四川盆地盆外缘安场向斜富有机质页岩储层精细刻画及水平井靶窗优选  

Micro-layer division,comparative evaluation,and target window optimization of horizontal well of marine high-quality shale gas intervals in residual syncline outside Sichuan Basin

作　　者：蓝宝锋 杨瑞东[1] 戴金星[3] 姜海申 赵明芳 龙珍 LAN Baofeng;YANG Ruidong;DAI Jinxing;JIANG Haishen;ZHAO Mingfang;LONG Zhen(Guizhou University,Guiyang 550000,China;Guizhou Energy Industry Research Institute Co.,Ltd,Guiyang 550000,China;PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China)

机构地区：[1]贵州大学,贵州贵阳550000 [2]贵州能源产业研究院有限公司,贵州贵阳550000 [3]中国石油勘探开发研究院,北京100083

出　　处：《天然气地球科学》2024年第12期2184-2195,共12页Natural Gas Geoscience

基　　金：贵州省找矿突破战略行动重大协同创新项目“贵州省页岩气效益开发关键技术及工程试验”(编号:黔科合战略找矿[2022]ZD005);贵州能源产业研究院有限公司页岩气院士工作站项目(编号:筑科合同[2021]45-2);贵州页岩气勘探开发科技创新基地项目(编号:黔科中引地[2022]4024)联合资助。

摘　　要：四川盆地外缘的复杂构造区“窄陡型”向斜内页岩气储层表现出较强的非均质性,给页岩气储层精细刻画及勘探开发井位部署带来挑战。基于安场向斜钻探成果,对盆外缘的安场向斜五峰组—龙马溪组富有机质页岩储层进行刻画。研究表明:(1)五峰组—龙马溪组富有机质页岩以深水陆棚相沉积为主,按岩电特征可将龙马溪组(S_(1)l)划分为2段5个小层,在区域上具有很好的对比性。(2)富有机质页岩储层有机质丰度总体较高,自下而上TOC值呈现先增大后减小的变化趋势,在S_(1)l_(1)~2小层有机质丰度最高(TOC值平均为5.04%),有机质类型主要为Ⅰ型,均进入过成熟中期演化阶段,以生成干气为主。(3)孔隙类型丰富,主要有沥青孔、干酪根孔、粒间孔及晶间孔等,实测孔隙度为1.08%~5.76%,整体较高(平均值为3.46%)。纵向上五峰组(O_(3)w)孔隙度最高,S_(1)l_(2)段最低。(4)现场解吸气量为0.7~3.1 m^(3)/t,平均为1.54 m^(3)/t,测井解释O_(3)w、S_(1)l_(1)~1、S_(1)l_(1)~2和S_(1)l_(1)~3小层总含气量相对较高。富有机质页岩段含气饱和度分布于50%~80%之间,整体较高。(5)页岩储层主要矿物成分为石英、黏土、长石,总体脆性矿物含量较高。其中O3w、S_(1)l_(1)~1、S_(1)l_(1)~2和S_(1)l_(1)~3小层脆性指数相对较高。该地区最小水平主应力平均值为50.0 MPa,最大水平主应力平均值为65.2 MPa,水平地应力差异系数在0.25~0.36之间,向核部应力差有增大的趋势。(6)综合评价认为O_(3)w、S_(1)l_(1)~1、S_(1)l_(1)~2和S_(1)l_(1)~3页岩储层段为Ⅰ类储层,S_(1)l_(1)~4页岩储层段为Ⅱ类储层,S_(1)l_(2)页岩储层段为Ⅲ类储层,S_(1)l_(1)~1-S_(1)l_(1)~3页岩储层段可作为主力开发层系。综合工程因素,S_(1)l_(1)~2页岩储层段为该地区水平井穿行的最优靶窗,压裂时缝网可有效沟通下部S_(1)l_(1)~1和上部S_(1)l_(1)~3储层段。该研究成果可为安场向斜及南方复杂向斜区The shale gas reservoir in the“narrow steep”syncline in the complex tectonic area of the outer edge of Sichuan Basin shows strong heterogeneity.Through the characterization of the organic-rich shale reservoir of the Wufeng-Longmaxi formations in the Anchang syncline outside the basin,the research shows that:(1)The organic-rich shale of the Wufeng-Longmaxi formations is mainly deposited in the deep water shelf facies.Com⁃bined with the petroelectric characteristics,the Longmaxi Formation(S1l)can be divided into two segments,and further divided into five sub-layers,which have a good regional contrast.(2)The organic matter abundance of the organic-rich shale reservoir is generally high,and the TOC shows a trend of increasing first and then de⁃creasing from bottom to top,and the organic matter abundance is the highest in the S_(1)l_(12) sub-layer(average 5.04%).The organic matter type is mainly type I,which has entered the mature stage of the middle evolution stage,and mainly generates dry gas.(3)The pore types are rich,mainly bitumen pore,kerogen pore,inter⁃granular pore,intercrystal pore,etc.The measured porosity is 1.08%-5.76%,which is relatively high(average 3.46%).Vertically,the Wufeng Formation(O_(3)w)has the highest porosity,and the S_(1)l_(2) has the lowest.(4)The field desorption gas is 0.7-3.1 m^(3)/t,with an average of 1.54 m^(3)/t.The total gas content in the O_(3)w,S_(1)l_(11),S_(1)l_(12) and S_(1)l_(13) sub-layers is relatively high.The gas saturation of the organic-rich shale segment is mainly distrib⁃uted between 50% and 80%,which is relatively high as a whole.(5)The main mineral compositions are quartz,clay,feldspar,and the overall brittle mineral content is high.The average value of the minimum horizon⁃tal principal stress is 50.0 MPa,and the average value of the maximum horizontal principal stress is 65.2 MPa.The horizontal in-situ stress difference coefficient is between 0.25 and 0.36,and the stress difference has an in⁃creasing trend toward the core.(6)The comprehensive evaluation

关 键 词：安场向斜 五峰组—龙马溪组 页岩气 小层划分与对比评价 水平井靶窗优选 

分 类 号：TE122.1[石油与天然气工程—油气勘探]