Research and analysis of trajectory control for Well Zhonggu 5-2H

Zhonggu No. 5 Block of Tarim Oilfield is characterized by deep reservoirs and narrow safe density window of drilling fluid. Being comprehensively affected by factors like wellbore diameter, drilling tool bending, etc., there is hardly any breakthrough in elongation of the horizontal section, which affects the productivity of horizontal wells. In order to improve the production of individual wells in fractured gas pools in Zhonggu buried hill limestone, studies were made on trajectory of ultra-deep long horizontal hole. In view of the difficulties in hole cleaning, drill-string bending, screw degumming, trajectory control, etc., the ?101.6 mm drill-pipe assembly, drilling tool bending simulation, safe weight on bit, hydraulic oscillator, high-temperature screw, high temperature MWD, optimized PDC drill bit together with controlled pressure drilling technology, etc. were used to drill the highly difficult, high temperature horizontal well with ultra-deep long horizontal section. The successful drilling of this super-long hole and staged fracturing in this horizontal section has provided a new method for trajectory control in ultra-deep, highly difficult and long horizontal holes. The research and its findings have some guiding significance in large scale drilling of horizontal wells in this region.