川北地区灯影组四段白云岩成岩演化对优质储层的控制作用  

Controls on the High-Quality Dolomite Reservoir of the 4th Member of Denying Formation Related to the Diagenetic Evolution,Northern Sichuan Basin

作　　者：罗青云 王剑 杜秋定 王铜山[4] 付修根 周刚[5] 李秋芬 韦恒叶 沈利军 和源 王永生 LUO QingYun;WANG Jian;DU QiuDing;WANG TongShan;FU XiuGen;ZHOU Gang;LI QiuFen;WEI HengYe;SHEN LiJun;HE Yuan;WANG YongSheng(School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Qiangtang Insitute of Sedimentary Basin,Southwest Petroleum University,Chengdu 610500,China;PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;PetroChina Southwest Oil&Gas Field Company,Chengdu 610041,China;PetroChina Hangzhou Research Insitute of Geology,Hangzhou 310023,China)

机构地区：[1]西南石油大学地球科学与技术学院,成都610500 [2]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500 [3]西南石油大学羌塘盆地研究院,成都610500 [4]中国石油天然气股份有限公司勘探开发研究院,北京100083 [5]中国石油天然气股份有限公司西南油气田分公司,成都610041 [6]中国石油杭州地质研究院,杭州310023

出　　处：《沉积学报》2024年第6期2174-2190,共17页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(41972121);四川省科技厅重点研发项目(2022YFS0466);中国石油—西南石油大学创新联合体项目(2020CX010100);中国石油天然气股份有限公司科学研究与技术开发项目(2021DJ05)。

摘　　要：【目的】四川盆地北部地区震旦系灯影组碳酸盐岩储层在形成过程中经历了多期成岩流体的叠加改造,对储层质量的优劣产生了重要影响。【方法】采用激光原位碳氧同位素和微区锶同位素、结合配套的岩石学、阴极发光等技术手段,系统研究了灯影组白云岩岩石学、成岩作用、成岩流体性质等特征,明确了不同成岩流体的成岩作用过程及其对储层物性的影响。【结果】(1)灯影组四段沉积微生物白云岩、颗粒白云岩和晶粒白云岩三大类岩石类型,藻纹层白云岩、叠层石白云岩及凝块石白云岩是优质储集岩,发育大量原生藻格架孔,是优质储层发育的基础;(2)灯影组四段白云岩优质储层发育与四种成岩环境有关,即蒸发海水环境、浅埋藏“封存”海水环境、中—深埋藏有机质成熟运移环境和构造—热液环境,不同成岩流体性质与优质储层改造的关系表明,埋藏有机酸和热液流体的溶蚀作用极大地改善了储层物性;(3)优质储层的发育受沉积环境、成岩过程及成岩流体、构造作用等相互控制与制约,其中有利的沉积相带是基础,成岩流体的溶蚀改造是关键,构造运动形成的断裂为深部流体活动提供了有利条件。【结论】灯影组四段白云岩优质储层改造的精细识别与定量改造程度的研究,为该地区油气勘探目标预测提供了沉积成岩方面的理论依据。[Objective]The carbonate rocks from the Sinian Dengying Formation in the northern Sichuan Basin experienced multi-stage fluid alteration,which has exerted a significant influence on the quality of the reservoir.[Methods]Laser in-situ carbon and oxygen isotopes,micro-area strontium isotopes,petrography,and cathodoluminescence were used to systematically analyze the petrology and diagenetic evolution of dolomite in the Dengying Formation.Based on this research,we clarified the diagenesis process of different diagenetic fluids and its influence on reservoir formation.[Results]The results indicate that:(1)The dolomite can be divided into three different lithofacies:microbial,granular,and crystalline.Growth-framework porosity of carbonates is the fundamental factor for developing high-quality reservoirs;therefore,laminated,stromatolite,and clotted dolomites with a large number of primary pores can be regarded as high-quality reservoir rocks.(2)Four diagenetic environments associated with the development of high-quality reservoirs were identified in the 4th member of the Dengying Formation,including evaporated seawater,shallow buried“trapped”seawater,medium-deep buried organic acid migration,and hydrothermal environments.Isopachous fibrous and blade cements precipitate in the evaporated seawater environment,and the cements have no cathodoluminescence.Theirδ13C,δ18O,and 87Sr/86Sr values agree with the Sinian seawater.Finecrystalline cements with moderate orange-red cathodoluminescence are precipitated in shallow buried“trapped”seawater environments,theδ13C,δ18O,and 87Sr/86Sr compositions of the cements are similar to the Sinian seawater,and samples have slightly lowerδ18O than that of Sinian seawater.The medium-crystalline cements precipitate in the medium-deep buried organic acid migration environment,while the cements feature strong orange-red cathodoluminescence and a relatively more negatively biasedδ18O.The 87Sr/86Sr value of the cements is sufficiently close to the Cambrian,indicating that the cement

关 键 词：四川盆地 震旦系 灯影组 微生物丘 储层改造 有机酸流体 热液 

分 类 号：P618.13[天文地球—矿床学]