【作者】 李景岩；

【导师】 孟凡顺； 王渝明；

【作者基本信息】 中国海洋大学 ， 海洋地球物理学， 2012， 博士

【摘要】 油阳开发进入高含水期,剩余油挖潜的难度增大,因此,储层研究向精细化、定量化发展,从储层的微观特征入手,搞清流体在储层中的渗流机理无疑是提高剩余油预测精度的有效途径,但储层的宏观特征和微观特征之间差距迥异,如何建立二者之间的联系,实现储层的宏、微观研究成果的有机结合并进一步预测剩余油分行还处于尝试和发展阶段。本论文在沉积岩石学、油层物理、油藏工程等理论的指导下,以杏南油田萨葡油层为例,分别研究了研究区储层的砂体类型、孔隙结构、渗流特点及微观剩余油赋存方式,以砂体类型为研究对象,孔隙结构为细分单元,提出了不同储层内剩余油的分布规律及不同储层挖潜措施。论文首先综合岩心、镜下、孔渗分析、压汞、驱替实验和数值模拟等方法对不同储层的微观及渗流特征进行了详细研究。将储层孔隙结构分为五类,从一类到五类孔隙结构的储层,粒度变细,孔隙结构变差。分析了地质作用对孔隙结构的影响,强水动力条件下形成的砂体粒度更粗,平均孔喉半径更大,对渗透率有贡献的大孔喉比例更多；弱水动力条件下形成的砂体特征相反。成岩作用不同程度的改造了各种储层,渗透率越低的储层由压实和胶结作用造成的减孔率越高,而渗透率越高的储层由溶蚀作用造成的增孔率越大。由于孔隙结构特点不同,其渗流特征各异,从一类到五类,束缚水饱和度增加,油相渗透率变化快,油水共存区减少,水相渗透率减小,含水率变化增快。反映孔隙结构较好的储层动用较为均匀,而孔隙结构较差的储层动用程度变差。综合岩心驱替实验、微孔渗流模拟及荧光剩余油观察分析,可见不同孔隙结构类型剩余油分布不同：一、二类孔隙结构的剩余油包括：与注水流向垂直的孔喉状剩余油,储层非均质性造成的角隅、吸附状剩余油,孔壁偏亲油所致的孔表薄膜状剩余油等。后三类孔隙结构孔喉较前两类孔隙结构变小,因绕流造成的粒间剩余油增多,除此之外,由于孔喉比增大,润湿性偏亲水,卡断、贾敏效应增加,使簇状剩余油增多。不同砂体内孔隙结构组合不同,分流河道砂体以前三类孔隙结构为主,且下部性质好于上部储层,即下部剩余油以孔喉状、角隅状、吸附和膜状等存在,可以通过改变注入方向,注入化学剂提高驱油效率等方法将这部分油挖潜出来；但中上部的油动用相对较少,应单独开采或打水平井开采。席状砂储层三、四、五类孔隙结构增多,孔喉半径减小,由于在此类储层中99%的渗透率贡献是由50-70％的大孔喉提供的,小孔喉内的油未动用,可见粒间剩余油较多；己动用的孔喉内剩余油则多是以角隅状、簇状形式存在的,此类油藏的开发应考虑利用压裂方法使动用程度提高,采用聚合物驱增加采收率。论文研究成果对精细确定剩余油分布规律,设计提高采收率方案以及有效挖潜剩余油具有指导意义。更多还原

【Abstract】 In high water cut period of old field, tapping the potential of remaining oil becomes more and more difficult, therefore, the reservoir research is developing toward the fine and quantitative direction, from the reservoir microscopic features, making clear fluid percolation mechanism in reservoir is effective way to enhance the accuracy of prediction of remaining oil distribution, but the gap between the macro and micro characteristics in reservoir is great, how to establish the link between the two, to integrate macro and micro research findings, and to predict the distribution of residual oil is still in the trying and development stage. In this paper, in the theory of sedimentary petrology, reservoir physics and reservoir engineering, in Xingnan oilfield, the Portuguese formation as an example, the reservoir sandbody types, pore structure, percolation characteristics and mode of occurrence of microscopic remaining oil are studied respectively. The sand body types are as the research object, pore structure types are as unit division, the remaining oil distribution law and potential tapping measures in different reservoir are put forward.In the paper, microscopic and flow characteristics of different reservoirs are studied in detail first with the data of integrated core, mirror, porosity and permeability analysis, mercury, displacement experiment and numerical simulation methods. The pore structure of the reservoir is divided into five categories, from one class to five class of the pore structure of the reservoir, particle size becomes finer, pore structure variation. The geological effect on the pore structure is Analysised. The sand body size is more coarse under the conditions of strong hydrodynamic, and average pore throat radius is more greater, the ratio of big pore throat that contribute to permeability is greater. Various reservoirs are modified in different degrees by Diagenesis. The lower the permeability of the reservoir is, the higher the reduction of porosity is by the compaction and cementation. The rate of enhanced hole of reservoir is higher by the dissolution. Since the pore structure characteristics are different, its flow characteristics are varying. From the first class the fifth class, the irreducible water saturation increases, the oil phase permeability changes faster, oil-water coexistence zone is reduced, water permeability decreased, and moisture content increases quickly. It’s showed that the reservoirs with better pore structure are more evenly.With core displacement experiment, micro percolation simulation and remaining oil study of visible fluorescence, remaining oil distribution in reservoirs with different pore structure is different:residual oil in the reservoir with the first and the second class of pore structure includes:pore throat remaining oil vertical to water flow, corner, adsorption of remaining oil caused by the heterogeneity and partial oil on hole wall. The pore throat radius of the other three kinds of pore structure are smaller than the previous two types of pore structure, intergranular residual oil is increases. In addition, the pore throat ratio increases and the wettability of partial hydrophilic, block, Jia Min effect increases, so that the cluster remaining oil increases.There are different combinations of pore structure in different sand body. The distributary channel sand body have the first, the second and the third class of pore structures, the properties at the lower part is better than the upper reservoir, the type of residual oil include the pore throat shape, corner shape, adsorption and membrane shape in lower part of reservoir. Changing the direction of injection, injection of polymer method can be used to enhance water oil displacement efficiency. There is more residual oil in the upper reservoir; it should be output by separate mining or drilling of horizontal wells. The pore structure type of sheet sand reservoir includes third, fouth and fifth type. In this kind of reservoirs, the pore throat radius decreases and small pore throat increases, but99%permeability contribution is provided by50-70%big pore throat, small throat oil unused, so intergranular residual oil is more. The remaining oil in the pore throat includes the corner shape, clusters form. This kind of reservoir should consider the use of fracturing method to improve the producing degree, increase oil recovery with polymer flooding.Research in this paper has guide significance on fine determine remaining oil distribution, designing enhanced oil recovery scheme and tapping the potential of residual oil.更多还原