为获得受载页岩准确的损伤演化规律和声发射特征,完善以往受载岩石损伤单调增大的理论,进一步扩展对受载岩石内部损伤演化机理的认识,对陆相页岩进行单轴压缩声发射试验.试验结果表明:页岩单轴压缩过程分为4个阶段:压密阶段-弹性变形阶段-弹塑性变形阶段-峰后破坏阶段,压密阶段、弹性变形阶段和弹塑性变形前期有少量声发射信号,页岩峰值应力前后有大量声发射信号,特别是峰后破坏阶段,声发射信号急剧上升,声发射探头能够捕捉岩石的压密、裂纹的扩展和连通信息,声发射信号能够反映页岩内部微细观损伤演化过程;页岩平行层理面方向和垂直层理面方向的岩石损伤演化和声发射特征差别较大,因此对于层理性岩石不能忽略层理对岩石力学性质的影响;页岩压密阶段内部的微孔洞、微裂隙、宏观裂缝、层理被压实,损伤减小,页岩弹性模量不降反增,应力-应变曲线呈下凹型,首次提出受载岩石损伤先减小后增大,建立了更加合理的基于声发射特征的页岩单轴压缩损伤本构模型.

针对润湿黏土甲烷吸附规律认识不足的问题,利用页岩扫描电镜图像将气体储集空间按不同尺寸和几何形状划分为等径圆形孔隙、扁平状椭圆孔隙及条带状裂缝3类,并依据干燥黏土气-固界面的Langmuir吸附式、润湿黏土气-液界面的Gibbs吸附式,建立考虑水敏性的页岩黏土气-液-固三相界面耦合甲烷吸附模型,结合考虑吸附相体积的游离气含量计算式,推导不同含水饱和度下页岩黏土的含气量预测方程.结果表明,与涪陵焦石坝地区页岩岩心现场解析数据相比,润湿黏土多相耦合模型的计算结果精度较高.研究结果对不同含水率下页岩黏土甲烷静态资源量的评估具有重要的指导意义.

通过国内外长期的理论研究和矿场实践,从研究区常规注水效果减弱,开发效果变差的现状分析,若要提高剩余油的采收率,需要在地层中施加一个不稳定压力场使得地层中油水不断进行交换和重新分布,因此开展周期注水是非常必要的.油藏若要采用周期注水,需明确储层非均质特征、油层不连通程度、注水工艺与注水量要求等基本参数,从而确定周期注水的方式以及合理的注水时机,以便取得良好的开发效果.

为准确评价陆相页岩储层脆性,基于COMSOL软件分析了影响页岩脆性的因素,利用X射线衍射仪和RTR-1000三轴测试系统对鄂尔多斯盆地南部W区块长7段15块页岩岩芯进行了矿物组分和力学性质测试.在此基础上,提出一种考虑页岩矿物组成和力学环境的脆性评价方法,并利用该方法指导区块内Y井页岩层段脆性评价.结果 表明,由于矿物组分和力学环境的差异巨大,海相页岩的脆性评价方法并不适用于陆相页岩;新的脆性评价方法能快速建立页岩气井脆性指数剖面,筛选出高脆性段.Y井的成功压裂表明新方法能有效预测页岩高脆性段,为压裂选层提供依据.

Aim To find a simple and practical prediction method for solving water saturation distribution and frontier saturation position at any moment in aeolotropic reservoir.Methods Based on the Buckley-Leverett Saturation Movement Equation and the grid theory of Numerical Reservoir Simulation,a bidimensional gridding aeolotropic reservoir model is established and a computational method is proposed for solving the above-mentioned problems via computer programming.Results Through being applied in practical petroleum production,this computational method can solve the water saturation and the frontier saturation position of any moment in reservoir model via linear interpolation of computational mathematics.Conclusion Practical applications prove that this computational method has strong universality,can be used for oilfield waterflooding dynamic prediction.

Due to deposition sequence, reservoir can be approximately considered as formation vertically consisting of many small layers with different physical properties. Meanwhile, the property distribution of these small layers, e.g. heterogeneity of the formation, has a great impact on reservoir development and its production performance. No matter how fine grid to be used, it is always difficult for traditional numerical simulation to couple the impact of vertical heterogeneity of the formation, that will inevitably result in significant calculation error. Therefore in order to overcome this defect and deliver better calculation results which are consistent along with real production performance, this paper derives a math model combined both analysis approach and numerical approach, which has a better description for vertical heterogeneity of formation by overlapping small layers and could deliver better calculation results by fine-gridding strata profile. The model could be applied to either predict further field production performance or conduct history match based on production history of field. This method has applied in actual production analysis and reservoir evaluation, and good results have been achieved.

计算相对渗透率时需要面对大量数据处理和繁多的求解模型以及复杂的计算过程.为了计算快捷、简便调用合适模型并提高求解效率,提出了用EXCEL结合VBA开发计算程序以批量处理实验数据并求解相对渗透率的方法.实例计算表明该方法能够快捷、准确地计算出结果并绘制相对渗透率曲线,简单易用,扩展性强.