川中地区秋林区块沙溪庙组致密砂岩气藏储层高强度体积压裂之路  

Practice of high-intensity volume fracturing in the Shaximiao Formation tight sandstone gas reservoirs of the Qiulin Block,Central Sichuan Basin

作　　者：郑有成[1] 韩旭 曾冀[2] 周长林 周朗 陈伟华[2] ZHENG Youcheng;HAN Xu;ZENG Ji;ZHOU Changlin;ZHOU Lang;CHEN Weihua(PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China;Engineering Technology Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610017,China;Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]中国石油西南油气田公司 [2]中国石油西南油气田公司工程技术研究院 [3]成都理工大学

出　　处：《天然气工业》2021年第2期92-99,共8页Natural Gas Industry

基　　金：中国石油西南油气田公司博士后工作站科学研究与技术开发项目“金华—中台山沙溪庙组致密砂岩气藏裂缝形态控制规律及改造技术研究”(编号:20190302-15)。

摘　　要：为了解决四川盆地中部秋林区块中侏罗统沙溪庙组致密砂岩气藏储层体积压裂改造的难题,探索高强度体积压裂技术的适应性,选取该区块沙溪庙组致密砂岩露头岩样,开展真三轴水力压裂物理模拟实验,并采用分段多簇压裂水平井的产量预测模型对水平井分簇射孔进行优化设计;然后,基于控液提砂模式,在该区域致密砂岩储层开展了三轮先导性试验。研究结果表明:①秋林区块沙溪庙组致密砂岩储层天然裂缝欠发育,水力压裂裂缝形态以对称双翼裂缝为主,难以形成复杂裂缝网络,并且储层具有中等—偏强水敏性,常规的体积压裂在该区域储层改造中不适用;②高强度体积压裂技术的内涵是通过段内多簇射孔形成多条独立的双翼裂缝,实施控液提砂的加砂模式,在保证高强度加砂的前提下减少入井液量,从而降低入井流体对地层的伤害;③秋林207-5-H2井压裂段数为10段,每段7~12簇,施工排量介于16~18 m^(3)/min,按照控液提砂模式累计泵注滑溜水12146 m^(3)、支撑剂4170 t,该井压裂后测试气产量达83.88×104 m^(3)/d,天然气无阻流量达214.05×10^(4)m^(3)/d;④随着簇间距减小,累计产气量逐渐提高,但当簇间距小于15 m以后,累计产气量增幅变小;⑤当加砂强度低于6 t/m时,随着加砂强度增大,水平井千米改造段长测试气产量整体呈现增大的趋势;加砂强度超过6 t/m后,随着加砂强度增大,千米改造段长测试气产量上升不明显;⑥随着井眼轨迹与水平最大主应力方向的夹角增大,千米改造段长测试气产量整体呈现增大的趋势,当水力裂缝与井眼呈近垂直的情况时,获得的有效泄流面积最大,千米改造段长测试气产量也最高。结论认为,该区高产井的压裂模式为:大夹角井眼轨迹、10 m左右射孔簇间距、5 t/m加砂强度、大排量滑溜水+组合粒径支撑剂连续加砂。In order to solve the difficulties in the volume fracturing stimulation of Middle Jurassic Shaximiao Formation tight sandstone reservoirs in the Qiulin Block of central Sichuan Basin and explore the adaptability of high-intensity volume fracturing technology,we selected the outcrop samples of Shaximiao Formation tight sandstone in the Qiulin Block to carry out the physical simulation experiment of true triaxial hydraulic fracturing.On this basis,horizontal well cluster perforation was optimally designed by using the production prediction model of staged multi-cluster fracturing horizontal wells.Then,based on the liquid control and proppant increase mode,three rounds of pilot tests were carried out on the tight sandstone reservoirs in this area.And the following research results were obtained.First,natural fractures in the Shaximiao Formation tight sandstone reservoir of the Qiulin Block are undeveloped,and hydraulic fractures are morphologically dominated by symmetric double-wing fractures,so complex fracture networks can be hardly formed.In addition,the reservoir is of medium to strong water sensitivity,so conventional volume fracturing is not adaptive to the reservoir stimulation in this block.Second,the connotation of high-intensity volume fracturing technology is to carry out multi-cluster perforation in each section to form multiple independent double-wing fractures and to implement the proppant injection mode of liquid control and proppant increase to reduce the inflow fluid while ensuring the high-intensity proppant injection,so as to reduce the damage of inflow fluid to the formation.Third,there are 10 fracturing sections in Well Qiulin 207-5-H2,with 7-12 clusters in each section,and the displacement is in the range of 16-18 m3/min.According to the fluid control and proppant increase mode,12146 m3 slick water and 4170 t proppant are injected in total.The tested production rate and absolute open flow of natural gas after the fracturing are up to 83.88×10^(4)m^(3)/d and 214.05×10^(4)m^(3)/d,respectively.F

关 键 词：致密砂岩气藏 体积压裂 高强度加砂 多簇射孔 滑溜水 秋林区块 中侏罗统沙溪庙组 四川盆地中部 

分 类 号：TE377[石油与天然气工程—油气田开发工程]