深层超深层煤层气保压取心工具设计

针对常规煤层气取心工具和油气井保温保压取心工具难以在深层煤储层中获得高价值煤心的问题,依据深层煤层气取心的技术要求,设计了一种具备保压和密闭功能的深层超深层煤层气取心工具。该工具的保压内筒材质优选承压能力高、摩阻力小的7075型硬质铝合金;提出的智能钻杆和帕尔贴集成设计的复合式保温外筒设计方向,有助于解决常规电池的电量不足和电压不稳等诸多问题;优化设计的液压提升机构和压力补偿总成,可确保球阀密封更加可靠,有效降低已获取的原位煤心因地层环境改变而引起的理化数据分析误差。室内试验结果表明,液压提升机构与密封球阀功能性联机试验正常,压力补偿机构可以长时间耐压30 MPa,且工具本体与各部件未发生变形,满足深层保压技术需要。研究结果可为深层超深层煤层气保压取心技术的现场应用提供参考。

Design of a Pressure-Preservation Coring Tool for Deep and Ultra-Deep Coalbed Methane Samples

Conventional coalbed methane coring tools and pressure/temperature-controlled oil-gas coring tools are difficult to obtain valuable coal cores from deep coal reservoirs.According to the technical requirements of sampling deep coalbed methane,a coring tool for sampling deep and ultra-deep coalbed methane has been developed with pressure preservation and occlusive functions.Through the analysis of a series of materials,the pressure-preservation inner cylinder is made of aluminum alloy which can resist high pressure and its friction is low.The design proposal is an intelligent drill pipe and a composite heat-insulating outer cylinder integrated with Peltiers,which is helpful to solve the problem of insufficient and unstable voltage provided by a conventional battery.The design of the hydraulic lifting mechanism and the pressure compensation assembly is optimized to ensure that ball valves can seal more reliably,and effectively protect underground coal cores from wrong physical and chemical data caused by the change of formation environment.Indoor interlocking tests verified that the hydraulic lifting mechanism and the ball valve worked normally,the pressure nitrogen compensation mechanism withstood 30 MPa for a long time,and the tool body and parts were not deformed,indicating they are effective for deep pressure preservation.The result is a reference to coring deep and extra-deep coalbed methane samples with pressure preservation.