The engineering design and economic evaluation of CBM cluster wells in fanzhuang block

Qinshui Basin in Shanxi province is the most active CBM (Coalbed Mathane) development area in China. Due to the complicated surface conditions, it is difficult to construct drilling site. Therefore, given the cost and the area covered, we decide to adopt cluster wells. This paper describes the characteristics, applicability, well pattern arrangement of cluster wells and its optimum design of well trajectory, including the well pattern arrangements of four, five and nine well-composition cluster wells and the comparison of optimum designs of well trajectory between four and nine well-composition cluster wells based on well TL-004. The results suggest that it is reasonable to apply four well-composition cluster wells. In addition, the paper also introduces the drilling technologies, like BHA design, drilling fluid design and cementing technology. Meanwhile it carries on economic evaluation for vertical wells, four and nine well-composition cluster wells, and finally considers four well-composition cluster wells to be the most economical technique.