川西南碳酸盐岩古岩溶储层岩石物理特征及识别——以广汉斜坡地区中三叠系雷口坡组四段3亚段为例  

Petrophysical characteristics and recognition of carbonate paleokarst reservoir in Southwestern Sichuan:Taking the third sub-member of the fourth member of Leikoupo Formation of Middle Triassic in Guanghan slope area as an example

作　　者：杨飞[1,2] 王顺 易杨[2] 刘雅博 韩冰 YANG Fei;WANG Shun;YI Yang;LIU Yabo;HAN Bing(Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education(Yangtze University),Wuhan 430100,Hubei;School of Geophysics and Petroleum Resources,Yangtze University,Wuhan 430100,Hubei)

机构地区：[1]油气资源与勘探技术教育部重点实验室(长江大学),湖北武汉430100 [2]长江大学地球物理与石油资源学院,湖北武汉430100

出　　处：《长江大学学报（自然科学版）》2022年第2期30-38,共9页Journal of Yangtze University(Natural Science Edition)

基　　金：国家重大科技专项“川西源内成藏体系成藏机理研究”(2016ZX05002-004-009)。

摘　　要：川西南广汉斜坡地区中三叠系雷口坡组四段(以下简称雷四段)储层主要为局限台地相碳酸盐岩,古岩溶储层发育好、沉积厚度大、分布范围广。其中雷口坡组四段3亚段(以下简称雷四3亚段)残留地层厚度最大,且发育大量与不整合相关的古岩溶储层,是该区油气勘探的重点层段之一。但是,现阶段对于研究区雷四3亚段的古岩溶储层岩石物理特征认识不清,对古岩溶储层边界刻画不明确。为此,在了解研究区雷四3亚段地层特征的基础上,通过井震结合的地震层位标定方式进行层位标定及层位追踪对比,弄清了雷四3亚段的构造特征;通过研究雷四3亚段的岩石物理特征,确定了研究区古岩溶储层的波阻抗阈值为16100g·m/(s·cm^(3));利用波形聚类分析方法进行雷四3亚段的地震相划分,再依据地震相反映的沉积相变化,明确了沉积相在平面上的展布特征;通过波阻抗反演求得地震波阻抗体,再利用前期岩石物理特征结果,将波阻抗体转换成古岩溶储层与非古岩溶储层岩性体,计算古岩溶储层厚度,预测了古岩溶储层有利区分布范围;最后通过叠合雷四3亚段古岩溶储层厚度图与古岩溶储层有利区图,优选出4个古岩溶圈闭。The reservoirs of the fourth member of Middle Triassic Leikoupo Formation in the Guanghan slope area of southwestern Sichuan are mainly confined platform facies carbonate rocks with well-developed paleokarst reservoirs,large deposit thickness and wide distribution.Among them,the thickness of the residual strata in the third sub-member of the fourth member of Leikoupo Formation is the largest,and a large number of unconformity-related paleokarst reservoirs are developed,which is one of the hot strata for oil and gas exploration in this area.However,at this stage,it is not clear about the petrophysical characteristics and the boundary characterization of the paleokarst reservoir in the third sub-member of the fourth member of Leikoupo Formation in the study area.Therefore,on the basis of understanding the stratigraphic characteristics of the 3^(rd) sub-member of the 4^(th) member of Leikoupo Formation in the study area,the seismic horizon calibration method combined with well and seismic was used to calibrate and trace the horizon,and the structural characteristics of the 3^(rd) sub-member of the 4th member of Leikoupo Formation were clarified.The wave impedance threshold of paleokarst reservoir in the study area was determined to be 16100g·m/(s·cm^(3))by studying the petrophysical characteristics of 3^(rd) sub-member of the 4^(th) member of Leikoupo Formation.The seismicfacies was divided by using the method of waveform clustering analysis,and the distribution characteristics of sedimentary facies on the plane were determined according to the changes of sedimentary facies reflected by seismic facies.The seismic wave impedance body was obtained by wave impedance inversion,and then the wave impedance body was converted into paleokarst reservoir and non-paleokarst reservoir lithology body by using the results of rock physical characteristics in the early stage.The thickness of paleokarst reservoir was calculated,and thevfavorable distribution range of paleokarst reservoir was predicted.Finally,four palaeokarst trap

关 键 词：四川盆地 古岩溶储层 地震属性 波阻抗反演 雷口坡组 广汉斜坡地区 

分 类 号：P618.44[天文地球—矿床学]