Borehole positioning method based on earth ellipse sphere

Abstract

The invention discloses a borehole positioning method based on the earth ellipse sphere. The borehole positioning method comprises obtaining the geodetic coordinates of the wellhead and the target point; determining the north-seeking standard and the wellhead coordinate system; calculating the geocentric coordinates of the wellhead and the target point; calculating the target point coordinate in the wellhead coordinate system; and designing the borehole trajectory. Because the influence of the curve of the earth ellipsoid surface is considered, and map projection and projection transformation problems are not involved, errors caused by map projection deformation and concomitant various error risks are eliminated, and therefore the precision and the reliability of borehole positioning and borehole trajectory designing can be substantially improved.

Description

technical field [0001] The invention relates to the technical field of oil and gas drilling, in particular to a wellbore positioning method based on an earth ellipsoid. Background technique [0002] Drilling engineers often use the wellhead coordinate system to design, monitor and control the wellbore trajectory, while geoscientists use the geodetic coordinate system to describe the earth structure and reservoir distribution. To adapt and meet the needs of oil and gas exploration and development, the problem of wellbore positioning must be solved first. [0003] The prior art is based on the principle of map projection to locate the wellbore, and design the wellbore trajectory according to the map projection coordinates of the wellhead and the target point, and the north direction is the coordinate north of the map projection plane. Because it involves map projection and projection transformation, there are some inherent defects, mainly as follows: [0004] (1) Coordinate ...

AI Technical Summary

Problems solved by technology

However, in actual work, this coordinate system conversion problem is often ignored and calculations such as wellbore anti-collision are performed directly, resulting in inaccurate calculation results

[0007] (2) Map projection problem

[0009] (3) The curvature of the earth ellipsoid

However, due to the lack of information such as the geodetic coordinates of the borehole trajectory, it does not directly represent the progress of the borehole trajectory in the formation, so it is not convenient for geosteering drilling

[0013] Therefore, the existing technology has defects such as map projection deformation and ellipsoidal curvature, which brings large errors and seriously affects the accuracy of borehole positioning and borehole trajectory design.

Images