摘要
四川盆地主要发育溢流相及喷溢相两类火山岩,其中川西南乐山地区二叠系上统峨眉山玄武岩储层厚度大、分布广、埋深浅,勘探开发潜力大。以玄武岩为主的溢流相火山岩储层低孔、低渗,仅发育微裂缝,压裂改造是其“增储上产”的重要手段。基于室内评价实验,明确了储层非均质性强、岩石力学性质高、酸溶蚀率低、敏感矿物含量高、地层能量低是制约压裂改造工艺效果的主控因素。在此基础上,探索形成了“前置酸降破+两段式加砂+助排快排”的复合酸压技术,优化工作液黏土稳定剂浓度为0.5%、前置酸配方为12%HCl+2%HF、助排剂浓度为0.5%。采用前置酸解堵降破、降阻水造缝、胶液携砂、液氮助排的复合改造技术可进一步提高改造效果,通过优化黏土稳定剂用量、助排剂浓度形成的低伤害压裂液体系,可有效降低液体伤害,提高返排效率。
Two types of volcanic rocks,overflow phase and effusive phase,are mainly developed in the Sichuan Basin.Among them,the Upper Permian Emeishan basalt reservoirs in Leshan area of southwestern Sichuan are thick,widely distributed and shallowly buried,indicating great potential for exploration and development.The overflow-phase volcanic reservoirs dominated by basalt are characterized of low porosity and low permeability,and microfractures developed only,so fracturing is an important means of increasing reserves and production.Based on laboratory evaluation experiments,it is clear that strong reservoir heterogeneity,good rock mechanical properties,low acid dissolution rate,high content of sensitive minerals,and low formation energy are the main controlling factors that restrict the effect of fracturing.On this basis,compound acid fracturing technology of "pad-acid for breakdown pressure decreasing+two-stage sand adding+quick drainage" was explored and formed.The optimized clay stabilizer concentration of working fluid is 0.5%,the pad acid formula is 12% HCl +2%HF,and the concentration of cleanup additive is 0.5%.The composite transformation technology of pad-acid for unblocking and breakdown pressure decreasing,fracturing with resistance-reducing water,sand-laden glue liquid,and liquid nitrogen cleanup can further improve the effect.The low-damage fracturing fluid system formed by optimizing clay stabilizer dosage and cleanup additive concentration can effectively reduce the fluid damage and improve the flowback efficiency.
作者
王峻峰
何颂根
马健
勾宗武
Wang Junfeng;He Songgen;Ma Jian;Gou Zongwu(Petroleum Engineering Technology Institute of SINOPEC Southwest Oil&Gas Company,Deyang Sichuan 618000)
出处
《中外能源》
CAS
2022年第9期38-42,共5页
Sino-Global Energy
关键词
玄武岩储层
复合酸压
前置酸
两段式加砂
液氮助排
返排效率
basalt reservoir
compound acid fracturing
pad acid
two-stage sand adding
liquid nitrogen cleanup
flowback efficiency
