Key Technologies for Drilling and Completing Horizontal Wells with Ultra-Long Horizontal Sections in the Sulige Tight Gas Reservoirs

The drilling and completion of horizontal wells with ultra-long horizontal sections in the tight gas reservoirs of Sulige Gas Field is subject to problems such as high circulating pump pressure, large friction torque, low rates of penetration (ROP), difficult borehole cleaning, and difficulties in running the completion casing string. In response, the technical difficulties in the drilling and completion of such wells were analyzed. Research was conducted on technologies such as optimized allocation of high-efficiency drilling tools and equipments, borehole trajectory design and control, horizontal section drilling acceleration and cleaning, rotary steering system (RSS) drilling, strong inhibition and lubrication water-base drilling fluid, and “rotary guide shoe + casing” floating running, etc. The key technologies for drilling and completing horizontal wells with ultra-long horizontal sections in the Sulige tight gas reservoirs were developed and applied in 2 wells with an average well depth of 7 027 m and an average horizontal section length of 3 719.5 m. The drilling cycle was 50.93 d, which meant that the proposed technologies achieved a favorable effect. Between the two wells, the Well Jing50-26H1, with a total depth (TD) of 7 388 m and a horizontal section length of 4 118 m, established the records as the deepest well in Changqing Oilfield and the longest horizontal section of onshore oil and gas wells in China at that time. The research and application show that the key technologies can provide technical support for the efficient exploration and development of the Sulige tight gas reservoirs and a reference for safe and efficient drilling and completion of horizontal wells with ultra-long horizontal sections in tight gas fields in China.