车西洼陷陡坡带沙三下亚段近岸水下扇储层成岩演化及其对储层物性影响

发布时间：2018-10-23 13:14

【摘要】：利用岩芯观察、铸体薄片、扫描电镜、阴极发光及岩石物性测试等多种资料,本文对济阳坳陷车西洼陷陡坡带沙三下亚段近岸水下扇储层进行了探讨。结果表明,车西洼陷沙三下段近岸水下扇储层岩石类型宏观上主要表现为泥质杂基支撑砾岩、碎屑支撑砾岩、砾质砂岩等沉积,微观上以岩屑砂岩和长石质岩屑砂岩为主,灰泥质杂基含量最高可达40%。车西洼陷沙三下段近岸水下扇储层为典型的特低孔、特低渗储层类型,其平均孔隙度和渗透率分别为3.42%、2.02×10~(-3)μm~2;但在3 500~4 000 m深度段发育异常高孔带,孔隙度可达10.2%,储集空间多为溶蚀孔和微裂缝。研究区储层经历了复杂的成岩演化过程,目前处于中成岩B期,其成岩演化序列为:压实作用/碳酸盐胶结→长石溶蚀/碳酸盐胶结物溶蚀→石英溶蚀/碳酸盐胶结/灰泥重结晶→石英加大/碳酸盐胶结溶蚀→碳酸盐胶结。不同亚相所经历的成岩演化有所差异,其中中扇辫状水道中远端及中扇前缘经历了多期溶蚀作用,储层物性相对较好,平均孔隙度分别可达4.5%,7.25%,为研究区近岸水下扇砂砾岩储层的"甜点区"。
[Abstract]:Based on the data of core observation, thin casting, scanning electron microscope, cathodoluminescence and petrophysical properties testing, this paper discusses the nearshore underwater fan reservoir in the lower section of Sha3 submember in the steep slope zone of Chexi depression, Jiyang depression. The results show that the rock types of the nearshore subaqueous fan reservoirs in the Lower Sha 3 member of the Chexi sag are mainly composed of muddy complex supporting conglomerate, clastic supporting conglomerate, gravel sandstone, etc. Microscopically, lithic sandstone and feldspathic lithoclastic sandstone are the main ones. The highest content of hetero-group in plaster is up to 40%. The near-shore subaqueous fan reservoir in the lower member of Sha 3 in the Chexi sag is a typical type of ultra-low porosity and ultra-low permeability reservoir. Its average porosity and permeability are 3.42 脳 10 ~ (-3) 渭 m ~ (-3) 渭 m ~ (-2), respectively, but the abnormal high porosity zone is developed in the depth of 3 500 ~ 4 000 m. Porosity can reach 10. 2 and the reservoir space is mainly composed of corrosion pores and micro fractures. The reservoir in the study area has undergone a complicated diagenetic evolution process and is now in the middle diagenesis B stage. The diagenetic evolution sequence is as follows: compaction / carbonate cementation feldspar dissolution / carbonate cementation dissolution of quartz / carbonate cementation / recrystallization of plaster quartz / carbonate cement dissolution / carbonate cementation. The diagenetic evolution of different subfacies is different, in which the distal and middle fan front of fan braided waterway undergo multi-stage dissolution, and the reservoir physical properties are relatively good. The average porosity can reach 4.5% and 7.25% respectively, which is the "dessert area" of the underwater fan sand and gravel reservoir in the study area.
【作者单位】：中国石化胜利油田地质科学研究院;油气资源与探测国家重点实验室;中国石油大学(北京)地球科学学院;
【基金】：国家自然科学基金项目(41272133) 国家科技重大专项专题(2011ZX05001-002-01)~~
【分类号】：P618.13

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