超临界水驱超稠油提高采收率热物理特性研究

超稠油资源的高效开发对于提高石油供给和保障我国石油安全意义重大。针对深层超稠油资源由于原始地层压力高、原油黏度大导致常规蒸汽驱无法有效开发的问题,本文提出超临界水驱开发深层超稠油的新思路。本文首先研制了超临界水驱油提高采收率实验平台,研发的管式填砂岩心模型能够模拟岩心升温和驱替的同步过程,然后开展了超临界水驱、蒸汽驱和热水驱对比实验研究,实验结果表明,相对于蒸汽驱,超临界水驱能显著提高采收率并具有更高的热效率,25MPa、400℃超临界水驱鲁克沁超稠油的采收率达到97.07%;获得了超临界水驱过程的温度场和驱替压差变化规律,发现了超临界水超覆现象,与蒸汽超覆相比,超临界水超覆发生晚且持续短,可扩大波及范围,提高采收率。

Thermophysical Characteristics of Enhanced Extra-heavy Oil Recovery by Supercritical Water Flooding

To develop extra-heavy oil is of great importance for China’s crude oil supply and security.However,due to the original high pressure and high oil viscosity,deep extra-heavy oil cannot be exploited efficiently by the existing technologies,for example steam flooding and in-situ combustion.This paper proposed to develop extra-heavy oil by supercritical water flooding.First,a new kind of tubular sand pack was developed to simulate the heating and displacing process simultaneously.Then supercritical water flooding,steam flooding and hot water flooding were carried out for comparison.The results indicated that supercritical water flooding can significantly enhance oil recovery compared with steam flooding,and the displacement efficiency reached 97.07% when injection parameters were25 MPa and 400℃.Additionally,the temperature field and pressure field in supercritical water flooding were examined.The phenomenon of supercritical water override was found,and it promoted enhanced oil recovery(EOR) because of its later occurrence and shorter duration relative to steam override.