New Trajectory Control Directional MWD Accuracy Prediction and Wellbore Positioning Method

Yao Aigou,Tagwa Ahmed Musa,Ahmed Abd Elaziz Ibrahim,Tang Fenglin

doi:10.3844/ajassp.2005.711.718

Abstract

The deviation control is to restrict the drilling direction of the bit from time to time. The drilling direction is of course depending on the direction of the resultant forces acting on the bit. What is the relationship between these directions? Are there any other influential factors? Answers to such questions, different points of view were subjected to analysis.

Highlights

In the rectangular coordinate system shown in Fig. l, the side forces RP and RQ are acting along X-axis and Y-axis respectively
It is clear that the drilling direction would not be the same as that of the resultant force and the magnitudes of planned/actual path depends on many influential factors, such as rock properties, formation characteristics, types of bit, etc
Hole Deviation Mathematical Definition: The wellbore trajectory is defined as a series of surveyed points in 3D space

Summary

INTRODUCTION

In the rectangular coordinate system shown in Fig. l, the side forces RP and RQ are acting along X-axis and Y-axis respectively. (TVD*), Inclination (I*) and azimuth (A*), respectively, planned values North, East, True Vertical Depth, Inclination and Azimuth These points are jointed together to form a continuous trajectory with a geometric calculations method. Hole Deviation Mathematical Definition: The wellbore trajectory is defined as a series of surveyed points in 3D space These points along the planned path are called the Measured Depth (MD*), associated with MD* is north (N*), east (E*), Total Vertical Depth. The aforementioned vector is orthogonal to the planned path at MD*, the required TVD” equals zero; i.e. Respective to hole deviation, a preferable method by which to American J. Applied Sci., 2 (3): 711-718, 2005 mathematically represent the entire planned drill path is to parametrically define each Cartesian coordinate and hole inclination and azimuth, in terms of measured depth.

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RESULTS AND CONCLUSION

Key to calculation options