Designing Technology Of Branch Well For Buried Hill Type Formation

Buried hill type reservoir is a type of inhomogeneous fractured reservoir controlled by the buried hill, the geological reserve of which is very rich, in Biantai of Liaohe Oilfield. Owing to the immature fractures and low formation pressure coefficient, deliverability of a common well is low and the declining rate is fast, but the deliverability can be improved efficiently by using a technology of branch well. Technology of branch well is a kind of new technology for drilling developed on the basis of the technologies of orientation well, high angle deviated well and horizontal well, and it is regarded as one of the most significant and innovative technologies that can improve the economic benefit of oil or gas well.Based on the studies on technologies and applications of branch well home and abroad, the problems existing in the technologies for branch well in Liaohe Oilfield and the corresponding ones which are need to solve are pointed out in this paper, including the designing of branch well path, path control and well completion.Therefore, in this paper, in order to solve the problems mentioned above, the principles, methods and procedures of designing of branch well path for buried hill type formation are presented; the methods of choosing branch well window for buried hill type formation are given; the methods of designing of string makeup and evaluation of that for buried hill type formation are given; the methods of path control for branch well window for buried hill type formation are given; the principles of designing of branch well completion and the methods of designing of completion string are given.The presented designing technology is applied to the Biantai-H3Z well, a dual branch fishbone horizontal well in Biantai buried hill type reservoir of Liaohe Oilfield, so that it can further enrich and perfect the theoretical research on the designing technology of branch well, and provide a technical support for popularizing and the application of branch well in buried hill type formation in Liaohe Oilfield.