Design method of three dimensional horizontal well pilot rail

The invention relates to a design method of three dimensional horizontal well pilot rail, belonging to the technical field of oil and gas well drilling. The method comprises the following steps: firstly, determining coordinates and vertical depths of a target spot A, a target spot B and a pilot target spot based on geological logging data and geophysical logging data, and sequentially determining a horizontal section well deviation azimuth angle and south-north coordinates and east-west coordinates of the pilot target spot; then calculating a pilot target spot well deviation angle based on the pilot rail parameter and the pilot target spot parameter, and determining other parameters required by the pilot rail; finally, achieving the design of the three dimensional horizontal well pilot rail based on the determined pilot rail parameter. The design method of three dimensional horizontal well pilot rail completely utilizes the main hole section to achieve the quantified design of the pilot rail, thereby avoiding wastage of footage, and providing convenience for on-site well drilling and oriented construction, reducing the cost of the drilling project.