Efficient drilling technologies for the igneous reservoir in Block P of the Junggar Basin

Block P in the Junggar Basin is an igneous reservoir and its drilling process faces many technical difficulties, such as low rate of penetration (ROP), poor well stability and difficult well deviation control, which restrict the drilling speed seriously. In this paper, the drilling technological difficulties were analyzed and then a series of drilling technologies were researched, including casing program optimization, efficient rock breaking bit selection, design of angle holding BHA in horizontal section, drilling fluid system optimization, cementing and completion technology optimization, and specific “leakage and overflow” treatment. In addition, a new drilling concept of “no plugging to leakage and no kicking to overflow” was put forward according to the characteristics of this block. Thus, the ROP and efficiency are improved. The field application shows that the average drilling cycle drops to 13.3 d, and average ROP in the Carboniferous reaches 12-16 m/h, so as to realize the efficient drilling in igneous reservoirs. The research results can provide theoretical guidance for the efficient drilling in igneous strata.