基于差异置信分析的稀油空气驱影响因素及其筛选标准研究

Study on Influence Factors and Screening Criteria of Air Flooding Based on Differential Confidence Analysis

注空气作为近年来富有创新且应用较为广泛的提高采收率技术,在稀油油藏的开发过程中取得了显著的成果,尤其是在解决稀油油藏的注水开发后期低产高含水问题上具有良好的发展前景,为了保证稀油注气开发的驱油效果,探究影响影响注气的因素至关重要.在大量的调研的基础上总结了国外的稀油油藏注气开发的矿场实例及油藏参数,通过差异置信法分析判断各个油藏参数是否对驱油效果产生影响,然后根据灰色关联法确定对驱油效果有影响的油藏参数影响程度大小,油藏温度是最为密切的影响因素,进一步根据正态母体平均数区间估计的方法得到各个油藏参数影响驱油效果的最佳参数范围,确定了涉及油藏温度、油藏压力等6项指标的稀油油藏的注空气开发筛选推荐标准,为今后稀油注气开发提供借鉴和指导.

Air injection,as a technology of enhanced oil recovery,has achieved good results in the development of light oil reservoir,especially to resolve the problem of low production and high water cut at late stage of water injection development.To ensure the optimum displacement result of light oil reservoir by air injection,it’s essential to study the influence factors that have a dramatic impact on the oil displacement efficiency of air injection.This article researched lots of foreign oil field examples and summarized the reservoir parameters,at the same time analyzed whether different reservoir parameters are the key factors which determines the success of air injection in light oil reservoir by differential confidence method.By comparison the value of statistic T and t which is derived from existed tables,if T>t,the parameters are the key factors of determines the success of air injection in light oil reservoir,otherwise the parameters are not.And then,influencing degree of reservoir parameters is evaluated by grey correlation method.The six influence factors(reservoir thickness,reservoir temperature,reservoir pressure,permeability,porosity and crude oil viscosity)identified are handled by dimensionless process,and by comparing reference sequences and comparative sequences,correlation degree of each reservoir parameter axe calculated.Then,the correlation degree of each reservoir parameter is graded to evaluate the influencing degree of each influence factor,and reservoir temperature is the biggest factor affecting the oil recovery.Finally,the confidence intervals of the reservoir parameters are obtained by mathematical statistics,so as to establish screening criteria for air injection in light oil reservoir,which will provide reference and guidance for the development of air injection in the future.