稠油开采中多元热复合流体相态的研究进展

Research advances in phase behavior of multi-component thermal fluids in heavy oil production

稠油的储量远超常规石油的储量,但因稠油黏度大和密度大的特点而难以开采,高效经济开发稠油已成为石油领域的研究重点。热复合开采技术是目前高效开发稠油油藏的关键技术,其中多元热复合流体的相态特征是稠油油藏开采流程设计与评价的关键。为此,从热复合开采技术中的混合气体系和稠油-气体系2个方面,系统地阐述了多元热复合流体相态的实验和理论研究现状。对于混合气体系相态,多采用静态法进行实验测试,使用状态方程结合混合规则进行理论预测,CO_(2),N_(2),H_(2)O和CH_(4)等常见气体分子组成的二元体系的相态测试趋于成熟,但缺少多元体系的测试数据与预测模型;对于稠油-气体系相态,总结了一般性实验流程与近年实验结果,提出一种加速油气相平衡的新型实验装置构想,指出目前理论预测在气体种类、注气量、气体扩散模型、二元相互作用系数等方面的不足。进而对多元热复合流体相态研究提出展望,以期促进热复合开采技术进一步的机理研究与参数优化。

The reserves of heavy oil far exceed those of conventional oil,but heavy oil is difficult to exploit due to its high viscosity and density.Thus,the efficient and economical development of heavy oil has become a research focus in the petroleum field.Hy-brid thermal recovery are critical for efficiently developing heavy oil reservoirs,and phase behavior of multi-component thermal flu-ids are the key to designing and evaluating the development processes of heavy oil reservoirs.Therefore,this paper systematically reviewed the current experimental and theoretical research on phase behavior in multi-component thermal fluids of mixed gas sys-tems and heavy oil-gas systems in hybrid thermal recovery.For phase behavior of mixed gas systems,static methods were em-ployed for experimental tests,and state equations and mixing rules were for theoretical prediction.Meanwhile,the phase test of the binary system composed of common gas molecules such as CO_(2),N_(2),H_(2)O,and CH_(4) tends to be mature,while there is a lack of test data and prediction models related to multivariate systems.For heavy oil-gas systems,general experimental processes and recent ex-perimental results were summarized to propose a new experimental device concept for accelerating oil-gas phase equilibrium.Addi-tionally,the disadvantages of current theoretical prediction in gas types,gas injection rates,gas diffusion models,and binary inter-action coefficients were pointed out.Furthermore,a prospect was presented for studying the phase behavior of multi-component thermal fluids to promote further mechanism research and parameter optimization of hybrid thermal recovery.