Drilling Engineering

1
Drilling Engineering
Directional Drilling
2
Directional Drilling
I
II
III

• When is it used?
• Type I Wells
• Type II Wells
• Type III Wells
• Directional Well Planning Design
• Survey Calculation Methods

3
Inclination Angle q, a, I
Direction Angle f, e, A
4
(No Transcript)
5
Max. Horiz. Depart. ?
6
(No Transcript)
7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
Type I
Type II
Type III
12
r
I
DL
Dy
r
I
Dx
13
(No Transcript)
14
Fig. 8.11
15
3D Wells
16
N18E
S23E

• Azimuth
• Angle

N55W
S20W
17
(No Transcript)
18
Example 1 Design of Directional Well

• Design a directional well with the following
  restrictions
• Total horizontal departure 4,500 ft
• True vertical depth (TVD) 12,500 ft
• Depth to kickoff point (KOP) 2,500 ft
• Rate of build of hole angle 1.5 deg/100
  ft
• Type I well (build and hold)

19
Example 1 Design of Directional Well

• (i) Determine the maximum hole angle
  required.
• (ii) What is the total measured depth (MD)?
• (MD well depth measured along the
  wellbore,
• not the vertical depth)

20
(i) Maximum Inclination Angle
21
(i) Maximum Inclination Angle
22
(ii) Measured Depth of Well
23
(ii) Measured Depth of Well
24

• The actual well path hardly ever coincides with
  the planned trajectory
• Important Hit target within specified radius

25
What is known? I1 , I2 , A1 , A2 , DL DMD1-2
Calculate b dogleg angle DLS b100/DL
26
(No Transcript)
27
(20)
28
Wellbore Surveying Methods

• Average Angle
• Balanced Tangential
• Minimum Curvature
• Radius of Curvature
• Tangential
• Other Topics
• Kicking off from Vertical
• Controlling Hole Angle

29
I, A, DMD
30
Example - Wellbore Survey Calculations

• The table below gives data from a directional
  survey.
• Survey Point Measured Depth Inclination
  Azimuth along the wellbore
  Angle Angle
• ft I, deg A, deg
• A 3,000 0 20
• B 3,200 6 6
• C 3,600 14 20
• D 4,000 24 80
• Based on known coordinates for point C well
  calculate the coordinates of point D using the
  above information.

31
Example - Wellbore Survey Calculations

• Point C has coordinates
• x 1,000 (ft) positive towards the east
• y 1,000 (ft) positive towards the north
• z 3,500 (ft) TVD, positive downwards

C
C
N (y)
N
Z
Dz
D
D
Dy
Dx
E (x)
32
Example - Wellbore Survey Calculations

• I. Calculate the x, y, and z coordinates of
  points D using
• (i) The Average Angle method
• (ii) The Balanced Tangential method
• (iii) The Minimum Curvature method
• (iv) The Radius of Curvature method
• (v) The Tangential method

33
The Average Angle Method

• Find the coordinates of point D using the
  Average Angle Method
• At point C, X 1,000 ft
• Y 1,000 ft
• Z 3,500 ft

34
The Average Angle Method
C
N (y)
C
Z
D
N
z
D
y
E (x)
x
35
The Average Angle Method
36
The Average Angle Method
This method utilizes the average of I1 and I2 as
an inclination, the average of A1 and A2 as a
direction, and assumes all of the survey interval
(DMD) to be tangent to the average angle.
From API Bulletin D20. Dec. 31, 1985
37
The Average Angle Method
38
The Average Angle Method
39
The Average Angle Method

• At Point D,
• X 1,000 99.76 1,099.76 ft
• Y 1,000 83.71 1,083.71 ft
• Z 3,500 378.21 3,878.21 ft

40
The Balanced Tangential Method
This method treats half the measured distance
(DMD/2) as being tangent to I1 and A1 and the
remainder of the measured distance (DMD/2) as
being tangent to I2 and A2.
From API Bulletin D20. Dec. 31, 1985
41
The Balanced Tangential Method
42
The Balanced Tangential Method
43
The Balanced Tangential Method
44
The Balanced Tangential Method

• At Point D,
• X 1,000 96.66 1,096.66 ft
• Y 1,000 59.59 1,059.59 ft
• Z 3,500 376.77 3,876.77 ft

45
Minimum Curvature Method
b
46
Minimum Curvature Method
This method smooths the two straight-line
segments of the Balanced Tangential Method using
the Ratio Factor RF. RF (2/DL) tan(DL/2)
(DL b and must be in radians)
47
Minimum Curvature Method

• The dogleg angle, b , is given by

48
Minimum Curvature Method

• The Ratio Factor,

2
49
Minimum Curvature Method
50
Minimum Curvature Method

• At Point D,
• X 1,000 97.72 1,097.72 ft
• Y 1,000 60.25 1,060.25 ft
• Z 3,500 380.91 3,888.91 ft

51
The Radius of Curvature Method
52
The Radius of Curvature Method
53
The Radius of Curvature Method
54
The Radius of Curvature Method

• At Point D,
• X 1,000 95.14 1,095.14 ft
• Y 1,000 79.83 1,079.83 ft
• Z 3,500 377.73 3,877.73 ft

55
The Tangential Method
56
The Tangential Method
57
The Tangential Method
58
Summary of Results (to the nearest ft)

• X Y Z
• Average Angle 1,100 1,084
  3,878
• Balanced Tangential 1,097 1,060 3,877
• Minimum Curvature 1,098 1,060 3,881
• Radius of Curvature 1,095 1,080 3,878
  
• Tangential Method 1,160 1,028 3,865
  

59
(No Transcript)
60
(No Transcript)
61
Building Hole Angle
62
Holding Hole Angle
63
(No Transcript)
64
CLOSURE
(HORIZONTAL) DEPARTURE
LEAD ANGLE
65
b
66
Tool Face Angle