Reservoir space types and the factors influencing the characteristics of spherulite in rhyolite  

作　　者：TIAN JingXiong SUN XiaoMeng ZHANG XuQing SHOU YongCheng 

机构地区：[1]College of Earth Sciences, Jilin University

出　　处：《Science China Earth Sciences》2013年第5期748-755,共8页中国科学（地球科学英文版）

基　　金：supported by National Basic Research Program of China (Grant No. 2009CB219305)

摘　　要：Oil-gas reservoir space types involving spherulite in pyromeride rocks are common in the Lower Cretaceous Shangkuli Formation, the Hailar Basin, China. The main types include interspherulite fissures, interlayer fissures, intraspherulite concentric rings and net microcracks, cavity pores, dissolution pores, and devitrification pores. The first two were found to restrict the effective plane porosity of interspherulite. Devitrification microporosities, microcracks, cavity pores, and spherulite diameter influence the effective plane porosity of intraspherulite. The degree of dissolution is determined by the degree of development and the type of intraspherulite microcracks. Another important role of ring and net microcracks is to connect devitrification pores to form a pore and fissure network. Finally, chilling contraction plays an important role in the form and development of interspherulite fissures, microcracks, and cavity pores. The diameter of spherulite restricts chilling contraction, especially when the diameter is between the common spherulites and lithophysae, thus benefiting microcrack and cavity pore formation. To summarize, devitrification microporosities represent excellent oil reservoir space, while offering micro-channels for the movement of formation water and organic fluids. However, the inclusion of microcracks improves this capacity.Oilgas reservoir space types involving spherulite in pyromeride rocks are common in the Lower Cretaceous Shangkuli For mation, the Hailar Basin, China. The main types include interspherulite fissures, interlayer fissures, intraspherulite concentric rings and net microcracks, cavity pores, dissolution pores, and devitrification pores. The first two were found to restrict the ef fective plane porosity of interspherulite. Devitrification microporosities, microcracks, cavity pores, and spherulite diameter in fluence the effective plane porosity of intraspherulite. The degree of dissolution is determined by the degree of development and the type of intraspherulite microcracks. Another important role of ring and net microcracks is to connect devitrification pores to form a pore and fissure network. Finally, chilling contraction plays an important role in the form and development of interspherulite fissures, microcracks, and cavity pores. The diameter of spherulite restricts chilling contraction, especially when the diameter is between the common spherulites and lithophysae, thus benefiting microcrack and cavity pore formation. To summarize, devitrification microporosities represent excellent oil reservoir space, while offering microchannels for the movement of formation water and organic fluids. However, the inclusion of microcracks improves this capacity.

关 键 词：Hailar Basin Shangkuli Formation SPHERULITE reservoir space chilling contraction DISSOLUTION DEVITRIFICATION 

分 类 号：P573[天文地球—矿物学]