.00 437.30 42.11 41.00 1640.00 1503.58 562.16 71.00 2840.00 2166.97 1545.6812.00 480.00 476.50 50.08 42.00 1680.00 1533.53 588.67 72.00 2880.00 2179.66 1583.6213.00 520.00 515.55 58.74 43.00 1720.00 1563.03 615.69 73.00 2920.00 2191.69 1621.7614.00 560.00 554.44 68.08 44.00 1760.00 1592.04 643.23 74.00 2960.00 2203.05 1660.1215.00 600.00 593.17 78.09 45.00 1800.00 1620.57 671.26 75.00 3000.00 2213.74 1698.6616.00 640.00 631.71 88.78 46.00 1840.00 1648.61 699.79 76.00 3040.00 2223.75 1737.3917.00 680.00 670.07 100.14 47.00 1880.00 1676.14 728.81 77.00 3080.00 2233.09 1776.2818.00 720.00 708.21 112.17 48.00 1920.00 1703.16 758.30 78.00 3120.00 2241.75 1815.3319.00 760.00 746.15 124.86 49.00 1960.00 1729.67 788.25 79.00 3160.00 2249.72 1854.5320.00 800.00 783.85 138.21 50.00 2000.00 1755.64 818.67 80.00 3200.00 2257.01 1893.8621.00 840.00 821.32 152.22 51.00 2040.00 1781.09 849.54 81.00 3240.00 2263.61 1933.3122.00 880.00 858.54 166.88 52.00 2080.00 1805.99 880.84 82.00 3280.00 2269.53 1972.8723.00 920.00 895.49 182.19 53.00 2120.00 1830.34 912.57 83.00 3320.00 2274.75 2012.5324.00 960.00 932.17 198.14 54.00 2160.00 1854.13 944.73 84.00 3360.00 2279.28 2052.27


PlanningPlanningBUILD RATE DEG/100 FEET = 1.5 RADIUS OF CURVATURE = 3819.72 FEET


10.00 666.67 663.29 58.03 40.00 2666.67 2455.27 893.64 70.00 4666.67 3589.36 2513.3011.00 733.33 728.84 70.18 41.00 2733.33 2505.96 936.94 71.00 4733.33 3611.61 2576.1412.00 800.00 794.16 83.47 42.00 2800.00 2555.89 981.11 72.00 4800.00 3632.77 2639.3613.00 866.67 859.25 97.90 43.00 2866.67 2605.04 1026.15 73.00 4866.67 3652.82 2702.9414.00 933.33 924.07 113.46 44.00 2933.33 2653.40 1072.04 74.00 4933.33 3671.75 2766.8615.00 1000.00 988.62 130.15 45.00 3000.00 2700.95 1118.77 75.00 5000.00 3689.56 2831.1016.00 1066.67 1052.86 147.97 46.00 3066.67 2747.68 1166.32 76.00 5066.67 3706.26 2895.6517.00 1133.33 1116.78 166.90 47.00 3133.33 2793.57 1214.68 77.00 5133.33 3721.82 2960.4718.00 1200.00 1180.36 186.95 48.00 3200.00 2838.60 1263.83 78.00 5200.00 3736.25 3025.5519.00 1266.67 1243.58 208.10 49.00 3266.67 2882.78 1313.76 79.00 5266.67 3749.54 3090.8820.00 1333.33 1306.42 230.36 50.00 3333.33 2926.07 1364.45 80.00 5333.33 3761.69 3156.4321.00 1400.00 1368.86 253.70 51.00 3400.00 2968.48 1415.89 81.00 5400.00 3772.69 3222.1822.00 1466.67 1430.89 278.14 52.00 3466.67 3009.98 1468.07 82.00 5466.67 3782.55 3288.1223.00 1533.33 1492.48 303.65 53.00 3533.33 3050.56 1520.95 83.00 5533.33 3791.25 3354.2124.00 1600.00 1553.62 330.23 54.00 3600.00 3090.22 1574.54 84.00 5600.00 3798.79 3420.45


PlanningPlanning

Build and drop sectionsBuild and drop sections


2000.002000.00 2000.002000.00 0.000.00

BuildBuild 960.00960.00 932.17932.17 198.14198.14Hold Hold

DropDrop 1600.001600.00 1553.621553.62 330.23330.23Vertical to TDVertical to TD


PlanningPlanning

Calculate the Calculate the TVDTVD and and DEPDEP of of the hold sectionthe hold section

TVD rem = 9800 – 2000 – 932.17 –1553.62 = 5314.21’DEP rem = 2926 – 198.14 – 330.23 = 2397.63’

Calculate the Calculate the MDMD of the hold of the hold sectionsection


PlanningPlanning

5.022 )( DEPTVDMD Δ+Δ=Δ

'05.5830)63.239721.5314( 5.022 =+=ΔMD


PlanningPlanning

The hold section can be entered The hold section can be entered into the tableinto the table


2000.002000.00 2000.002000.00 0.000.00

BuildBuild 960.00960.00 932.17932.17 198.14198.14Hold Hold 5830.055830.05 5314.215314.21 2397.632397.63DropDrop 1600.001600.00 1553.621553.62 330.23330.23Vertical to TDVertical to TD


PlanningPlanning

Add the vertical to total depthAdd the vertical to total depth


2000.002000.00 2000.002000.00 0.000.00

BuildBuild 960.00960.00 932.17932.17 198.14198.14Hold Hold 5830.055830.05 5314.215314.21 2397.632397.63DropDrop 1600.001600.00 1553.621553.62 330.23330.23Vertical to TDVertical to TD 200.00200.00 200.00200.00 0.000.00TotalTotal 10,590.0510,590.05 10,000.0010,000.00 2926.002926.00


PlanningPlanning


PlanningPlanning

The hold inclination can also be The hold inclination can also be calculated using trigonometrycalculated using trigonometryYou draw a picture of the well You draw a picture of the well and then solve for the angle of and then solve for the angle of inclination based on the inclination based on the trianglestriangles


PlanningPlanning

The well has a The well has a kickoff point of kickoff point of 20002000’’, a build rate , a build rate of 2of 2°°/100/100’’, and , and a a target of 9800target of 9800’’

TVD TVD

and 4060and 4060’’

DEPDEPCalculate the Calculate the inclination inclination II

2000’

9800’

I

I

Ar = 2864.79’

7800

’

B C

D

DEP = 4060’

Fayez

Text Box

r = 180 / Br * π


PlanningPlanning

Calculate the length Calculate the length of line BC from the of line BC from the DEP and the radius DEP and the radius of curvature of the of curvature of the buildbuild

2000’

9800’

I

I

Ar = 2864.79’

7800

’

B C

D

DEP = 4060’

'21.119579.28644060

=−=

BCBC


PlanningPlanning

Calculate angle A of Calculate angle A of triangle ABC where triangle ABC where B is a right angleB is a right angle

2000’

9800’

I

I

Ar = 2864.79’

7800

’

B C

D

DEP = 4060’

o71.8

780021.1195tan

tan

1

=

⎟⎠⎞

⎜⎝⎛=

=

−

A

A

ABBCA


PlanningPlanning

Calculate the length Calculate the length of side ACof side AC

2000’

9800’

I

I

Ar = 2864.79’

7800

’

B C

D

DEP = 4060’

( )04.789171.8cos

7800

cos

=

=

=

AC

AC

ACABA


PlanningPlanning

Calculate angle A of Calculate angle A of triangle ADC where triangle ADC where D is a right angleD is a right angle

2000’

9800’

I

I

Ar = 2864.79’

7800

’

B C

D

DEP = 4060’

o71.68

04.789179.2864cos

cos

1

=

⎟⎠⎞

⎜⎝⎛=

=

−

A

A

ACADA


PlanningPlanning

Calculate the angle Calculate the angle A of DABA of DAB

2000’

9800’

I

I

Ar = 2864.79’

7800

’

B C

D

DEP = 4060’

o0.60

71.871.68

=

−=

I

I


PlanningPlanning

Calculate the Calculate the inclination required inclination required to hit the targetto hit the target

2000’

9800’

I

I

Ar = 2864.79’

7800

’

B C

D

DEP = 4060’

o0.30

0.6090

=

−=

I

I


PlanningPlanning

The hold inclination can also be The hold inclination can also be calculated using a method calculated using a method developed by Wiggins, et. al. developed by Wiggins, et. al. called the single equationcalled the single equationSingle equation simplifies Single equation simplifies horizontal, directional planninghorizontal, directional planningHowever, a number of equations However, a number of equations must be solved before using the must be solved before using the single equationsingle equation


PlanningPlanning

The paper is still one of the The paper is still one of the simplest methods for calculating simplest methods for calculating the hold inclinationthe hold inclinationIt works for both a type I and It works for both a type I and type II welltype II wellIt even works for horizontal wells It even works for horizontal wells with a tangent sectionwith a tangent section


PlanningPlanning(4-1)

(4-2)

(4-3)

(4-4)

(4-5)

(4-6)

(4-7)

Single Equation

rBr

π180

1 =

rBr

π180

2 =

21 rrR +=

14 TVDTVDTVD −=

RDEPX −= 4

[ ] 2/1222 RXTVDL −+=

( ) ( )⎥⎦⎤

⎢⎣⎡

++

= −22

1sinLR

LXRTVDI


PlanningPlanning

NomenclatureNomenclaturer1

TVD1

I

TVD2

TVD4

DEP2

DEP3

DEP4

I

r2

I

TVD3

Tru

e V

ertic

al D

epth

Departure


PlanningPlanning

The equations can be used to The equations can be used to determine the hold inclination in determine the hold inclination in Example 4Example 4--3 (page 43 (page 4--24), which 24), which is the same problem as Example is the same problem as Example 44--11

TVD1 = KOP = 2000’TVD4 = Target TVD = 9800’DEP4 = Target DEP = 2926’


PlanningPlanning

Calculate Calculate rr11

and and rr22

Since there is no dropSince there is no drop

14eqn'79.2864)100/2(

1801801 −===

ππ rBr

24eqn02 −=r


PlanningPlanning

Calculate Calculate RR from equation 4from equation 4--33

Calculate Calculate TVDTVD from equation 4from equation 4--44

34eqn79.2864079.286421 −=+=+= rrR

44eqn78002000980014 −=−=−= TVDTVDTVD


PlanningPlanning

Calculate Calculate XX with equation 4with equation 4--55

Calculate Calculate LL with equation 4with equation 4--66

54eqn21.6179.286429264 −=−=−= RDEPX

[ ] [ ]12.7255

64eqn79.286421.617800 212222

1222

=−−+=−+=

LRXTVDL


PlanningPlanning

Calculate the hold angle with equation Calculate the hold angle with equation 44--77

The hold inclination needs to be 22The hold inclination needs to be 22oo

( ) ( )

[ ]o

1

221

221

0.22

3746.0sin12.725579.2864

)12.7255)(21.61()79.2864)(7800(sin

74eqnsin

=

=

⎥⎦⎤

⎢⎣⎡

++

=

−⎥⎦⎤

⎢⎣⎡

++

=

−

−

−

I

I

I

LRLXRTVDI


PlanningPlanning

Example 4Example 4--4 on page 44 on page 4--2525Given the same problem as Example 4-2 on page 4-13Calculate the hold angle with the “single equation” for the Type II well


PlanningPlanning


and and rr22

14eqn'83.2291)100/5.2(

1801801 −===

ππ rBr

24eqn'72.3819)100/5.1(

1801802 −===

ππ rBr


PlanningPlanning



55.611171.381983.229121 =+=+= rrR

78002000980014 =−=−= TVDTVDTVD


PlanningPlanning



55.318555.611129264 −=−=−= RDEPX

[ ][ ]

71.579955.6111)55.3185(7800 2

1222

21222

=−−+=

−+=

LL

RXTVDL


PlanningPlanning


( ) ( )

o

221

221

28.2407.579955.6111

)71.5799)(55.3185()55.6111)(7800(sin

sin

=

⎥⎦⎤

⎢⎣⎡

+−+

=

⎥⎦⎤

⎢⎣⎡

++

=

−

−

I

I

LRLXRTVDI


PlanningPlanning

Class Problem Class Problem ––

Problem 2 on page Problem 2 on page 44--3939

Target TVD = 2850 mTarget DEP = 800 mDrill an “S” curve or type II wellboreKOP = 626 mBuild rate = 1.5o/30 mDrop rate = 1.5o/30 mBe vertical at a TVD of 2850 m


PlanningPlanning

TVDTVD4 4 = 2850m= 2850mTVDTVD1 1 = 626m= 626mBuild = 1.5Build = 1.5ºº/30m/30mDrop = 1.5Drop = 1.5ºº/30m/30mDEPDEP4 4 = 800m= 800mII = 24.99= 24.99ºº

1.5/30m

626

I

TVD2

2850

DEP2

DEP3

800

I

1.5/30m

I

TVD3

Tru

e V

ertic

al D

epth

Departure

Find the hold Inclination


PlanningPlanning


and and rr22

m 92.1145)30/5.1(

1801801 ===

ππ rBr

m 92.1145)30/5.1(

1801802 ===

ππ rBr


PlanningPlanning



84.229192.114592.114521 =+=+= rrR

2224626285014 =−=−= TVDTVDTVD


PlanningPlanning



84.149184.22918004 −=−=−= RDEPX

[ ][ ]

36.138584.2291)84.1491(2224 2

1222

21222

=−−+=

−+=

LL

RXTVDL


PlanningPlanning


( ) ( )

( )o

1

221

221

99.24

4225.0sin36.138584.2291

)36.1385)(83.1491()84.2291)(2224(sin

sin

=

=

⎥⎦⎤

⎢⎣⎡

+−+

=

⎥⎦⎤

⎢⎣⎡

++

=

−

−

−

I

I

I

LRLXRTVDI


Horizontal PlanningHorizontal Planning

Planning a horizontal well is Planning a horizontal well is different from a normal different from a normal directional welldirectional wellIt takes more coordination It takes more coordination between disciplines within the between disciplines within the company and with service company and with service companiescompanies



Normal Directional WellNormal Directional WellTarget is defined by departure and TVDTarget has tolerances in the horizontal plane (North and East)Target may be plus or minus 100 feet or 30 meters



Horizontal WellHorizontal WellTarget is a TVD target and is usually more important than the DEP targetTarget tolerances are much smallerThe formation thickness can be anywhere from 3 feet (1 m) to more than 100 feet (30 m)It is harder to hit the target and takes greater care



Gather InformationGather InformationOffset well data such as bit records, mud logs, open hole logs, daily drilling reports, directional information, etc.There are few if any horizontal exploratory wells



First, Define the Reason for First, Define the Reason for Drilling the Horizontal WellDrilling the Horizontal Well

Prevent water or gas coningIntersect vertical fracturesIncreased reservoir exposure to increase productionAvoid vertical fractures to minimize water production, etc.



The reason for drilling the The reason for drilling the horizontal drives the completion horizontal drives the completion which drives the drillingwhich drives the drillingIf drilled to prevent water coning, If drilled to prevent water coning, the wellbore would be placed the wellbore would be placed near the top of the reservoir, etc.near the top of the reservoir, etc.



GeologyGeologyThe geology in a horizontal well is extremely importantTVD targets can be very small and bed dip can be a major considerationMost often geology can be more complicated than predicted



Planned Geology

Actual Geology

Resulted in a technical success and an economic failure



If the geology is not precisely known, the drilling engineer must allow for geologic interpretation while drillingWill probably require some geosteering tools


Horizontal PlanningHorizontal PlanningMay drill a pilot hole, log, plug back and sidetrackUsually better to drill pilot hole at some angle

GeologicalGeological

CorrelationCorrelation

GasGas

IdentificationIdentificationof Formation andof Formation andFluid InterfacesFluid Interfaces

WaterWater

OilOil

Optimized PlacementOptimized Placementof Completionof Completion



If the geologic data is If the geologic data is inadequate, the chances of a inadequate, the chances of a commercially viable horizontal commercially viable horizontal wellbore decreases significantlywellbore decreases significantly



Placement of Horizontal Within Placement of Horizontal Within the Zonethe Zone

Top for water coningBottom for gas coningTraverse for natural fractures or in a portion more highly fractured



The well may be drilled from top The well may be drilled from top to bottom to counteract vertical to bottom to counteract vertical permeability barrierspermeability barriers

Shale

Shale

Fractured Reservoir



Placement of Horizontal Within Placement of Horizontal Within the Zonethe Zone

Fracture orientation determines direction of horizontalMay be placed in a portion of the reservoir not swept by a water flood



Completion requirementsCompletion requirementsOpen hole, slotted liner, screen, gravel pack, cased and cemented, slotted liner and ECP’s.Hole size requirementsFlowing well, gas lift, submersible pump, rod pump, hydraulic pump, PCP pump



Contingency for future problems with water or gas coningDoes the build curve need to be cased and cementedSidetracking existing well or drilling a new well



Determining build rateDetermining build rateNew well or sidetrack existing wellLess directional drilling costs less money (higher build rates to a point)Steerable versus non-steerable (hitting the target)Hole size



Fluid level and pumping methodGenerally you pick either the build rate or the kick off point and calculate the otherMost of the time, the build rate is selected and the kick off point is calculatedThe final inclination is determined by the bed dip



Build rate accuracy of directional Build rate accuracy of directional equipmentequipment

Generally not greater than plus or minus 10%, may be worse in some areasHave to plan for possible deviation from predicted versus actual performance



DEPARTURE

TVD

500.00

550.00

600.00

650.00

700.00

750.00

800.000.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00 900.00

20 /100' 8 /100'

10%

-10%

10%

-10%

o o



Plan tangent section−

Short section in build curve planned to be straight

−

Requires multiple trips unless build rate is low enough to use steerable

Fractional orientation−

Kick off higher than required and kill some build rate by rotating the motor for a short distance several times

−

Must be steerable to an extent



Tangent Section Inclusive

Fractional Orientation

Smooth Arc



Drill with a steerable system−

Can adjust build rate by sliding and rotating but the build rate is limited

Can also wag the motor−

Orient left and right of high side to kill some of the build rate

−

More dogleg severity in the build section−

Difficult to predict the results



Soft landing−

Plan for a lower build rate in the last ~20 degrees of build and run a steerable motor in that section

Soft LandingSoft Landing

++

++rr11

rr22



Horizontal planning requires Horizontal planning requires input from:input from:

GeologyDrillingReservoirProductionService companies



FAILING TO PLAN IS PLANNING FAILING TO PLAN IS PLANNING TO FAILTO FAIL



Example 4Example 4--5 (page 45 (page 4--33) shows 33) shows how to calculate the kickoff point how to calculate the kickoff point for a horizontal well with a for a horizontal well with a planned tangent sectionplanned tangent section

Target TVD = 4800 feetBuild rate = 12o/100 feetTangent section at 60o

Tangent section length = 50’ TVD





Calculate the TVD required in the Calculate the TVD required in the first build section to 60first build section to 60oo

( )( )( )12

12 sinsin180II

IIMDTVD−

−Δ=Δ

π

( )( )( ) feet 50.413

0600sin60sin500180

=−

−=Δ

πTVD

feet 500100/12

06012 =−

=−

=ΔrBIIMD



Calculate the TVD required in the Calculate the TVD required in the second build section from 60second build section from 60oo

to to

9090oo

( )( )( ) feet 97.63

609060sin90sin250180

=−

−=Δ

πTVD

feet 250100/12609012 =

−=

−=Δ

rBIIMD



The TVD of the tangent section is The TVD of the tangent section is 50 feet50 feetCalculate the KOPCalculate the KOP

KOP = 4800 – 413.50 – 50 – 63.97KOP = 4272.53 feet



Seldom is the bed dip 0Seldom is the bed dip 0oo

making making the calculation of the kickoff the calculation of the kickoff point more complicatedpoint more complicatedExample 4Example 4--6 (page 46 (page 4--34) shows 34) shows how to calculate a KOP when the how to calculate a KOP when the bed dips at 5bed dips at 5oo



Apparent bed dip is 5o (drilling down dip)Build rate = 14o/100 feetBed thickness = 50 feetTVD of the target below the surface location is 4000 feetWant to drill from the top of the producing formation at the beginning of the horizontal to the bottom at the end of the horizontal



Vertical Section, feet

Tru

e V

ertic

al D

epth

, fee

t

Kick off point

4000 feetFormation Top

B

C

AD

EIncreased TVD

to Target

Difference between beddip and wellbore angle

Want to drill from the top of the formation to the bottom of the formation in 2,000 feet of horizontal section



Calculate angle A in triangle ABCCalculate angle A in triangle ABC

The inclination of the horizontal The inclination of the horizontal would be 90would be 90oo

minus the bed dip minus the bed dip

minus the angle Aminus the angle AI = 90 – 5 – 1.43 = 83.57o

⎟⎠⎞

⎜⎝⎛= −

ACBCA 1sin

o43.1200050sin 1 =⎟

⎠⎞

⎜⎝⎛= −A



Vertical Section, feet

Tru

e V

ertic

al D

epth

, fee

t

Kick off point

4000 feetFormation Top

B

C

AD

EIncreased TVD

to Target

Difference between beddip and wellbore angle



Calculate the DEP to reach the Calculate the DEP to reach the horizontal inclination of 83.57horizontal inclination of 83.57oo

( )( )( )12

21 coscos180II

IIMDDEP−

−Δ=Δ

π

( )( )( ) feet 42.363

057.8357.83cos0cos93.596180

=−−

=Δπ

DEP

feet 93.596100/14

057.8312 =−

=−

=ΔrBIIMD



Calculate the length of side DE in Calculate the length of side DE in triangle ADEtriangle ADE

The formation will be The formation will be encountered 31.80 feet deeper at encountered 31.80 feet deeper at a a DEPDEP of 363.42 feetof 363.42 feet

AEDEA =tan

AEADE ×= tan

( ) feet 80.3142.3635tan =×=DE



Calculate the TVD for the build Calculate the TVD for the build curvecurve

( )( )( )12

12 sinsin180II

IIMDTVD−

−Δ=Δ

π

( )( )( ) feet 68.406

057.830sin57.83sin93.596180

=−

−=Δ

πTVD



Calculate the kickoff pointCalculate the kickoff pointKOP = 4000 + 31.80 – 406.68KOP = 3625.12 feet



Class problem Class problem ––

Problem 3 on Problem 3 on page 4page 4--3939

Same as example 4-6 but drilling up dip instead of down dipWhat is the hold inclination of the horizontal and the kickoff point



4000 ft

A

B

CD

E

KOP 3553.50’

1.43o

Angle of Horiz. = 93.57o

ΔDEP=434.74’DE=38.04’

ΔTVD= 408.46’



Calculate angle A in triangle ABCCalculate angle A in triangle ABC

The inclination of the horizontal The inclination of the horizontal would be 90would be 90oo

plus the bed dip plus the bed dip

minus the angle Aminus the angle AI = 90 + 5 – 1.43 = 93.57o

⎟⎠⎞

⎜⎝⎛= −

ACBCA 1sin

o43.1200050sin 1 =⎟

⎠⎞

⎜⎝⎛= −A



Calculate the Calculate the DEPDEP to reach the to reach the horizontal inclination of 93.57horizontal inclination of 93.57oo

( )( )( )12

21 coscos180II

IIMDDEP−

−Δ=Δ

π

( )( )( ) feet 74.434

057.9357.93cos0cos36.668180

=−−

=Δπ

DEP

feet 36.668100/14

057.9312 =−

=−

=ΔrBIIMD



4000 ft

A

B

CD

E



Calculate the length of side DE in Calculate the length of side DE in triangle ADEtriangle ADE

The formation will be The formation will be encountered 38.04 feet shallower encountered 38.04 feet shallower at a at a DEPDEP of 434.74 feetof 434.74 feet

ADDEA =tan

ADADE ×= tan

( ) feet 04.3874.4345tan =×=DE



Calculate the TVD for the build Calculate the TVD for the build curvecurve

( )( )( )12

12 sinsin180II

IIMDTVD−

−Δ=Δ

π

( )( )( ) feet 46.408

057.930sin57.93sin36.668180

=−

−=Δ

πTVD



Calculate the kickoff pointCalculate the kickoff pointKOP = 4000 – 38.04 – 408.46KOP = 3553.50 feet


GeosteeringGeosteering

Geosteering is the drilling of a Geosteering is the drilling of a horizontal, or other deviated horizontal, or other deviated well, where decisions on well well, where decisions on well path adjustment are made based path adjustment are made based on real time geologic and on real time geologic and reservoir datareservoir data



Geosteering is required when the Geosteering is required when the marker is ill defined, target marker is ill defined, target tolerances are tight or geology tolerances are tight or geology so complicated that as to make so complicated that as to make conventional directional drilling conventional directional drilling impractical (geometric steering)impractical (geometric steering)



Geosteering methodsGeosteering methodsDrilling rateSamplesLWD (Logging While Drilling)−

Gamma ray−

Resistivity−

Density –

Neutron−

Sonic



Because of the inaccuracy of Because of the inaccuracy of directional surveys and geology, directional surveys and geology, it may not be possible to it may not be possible to establish a horizontal wellbore establish a horizontal wellbore within the pay zone in small within the pay zone in small targets (geometric steering)targets (geometric steering)Geosteering is required in order Geosteering is required in order to accomplish the taskto accomplish the task



Geologic Geologic markers can be markers can be used to used to establish the establish the wellbore within wellbore within the pay zone if a the pay zone if a consistent consistent geologic marker geologic marker existsexists

Reservoir

Geologic Marker



Penetration rate may indicate Penetration rate may indicate geologic markersgeologic markersSamples can be used to Samples can be used to determine the depth of geologic determine the depth of geologic markers though it is not markers though it is not extremely accurateextremely accurateLWD data can be used to LWD data can be used to determine geologic markersdetermine geologic markers



Typical layout of Typical layout of LWD tools within LWD tools within the directional the directional bottomhole bottomhole assemblyassemblyEvery well does not Every well does not require all of these require all of these toolstools

Neutron

Density

DirectionMeasurements

GR

Resistivity

InclinationGRButton Resistivity

Resistivity at BitFeet from Bit

0 ft

20 ft

40 ft

60 ft

80 ft

100 ft

120 ftNeutron

Density

DirectionMeasurements

GR

Resistivity

InclinationGRButton Resistivity

Resistivity at BitFeet from Bit

0 ft

20 ft

40 ft

60 ft

80 ft

100 ft

120 ft



Deep resistivity Deep resistivity can be used to can be used to detect bed detect bed boundariesboundaries

aa

Inductive

ResistivityInductive AttenuationAttenuationResistivity

AzimuthalResistivity Near-Bit

Electrical Resistivity

Non-Pay

Drilling Distance to Contact

Propagation

aa

Inductive




Non-Pay


Propagation

aa

Inductive




Non-Pay


Propagation



Once the well is Once the well is within the within the reservoir, it reservoir, it must be kept in must be kept in the reservoirthe reservoirLWD such as GR LWD such as GR and resistivityand resistivity

Top Reservoir

Base Reservoir



Azimuthal Azimuthal resistivity and resistivity and GR can be used GR can be used to determine if to determine if the wellbore is the wellbore is close to the top close to the top or bottom of the or bottom of the formationformation



Sometimes it is Sometimes it is desirable to desirable to remain a fixed remain a fixed distance above distance above the oil/water the oil/water contactcontactResistivity toolResistivity tool

Top Reservoir

Oil

Water



Drilling fault Drilling fault blocksblocksMust recognize Must recognize when a fault is when a fault is encountered encountered and reestablish and reestablish the wellbore the wellbore within the pay within the pay zonezone

Geologic Faults


GeosteeringGeosteeringOnce the wellbore Once the wellbore has exited a pay has exited a pay zone, it takes time zone, it takes time to get the wellbore to get the wellbore back in the zoneback in the zoneIt depends upon It depends upon the angle leaving the angle leaving the zone, the DLS the zone, the DLS of the motor, and of the motor, and the distance of the the distance of the sensor from the bitsensor from the bit

ba

c

d

f g

e

a) Angle of Incidenceb) Bit-to-Sensor Detection Distancec) Decision Reaction Distanced) Correction Curve Ratee) Hold Distance to Re-entryf) Anticipated Changes in Structureg) Curve Distance to Recovery

Recovery Parameters

250

200

150

100

50

01 2 3 4 5 6

Bad Exit Angle of Incidence, deg

Dis

tanc

e to

Re-

entr

y, ft

b = 50 ft bit

b = 50 ft bit--sens d=4

sens d=4°°/100 ft

/100 ft

b = 50 ft bit-sens d=6°°/100 ft

b = 50 ft bit-sens d=4°°/1

00 ft


ba

c

d

f g

e


Recovery Parameters

250

200

150

100

50

01 2 3 4 5 6


Dis

tanc

e to

Re-

entr

y, ft

b = 50 ft bit


sens d=4°°/100 ft

/100 ft



00 ft


ba

c

d

f g

e


Recovery Parameters

250

200

150

100

50

01 2 3 4 5 6


Dis

tanc

e to

Re-

entr

y, ft

b = 50 ft bit


sens d=4°°/100 ft

/100 ft



00 ft




If you want to use LWD, three If you want to use LWD, three groups need to work togethergroups need to work together

DrillingGeology The MWD vendor


PlanningPlanning


PlanningPlanning


PlanningPlanning


PlanningPlanning


PlanningPlanning

Directional Well Planning Directional Well Planning

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