溶剂辅助重力泄油技术开采稠油室内试验

Indoor Test of Heavy Oil Recovery by Gravity Drainage with Solvent

多孔介质和Hele-Shaw设备中的溶剂辅助重力泄油开采机理不同,特别是两者产生脱沥青作用的压力范围是否一致及增产幅度的差别程度如何尚不明确。为研究溶剂辅助重力泄油技术开采多孔介质中稠油的机理,建立了3层结构的溶剂辅助重力泄油可视化填砂模型,对高渗岩心溶剂辅助重力泄油不同注入压力与泄油速率关系及相同注入压力下不同渗透率岩心溶剂辅助重力泄油脱沥青降黏作用和堵塞流动通道的复合作用机理进行了室内试验研究。试验结果表明:多孔介质溶剂脱沥青作用出现在饱和蒸气压附近,试验泄油速度提高3倍,但脱沥青作用发生的压力范围较小;脱沥青作用会造成低渗地层部分孔喉堵塞。因此,低渗地层VAPEX溶剂注入压力应低于溶剂的饱和蒸气压,而高渗地层则可以充分利用脱沥青降黏作用来提高泄油速率。

VAPEX in Hele-Shaw and porous media are different in mechanism, we are especially uncertain whether their pressure ranges of deasphalting are the same and the degree of difference in increasing oil production. In order to study the mechanism of VAPEX in porous media, a three-layer sand-packed physical model for VAPEX was built. VAPEX tests in high permeability cores were conducted to find the relationship between operating pressures and production rates, and several tests were conducted to study the effect of asphaltene precipitation on different permeability of cores under the same pressure. The experiment re- suits show that deasphalting in porous medium happens near saturated vapour pressure,oil drainage ratio increased by three times, but deasphalt appeared in narrow pressure ranges, the asphaltene deposition would plug part of the pore throats, so the operating pressure should be lower than the solvent＇s saturated vapour pressure, but for high permeability formations, the lower viscosity in deasphalting can be fully used to improve production rate.