潜江凹陷页岩油藏渗流特征物理模拟及影响因素分析

Physical Simulation and Influencing Factor Analysis of the Flow Characteristics in the Shale Oil Reservoir of Qianjiang Depression

针对目前低渗储层渗流特征实验精度低、实验仪器微泄露无法有效确定等缺点,利用自行研制的封闭式高精度致密储层渗流特征测试方法,结合核磁共振和大面积扫描电镜成像(MAPS)技术,研究了潜江凹陷致密页岩油渗流特征及微观孔隙结构对其渗流特征的影响。结果表明:在渗透率小于0. 100 mD时,流体渗流特征表现为典型的“勺型”曲线;当渗透率为0. 100-1.000 mD时,流体以线性渗流为主;当渗透率大于1.000 mD时,流体渗流曲线表现出“反勺型”特征;页岩油渗流特征主要由边界层和应力敏感共同决定;应力敏感对含有微裂缝储层渗流能力的影响要大于对基质储层的影响。该研究结果对页岩油藏高效开发具有重要理论指导意义。

In order to improve the test precision, uncertainty of instrument micro-leakage and other disadvantages in the conventional low-permeability reservoir seepage experiments, a self-developed close high-precision seepage test system for the tight reservoir was used to study the seepage mechanism and its effects on the microscopic pore structure in the shale oil reservoir of Qianjiang Depression by combining with nuclear magnetic resonance and mas sive scanning electron microscopy ( MAPS) technology. Result indicates that the fluid seepage shows a typical "spoon" curve when the reservoir permeability is less than 0. 100 mD. The fluid seepage is dominated by linear flow when the reservoir permeability is ranged from 0. 100 to 1. 000 mD. The fluid seepage is featured by "non-spoon" curve when the reservoir permeability exceeds 1. 000 mD. The shale oil seepage performance is mainly dependent on the boundary layer and stress sensitivity. Comparing to the conventional matrix shale oil reservoir, the fluid seepage performance of fractured reservoir depends more on stress sensitivity. This research could provide certain theoretical guidance for the efficient development of shale oil reservoir.