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
邱玉超 1许强 2李一博 2邓伟 2郑超 3赵正望 3金值民 3谭秀成2
作者信息
- 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;西南石油大学,四川 成都 610500;中国石油西南油气田分公司,四川 成都 610041
- 2. 西南石油大学天然气地质四川省重点实验室,四川 成都 610500;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
- 折叠
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.
Abstract
The fourth member of the Upper Triassic Xujiahe Formation in the Tianfu Area of the Sichuan Basin(re-ferred to as the T3x4)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 pre-diction.The distribution characteristics of the T3x4 sandstone in the Upper Triassic Xujiahe Formation were well characterized with waveform indication simulation method.The results indicate that the T3x4 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 po-rosity variations,it is proposed that the T3x4 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 physi-cal characteristics and significant thickness,making them promising exploration areas.The study results provide val-uable insights for the in-depth exploration of the T3x4.
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Key words
thick Sandstone/Sandstone characterization/waveform indication simulation/well-seismic integration/reservoir prediction/Xujiahe Formation/Sichuan Basin引用本文复制引用
基金项目
国家自然科学基金(42272257)
中国石油西南油气田分公司科技项目(20230301-09)
出版年
2024
国家科技期刊平台
NSTL
万方数据