基于地质储量结构变化的采收率演变趋势

Research on overall recovery rate variations of dynamically changing OOIP

不同类型油藏逐次投入开发,使油公司储量不断增长,储量结构发生变化,整体采收率也随之改变。建立以储量为自变量的常微分方程表征了整体采收率随储量增长的内在关系,并定量剖析了中国石化2011年后新投入储量、老区已开发储量与整体采收率的演变趋势。分析结果表明,整体采收率随储量增长是一个总量与增量、存量的关系,影响油公司整体采收率的主要因素是投入储量的品质及其储量比例,随新投储量品质变差及其储量占比的提高,油公司整体采收率呈逐渐降低的趋势。通过对中国石化不同类型油藏采收率状况及主控因素的分析,提出了"立足水驱、完善热采、拓展化学驱、加大注气和微生物采油力度、探索变革性EOR新技术"的提高采收率技术思路及攻关方向。

With different types of oil reservoirs being put into development in a proper order according to their respective characteristics,operators may be rewarded with more reserves in a given field.However,with reservoir combinations varying,the overall recovery rates of the field change as well.An ordinary differential equation with reserve as independent variable is established to characterize the changing trend of overall recovery rates with increasing reserves and to quantitatively analyze the overall recovery rate changes of Sinopec’s reserves that had been successively put into development(or already under development)from 2011 to 2018.The results show that the relationship between the overall recovery rate and reserve increase can be simplified as the total versus the incremental or the remaining.The main factors influencing the overall recovery rate are the quality and proportion of reserve of a certain reservoir in the whole context.The overall recovery rate of a given field is generally decreasing as more and more hard-to-get reserves are put into development.Following the analysis of the recovery rates of various oil reservoir combinations operated by Sinopec and the factors that influence the rate changes,we propose that future EOR study should be focused on improving the efficiency of water flooding and thermal EOR,expanding the application of chemical flooding,gas injection and microbial recovery,and exploring the possibilities of developing innovative EOR technologies.