Design and Practice of Gas Drilling in Non-target Zone Section of Well Gushen-3

Abstract:

Well Gushen-3 is a risk wildcat well in Gulong faulted zone of the rift area in the western part of Songliao basin, the target layer is Yingcheng group. The gas drilling was used in the non-target zone section of 3180～4460 m, that was Quantou formation～Denglouku formation, the total footage was 1208.72 m. By the effluent prediction and according to the features of gas drilling, optimizations were made to well structure design, BHA design, bits and parameters as well as gas injection rate; drilling by gas-liquid conversion, the mechanical drilling speed reached 6.36 m/h, which was 4.54 times increasing than the adjacent well Gushen 1 (average ROP of 1.40 m/h); and the drilling cycle was shortened 43.56 days. The new records of gas drilling were created that footage and service life reached 674.87 m and 101.88 h with a single bit.