陡坡带深层砂砾岩体母岩类型差异机理及其对成岩演化的控制作用  

Distribution Mechanism of Different Types of Gravel Parent Rocks and Its Control Effecton Diagenetic Evolution in Steep Slope Zones of Faulted Basins

作　　者：田国庆 刘志凯 吴百勇 罗吉力欣 邓宝康 TIAN Guoqing;LIU Zhikai;WU Baiyong;LUO Jiexin;DENG Baokang(No.6 Gas Production Plant,PetroChina Changing Oilfield Company,Xi’an,Shaanxi 710018,China;Sichuan OGT Oilfield Technology Development Co.,Ltd.,Chengdu,Sichuan 610041,China)

机构地区：[1]中国石油长庆油田分公司第六采气厂,陕西西安710018 [2]四川奥吉特油田科技开发有限公司,四川成都610041

出　　处：《西安石油大学学报（自然科学版）》2024年第6期1-9,20,共10页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：中国石油集团综合研究项目“致密砂岩气藏控递减技术研究与试验”(2022DJ05)。

摘　　要：勘探实践证实断陷盆地陡坡带深层砂砾岩母岩类型分布往往具有差异性。为探寻造成母岩类型差异分布的机理及其对砂砾岩成岩演化的控制作用,以渤海湾盆地车镇凹陷沙三下亚段为例,基于岩心、测井、地震及大量分析化验资料,研究砂砾岩母岩类型、母岩分布、母岩成因及成岩演化规律。结果表明:车镇凹陷沙三下亚段砂砾岩自西向东依次发育碳酸盐岩、混合型及长英质3种母岩类型,母岩类型的有序变化主要受控于剥蚀区埕子口凸起自西向东依次裸露下古生界碳酸盐岩、太古界变质岩的特点,根本上受剥蚀区西强东弱的构造抬升幅度影响;不同母岩类型砂砾岩岩屑成分的差异性不但决定着自身抗压实能力强弱差异,还影响着酸性溶蚀强度的差异;碳酸盐岩母岩抗压实能力弱但可溶于酸性流体的矿物多,有利储层主要分布在3200 m以浅;长英质母岩抗压实能力强但可溶于酸性流体的矿物少,有利储层主要分布在3800 m以浅;混合型母岩兼具较强抗压实能力与较多可溶于酸性流体矿物优势,有利储层底界深度可达4400 m。Exploration practice has confirmed that there are differences in distribution of the types of parent rocks about sandy conglomerate in steep slope zones of faulted basins.In order to explore the mechanisms that cause the differences and their controlling effects on the diagenetic evolution of sandy conglomerate,taking the lower part of the third member of Shahejie Formation in Chezhen Depression of Bohai Bay Basin as an example,the types,distribution,genesis,and diagenetic evolution laws of sandy conglomerate parent rocks were studied based on core,logging,seismic,and a large amount of analytical laboratory data.The results indicate that there developed three types of parent rocks of sandy conglomerate in the study area from west to east:carbonate rocks,mixed rocks,and feldspar quartzite rocks.The ordered change in parent rock types are mainly controlled by the characteristics of the Chengzikou uplift in the erosion zone that Lower Paleozoic carbonate rocks and Precambrian metamorphic rocks are exposed from west to east,and are fundamentally influenced by the tectonic uplift amplitude which is stronger in the west and weaker in the east of the erosion zone.The differences in the fragment composition of different parent rock types of sandy conglomerate not only determine the difference of their own compaction strength,but also affect the differences in acidic dissolution strength.The carbonate rock parent rock has weak resistance to compaction but is rich in minerals soluble in acidic fluids,and favorable reservoirs are mainly distributed above 3200 meters.The feldspar quartzite parent rock has strong resistance to compaction,but there are few minerals soluble in acidic fluids,and favorable reservoirs are mainly distributed above 3800 meters.The mixed parent rock has relative strong resistance to compaction and a moderate amount of minerals soluble in acidic fluids,and the bottom boundary depth of favorable reservoirs is up to 4400 meters.

关 键 词：砂砾岩体 母岩类型 成岩演化 有利储层 车镇凹陷 沙三下亚段 

分 类 号：TE122.2[石油与天然气工程—油气勘探]