西昌盆地东吴期深部热液作用及其对志留系碳酸盐岩储层的改造  

THE HYDROTHERMAL FLUIDS PROCESS OF DONGWUNIAN PERIOD AND RELATED ALTERATION TO CARBONATE RESERVOIR OF SILURIAN IN XICHANG BASIN

作　　者：李国蓉[1,2] 刘树根[1,2] 宋来明[3] 于海波[4] 周大志[1,2] 程流[1,2] 

机构地区：[1]油气藏地质及开发工程国家重点实验室(成都理工大学),四川成都610059 [2]成都理工大学能源学院,四川成都610059 [3]中国海洋石油总公司,北京100010 [4]中国海洋石油总公司天津分公司,天津300452

出　　处：《矿物岩石》2009年第4期60-65,共6页Mineralogy and Petrology

基　　金：973项目(编号:G1999043309)

摘　　要：晚古生代中国西南地区发生了"峨眉地裂运动",与此相关的深部热液作用在西昌盆地非常发育发育。对QB1井的研究表明,志留系第Ⅲ期裂缝及其中充填的异形白云石和石英是东吴期热液作用的产物,异形白云石的δ13C值、δ18O值异常偏负、锶同位素值异常偏高、异形白云石和石英内原生包裹体气相部分富含氮气(N2)是这一期热液作用的地球化学标志;深部热液为幔源岩浆热液与盆地基底深变质岩地层热液的混合液,它们沿垂向断裂通道和侧向裂缝系统运移进入志留系,导致了不规则的张性热液破裂裂缝的形成、裂缝内异形白云石和石英的部分沉淀、以及溶蚀作用的发生;它们产生的缝洞系统,对西昌盆地志留系裂缝性储层的形成有重要贡献。In the late Paleozoic, Emei tafrogeny occurred in the southeast China and resulted in well developed hydrothermal process in deep layer and related fracturing process in the Xichang Basin,evidenced by the formation of saddle dolomite and quartz in the third stage of fractures in well QB1. Analysis of saddle dolomite showed a low δ^13C and δ^18O value and high ^87Sr/^86Sr value, and abundant N2 occurred in the gas phase of primary inclusion within the saddle dolomite and quartz. All geochemical characters demonstrated the existence of hydrothermal fluids process. Deep hydrothermal fluids,derived from mantle magma hydrothermal fluids and basin floor metamorphic hydrothermal fluids,migrated into Silurian rocks along vertical and lateral fractures, resulting in the formation of irregular tensile hydrothermal fracture system, the precipitation of saddle dolomite and quartz in fractures, as well as the occurrence of dissolution. It was considered that the hydrothermal fractures played an important role in the formation of fracture reservoir in Silurian in the Xiehang Basin.

关 键 词：西昌盆地 志留系 东吴期 热液作用 碳酸盐岩储层 

分 类 号：TE122.221[石油与天然气工程—油气勘探]