致密油藏热水驱增油机理定性分析及定量评价

针对致密油藏提高采收率的需求，选取目标区块，利用油田现场提供的岩心、原油等样品，采用室内实验研究了考虑启动压力变化的热水驱增油机理，并利用数值模拟方法对热水驱各增油机理进行了定量评价。室内实验结果表明，热膨胀作用、降低启动压力、热降黏作用、降低界面张力、改善相渗曲线是致密油藏热水驱的驱油机理，且热膨胀和降低启动压力是主要增油机理。数值模拟结果表明，100 ℃、150 ℃热水驱，热膨胀作用和降低启动压力作用增油贡献率最大（其中热膨胀作用贡献率分别为29.79%和33.28%，降低启动压力作用贡献率分别为31.66%和30.48%），其次是相渗改善和热降黏机理，降低界面张力机理的贡献率最低（分别为7.08%和6.27%），模拟结果进一步验证了实验研究结果的正确性。

Qualitative analysis and quantitative evaluation on the stimulation mechanisms of hot water flooding in tight oil reservoirs

To enhance the recovery factor of tight oil reservoirs, the target block was selected. Then, based on the core and crude oil data collected in the feld, the stimulation mechanisms of hot water fooding considering variable threshold pressure were investigated by means of laboratory experiment. And fnally, all stimulation mechanisms of hot water fooding were quantitatively evaluated by using the numerical simulation method. The laboratory experiment results show that thermal expansion, threshold pressure decline, thermal viscosity reduction, interfacial tension decrease and relative permeability curve improvement are the oil displacement mechanisms of hot water fooding in tight oil reservoirs, and thermal expansion and threshold pressure decline are the main stimulation mechanisms. Numerical simulation results indicate that the contribution ratios of thermal expansion and threshold pressure decline are the highest when hot water fooding is carried out at 100 ℃ and 150 ℃. The contribution ratio of thermal expansion is 29.79% and 33.28%, respectively, and that of threshold pressure decline is 31.66% and 30.48%, respectively. Relative permeability improvement and thermal viscosity reduction take the second place, and the contribution ratio of interfacial tension decrease is the lowest (7.08% and 6.27%, respectively).Obviously, the correctness of experimental results is verifed further by the simulation results.