低渗透油藏多段塞微生物驱开发指标预测

Development index prediction of multi-slug microbial flooding in low permeability reservoir

关键词:  低渗透油藏  多段塞  微生物驱  开发指标  矿场应用  含水率变化规律  指数递减

Key words:  low permeability reservoir  multi-slug injection  microbial flooding  development index  field application  water cut variation rule  exponential decline

摘要:

油藏条件不同,微生物驱油体系的提高采收率能力和油藏适应性也有所差别,需要合理的注入参数对开发指标进行预测。通过模拟不同注入方式微生物驱油实验优化注入参数,在实验基础上综合运用前缘推进理论和经验回归方法,考虑微生物降低原油黏度以及影响油水相对渗透率等客观因素,建立一种将油井产能和含水变化规律结合的预测模型来预测微生物驱开发指标。微生物驱油实验表明,多段塞微生物驱较单一段塞微生物驱采收率可提高9.24％,见水时间能延长40.10％～40.14％,无水采收率提高18.44％;用该模型能较准确地预测微生物吞吐开井后的产油量、增油量、产液量和含水率,单井预测误差小于10％,区块总体产液量和产油量预测误差均小于3％,含水率仅为0.25％。矿场试验采用五级段塞交替注入调剖用微生物与驱油用微生物,试验区含水上升率由8.1％下降至-4.3％,综合递减率由13.3％下降到4.4％,控水稳油效果明显。

Abstract:

Different reservoir conditions cause the different effect of microbial enhanced recovery and its adaptability to the reservoir, the optimized injection parameters predicting the development index are needed. On the basis of frontal advance theory and experienced regression method using experiment data, plus considering some objective factors, such as the oil viscosity reduction by the microorganism and oil-water relative permeability influence, a prediction model was established. This model can predict the development index for microbial flooding through the combination of oil well productivity and variation of water cut. Microbial flooding experiments show that the multi-slug can improve the recovery by 9.24％ compared with single-slug. Also the water breakthrough time of multi-slug microbial flooding can be extended by 40.10％-40.14％, and the water-free oil recovery can be increased by 18.44％. This model can predict almost exactly the dynamic oil production, liquid production and water cut of the microbial stimulation well. The max relative forecasting error of single well is less than 10％, the total error of the block is less than 3％, and the forecasting error of water cut is only 0.25％. In the field experiment, five slugs are adopted to inject the profile control microorganism and oil displacement microorganism alternately. In the test block the increased rate of water cut decreases from 8.1％ to -4.3％, and the composite decline rate decreases from 13.3％ to 4.4％, indicating the effect of water control and oil production stabilization is significant.