大庆油区芳48断块CO_2吞吐室内实验

Laboratory experiment of CO_2 stimulation in Fang48 fault block in Daqing Oilfield

针对大庆油区芳48断块渗透率低、天然能量不足、注水困难、产量递减速度较快的情况,进行了CO2吞吐室内实验。通过对CO2吞吐的采收率、换油率、生产气油比等指标进行评价,探索了该油藏进行CO2吞吐开采的可行性。结果表明,CO2吞吐对于开采该油藏具有非常好的效果,但其效果与注入压力、吞吐周期有关。第1轮吞吐的采收率、换油率最高,采收率均超过8.05%,平均为12.42%,换油率超过5.33L/m3,平均为14.53L/m3。随着吞吐周期的增加,各周期的采收率、换油率下降,生产气油比增加,采收率的贡献主要在前2个周期。芳48断块CO2吞吐前3个周期当注入压力分别为3,2和4MPa时采收率、换油率最大。

The characteristics of Fang48 fault block are low permeability, insufficient natural energy, difficult to inject water and high production decline speed. Laboratory experiment of CO2 stimulation was made. Feasibility evaluation on exploiting this oil reservoir by technology of CO2 huff and puff ( CHP) was carried out through laboratory experiments on recovery efficiency, oil/gas exchange ratio, gas-oil ratio, and others. The results show that CHP is a quite good way to develop this reservoir, but its performance is correlated with the gas injection pressure and the cycle of CHP. The highest recovery factor and oil/gas exchange ratio are obtained in the first run ,recovery efficiency being all above8. 05% with a average of 12. 42% ,and oil/gas exchange ratios all over 5. 33L/m3 ( CO2) with 14. 53L/m3 (CO2) as the average. With the increasing of CHP runs, the recovery efficiency and oil/gas exchange ratio decline and the gas -oil ratio raises. The recovery efficiency is mainly contributed by the first two CHP cycles. The highest recovery efficiency and oil/gas exchange ratio are a-rhieved when injection pressures of 3MPa,2MPa and 4MPa are applied respectively.