低渗透砂岩油藏平面径向渗流流态分布

为了研究低渗透储集层中流体非达西渗流规律，在室内非达西渗流实验的基础上，将低渗透储集层中流体的渗流分为非流动、非线性渗流和拟线性渗流3种渗流状态并给出了各渗流状态的渗流方程，以此为依据，推导出了单相平面径向渗流流态分布规律公式，可用以定量地确定油井周围3种流态的分布范围。两相平面径向渗流流场中各点的饱和度不断变化，拟线性渗流区、非线性渗流区的范围也不断变化，因此在确定流态分布范围时，应在单相最小驱替压力梯度和临界驱替压力梯度公式中乘以两相驱替系数。根据流态分布，提出了确定低渗透油藏合理井距的方法和理论公式。应用该研究成果对国内5个典型加密试验区进行了井距计算，取得了较好的效果。图4表1参9

Flow state distribution of areal radial flow in low permeability sandstone reservoir

For the purpose of studying the non-Darcy flow rule of fluid in low permeability reservoir, the reservoirs flowing state was divided into three types, no-flow, nonlinear flow and pseudo-linear flow, and the corresponding flow equations were built based on lab results of non-Darey flow, and flow state distribution formulas of areal radial-flow of single-phase were deduced for quantitatively analyzing the flow state distribution around production wells. In the two phase areal radialflow, the fluid saturation distribution in flow field changed constantly, the distribution of nonlinear flow and pseudo-linear flow changed, too. In calculating the flow state distribution of two-phase flow, the two-phase displacement coefficient was considered in the single-phase formulas of minimum displacement pressure gradient and critical displacement pressure gradient. According to the analyses of fluid flow state, the method and theoretical formula for designing reasonable well space of low permeability reservoir were put forward, and the results have been applied to infill well space of pilot block in Shengli Oilfield, and achieved good effect.