控制储层中异常高孔带发育的成岩作用——以琼东南盆地西部崖城区为例

发布时间：2018-04-09 16:37

本文选题：异常高孔带　切入点：成岩作用　出处：《中国矿业大学学报》2017年02期

【摘要】：基于大量物性数据和沉积构造背景,利用铸体薄片、有机地球化学和流体包裹体技术,研究了控制琼东南盆地西部崖城区储层异常高孔带发育的成岩作用.认为崖城区三段异常高孔带的成因不同,控制其发育的主要成岩作用分别为有机酸溶蚀与大气淡水淋滤作用,热流体溶蚀作用和有机质生成天然气引起的超压保持作用.研究结果表明:崖城区共发育3段异常高孔带,分布于2 400~3 100m,3 600~4 100m和4 500~4 800m.第1段异常高孔带属于有机酸和大气淡水混合溶蚀型,即有机质早期大量释放的有机酸和大气淡水共同溶解了长石、碳酸盐胶结物等产生次生孔,早期绿泥石包壳未起有效作用.第2段异常高孔带属于热流溶蚀型,热流体使烃源岩加快熟化从而延长有机酸的产出期,而且促使蒙脱石迅速转化为伊利石从而释放更多的H~+;深部流体携带大量酸性组分且具有较强的流体性,可以对储层产生淋滤,也加快了Al~(3+)的迁移;更高的温压可以促进溶蚀反应的发生,提高溶解度.第3段异常高孔带属于超压保持性型,强超压有效抑制了压实作用和自生矿物发育,保持了孔隙度.超压体系向上集中排放形成热流体使得该段超压储层硅质流失,致使自生石英未规模发育.伊蒙转化反应被提前而且超压对该反应也有抑制作用,使得自生伊利石未大量形成.该区天然气充注期为晚期,烃类侵位未能抑制石英等自生矿物的生长,但盆地晚期快速沉降使得源岩大量生成天然气促使超压形成,间接贡献了第3段异常高孔带的发育.
[Abstract]:Based on a great deal of physical property data and sedimentary tectonic background, diagenesis controlling the development of abnormal high porosity zone in Yacheng district of western Qiongdongnan basin was studied by using cast thin sheet, organic geochemistry and fluid inclusion technique.It is considered that the genesis of the abnormal high porosity zone in the three sections of Yancheng District is different. The main diagenesis controlling its development are organic acid dissolution and atmospheric fresh water leaching, thermal fluid dissolution and overpressure retention caused by the formation of natural gas by organic matter.The results show that there are 3 abnormal high pore zones in Yancheng district, which are distributed in 2 400 ~ 3 100 m ~ 3 600 ~ 4 100 m and 4 500 ~ 4 800 m ~ (-1).The anomalous high pore zone of the first member belongs to the mixed corrosion type of organic acid and atmospheric fresh water, that is, the organic acid released in the early stage of organic matter and atmospheric fresh water dissolved feldspar, carbonate cement, etc., and produced secondary pores.The early chlorite cladding did not play an effective role.The abnormal high porosity zone of the second member belongs to the heat flow dissolution type, which accelerates the maturation of the source rocks and prolongs the production period of organic acids, and promotes the rapid conversion of montmorillonite to Illite, thus releasing more H-;Deep fluids carry a large number of acidic components and have strong fluidity, which can cause leaching to the reservoir and accelerate the migration of Al~(3, and higher temperature and pressure can promote the occurrence of dissolution reaction and improve the solubility.The abnormal high pore zone in section 3 belongs to the type of overpressure retention. Strong overpressure effectively inhibits compaction and the development of authigenic minerals and keeps porosity.The overpressure system is discharged up and concentrated to form a thermal fluid, which causes siliceous loss in the overpressure reservoir, which leads to the undeveloped size of the authigenic quartz.The Aemon transformation reaction was advanced and overpressure inhibited the reaction, resulting in the formation of authigenic Illite.The hydrocarbon emplacement failed to inhibit the growth of authigenic minerals such as quartz, but the rapid subsidence in the late stage of the basin resulted in a large amount of natural gas generated from the source rocks and the formation of overpressure, which indirectly contributed to the development of the abnormal high porosity zone in the third member.
【作者单位】：中国地质大学构造与油气资源教育部重点实验室;甘肃省油气资源研究重点实验室中国科学院油气资源研究重点实验室;西北大学地质系;中海石油(中国)有限公司湛江分公司;
【基金】：国家重大科技专项(2011ZX05023-004-010)
【分类号】：P618.13

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