重载超高温超高压尾管固井工具的研制与应用OA

Well SDTK1 is China's first myriametre scientific exploration well.There exists extreme downhole conditions,including ultra-deep,ultra-high temperature,ultra-high pressure,and ultra-heavy load,in its drilling and completion.Moreover,it faces technical challenges caused by long open holes of the fourth and fifth spud sections,such as premature circulation and multiple circulation operations during liner running,which are highly likely to induce cementing failure.To address these challenges,based on the technical concept of"smooth RIH,firm setting,free release,tight sealing,reliable isolation,and effective POOH",the structural integrity and sealing reliability of key cementing tools(e.g.liner hanger,float collar,float shoe,and drill pipe plug)were systematically analyzed,and a set of heavy-load,ultra-high temperature and ultra-high pressure liner cementing technologies were developed.The following results are obtained.(i)The liner hanger is structurally reinforced,achieving"smooth RIH".(ii)A two-stage independent fluid-actuated setting mechanism is adopted to realize the hanger setting function,achieving"firm setting".(iii)The single-start high-pitch release mechanism and a new type of engaged accompanying sand prevention shield are adopted to enable the drilling tools to run out immediately after cementing,achieving"free release".(iv)High-reliability sealing float collar and float shoe are employed to ensure the reliable sealing of non-return valves,achieving"tight sealing".(v)Drill pipe plug is structurally optimized with optimal materials,achieving"reliable isolation".(vi)A"bare-type"central tube is used,achieving"effective POOH".It is concluded that the technologies effectively address the cementing challenges under extreme downhole conditions of ultra-deep,ultra-high temperature,ultra-high pressure,and ultra-heavy load,and have achieved good application results in the fourth and fifth spud sections of Well SDTK1.They provide technical support for the oil and gas development in ultra-deep wells in China and promote the iterative upgrading of domestic cementing tools.