Key drilling technologies for tight gas horizontal wells in Sichuan Basin
In order to clarify the technical difficulties of tight horizontal well drilling engineering in Sichuan Basin,the author carried out various aspects of work such as such as formation pressure prediction and stress analysis,well trajectory design optimization,drilling parameters and equipment optimization,optimization of drilling fluid system and parameters,casing running simulation prediction and casing strength verification.The results indicate that:1)The formation collapse pressure of the southwest tight gas horizontal well is 1.55～1.60 g/cm3.When the drilling direction of the horizontal section is about 105° and 15°,the wellbore stability is good and beneficial for reservoir fracturing.2)Adopting"two-dimensional"trajectory design,the torque of the drilling tool assembly is reduced by more than 15％,the friction is reduced by more than 20％,and the ROP can be increased by more than 45％in directional section;3)The drilling rig is equipped with a DQ50DBS top drive device,equipped with 2 to 3 1600HP drilling pumps and NC52 non-standard DP.The drilling flow rate is controlled over 351/s,which can ensure wellbore cleanliness and debris carrying efficiency;4)The use of a white oil based drilling fluid system and the addition of"rigid particles+resin fibers+asphalt particles"for sealing to ensure the stability of the wellbore;5)Select P110 steel grade,10.54 mm wall thickness completion casing,and adopting the rotating method to reduce the running casing friction by more than 12％while meeting the requirements of fracturing construction.The above achievements have guiding significance for accelerating the exploration and development process of tight gas in the Sichuan Basin.
tight gashorizontal wellsexploration and development integrationkey drilling technology
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