低渗油藏CO_2驱提高采收率与埋存中的有效设计(英文)

EFFECTIVE DESIGN OF CO_2 FLOODING FOR EOR & SEQUESTRATION IN TIGHT RESERVOIRS

由于具有较低的粘度和注入能力,CO2驱在低渗油田开发中相比衰竭和注水开发有明显的优势,而其开发效果受地质条件、油藏能量、流体特征及工艺技术等多种因素影响.常规的油藏数值模拟方法只能进行单次单因素分析,且不能分析不同因素之间的交互作用,难以满足上述低渗油藏CO2驱中的多因素多水平的研究需要.作者将实验设计方法引入上述CO2驱优化设计的数值模拟研究中,利用该方法可以利用少量具有代表性的CO2方案,最大量地获取需要的敏感性分析信息,从而有效提高数值模拟方法的效率.采用上述方法分析了低渗油藏CO2驱中的关键因素以及它们之间的交互作用,确定了适合低渗油藏条件的CO2驱注采方式、注采井型及其优化组合.研究表明,利用大斜度井连续注CO2,结合生产井生产气油比和油藏平均压力实施开关井控制方法可以增加注入能力、缩短开发周期,并能够同时获得油藏采收率和温室气体埋存的联合优化效果;研究同时发现存在相渗滞后作用的情况下油藏CO2埋存潜力较大.

With lower viscosity and higher injeetivity, CO2 flooding has some advantages in tight reservoirs than depletion and water flooding, which can co-optimization the enhanced oil recovery and sequestration. The performance of CO2 flooding design is determined by different geological as well as engineering aspects. Considering the tight nature and relative permeability hysteresis in tight reservoirs, the CO2 flooding design in more very complicated with more challenges. The reservoir simulations were often performed in one factor at one time experimental design, in which the interactions between different parameters or factors are not taken into account. In this paper CO2 flooding optimization was simulated with com- positional simulator ＂GEM＂ with experimental design to enhance the simulation efficiency and maximize the information gained from each uncertainty analysis. The key parameters and their interactions during CO2 flooding in tight reservoirs for EOR and sequestration were determined. This paper shows that continuous CO2 injection using directional injectors coupled producers＇ Well Control method is the best scheme during CO2 flooding in tight reservoirs, which can give higher oil recovery and the most CO2 sequestration.