Research On Three Dimensional Detouring Obstacle Directional Well Trajectory Design Theory

Three dimensional directional well is the directional well, which borehole axis is not below to any vertical plane in space. The borehole axis could be in three dimensional spaces or in deviated plane. 3D directional well have the changes of both deviation and azimuth. There is the need to make detouring obstacle trajectory design if there are such obstacles as existing wells, complex formations etc which could not be crossed over in the vertical plane containing well head and target.The 3D detouring obstacle directional well trajectory design model and equations are mainly studied in this paper. To build up the obstacle model, the definition of feasible region, obstacle range and feasible range is given out to determine which existing neighbor well and which section of the well block the design. After that the design model in horizontal projection plane and vertical section plane is proposed based on the obstacle model, which also lead to the complete detouring obstacle well trajectory design model and equations. Besides that the design while drilling is also analyzed in this paper and the design while drilling models are proposed.The double plane detouring obstacle well trajectory design model proposed in this paper divides the three dimensional design to horizontal projection and vertical section designs which detours obstacles with deviation and azimuth change. Combining the horizontal projection and vertical section designs, the whole well trajectory design model and equations are proposed.The problem how to adjust the detouring obstacle design is also analyzed in this paper. Concerning with the two situations that well trajectory approaches neighbor well or far away from neighbor well, the detailed computation models and equations are introduced in this paper.