Zeolite diagenesis and its control on petroleum reservoir quality of Permian in northwestern margin of Junggar Basin,China  

作　　者：ZHU ShiFa ZHU XiaoMin WANG XuLong LIU ZhenYu 

机构地区：[1]State Key Laboratory of Petroleum Resource and Prospecting,Beijing 102249,China [2]College of Geosciences,China University of Petroleum,Beijing 102249,China [3]Research Institute of Petroleum Exploration and Development,Xinjiang Oilfield Company,China National Petroleum Corporation,Karamay 834000,China

出　　处：《Science China Earth Sciences》2012年第3期386-396,共11页中国科学（地球科学英文版）

基　　金：supported by National Basic Research Program of China(Grant No. 2006CB202306)

摘　　要：Recently, silicate diagenesis has been the focus of many studies because of its impact on porosity and permeability in sedimentary rocks. In the process of diagenetic evolution, the crystallization, cementation, and corrosion of zeolite （as a diagenetic mineral） have different effects on properties of Permian reservoirs in the study area. In the Permian sediments in the no,inwestern margin of the Junggar Basin, Zeolite minerals have formed during diagenesis in an open hydrologic system, related to the hydration of abundant volcanic glass. Chemical property of groundwater, pH of pore water, cation property and ratios have directly influenced the transformation among various zeolites and the dissolution of zeolite mineral. The main species of zeolite include analcime, heulandite, and laumontite. Transformations of these minerals during diagenesis are： volcanic glass→ clinoptilolite→analcime→heulandite→laumontite. Corrosion of analcime obviously improved reservoir quality. Extensive heulandite cementation developed and intensively reduced reservoir pore spaces. Early zeolite cementation protected pore structure against compaction and provided substance for late dissolution. The dissolution of analcime was closely related with the organic acid recharged by hydrocarbon source rocks and the NaHCO3 type formation water in the Permian, and was sensitive to permeability of rocks. Within the CaCl2 type formation water, heulandite and laumontite were hardly dissolved. In the study area, the belt with dissolved analcime is the area for the development of secondary pores and favorable reservoirs.Recently, silicate diagenesis has been the focus of many studies because of its impact on porosity and permeability in sedimentary rocks. In the process of diagenetic evolution, the crystallization, cementation, and corrosion of zeolite (as a diagenetic mineral) have different effects on properties of Permian reservoirs in the study area. In the Permian sediments in the northwestern margin of the Junggar Basin, Zeolite minerals have formed during diagenesis in an open hydrologic system, related to the hydration of abundant volcanic glass. Chemical property of groundwater, pH of pore water, cation property and ratios have directly influenced the transformation among various zeolites and the dissolution of zeolite mineral. The main species of zeolite include analcime, heulandite, and laumontite. Transformations of these minerals during diagenesis are: volcanic glass→ clinoptilolite→analcime→heulandite→laumontite. Corrosion of analcime obviously improved reservoir quality. Extensive heulandite cementation developed and intensively reduced reservoir pore spaces. Early zeolite cementation protected pore structure against compaction and provided substance for late dissolution. The dissolution of analcime was closely related with the organic acid recharged by hydrocarbon source rocks and the NaHCO3 type formation water in the Permian, and was sensitive to permeability of rocks. Within the CaCl2 type formation water, heulandite and laumontite were hardly dissolved. In the study area, the belt with dissolved analcime is the area for the development of secondary pores and favorable reservoirs.

关 键 词：natural zeolite DIAGENESIS volcanic glass secondary pore Junggar basin 

分 类 号：P618.130.2[天文地球—矿床学] TQ171.733[天文地球—地质学]