油藏工程启动压力梯度深度探究

Research on the Starting Pressure Gradient in Reservoir Engineering

利用微流量计量仪,通过"压差-流量"法,精确测定了油藏水驱和乳状液驱的启动压力梯度,深入分析了油藏非线性渗流特征,重点研究了乳状液对油藏启动压力梯度的影响和作用机理。结果表明,油藏的压差-流量曲线是一条上凹型曲线,这条曲线并不具备达西特征,相反,拥有非达西渗流特征。启动压力梯度和渗透率之间存在某种关系,经过研究之后发现是乘幂关系。渗透率减小时,启动压力梯度会增大。水驱平均启动压力梯度为0.05 MPa/m,乳状液驱平均启动压力梯度为0.039 MPa/m。乳状液之所以会有效降低启动压力梯度,是因为它能够显著降低界面张力,减小了边界层的渗流阻力。乳状液界面张力越低,启动压力梯度也就越小。

Using micro flow meter, by the ＂differential pressure flow＂ method, the start-up pressure gradients of reservoir water drive and emulsion flooding were precisely determined, and the nonlinear seepage characteristics of reservoir were analyzed. The influence and mechanism of emulsion on the start-up pressure gradient of reservoir were mainly studied. The results showed that the pressure difference flow curve of the reservoir was a concave curve, and it had not the characteristics of Darcy flow; the starting pressure gradient had exponential relationship with the permeability, the starting pressure gradient increased with the decrease of permeability, the water flooding average starting pressure gradient was 0.05 MPa/m, the emulsion flooding starting pressure gradient was 0.039 MPa/m;the lower the interfacial tension of the emulsion, the smaller the starting pressure gradient.