冀东油田浅层非均质油藏CO_2驱数值模拟与方案设计

Numerical Simulation and Scheme Design of CO_2 Flooding in Shallow Heterogeneous Reservoirs of Jidong Oilfield

冀东油田高浅北区Ng6(馆陶组6层)油藏属于天然边底水驱普通稠油油藏,为了改善开发效果,决定在主体部位开展CO2驱油试验。建立了符合油藏特点的三维地质模型,应用数值模拟技术,对3种不同CO2注气方式—连续气驱、气水交替驱、气+泡沫交替驱进行了评价筛选,并进行注气参数的筛选优化。由于Ng6油藏非均质性比较严重,为防止注气过程中过早地发生气窜,在注气前,进行了前期调剖段塞进行。计算结果表明:试验区对CO2驱具有较好适应性,以CO2+泡沫交替注入(气泡沫体积比)为最佳允驱替方式,CO2的最佳用量为0.055HCPV,预测试验区的综合含水达到99.2%时的采收率比边底水驱提高2.29个百分点。

Ng6 reservoir( No. 6 reservoir in Guantao Formation) in Gaoqianbei Area of Jidong Oilfield belonged to a common heavy oil reservoir flooded with natural bottom and edge water,to improve the development effect,it was determined that CO2flooding should be used in major development areas. A 3D geological model which was consistent with reservoir characteristics was established,and numerical simulation technology was used for evaluating and selecting the gas injection methods,such as continuous gas injection,alternative gas injection and gas plus foam flooding displacement,and gas injection parameters were chosen and optimized. Because of more serious heterogeneity in Ng6 reservoir,to prevent earlier gas channeling in the gas injection process,the gas plugs foam for profile control were chosen before gas injection. The result shows that CO2flooding is well adaptable for the test area. The optimal displacement mode is CO2+ foam alternating injection( volumetric ratio of gas foam),the optimal CO2dosage is 0. 055PV. It is estimated that when the integral water-cut is 99. 2% in the test area,its oil recovery should be 2. 29% higher than that of edge water flooding.