摘要
体积压裂是实现页岩气商业开发的必要技术手段,但其增产机理和各种辅助增产措施的有效性需要进一步探索。通过页岩酸蚀裂缝渗透率测试实验,探究了碳酸盐矿物含量、酸液类型和浓度、支撑剂对页岩酸蚀剪切裂缝渗透率的影响,并借助CT扫描研究了页岩酸蚀前后的微观孔吼结构变化。结果表明:碳酸盐含量为2%的页岩采用11. 25%HCl+6. 75%HF的土酸配方可得到最佳酸蚀效果,碳酸盐含量为15%的页岩采用浓度为7. 5%左右的HCl酸蚀效果最佳。碳酸盐含量为25%的页岩采用2. 5%左右的HCl效果最佳;若页岩中钙质胶结的天然裂缝发育,应适当提高最优酸液浓度。页岩基质渗透率极低,如果储层中开启的天然裂缝或钙质充填裂缝不发育,即使是高浓度的酸液也不能将岩心驱透。该实验研究成果为页岩储层水力压裂的有效设计提供了更多有价值的信息。
Volume fracturing is a necessary technical means to realize commercial development of shale gas,but the effectiveness of its stimulation mechanism and various auxiliary production-enhancing measures still needs further exploration.The effects of carbonate content,acid type and concentration and proppant on the permeability of acid-etching shear fractures in shale reservoir were investigated through experiments testing the permeability of acid-etching fractures,and the changes of the microscopic pore throat structures before and after acid etching were studied by CT scanning.The results show that when the carbonate content of shale is about 2%,the best acid etching effect can be obtained by using the mud acid formula of about 11.25%HCl+6.75%HF,while for the shale with a carbonate content of 15%,the acid concentration should be about 7.5%HCl for the best acid-etching effect,and for the shale with a carbonate content of 25%,the acid concentration should be about 2.5%HCl.If natural fractures filled with calcium cements are well developed in shale reservoir,optimal acid concentration should be raised appropriately.Nevertheless,if open natural fractures or fractures filled with calcium cements are not well developed in the shale reservoir,even acid with high concentration cannot drive through the cores due to the extremely low matrix permeability in shale.The experimental results provide more valuable information for the design of effective hydraulic fracturing in shale reservoirs.
作者
房好青
郭天魁
王洋
翟乃城
曲占庆
Fang Haoqing;Guo Tiankui;Wang Yang;Zhai Naicheng;Qu Zhanqing(Research Institute of Petroleum Engineering of Northwest Oilfield Company Ltd.,SINOPEC,Urumqi,Xinjiang 830001,China;School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,Shandong 266580,China)
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2018年第6期1336-1342,共7页
Oil & Gas Geology
基金
国家自然科学基金项目(51874338)
青岛市应用基础研究计划项目(17-1-1-20-jch)
中央高校基本科研业务费专项资金资助项目(17CX02077)
关键词
水力压裂
酸蚀
CT扫描
裂缝渗透率
页岩
涪陵地区
四川盆地
hydraulic fracturing
acid etching
CT scanning
fracture permeability
shale
Fuling area
Sichuan Basin
