砂岩储层油水相对渗透率曲线表征模型及其在数值模拟中的应用

以胜利油田孤岛油田新近系馆陶组砂岩储层为例，在岩心油水相渗测试实验及地质认识的基础上，建立了油水相对渗透率曲线表征模型，并通过数值模拟建立了砂岩油藏开采动态模型，探讨了不同韵律性、不同开发方式下相渗模型的适用条件及对开发结果的影响。研究结果表明:①分别拟合气测渗透率、平均孔喉半径等7个影响相渗曲线的参数和相渗曲线端点以及曲线形态之间的相关性，通过交替条件期望法进行多元回归，以气测渗透率和平均孔喉半径建立了束缚水饱和度计算模型，以渗透率变异系数和特征结构参数建立了残余油饱和度计算模型，以气测渗透率建立了束缚水下油相相对渗透率计算模型，以渗透率变异系数和特征结构参数建立了残余油下水相相对渗透率计算模型，4个端点表征模型的绝对误差都小于0.1；以霍纳普相渗曲线形态指数经验公式为基础，利用均质系数建立了油相相渗曲线形态表征模型，利用渗透率变异系数和孔喉比建立了水相相渗曲线形态表征模型，2个形态表征模型的绝对误差小于1.7，模型可靠。②在砂岩储层衰竭式开发模拟中，生产动态主要受油相相渗的影响，利用油水相渗曲线模型推导出的相渗曲线再进行归一化处理，在一定程度上能够消除储层非均质性带来的影响；在注水开发模拟中，储层的非均质性会加剧水相相渗对生产动态的影响，模拟时采用对产油量贡献最大的储层的相渗曲线更能接近实际生产动态。

Characterization model of oil-water relative permeability curves of sandstone reservoir and its application in numerical simulation

Taking the sandstone reservoirs of Neogene Guantao Formation in Gudao oilfield of Shengli Oilfield as an example，based on oil-water relative permeability test and geological knowledge，the characterization model of oil-water relative permeability curves was established. The sandstone reservoir model was established by numerical simulation method，and the applicable conditions of model under different rhythms and different development methods and the influence on development results were discussed. The results show that: (1) The correlations of 7 parameters affecting relative permeability curves，such as permeability measured with gas and average pore-throat radius，with endpoints of relative permeability curves and the shape of curves were respectively fitted. Multiple regression method was carried out by using the alternate conditional expectation method，irreducible water saturation calculation model was established based on permeability measured with gas and average pore-throat radius，and residual oil saturation calculation model was established based on permeability variation coefficient and significant parameters. Based on permeability measured with gas，calculation model for relative permeability of oil phase under irreducible water was established. Based on coefficient of variation and significant parameters， calculation model for relative permeability of water phase under residual oil was also established. The absolute errors of the four endpoint characterization models are all less than 0.1. Referring to Honarpour empirical formula， relative permeability curve shape calculation model of oil phase was established based on uniformity coefficient， and relative permeability curve shape calculation model of water phase was established based on permeability variation coefficient and pore-throat ratio. The absolute errors of the two models are less than 1.7，which proves the reliability of models. (2) In the depletion development simulation of sandstone reservoirs，the production performance is mainly controlled by the relative permeability of oil phase. Normalizing curves derived from the model can eliminate the influence of reservoir heterogeneity to a certain extent. In simulated waterflood development，reservoir heterogeneity can exacerbate the impact of water phase relative permeability on production performance. In the simulation，the relative permeability curve of the reservoir that contributes the most to oil production can be closer to the actual production.