四川盆地天府地区上三叠统须家河组四段致密储层砂体刻画及有利储层预测  

Characterization of Tight Sandstone Reservoirs and Prediction of Favorable Reservoirs in the Fourth Member of the Upper Triassic Xujiahe Formation in the Tianfu Area of the Sichuan Basin

作　　者：邱玉超 许强[1,2] 李一博 邓伟 郑超 赵正望[3] 金值民[3] 谭秀成 Qiu Yuchao;Xu Qiang;Li Yibo;Deng Wei;Zheng Chao;Zhao Zhengwang;Jin Zhimin;Tan Xiucheng(Sichuan Province key Laboratory of Natural Gas Geology,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Southwest Petroleum University,Chengdu,Sichuan 610500,China;PetroChina Southwest Oil and Gas Field Company,Chengdu,Sichuan 610041,China)

机构地区：[1]西南石油大学天然气地质四川省重点实验室,四川成都610500 [2]西南石油大学,四川成都610500 [3]中国石油西南油气田分公司,四川成都610041

出　　处：《特种油气藏》2024年第3期18-26,共9页Special Oil & Gas Reservoirs

基　　金：国家自然科学基金“林周盆地晚白垩世从海到山对冈底斯俯冲-碰撞隆升过程的制约”(42272257);中国石油西南油气田分公司科技项目“四川盆地须家河组致密储层特征和成藏规律研究”(20230301-09)。

摘　　要：四川盆地天府地区上三叠统须家河组四段(简称须四段)厚层砂岩夹薄层泥岩发育,为当前致密砂岩气的重要勘探层系。但受限于地震纵向分辨率,常规方法难以区分薄层泥岩,对该层段砂岩的精细刻画一直缺乏有效的手段,制约了对盆地砂体展布规律和有利目标区的认识。针对上述问题,建立钻井资料与地震相映射关系,在自然伽马曲线约束下,寻找最佳反演频率参数,提高井间砂体预测精度。采用波形指示模拟的方法精细刻画了上三叠统须家河组四段砂岩的展布特征。结果表明:须四段砂岩具有西厚(55.0~100.0 m)、东薄(15.0~50.0 m)的特征;与须三段相比,砂体厚薄变化转换带(坡折带)向克拉通内部迁移。统计地震工区内22口井数据,坡折带以西砂岩平均孔隙度高(8.0%)、储层厚度大(45.4 m)。结合构造演化、沉积相带展布、砂岩厚度和孔隙度变化,认为四川盆地天府地区上三叠统须家河组四段具有构造控坡折带、坡折带控储层的规律。坡折带以西的储层物性好、厚度大,为勘探有利区。研究结果对须四段勘探深入具有借鉴作用。The fourth member of the Upper Triassic Xujiahe Formation in the Tianfu Area of the Sichuan Basin(referred to as the T 3 x 4)is characterized by thick sandstone layers interbedded with thin mudstone layers,making it a crucial exploration target for tight sandstone gas reservoirs.However,due to limitations in seismic vertical resolution,thin mudstone layers are hard to be determined by conventional methods,hindering the precise characterization of sandstone in this interval.This limitation has impeded the understanding of the distribution patterns of sand bodies in the basin and identification of favorable target areas.To address these issues,this study integrates drilling data with seismic facies and establishes a mapping relationship between the two.Under the constraint of natural gamma-ray curves,optimal inversion frequency parameters were sought to enhance the accuracy of inter-well sand body prediction.The distribution characteristics of the T 3 x 4 sandstone in the Upper Triassic Xujiahe Formation were well characterized with waveform indication simulation method.The results indicate that the T 3 x 4 sandstone exhibits characteristics of being thick in the west(55.0 to 100.0 m)and thin in the east(15.0 to 50.0 m).Compared to the third member of the Xujiahe Formation,the transition zone of sand body thickness variation(slope break zone)has migrated towards the interior of the craton.Analyzing data from 18 wells within the seismic working area,it was observed that beneath the slope break zone,the sandstone has a high average porosity(8.0%)and a large reservoir thickness(45.4 m).Considering tectonic evolution,sedimentary facies distribution,sandstone thickness,and porosity variations,it is proposed that the T 3 x 4 follows a pattern of structures control slope break zones,and slope break zones control reservoirs.Regions below the slope break zones exhibit favorable reservoir properties with good physical characteristics and significant thickness,making them promising exploration areas.The study results provide

关 键 词：致密砂岩 砂体刻画 波形指示模拟 井震结合 储层预测 须家河组 四川盆地 

分 类 号：TE121[石油与天然气工程—油气勘探]