摘要:
济阳坳陷是渤海湾盆地的一个次级构造单元,其中部阳信—花沟—平南地区是主要的二氧化碳 (CO2 )气藏产出区。该地区CO2 气藏的储层主要有下古生界海相碳酸盐岩、下第三系湖相碳酸盐岩和三角洲相砂岩、以及上第三系河流相砂岩。下古生界碳酸盐岩储层分布于其北部潜山带,储集空间以构造裂缝和溶蚀孔隙为主。下第三系湖相碳酸盐岩储层分布于平方王地区的沙四和沙一段。下第三系三角洲相砂岩储层主要发育于高青—平南、林樊家和阳信等地的沙河街组。上第三系河流相砂岩储层分布十分广泛,但总体来讲,其北部地层砂泥比 (5 0 %～ 70 % )较高,砂岩单层厚度 (2 0～ 40m)大,孔隙度大,渗透率高;而南部地层砂泥比小,砂岩单层厚度薄,孔隙度小,渗透率低。研究区CO2 气藏的盖层以泥质岩类为主,致密砾岩次之。它们均为有效盖层。沙三段、沙一段、馆陶组上部至明化镇组下部泥质岩集中段是CO2 气藏最重要的三大区域盖层。沙四段致密砂砾岩盖层主要分布于八里泊残丘潜山的顶部,构成潜山圈团的盖层,其渗透性很低。与烃类甲烷气藏相比,两者的储层类型基本相同,但对于盖层而言,由于CO2气分子半径较烃类甲烷气分子半径大,因而CO2 气藏对盖层的要求比烃类甲烷气藏低。
Abstract:
Jiyang Depression is one of the sub basins in Bohaiwan basin. Carbon dioxide (CO2 pools occur in Yangxing Huagou Pingnan area, the center of Jiyang Depression. Reservoirs of the CO2 pools are the marine carbonate rocks in lower Palaeozoic Era, the lake carbonate rocks and delta sandstone in Eogene System, and the fluvial sandstone in Neogene System. The marine carbonate rock reservoirs are in the north of the area and the reservoir spaces are the structural and solution gaps. The lake carbonate rock reservoirs are in No.4 and 1 sections of Shahejie Formation in Pinfangwang area. The delta sandstone reservoirs, which total thickness are 100m～600m,porosity range from 11.5%～33% and permeability from 6.5×10 -3 m2～83×10-3 m2, are in Shahejie Formation in Gaoqing Pingnan, Lingfanjia and Yangxing area, respectively. The fluvial sandstone reservoirs are widely distributed in Yangxing Huagou Pingnan area. In generally, the sand and mud ratios, porosity and permeability of the fluvial sandstone reservoirs in the north are higher than that in the south of the area. Seals of CO2 pools in Yangxing Huagou Pingnan area are mudstone and compact conglomerate and they all are effective seals. The mudstone seals are mainly distributed in No.3 and 1 sections of Shahejie Formation in Eogene System and upper Guantao Formation and Minghuazheng Formation in Neogene System. The compact conglomerate seals, which permeability are very low, occur in No.4 section on the sub mountain in Balibo of the north of Yangxing Huagou Pingnan area.Comparison of reservoir and seal between CO2 pools and hydrogen gas pools, two kinds of pools are of similar reservoir. And CO2 pools have poor qualitiy seal.
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