基于Box-Behnken Design法的底水油藏氮气泡沫驱影响因素分析

Study on influencing factors of nitrogen foam flooding in bottom water reservoir based on Box-Behnken Design method

为了定量和定性地研究底水油藏氮气泡沫驱过程中地层韵律性、起泡剂质量分数和气液比等因素对驱油效果的影响,利用CMG数值模拟软件建立底水油藏模型,根据响应曲面法的Box-Behnken Design(BBD)中心组合设计原理和单因素分析法,分别设计氮气泡沫驱实验方案并对实验结果进行分析,确定了各因素与采收率增值之间的数学回归模型,明确了各因素对氮气泡沫驱效果的影响顺序以及影响规律,并对其进行优选。研究结果表明,数学回归模型对实验数据拟合效果好,各因素对采收率增值的影响显著性由大到小依次为地层韵律性、起泡剂质量分数、气液比。在正韵律地层、起泡剂质量分数为6%、气液比为1:2~1:1的实验条件下,采收率增值较大。从定量和定性2个方面研究底水油藏氮气泡沫驱影响因素,能够更直观地得到各因素对采收率增值的影响规律。

In order to quantitatively and qualitatively study the effect of formation rhythm,concentration of foaming agent and gas liquid ratio on oil displacement efficiency during nitrogen foam flooding process in bottom water reservoir,the bot-tom water reservoir model was established by CMG numerical simulation software,and the test scheme was separately de-signed according to the design principle of Box-Behnken Design(BBD)center combination in response surface methodolo-gy and single factor analysis.The mathematical regression model between the factors and the increment of oil recovery was established,and the degree of influence of all factors on recovery increment and their effect were clarified.In addition,the factors were optimized.The results show that the mathematical regression model has a good fitting effect on the experimen-tal data and the effects sequence from large to small is formation rhythm,foaming agent concentration and gas liquid ratio.Under the experimental conditions of positive rhythm formation,6%of concentration of foaming agent and 1∶2-1∶1 of the gas liquid ratio,the recovery increment is higher.Quantitative and qualitative study on the influence of various factors on the recovery increment has great significance to deeply understand the mechanism of nitrogen foam flooding for EOR in sim?ilar bottom water reservoirs.