一种基于水淹影响的相渗曲线重构方法

Method for Reconstructing Relative Permeability Curves Based on Flooding Effect

针对储层水淹对地层流体渗流规律影响刻画较难的问题,基于渤海典型疏松砂岩稀油油藏LD油田和稠油油藏Q油田密闭取芯井岩芯样品,开展水淹程度对油水相渗曲线影响实验研究。基于水淹对相渗影响认识,提取不同水淹程度下相渗曲线特征参数并重新组合,建立两种类型油藏考虑水淹影响的"全寿命"油水相对渗透率曲线。实验结果表明,与采用未水淹、弱水淹层段岩石样品完成的油水相对渗透率曲线相比,中水淹、强水淹层段相渗曲线束缚水饱和度更高,残余油饱和度更低,等渗点更偏右,驱油效率更高。与不考虑水淹情况相比,考虑水淹影响的重构相对渗透率曲线,其残余油饱和度和束缚水饱和度更低,含水饱和度相同时,两相相对渗透率均呈现整体降低趋势,最终驱油效率增大。与不考虑水淹影响的方案相比,考虑水淹影响的重构相渗在Q油田矿场数值模拟中应用,在含水98%时的采出程度提高近1%。

Targeting the problem of difficulty in summarizing the influence of reservoir flooding on the laws of formation fluid seepage, a study on the influence of the flooding effect on oil–water relative permeability curve was conducted. The study used core samples from confined coring wells in Oilfield LD, which is an unconsolidated sand reservoir of thin oil rims, typically found in the Bohai Sea, and in Oilfield Q of heavy oil rims. Based on the influence of flooding effect on relative permeability,parameters characterizing the infiltration curves under different degrees of flooding were extracted and regrouped to construct the"full life cycle"oil–water relative permeability curves of the two types of reservoirs by considering the flooding effect.Experimental results show that, compared with the oil–water relative permeability curves of unflooded and weakly flooded samples, oil–water relative permeability curves obtained from layers that underwent medium to heavy flooding had higher saturation of the bound water and lower saturation of the residual oil with higher oil displacement efficiency, and their points of equivalent permeability were closer to the right. Reconstructed relative permeability curves that consider the flooding effect had lower saturation of residual oil and bound water than those that do not. When they both had the same water saturation, their two-phase relative permeability showed an overall downward trend with an enhanced oil displacement efficiency at the end.Applying the reconstructed relative permeability that considered the flooding effect into numerical simulation for Oilfield Q led to an improvement in the recovery percentage of almost 1% at 98% water content.