开展了致密砂岩储层微观孔隙结构特征及渗流特性测试,旨在为SⅢ致密砂岩储层后续高效开采提供重要的理论基础.高压压汞实验结果表明:SⅢ致密砂岩储层孔隙结构按照储层物性综合评价,可划分为Ⅰ、Ⅱ、Ⅲ类,主要以Ⅰ类孔隙类型为主;Ⅰ类孔隙岩心储层分选性较差(4.17)、排驱压力较低(0.49 MPa)且最大进汞饱和度较高(74.55％),连通性较好.低速渗流实验结果表明:渗流过程中存在启动压力;储层存在水敏性;单相气、油、水启动压力梯度均与渗透率和孔隙度之间呈幂指数相关;SⅢ致密砂岩储层不适宜采用水驱而适宜采用气驱开发方式进行有效开发.

为有效解决S358高凝油藏注气难度大、压裂后气驱流度比过大容易气窜导致驱油效率低的问题,开展了室内注气相态及长岩心驱替机理实验.通过地层条件下高凝油注CO2、干气、烟道气、减氧空气(N290％+O210％)PVT相态实验,分析了4种注入气与高凝油接触的增溶膨胀、降黏、降低界面张力等特性机理,优选了CO2作为注入气.通过5组不同复合方式的高温高压长岩心驱替实验,评价了CO2复合驱油防窜提采效果.实验结果表明,CO2+弱凝胶、CO2+泡沫的驱替效果最好,最终驱油效率分别为70.101％、68.212％.研究结果说明,CO2复合驱段塞的注入使得驱替阻力增大,导致裂缝导流能力降低,对改善微观波及体积起到关键性作用.其中,CO2+弱凝胶、CO2+泡沫的驱替方式提采效果最佳,研究结果可为该区块高凝油的高效开发提供实验基础.

裂缝性潜山油藏为典型的双重介质油藏,积极开展注气提高采收率研究对开发这类油藏具有重要意义.针对气驱开发过程中存在的气窜问题进行研究,以兴隆台裂缝性潜山油藏为例,建立双重孔隙介质油藏数值模拟模型,基于数值模拟方法,分析不同气窜方向的生产气油比特征曲线,分析、确定实际生产井发生气窜的来源及形成气窜的时间,从而建立一种新的、成本低、操作简便的潜山油藏气窜识别方法.利用该识别方法对兴古7潜山油藏实际气窜井7-H2井进行识别,结果表明:不同气窜类型存在不同气油比导数曲线特征,底部气窜气油比及导数曲线特征可分为5个阶段,气窜形成于第三阶段,形成气窜之后气油比导数曲线明显向下;顶部气窜气油比及导数曲线特征可分为3个阶段,气窜形成于第三阶段,导数曲线明显向上;横向气窜气油比及导数曲线特征可分为3个阶段,气窜形成于第三阶段,导数曲线基本保持水平.7-H2井在425天左右发生气窜,导数曲线明显向下,气窜类型属于底部气窜.经气体示踪剂监测方法验证,识别结果与实际油井的气窜情况分析一致,证明该识别方法具有良好的准确性及可靠性,能够有效识别气窜来源,为针对性的减缓气窜调控措施提供了有力支持.

In order to verify the influence of different injected fluids on recovery of fractured metamorphic rock reservoir, a series of indoor experiments are conducted. Firstly, combination core imbibition experiment shows that the imbibition ability of basement is so weak that its effect can be ignored. Secondly, threshold pressure gradient experiment of kerf short core shows that the highest threshold pressure gradient is 0.155 MPa/m. This value is less than 1.6 MPa/m and 1.2 MPa/m that correspond to 25.4 MPa and 38.6 MPa used in long core displacement experiment, thereby making sure the experiment successfully. Finally, using two ways of pulse displacement and continuous displacement, long core displacement experiment is carried out. The injected fluids include gas, N2 and water. The result shows that the best injected fluid is gas, the medium is water and the worst is N2.

Based on simulate reservoir formation conditions of Huan 26 block,study the effect of CO2 flooding by using slim tube experiment and determine the MMP of CO2 and the formation oil.The results show that,in the same volume of CO2 injection,the higher injection pressure,the greater the accumulated recovery;CO2 begin breakthrough and produced gas oil ratio rapid increase when gas injection volume is reached(0.62~0.8) PV,the higher injection pressure,the more injection volume when CO2 breakthrough,but the produced gas oil ratio increase faster after CO2 breakthrough.The MMP of CO2 and formation oil in Huan 26 is 23.6 MPa,which can reach CO2 miscible flooding in formation pressure.The injection pressure as high as possible flooding when conduct CO2 immiscible displacement and so can obtaine better displacement effect.

Old oilfield is usually developed at low recovery rate.It is proposed to improve old oilfield development response and recovery factor by secondary recovery,and the standard of supporting technology has been set up for secondary recovery.Taking Xinhai 27 block,a conventional heavy oil reservoir,as an example,secondary development has been studied by using horizontal well based on precise reservoir description and reservoir engineering study.The result of implementation is remarkable,with an anticipated improvement of recovery factor of 10.2%.

在开发效果评价基础上,应用统计分析方法,建立了注水开发合理控制的数学摸型,为寻求开发过程的最优控制、提高开发效果进行了探索性研究.提出了采收率损失率的概念及注采井数比对采收率损失的影响.经过分析,给出了辽河油区注采井数比下的采收率损失量及提高采收率的潜力.