A new calculation method of well trajectory of joint control

Well trajectory control is the basic operation task of directional well engineers, and in the past, the control parameters were often estimated according to experience. In this paper, a mathematic model was established based on the constant tool face angle curve for the “combined+sliding” drilling process of joint. Then, two algorithms to solve this mathematical model were provided according to the concept of optimization, and the optimal design scheme of construction parameters was worked out. Finally, the algorithms were verified sufficiently by using the theoretical model data. It is indicated that the algorithms can inversely calculate the theoretical model parameters with quite high numerical accuracy (10⁻⁹). And as for the actual drilling data, the accuracy is 10⁻², which meets the accuracy requirement of the engineering. This method can be used by the on-site directional well engineers to perform daily design of control parameters. And combined with the real-time acquisition of MWD data, its application prospect in the real-time drilling feedback control of electric control system is extensive.