Constrains of eruption environment and hydrothermal fluid on the Permian pyroclastic reservoirs in the Sichuan Basin,SW China  

作　　者：Xiaohong Liu Yiqian Zhuo Mingyou Feng Benjian Zhang Maolong Xia Xingzhi Wang 

机构地区：[1]School of Geoscience and Technology,Southwest Petroleum University,Chengdu,610500,China [2]Natural Gas Geology Key Laboratory of Sichuan Province,Chengdu,610500,China [3]Northwest Sichuan Mining District,PetroChina Southwest Oil and Gas Filed Company,Jiangyou,621709,China [4]PetroChina Southwest Oil and Gas Field Company Exploration and Development Research Institute,Chengdu,610041,China

出　　处：《Petroleum》2022年第1期17-30,共14页油气（英文）

基　　金：This work was granted by the National Natural Science Foundation of China(Grant No.41202109);the National Major Science and Technology Projects of China(Grant No.2016ZX05007004001);the Innovation Foundation of PetroChina Carbonate Key laboratory(RIPED-HZDZY-2019-JS-695);the China Scholarship Council.Thanks are expressed to our colleagues involved in igneous rocks researching in the Sichuan Basin,as well as to several anonymous reviewers from which this article has benefited.

摘　　要：A breakthrough has been recently made in the hydrocarbon exploration of the Permian pyroclastic rocks in the Jianyang Area,western Sichuan Basin,China.With an aim to decipher the impacts of the eruption environment,the temperature of hydrothermal fluids,and the paleo-salinity on the formation of authigenic mineral assemblage and pores,this study implements comprehensive petrographic and geochemical studies through the integrated core and thin section analyses.The data presented demonstrate that the Permian volcanic intervals are intensively affected by an event of Emei taphrogeny.During basaltic magma upward migration,fractional crystallization of anorthose results in slightlyalkaline magma.The specific pyroclastic rocks are formed by the eruption of slightly-alkaline magma in the sea or a salt lake and subsequent hydrothermal alteration.During deposition and diagenesis,the authigenic mineral association is constrained jointly by the sodium-rich and high salinity water environment,and mid-high temperature,high-salinity hydrothermal fluid.Specifically,the sodium-rich hydrothermal fluid,which may sustain till the late diagenesis stage,caused pervasive albitization of pyroclastic rocks,then leading to mineral transformation and formation of a series of mineral associations.Therefore,zeolitization of volcanic glass and vesicle-infillings of zeolite is an essential condition for later mineral transformation and dissolution.Albitization of analcite,recrystallization induced by deep hydrothermal fluids,and both meteoric and deep burial dissolution expanding the micro-pore space ultimately formed porous pyroclastic reservoirs.

关 键 词：PERMIAN Pyroclastic rock Eruption environment Hydrothermal fluid Sichuan basin Southwest China 

分 类 号：P618.13[天文地球—矿床学]