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基于地质背景和大量钻测资料,利用流体包裹体和成岩矿物组合的地球化学特征,以成岩流体类型和活动历史为视角,综合分析了琼东南盆地东部宝岛凹陷北缘储层异常高孔带的动态成因过程。研究区发育了三段异常高孔带,其中前两段在全区均有发育,第三段仅在BD19-2构造部分井发育。控制该区异常高孔带发育的流体类型为有机酸、大气淡水、烃类、热流体和无机幔源CO_2。在中新世早中期,大气水淋滤引起溶蚀,持续至中新世中期;中新世末期陵一段泥岩生排的有机酸进入储层,再次发生溶蚀形成次生孔,第四纪热流体的溶蚀作用最终形成第一段异常高孔带。中新世末期陵二段泥岩排出的有机酸引起溶蚀,持续到上新世中期,上新世早期天然气充注抑制了碳酸盐胶结物充填孔隙,与此同时热流体活动也引发溶蚀,综合形成第二段异常高孔带。中新世早期下伏崖城组源岩开始生排有机酸引起溶蚀,持续至中新世中期,中新世末期陵二段泥岩开始生排有机酸再次引起溶蚀,持续至上新世中期,中新世中期天然气充注抑制了碳酸盐胶结物充填孔隙,上新世富幔源CO_2的热流体开始活动溶蚀,综合形成第三段异常高孔带。
Based on the geologic background and a large number of drilling data, the geochemical characteristics of fluid inclusions and diagenetic mineral assemblages are used to analyze the types and activity history of diagenetic fluids. The abnormal high porosity zones in the northern margin of the Baojain Sag in eastern Qiongdongnan Basin The dynamic process of formation. In the study area, there are three sections of abnormal high-porosity zone, of which the first two sections are all developed in the whole area and the third one is only developed in the well of BD19-2. The types of fluids controlling the development of anomalously high porosity zones in this area are organic acids, atmospheric freshwater, hydrocarbons, thermal fluids and mantle source CO 2. In the early and middle Miocene, the leaching of atmospheric water caused dissolution, continuing to the mid-Miocene; the organic acid generated by mudstone in the late Miocene entered the reservoir and dissolved again to form secondary pores. Quaternary thermal fluid The dissolution of the final formation of the first abnormal high pore zone. The organic acid emanating from the mudstone of the second member of the second Miocene resulted in dissolution until the mid-stage of the Pliocene, filling of the carbonate cements was suppressed by the filling of natural gas in the early Pliocene, and thermal fluid activity also initiated erosion and synthesis The second abnormal high porosity zone was formed. The source rocks of the Lower Yacheng Formation in the Early Miocene started to erode due to organic anomalies and lasted until the middle stage of the Middle Miocene. Mist organic anomalies began to erode again from the second stage of the Miocene, The filling of carbonates in the mid-Miocene gas suppressed the pore filling of carbonate cements, and the thermal fluid in the Upper Pleistocene mantle source CO_2 started to move and dissolved, forming the third abnormally high porosity zone.