DRILLING - DIRECTIONAL SURVEY

Wellbore Trajectory (3D)

INPUT   DATA ♥ EXAMPLE Of Input/Output

Title  

Station   Measured   Inclination   Azimuth   True vertical   X-location   Y-location  
# depth (ft) angle (°) angle (°) depth (ft) (ft)(ft)
1
2
3
4
5
6
7
8
9
10  
11
12
13
14
15
16
17
18
19
20
Target

     Reset

OUTPUT   VARIABLES   &   GRAPHS

Station Measured Inclination Azimuth   True vertical X-location Y-location
# depth (ft) angle (°) angle (°) depth (ft) (ft)(ft)
1
2
3
:
:
19
20
THEORY  &   FORMULAE

Wellbore Trajectory (3D)

The immediate objective of a directional survey of a well is to determine the X-Y-Z coordinates of a series of measuring points (stations) along the wellbore based on three things that are known at these points:

  - the location of the first point P0 at surface or tie-in point
  - the measured distance between any two points along the wellbore
  - the wellbore direction (Inclination and Azimuth) at each point

The Inclination angle (φ) is the angle with respect to the vertical (0 to 89.5°), and the Azimuth bearing (θ) is the angle in the horizontal plane in a clockwise sense with respect to the North (0 to 359.5°).

The convention followed here is that the Z-direction points vertically downwards, and the the Z-distance gives the True vertical depth. The X-direction aligns with the magnetic North and Y-direction points to the East.

Thus, given:
  i) the point P0 = (X0,Y0,Z0)
  ii) the distance, S1 between P0 and P1
  iii) the well direction determined by inclination φ0 and azimuth θ0 at P0, and similarly by φ1 and θ1 at P1,
Find P1 = (X1,Y1,Z1).

The most widely-used and an accurate method for computing these coordinates is the Minimum Curvature Method. According to this method, the solution of the problem is as follows:

    

BIBLIOGRAPHY