CO_2吞吐降压开采模拟实验研究

SIMULATION TEST ON CO_2 HUFF-N-PUFF DEPRESSURIZATION PRODUCTION

文章通过长岩心填砂管物理模拟实验,分析了CO_2吞吐降压开采过程各阶段的特征,研究了生产压差、降压开采方式、注入量、注入速度及关井时间对CO_2吞吐效果的影响。实验结果表明,中低黏度原油开采、气体驱动开采阶段为CO_2吞吐降压开采主要的产油阶段;多周期吞吐时增产原油主要依靠气体驱动阶段,增产原油机理主要是溶气驱的作用;实验得到换油率最高时CO_2的注入压力为5 MPa,CO_2注入量为0.166 8 mol,关井平衡时间为6 h;降压开采时存在一个合理的生产压差值。研究结果可为CO_2吞吐注采参数的优选提供有力依据。

In this paper,through the physical simulation experiments on long-core sand packed tube,each stage of CO_2huff-n-puff depressurization production was analyzed,and the effects of production pressure differential,depressurization stimulation method,injection volume,injection rate and shut-in time on CO_2huff-n-puff stimulation were studied. The experimental results showed that the low-medium viscosity crude oil production and gas-drive production stage were the main oil production stage for CO_2huff-n-puff stimulation. For multi-cycle stimulation,the oil production improvement mainly produced by the solution gas drive during gas-drive stage. The highest oil replacement ratio was obtained when the CO_2 injection pressure being5 MPa,the CO_2 injection volume 0. 1668 mol,and the balance time after shut-in 6h. And the optimal production was obtained at a certain reasonable production pressure differential. This experimental study will provide powerful reference for the optimization of CO_2huff-n-puff stimulation parameters.