煤层气U形井水力喷砂压裂技术

Hydrajet Fracturing Technology of U-Shape Coal Bed Methane Wells

吴春方 陈作 刘建坤 窦亮彬 刘善勇

Wu Chunfang Chen Zuo Liu Jiankun Dou Liangbin Liu Shanyong

中国石化石油工程技术研究院, 北京 100101; 油气资源与探测国家重点实验室(中国石油大学(北京)), 北京 102249

Sinopec Research Institute of Petroleum Engineering, Beijing, 100101, China; State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing, 102249, China

为了解决煤层气U形井水力喷砂压裂时射孔砂难以由施工井上返、管柱易砂卡的难题,在对比分析水平井水力喷砂压裂工艺的基础上,根据U形井的井身结构特点,对水力喷砂压裂工具进行了改进,将扶正器的直流流道改为螺旋流道;组合式陶瓷喷嘴改为整体式合金喷嘴;对施工工艺进行了改进,射孔砂和返排液由U形井的直井返出;对工艺参数进行了优化,优选得到最佳喷嘴直径为6 mm,油管排量为2.0 m3/min。现场试验表明,采用改进后的工具和优化的工艺参数避免了管柱砂卡。试验井采用优化的工艺参数,顺利压裂4段,注入活性水1 932 m3,加砂90 m3,最高砂比达到23%。试验井排水降压3个月后产气,目前日产气稳定在500 m3左右,累计产气75 000 m3,增产效果良好。这表明,采用改进的水力喷射压裂工具、工艺及优化的工艺参数能够解决煤层气U形井的压裂难题,为后续煤层气U形井的压裂改造提供了一种技术手段。

In hydrajet fracturing on U-shape coal bed methane (CBM) well,the abrasive perforating sand is difficult to return to the ground and may cause sand sticking.To solve this problem,design of the tool was modified on the basis of horizontal well hydrajet fracturing techniques.First,the centralizer channel was changed from direct to spiral and the nozzle was changed from built-up ceramic to monolithic alloy.Second,operation process was modified,in which both the perforation sand and flowback fluid return to the ground from the vertical well.Finally,the optimized nozzle diameter of 6 mm and optimum tubing displacement of 2.0 m3/min were determined.Field test showed that the modified tools and techniques could effectively avoid sand sticking.4 stage fracturing treatments were finished in the well successfully by using the optimized parameters,with slick water injection of 1 932 m3,sand of 90 m3,and the highest sand ratio reached 23%.After dewatering and depressurization for 3 months,the well started to produce with stable production of 500 m3 per day and the accumulated gas of about 75 000 m3.With the modified tools,techniques and optimized parameters,the problem in the U-shape CBM well fracturing had been addressed and it would provide a reference for subsequent U-shape CBM well fracturing.

国家科技重大专项"复杂地层储层改造关键技术研究"(编号:2011ZX05031-004-003);国家科技重大专项"连续油管分层压裂工艺技术研究"(编号:2011ZX05045-03-03WX)资助。

https://doi.org/10.3969/j.issn.1001-0890.2013.04.023