Study Of Weak Alkaline/surfactant/polymer(ASP) Formulation Optimization Applied In Xinjiang Conglomerate Reservoir

Aiming at the problems of high water content and serious heterogeneity of conglomerate reservoir in Xinjiang Oilfield.Carried out the relevant research of weak alkaline/surfactant/polymer（ASP）formulation optimization.The correlation between the displacement performance of ASP formulation and the recovery increment of conglomerate reservoir is studied.The influence law of interfacial tension,viscosity ratio of oil and water and emulsifying property on the recovery increment are discussed mainly.The performance requirement and system composition of ASP formulation with high recovery increment were given.The 16 formulations of ASP system with specially appointed displacement performance was selected through orthogonal experiment design and interfacial tension,viscosity and emulsification performance test.Based on the experimental results of oil displacement in homogeneous and heterogeneous conglomerate model,the basic requirements for the performance and the formulation of ASP system under the condition of homogeneous and heterogeneous conglomerate reservoirs with high recovery increment of more than 20%are analyzed and clarified.Under the condition of homogeneous conglomerate reservoir is different from the sandstone reservoir,the recovery ratio of oil can be increased by more than 20%when the interfacial tension reaches 10^-2mN/m while it is necessary to reach the 10^-3mN/m ultra low under the condition of sandstone reservoir.Under the condition of heterogeneity,20%of the oil recovery increment is more demanding on the performance of the ASP system:10^-3mN/m ultra low interfacial tension and satisfy the viscosity ratio over 4 or has high emulsifying power;or interfacial tension reaches 10^-2mN/m and satisfy the viscosity ratio over 4 and has high emulsifying power.The interfacial tension is the key factor to influence the recovery increment of the ASP flooding in conglomerate reservoir.And water oil viscosity ratio is an important factor.Under the condition of homogeneous,when the interfacial tension is high(>10^-1mN/m),the recovery increment of the ASP flooding increases with the increase of the viscosity ratio;when the interfacial tension is low(<10^-2mN/m),the influence of the viscosity ratio is related to the permeability,With the decrease of the permeability,the requirement of the high recovery ratio of the conglomerate reservoir is increasing.While under heterogeneous conditions,with the increase of viscosity ratio,oil recovery increment increased.Emulsifying property has some influence on the recovery increment.Under the condition of homogeneous,when the interfacial tension is high（10⁰mN/m）or the water oil viscosity is low（1）,the high emulsifying power is beneficial to the improvement of oil recovery.While under heterogeneous conditions,high emulsifying power is necessary to high recovery increment of more than 20%in the ASP flooding.