断陷湖盆斜坡带储层差异性成岩—成储模式——以渤海湾盆地埕北低凸起东部斜坡带东营组为例  

Differential Diagenesis-reservoir Formation Model of the Slope Belt of a Faulted Lacustrine Basin:Case study of the Dongying Formation in the eastern slope belt of the Chengbei low uplift,Bohai Bay Basin

作　　者：袁静[1] 周涛[2] 景安语 孙超 马立驰 吴根杰 YUAN Jing;ZHOU Tao;JING AnYu;SUN Chao;MA LiChi;WU GenJie(School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266580,China;Research Institute of Oil and Gas Technology,PetroChina Changqing Oilfield Company,Xi’an 710018,China;Research Institute of Exploration and Development,Shengli Oilfield,SINOPEC,Dongying,Shandong 257000,China;Research Institute of Petroleum Exploration and Development,SINOPEC,Beijing 102206,China;Qinghai Oilfield,CNPC,Dunhuang,Gansu 736200,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]长庆油田分公司油气工艺研究院,西安710018 [3]中石化胜利油田分公司勘探开发研究院,山东东营257000 [4]中石化石油勘探开发研究院,北京102206 [5]中国石油青海油田分公司,甘肃敦煌736200

出　　处：《沉积学报》2023年第3期804-817,共14页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(42072134)。

摘　　要：以渤海湾盆地渤中凹陷埕北低凸起东部斜坡带古近系东营组为例,综合运用薄片鉴定、物性分析、扫描电镜观察、X射线衍射和镜质体反射率分析等手段,结合区域地质研究成果,研究断陷湖盆斜坡带不同构造单元主力含油层位的成岩作用及其与储层物性的关系。结果表明:埕北低凸起东部斜坡带东(东营组)三亚段二砂组至东三段整体处于中成岩A期,由浅至深发育4个次生孔隙发育带,储集空间以溶蚀孔隙和微裂缝为主,各构造单元储层成岩和孔隙演化差异明显。酸性溶蚀作用是第一坡折带储层物性改善的重要因素;第二坡折带在中成岩A1和A2亚期分别由酸溶性孔隙和层间裂缝改善储层物性;碱性溶蚀作用形成连通性较好的溶蚀孔隙是断阶带深部储层物性得以改善的重要因素;洼陷带则由孔隙—裂缝复合系统作为重要储集空间,微裂缝的发育对物性改善具有重要意义。中浅层砂(砾)岩储层的物性与厚度负相关,单层厚度小于4 m者物性相对更好;深层储层中压裂缝和超压裂缝的广泛发育连通溶蚀孔隙改善了储集物性,层厚超过4 m的含砾砂岩物性好于同厚度的砂岩。基于上述认识,建立了研究区主要构造单元东营组主力含油层位的差异性成岩—成储模式。The diagenesis of the major oil-bearing strata in the main tectonic units of the Paleogene Dongying Formation in the eastern slope belt of the Chengbei low uplift in the Bozhong Depression,Bohai Bay Basin,was studied as an example of the relationship between reservoir properties in the slope belt of a faulted lacustrine basin.The main methods included thin-section identification,physical property analysis,scanning electron microscopy,X-ray diffraction analysis and vitrinite reflectance analysis,in combination with regional geological research results.It was found that,from sand group Ed23 to member 3 of the Dongying Formation,this area is generally at the middle diagenetic stage A.Four secondary pore development zones are present from shallow to deep.The main reservoir space types are secondary pores and micro-fractures.The diagenesis and pore evolution of reservoirs in the different tectonic units are clearly different.Acidic dissolution has been an important factor in improving reservoir physical properties in the first slope-break belt.In the second slope-break belt,acidic dissolution in the A1 sub-stage of the middle diagenetic stage was the main factor.Interlayer fracturing improves the physical properties of the reservoir in the A2 substage.The connected dissolution pores formed by alkaline dissolution is an important factor in the improvement of physical properties of deep reservoirs in fault step zones.In the sag area,a complex pore/fracture system is the most important reservoir space.The carbonate content restricts the improvement of reservoir physical properties.The physical properties of shallow-to-middle depth(pebbly) sandstone reservoir negatively correlate with its thickness:single layers less than 4 m thick have the better physical properties.Layers thicker than 4 m have better physical properties than normal(non-pebbly) sandstone of the same thickness,although normal sandstone still has reservoir capacity with main reservoir space consisting of compression and overpressure fractures connected to

关 键 词：成岩作用 储层物性 差异性 成岩—成储模式 斜坡带 渤中凹陷 

分 类 号：P618.13[天文地球—矿床学]