冀东油田高浅北油藏天然气泡沫驱泡沫体系优选

模拟冀东油田高浅北区油藏油水条件,综合考虑起泡剂起泡能力、半衰期及界面张力评价指标,初步筛选出CEA/FSA1、CEA/DHF-1两种复配泡沫体系,质量比均为7:3,二者的起泡体积分别为152、140mL,半衰期分别为72、63 min,无因次筛选系数分别为21.144、19.881,界面张力达到10^-3数量级。泡沫性能评价研究结果表明,CEA/FSA1与冀东原油作用后,起泡体积降至110mL,半衰期降至40min,无因次筛选系数为1.180,耐油性较好,并且耐温抗老化能力较强。优选CEA/FSA1为该油藏天然气泡沫驱油起泡剂,起泡剂加量为0.5%。单管封堵实验中,单一CEA/FSA1泡沫阻力因子为127,封堵性较好;CEA/FSA1和爱森聚合物组成的强化泡沫的阻力因子为438,二者匹配性良好。双管驱油实验中,水驱后强化泡沫驱可提高采出程度22.9%,高、低渗模型的采出程度分别提高18.8%、27.0%。

Optimization of Natural Gas Foam Flooding in Gaoqianbei Reservoir of Jidong Oilfield

Considering the evaluation indexes of foaming capability, foam half-life time and interfacial tension, CEA/FSA1 and CEA/DHF-1 in mass ratio 7:3 were firstly chosen as two kinds of mixed foam systems in the simulated water-oil condition of Gaoqianbei reservoir of Jidong oilfield. The comprehensive properties of CEA/FSA1 and CEA/DHF-1 was good with 152 mL and 140 mL foaming volume, 72 min and 63 min half-life time, 21.144 and 19.881 dimensionless filter coefficient, and 10-3 magnitude interfacial tension, respectively. The foam performance evaluation experiments showed that the foaming volume decreased to 110 mL, the half-life time decreased to 40 min, and the dimensionless filter coefficient decreased to 1.180 when CEA/FSA1 reacted with Jidong oil. Compared to CEA/DHF-1, CEA/FSA1 had better oil tolerance, temperature tolerance and aging resistance ability. It was recommended as foam agent for natural gas foam flooding in Gaoqianbei reservoir of Jidong oilfield and the dosage was of 0.5%. The single tube blocking experiment showed that the resistance factor of CEA/FSA1 was of 127, which meant CEA/FSA1 had good plugging performance. When CEA/FSA1 was mixed with Aisen polymer, the resistance factor of enhanced foam system was of 438, which meant the compatibility of CEA/FSA1 and Aisen polymer was good. In double tube displacement experiment, the recovery ratio of enhanced foam flooding increased by 22.9% and that of high and low permeability tubes increased by 18.8% and 27.0% respectively after water flooding.