川西南地区二叠纪火山岩储层类型及其主控因素分析  

Permian volcanic reservoir types and main controlling factors in Southwest Sichuan

作　　者：熊绍云 史志伟 王尉 张豪 刘冉 苏旺[4] 李亚 姚倩颖 张建勇 江青春[4] XIONG Shaoyun;SHI Zhiwei;WANG Wei;ZHANG Hao;LIU Ran;SU Wang;LI Ya;YAO Qianying;ZHANG Jianyong;JIANG Qingchun(PetroChina Hangzhou Research Institute of Geology,Hangzhou 310023,China;School of Earth Sciences and Resources,China University of Geoscience,Beijing 100083,China;Exploration and Development Research Institute of PetroChina Southwest Oil&Gasfield Company,Chengdu 610041,China;Research Institute of Petroleum Exploration&Development,PetroChina,Beijing 100083,China)

机构地区：[1]中国石油杭州地质研究院,浙江杭州310023 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国石油西南油气田公司勘探开发研究院,四川成都610041 [4]中国石油勘探开发研究院,北京100083

出　　处：《天然气地球科学》2022年第6期899-916,共18页Natural Gas Geoscience

基　　金：中国石油科技项目“深层—超深层油气富集规律与区带目标评价”(编号:2018A-0105)资助。

摘　　要：二叠纪火山岩作为川西南地区重要的储层类型已成为近些年研究热点之一。通过对川西南地区二叠纪火山岩孔隙度和渗透率分析发现,爆发相火山碎屑流亚相的粗面安山质火山碎屑岩储层物性最好,其次为溢流相上部亚相的自碎角砾岩以及爆发相的粗面玄武质熔结火山碎屑岩,熔岩类储集物性较差。通过岩心、野外及镜下观察,火山岩储集空间主要为溶蚀孔洞和裂缝,钠长石晶间微孔对粗面安山质熔结凝灰岩储层贡献较大。火山岩岩相是储层发育的基础,溢流相上部亚相和爆发相火山碎屑流亚相近—中源堆积是储层发育的有利相带,火山碎屑流亚相近—中源堆积内部储层非均质性强,每个喷发单元上部及下部储集物性好于中部。经历冷凝固结成岩和热液作用阶段,粗面玄武质熔结火山碎屑岩及溢流相上部亚相的自碎角砾岩储层孔隙度由25%~30%迅速减少至5%~10%;由于大量钠长石晶间微孔的形成抵消了一部分在此成岩过程损失的孔隙,粗面安山质熔结凝灰岩经历该期成岩作用孔隙度损失了10%左右。低温低盐度包裹体揭示了储层孔洞中第一期方解石及石英胶结物形成于火山停止喷发后的浅—中埋藏期,有机质未成熟—低成熟,未发生大规模排烃,有机酸对储层溶蚀作用有限,表明早期表生成岩阶段的风化淋滤作用是储层改善和保存的关键;埋藏期为孔洞连续充填阶段,有机酸溶蚀作用对储层改善有限。As an important reservoir type in Southwest Sichuan,Permian volcanic rocks have become one of the research hotspots in recent years.Through the analysis of the porosity and permeability from Permian volcanic rocks in Southwest Sichuan,it is found that the trachyte andesitic pyroclastic rock reservoir of explosive facies pyroclastic flow subfacies is the best,followed by the self broken breccia of the upper subfacies in overflow facies and the trachyte basaltic fused pyroclastic rock of explosive facies.The porosity and permeability of lava reservoirs are poor.Through core,outcrops and microscopic observation,the reservoir space of volcanic rock is mainly dissolution holes and fractures,and the intergranular micropores of albite make a great contribution to the reservoir of trachy and esitic fused tuff.Volcanic rock facies are the basis of reservoir development.The upper subfacies of overflow facies and explosive facies are similar.Pyroclastic flow sub-middle source accumulation is a favorable facies belt for reservoir development.The reservoir heterogeneity of pyroclastic flow sub-middle source accumulation is strong,and the reservoir physical properties in the upper and lower parts of each eruption unit are better than those in the middle.Through condensation consolidation diagenesis and hydrothermal process,the porosity of trachytic basaltic fusion breccia and self broken breccia in the upper subfacies of overflow facies decreases rapidly from 25%-30% to 5%-10%;Due to the formation of a large number of intergranular micropores of albite offsetting part of the pores lost in this diagenetic process,the porosity of trachytic andesitic fused tuff lost about 10% during this diagenesis.Low temperature and low salinity inclusions reveal that the first stage calcite and quartz cements in the reservoir pores were formed in shallow to medium burial after the volcanic eruption stopped,the organic matter was immature to low mature,there was no large-scale hydrocarbon expulsion,and the dissolution of organic acids to the re

关 键 词：川西南地区 二叠纪 火山岩储层 火山岩岩相 早期表生成岩阶段 风化淋滤作用 储层发育主控因素 

分 类 号：TE122.2[石油与天然气工程—油气勘探]