黄骅坳陷歧南凹陷古近系沙河街组储集层物性影响因素分析  

Analysis of controlling factors on reservoir petrophysics of the Paleogene Shahejie Formation in Qinan Sag of Huanghua Depression

作　　者：刘正华[1] 杨香华[1] 陈红汉[1] 韦阿娟[2] 郝利华[2] 

机构地区：[1]中国地质大学武汉石油系,湖北武汉430074 [2]大港油田勘探开发研究院,天津300280

出　　处：《古地理学报》2009年第4期435-445,共11页Journal of Palaeogeography：Chinese Edition

基　　金：大港油田勘探开发研究院项目“歧南水道沙河街组沉积微相研究与有利储集相带分析”(编号:2005-kt-001)资助

摘　　要：黄骅坳陷歧南凹陷是个活跃的生烃凹陷,古近系沙河街组发育良好的储集砂体,具有一定的勘探潜力。通过岩石铸体薄片、扫描电镜、阴极发光和X衍射等技术,对研究区储集层岩石组分和储集层孔隙类型进行了识别鉴定。发现次生孔隙在不同构造单元分布不同。西部羊三木—扣村—仙庄缓坡带次生孔隙主要分布于3个带:①1650～1800,m,②2300～2600,m,③2880～2920m。埕北断阶带次生孔隙分布于2200～2800m。凹陷中心带次生孔隙分布在2900～3500,m。研究区以岩屑砂岩和长石岩屑砂岩为主,成分成熟度和结构成熟度低,具备次生孔隙发育的物质基础。沉积环境对储集层物性有一定的影响。在同等埋深的几类碎屑沉积砂体中,湖岸滩坝的储集物性最好,重力流主水道和近岸水下扇扇中水道相对较好,近岸水下扇间湾、扇端沉积以及重力流水道侧翼和末梢沉积较差。次生孔隙形成的主要机理为:①黏土包膜的发育有利于次生孔隙的发育。②有机质向烃类转换中形成的有机酸以及黏土矿物蒙脱石向伊利石转换过程中形成的酸性溶液,对长石和岩屑颗粒产生溶蚀,有利于次生孔隙的发育。③进入砂岩储集层中的孔隙水的活跃性影响次生孔隙的发育。④油气充注过程中溶解作用大于胶结作用,油气充注末期次生孔隙发育。⑤断层和不整合附近由于大气淡水中溶有大量CO2,进入储集层易形成碳酸,易于溶蚀长石等矿物,有利于次生孔隙发育。In China, theories on secondary porosity of deep reservoirs need breakthrough urgently. The Qinan Sag, located in the Huanghua Depression, is an active hydrocarbon generation sag, and develops favorable reservoir sandbodies in the Paleogene Shahejie Formation, and has a significant exploration potential. Using thin sections, scanning electron microscope （SEM） , cathodoluminescence, X-diffraction methods, integrated with measured reservoir properties and log interpretation, the authors summarized that distribution of secondary pores was different in different tectonic units. In the west slope, secondary pores were distributed in 3 belts： 1650 - 1800 m, 2300 - 2600 m and 2880-2920 m. In the eastern Chengbei faulted belt, secondary pores were distributed in 2200 - 2800 m. In the central zone of the sag, secondary pores were distributed in 2900 -3500 m. Lithic sandstone and arkosic arenite sandstone are the dominant rock types in the study area with low component and texture maturity which made the material ba- sis for secondary pore development. Sedimentary environment also had some influence on reservoir quality. Lake shore zone and bar sandbodies possess thebest reservoir petrophysics. They are followed by main gravity-flow channel sandbodies and channel of middle fan in subaqueous fan. The flank-distal sandbodies of gravity-flow channel and middle-bay in subaqueous fan constitute poor to fair reservoirs. The main mechanisms for secondary pore formation are as follows ： ①The development of clay coating is favorable for development of secondary pore. ② The organic acid which formed during the process of organic material transforming into hydrocarbon and the acidic solution forned in resulting from the conversion of montmorillonite into illite could dissolve the feldspar and lithic grains. Asaresult, secondary pores could the develop. ③The activity of pore water entering into the sandbody reservoir influences the development of secondary pore. ④The dissolution dominated cementation during the hydroca

关 键 词：黄骅坳陷 歧南凹陷 古近系 沙河街组 深部储集层 储集层物性 

分 类 号：TE122.221[石油与天然气工程—油气勘探]