The fourth member of the Upper Triassic Xujiahe Formation in the Tianfu Area of the Sichuan Basin (referred 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 prediction.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 porosity 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 physical characteristics and significant thickness,making them promising exploration areas.The study results provide valuable insights for the in-depth exploration of the T3x4.
[1] 李伟,邹才能,杨金利,等.四川盆地上三叠统须家河组气藏类型与富集高产主控因素[J].沉积学报,2010,28(5):1037-1045.
LI Wei,ZOU Caineng,YANG Jinli,et al.Types and controlling factors of accumulation and high productivity in the Upper Triassic Xujiahe Formation gas reservoirs, Sichuan Basin[J].Acta Sedimentologica Sinica, 2010, 28(5): 1037-1045.
[2] 赵文智,卞从胜,徐春春,等.四川盆地须家河组须一、三和五段天然气源内成藏潜力与有利区评价[J].石油勘探与开发,2011,38(4):385-393.
ZHAO Wenzhi,BIAN Congsheng,XU Chunchun,et al.Assessment on gas accumulation potential and favorable plays within the Xu-1, 3 and 5 Members of Xujiahe Formation in Sichuan Basin[J].Petroleum Exploration and Development, 2011, 38(4): 385-393.
[3] 杨雨,文龙,周刚,等.四川盆地油气勘探新领域、新类型及资源潜力[J].石油学报, 2023,44(12):2045-2069.
YANG Yu,WEN Long,ZHOU Gang,et al.New fields,new types and resource potentials of hydrocarbon exploration in Sichuan Basin[J].Acta Petrolei Sinica, 2023, 44(12): 2045-2069.
[4] 晁彩霞,于俊峰,王玉,等.基于地震波形指示反演的东方B气田海底扇砂体精细刻画[J].海相油气地质,2021,26(3):281-288.
CHAO Caixia,YU Junfeng,WANG Yu,et al.Fine characterization of submarine fan sand body in Dongfang B Gas Field based on waveform indication inversion[J].Marine Origin Petroleum Geology,2021,26(3):281-288.
[5] 陈祖庆,王静波.基于压缩感知的稀疏脉冲反射系数谱反演方法研究[J].石油物探,2015,54(4):459-466.
CHEN Zuqing,WANG Jingbo.A spectral inversion method of sparse-spike reflection coefficients based on compressed sensing[J].Geophysical Prospecting for Petroleum, 2015, 54(4): 459-466.
[6] 陈建江.AVO三参数反演方法研究[D].北京:中国石油大学(北京),2008.
CHEN Jianjiang.Research on AVO three-parameter inversion method[D].Beijing:China University of Petroleum( Beijing),2008.
[7] 陈彦虎.地震波形指示反演方法、原理及其应用[D].北京:中国地质大学(北京),2020.
CHEN Yanhu.Seismic waveform inversion method, principle and its application[D].Beijing:China University of Geosciences(Beijing),2020.
[8] 王新红.弹性波阻抗反演在稠油热采地震监测中的应用[J].地球物理学进展,2007,22(1):186-191.
WANG Xinhong.Application of elastic impendence inversion in seismic monitoring of the heavy-oil thermal recovery[J].Progress in Geophysics, 2007, 22(1): 186-191.
[9] XU Wenqiao,YIN Hongwei,JIA Dong,et al.Structural features and evolution of the northwestern Sichuan Basin:insights from siscrete numerical simulations[J].Frontiers in Earth Science,2021,9:653395.
[10] LIU Shugen,YANG Yu,DENG Bin,et al.Tectonic evolution of the Sichuan Basin,southwest China[J].Earth-Science Reviews,2021,213:103470
[11] 王金琪.安县构造运动[J].石油与天然气地质,1990,11(3):223-234.
WANG Jinqi.Anxian tectonic movement[J].Oil & Gas Geology,1990,11(3):223-234.
[12] 唐大海,谭秀成,王小娟,等.四川盆地须家河组致密气藏成藏要素及有利区带评价[J].特种油气藏,2020,27(3):40-46.
TANG Dahai,TAN Xiucheng,WANG Xiaojuan,et al.Tight gas accumulation elements and favorable zone evaluation of Xujiahe Formation in Sichuan Basin[J].Special Oil & Gas Reservoirs,2020,27(3):40-46.
[13] 汪泽成,施亦做,文龙,等.用超级盆地思维挖掘四川盆地油气资源潜力的探讨[J].石油勘探与开发, 2022,49(5):847-858.
WANG Zecheng,SHI Yizuo,WEN Long,et al.Exploring the potential of oil and gas resources in Sichuan Basin with super basin thinking[J]. Petroleum Exploration and Development, 2022, 49(5): 847-858.
[14] 林良彪,余瑜,南红丽,等.四川盆地川西坳陷上三叠统须家河组四段储层致密化过程及其与油气成藏的耦合关系[J].石油与天然气地质,2021,42(4):816-828.
LIN Liangbiao,YU Yu,NAN Hongli,et al.Reservoir tightening process and its coupling relationship with hydrocarbon accumulation in the Fourth Member of Upper Triassic Xujiahe Formation in the western Sichuan Depression,Sichuan Basin[J].Oil & Gas Geology,2021,42(4):816-828.
[15] 孙衍鹏,何登发.四川盆地北部剑阁古隆起的厘定及其基本特征[J].地质学报,2013,87(5):609-620.
SUN Yanpeng,HE Dengfa.Discovery of the Jiange Paleo-uplift in north Sichuan Basin and its basic characteristics[J].Acta Geologica Sinica,2013,87(5):609-620.
[16] 魏国齐,杨威,金惠,等.四川盆地上三叠统有利储层展布与勘探方向[J].天然气工业,2010,30(1):11-14,135.
WEI Guoqi,YANG Wei,JIN Hui,et al.Distribution of favorable reservoirs and exploration targets in the Upper Triassic of the Sichuan Basin[J].Natural Gas Industry,2010,30(1):11-14,135.
[17] 李双建,李智,张磊,等.四川盆地川西坳陷三叠系盐下超深层油气成藏条件与勘探方向[J]. 石油与天然气地质,2023,44(6):1555-1567.
LI Shuangjian,LI Zhi,ZHANG Lei,et al.Hydrocarbon accumulation conditions and exploration targets of the Triassic subsalt ultra-deep sequences in the western Sichuan Depression, Sichuan Basin[J].Oil & Gas Geology,2023,44(6):1555-1567.
[18] 赵向原,游瑜春,胡向阳,等.基于成因机理及主控因素约束的多尺度裂缝“分级-分期-分组”建模方法——以四川盆地元坝地区上二叠统长兴组生物礁相碳酸盐岩储层为例[J]. 石油与天然气地质,2023,44(1):213-225.
ZHAO Xiangyuan,YOU Yuchun,HU Xiangyang,et al."Classified-staged-grouped" 3D modeling of multi-scale fractures constrained by genetic mechanisms and main controlling factors:a case study on biohermal carbonate reservoir of the Upper Permian Changxing Fm. in Yuanba Area,Sichuan Basin[J].Oil & Gas Geology,2023,44(1):213-225.
