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为深入了解张性裂缝结构中流体渗流特征,采用物理实验和数值模拟相结合的方法,系统研究流体在页岩张性裂缝中的渗流特征。将Barnett页岩岩心劈裂成张性裂缝,并采集裂缝面数据,将其作为物理模型,同时采用LBM-BKG方法 D3Q19模型研究流体在张性裂缝中的流动。研究尺度依次为整体、截面、截线、离散单元体,考察各尺度下渗流场特征参数分布,并分析原因。研究表明:整体上,沿渗流横向和纵向上压力均呈线性分布,横向各截线上压力呈波动式线性分布,纵向截线上压力分布呈非线性;缝面端部局部区域会产生回流区,回流区与粗糙性及粗糙性变化程度有关;近平均速度的速度等值面间基本呈平行分布,速度较大时,等值面基本对应于端面相对平缓的区域;沿同一流线,渗流速度略有差别;整体渗流为稳态,不代表渗流场各处速度相等,离散的渗流单元体的渗流速度各不相同;三维粗糙性造成了渗流速度的三维分布,但主要以渗流方向和垂向上渗流速度为主。该项研究对深入理解页岩等裂缝发育储层的裂缝系统渗流具有重要意义。
In order to further understand the characteristics of fluid seepage in the zonal fractures, the physical experiment and numerical simulation are combined to systematically study the seepage characteristics of the fluid in the zonal fractures. The Barnett shale cores were fractured into tensional fractures, and the fracture surface data were collected and used as physical model. Meanwhile, the flow in the tension fracture was studied by the LBQ-BKG method D3Q19 model. The research scale followed by whole, section, section line, discrete element body, investigated the distribution of characteristic parameters of seepage field under various scales and analyzed the reasons. The results show that on the whole, the pressure in horizontal and vertical direction along the seepage flow is linearly distributed, the pressure in each transverse cross-sectional line is fluctuating linearly, and the pressure distribution in longitudinal cross-sectional line is nonlinear. The backflow zone , And the reflow zone is related to the degree of roughness and roughness changes. The velocity isosceles of the near average velocity are basically parallel to each other. When the velocity is high, the isosurface corresponds to the relatively flat region. Along the same flow line, seepage The seepage velocity is slightly different; the overall seepage flow is steady state, it does not mean that the seepage velocity is equal everywhere, and the percolation velocity of discrete seepage units varies; the three-dimensional roughness leads to the three-dimensional distribution of seepage velocity, Infiltration upward speed-based. This study is of great significance for understanding the seepage of fractured systems in fractured reservoirs such as shale.