深层保压密闭取心技术在徐深12井的应用

Application of submerged pressure maintaining sealed coring techniques to Well Xushen-12

保压取心技术是一项能够保持或接近地层压力的取心技术,采用保压取心工具和密闭液,通过在井底实现外筒的差动,关闭内筒的球阀,将岩心密封在内筒中,并通过压力补偿装置,保证取心过程中岩心中油气水不散失,从而取得具有原始地层压力的岩心,对取全取准地层资料具有重要意义。2006年研制出一种适合于大庆深层的BYM-Ⅲ型保压取心工具,并在徐深12井深层成功应用。针对深层火山岩地层特点,采用孕镶金刚石取心钻头、优选球阀总成材质、增设球阀关闭保护机构、改进密封材料及形式、采用抗高温密闭液、改进充压工艺,采用液氮冷冻技术,优选钻进参数等技术措施,成功完成了1筒保压取心施工,对正确认识该区块地质情况、计算含气储量、制定合理的开发方案等提供了大量的基础资料和解释依据。

The pressure maintaining coring technique is a coring technique that can keep or be close to formation pressure.It is of great significance to obtain complete and exact formation data by applying pressure maintaining tools and sealing fluid,realizing the differential motion of outer cylinders at the bottom of wells,closing the ball valves of inner cylinders,sealing cores in inner cylinders,preventing oil-gas-water losses from cores during the process of coring,and then obtaining the cores of original formation pressure.In 2006,a new type of pressure maintaining coring tool,BYM-III,suitable for Daqing deep layers,is developed and successfully applied to the deep layers of Well Xushen-12.In view of the characteristics of deep volcanic strata,the operation of one pressure core barrel is successfully completed,based on using impregnated diamond coring bits,selecting assembly materials of ball valves,increasing protection structures for closing ball valves,improving sealing materials and forms,applying sealing fluid resisting high temperature,enhancing pressure-filled technology,employing liquid nitrogen refrigeration technology,and optimizing drilling parameters.This provides abundant basic data and interpretation basis for having correct cognition of the geological conditions of the area,calculating gas reserves,and making reasonable development plans.