Research And Implementation On Wellbore Trajectory Design

Horizontal wells, the main special wells, is an application technology with bright prospects for development, is promoted rapidly in oil and gas development field and has become a major hot spot in oil industry of exploration and development. Horizontal wells has abilities of increasing well production, reducing operating costs and significantly increasing comprehensive benefits of oil and gas exploration and development. The application of horizontal well technology has brought tremendous benefits to oil field exploitation, and also a new concept to the development and design.This paper discusses the mathematical models of two-dimensional well trajectory design, three-dimensional by-passing-obstructions well trajectory design and three-dimensional drift well trajectory design, calculation formula and algorithm steps. The solving problem of three-dimensional drift well trajectory design model is mainly discussed. The constraint equations of three-dimensional drift well trajectory are nonlinear. The general iteration method is often diffuse, so it is hard to solve the constraint equations. In this paper, the convergence is ensured in the solution process through improving iterative formulas.When optimized problems of wellbore trajectory are studied, the nonlinear programming method under nonlinear constraints to well trajectory design is introduced. Nonlinear optimization mathematical model of two-dimensional horizontal wells trajectory design is established. An optimization method for well trajectory design while drilling is given. The method can not only satisfy the oilfield construction condition and the well trajectory design while drilling, but also assure the designed well trajectory to be the most slip, the shortest and possible optimized well trajectory.Finally, several calculation methods of directional well trajectory are summarized. Trajectory design program is worked out, which can be used easily and calculated quickly and precisely. This can design a feasible well trajectory by adjusting the parameters and can be used as an assistant tool in studying optimized design methods of well trajectory.