四川盆地永川区块五峰组—龙马溪组深层页岩可压性评价  

Evaluation on the fracability of deep shale in Wufeng-Longmaxi Formation,Yongchuan block,Sichuan Basin

作　　者：陶祖文[1] 李钦[1] 徐力群[2] 徐单峰 Tao Zuwen;Li Qin;Xu Liqun;Xu Danfeng(Downhole Operation Branch,Sinopec Southwest Petroleum Engineering Company limited,Deyang,Sichuan 618000,China;Oil&Gas Engineering Research Institute,PetroChina Tarim Oilfield Company,Korla,Xinjiang 841000,China;Hunan Drilling Branch,Sinopec Southwest Petroleum Engineering Company limited,Changsha,Hunan 410000,China)

机构地区：[1]中国石化西南石油工程有限公司井下作业分公司,四川德阳618000 [2]中国石油塔里木油田公司油气工程研究院,新疆库尔勒841000 [3]中国石化西南石油工程有限公司湖南钻井分公司,湖南长沙410000

出　　处：《天然气技术与经济》2020年第5期7-12,27,共7页Natural Gas Technology and Economy

摘　　要：为了开展四川盆地永川区块3500 m以深页岩气储层的可压性评价,以该区块上奥陶统五峰组—下志留统龙马溪组深层页岩储层岩心为研究对象,研究了页岩岩心的单轴岩石力学性能参数、三轴岩石力学性能参数、X射线衍射成分分析,以及脆性指数、水平差应力系数、成岩作用、断裂韧性对深层页岩可压性的影响,并且通过层次分析法确定了4个主要影响因素的权重值,建立了永川区块五峰组—龙马溪组深层页岩可压性评价模型;进而利用永川区块5口页岩气井压裂施工过程中的停泵压力对模型进行验证,并运用该模型指导了YY5-2井现场24段压裂施工。研究结果表明:①基于脆性指数、水平差应力系数、成岩作用、断裂韧性建立的可压性评价模型能够较好地反映永川区块深层页岩的可压性,利用该模型进行页岩储层可压性分级对现场压裂施工具有指导作用;②基于脆性指数、水平差应力系数、成岩作用、断裂韧性建立的可压性评价模型与停泵压力的相关性仅为83.13%,为提高永川区块五峰组—龙马溪组深层页岩可压性模型的预测精度,还需要进一步考虑其他因素对于可压性的影响。In order to evaluate the fracability of some shale reservoirs with burial depth over 3500 m,many cores sampled from deep shale reservoirs of Wufeng-Longmaxi Formation in Yongchuan block were taken as objectives to analyze the uniaxial and triaxial rock mechanical parameters,and X-diffraction composition and study the effects of brittleness index,horizontal stress difference coefficient,diagenesis,and fracture toughness on this fracability.The weight of these four affecting factors was determined by means of analytical hierarchy process(AHP).And one model to evaluate the fracability was established and then verified by using pump-off pressure in five shale gas wells during fracturing.Furthermore,this model was used to guide a 24-staged fracturing for YY5-2 well.Results show that(1)this established model based on brittleness index,horizontal stress difference coefficient,diagenesis,and fracture toughness can not only better reflect the fracability of deep shale in Yongchuan block but also be used to classify the fracability so as to guide on-site fracturing;and(2)it is only 83.13% correlated with the pump-off pressure.Therefore,in order to improve its accuracy to evaluate the fracability in Wufeng-Longmaxi Formation,it is necessary to further consider other factors affecting the fracability.

关 键 词：四川盆地 永川区块 五峰—龙马溪组 深层页岩气 可压性 脆性指数 水平差应力系数 断裂韧性 

分 类 号：P618.13[天文地球—矿床学]