Diagenetic history and porosity evolution of the Middle Permian clastic-carbonate mixed system,Indus Basin,Pakistan:Implications for reservoir development  

作　　者：Bilal Wadood Suleman Khan Michael Wagreich Torsten Vennemann Hong Li Matee Ullah Katerina Schöpfer 

机构地区：[1]Department of Geology,University of Swabi,Anbar-Swabi,23561,Pakistan [2]State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an,710069,China [3]Department of Geology,University of Vienna,Vienna,A-1090,Austria [4]Department of Geology,University of Peshawar,Peshawar,25120,Pakistan [5]Institute of Earth Surface Dynamics,University of Lausanne,Lausanne,CH-1015,Switzerland [6]Department of Lithospheric Research,University of Vienna,Vienna,A-1090,Austria

出　　处：《Energy Geoscience》2024年第4期156-173,共18页能源地球科学（英文）

基　　金：funded by the National Natural Science Foundation of China(Grant/Award Numbers:41272115,41572086);OeAD(Austria's Agency for Education and Internationalization).

摘　　要：This study deals with unraveling the diagenesis-induced porosity evolution in a mixed clastic-carbonate sequence of the Middle Permian Indus Basin,Pakistan.Multiple data sets including outcrop,petrography,cathodoluminescence,scanning electron microscopy(SEM),mineralogy,and geochemical isotopic compositions were integrated to establish a link between porosity evolution and diagenesis.The spatial thickness and facies variations of the strata at outcrop scale are inherently controlled by the underlying bathymetry of the basin with deepening westward trend.The low values ofδ^(18)O of the target strata,relative to average values of the Permian carbonate,hints to diagenetic alteration in the strata.The data sets used in this study reveal modification of the strata in four environments,that is,i)early marine diagenesis indicated by micritization,pervasive dolomitization and isopachous fibrous cements,followed by ii)meteoric dissolution,and iii)shallow burial diagenetic processes including the precipitation of blocky cement,compaction of skeletal and non-skeletal allochems,and stylolites,and iv)a deep burial environment,characterized by pressure solution,and micro-fractures.The clastic intervals host subangular to subrounded quartz grains,floating textures,and almost complete absence of deleterious clay minerals,consequently resulting in the preservation of primary porosity.The primary porosity of carbonate intervals is preserved in the form of intercrystalline and intracrystalline porosity.The secondary porosity evolved through various diagenetic phases in the form of fractures and dissolution.The diagenetic solution mediated by organic matter in carbonates may have experienced both bacterial decomposition and thermochemical sulfate reduction,precipitating sulfides within the pores.The plug porosity/permeability analyses generally suggest high porosity in the siliciclastic unit,and carbonates with wackestone fabric while lower values were observed for the inner shelf pure carbonate facies.However,both intervals show ve

关 键 词：Reservoir DIAGENESIS POROSITY PERMIAN Indus Basin 

分 类 号：P58[天文地球—岩石学]