Wang Zhuangzhuang, Ma Minglu, Sun Yuanxiang
School of Science, Qingdao University of Technology, Qingdao 266520, Shandong, China.
Shandong Weima Pumps Manufacturing Co., Ltd., Jinan 271100, Shandong, China.
ACS Omega. 2022 May 31;7(23):20044-20052. doi: 10.1021/acsomega.2c01879. eCollection 2022 Jun 14.
The anomalously high recovery of solution gas drive in some heavy oil reservoirs has been associated with foamy oil. The effects of external factors such as temperature, permeability, and the pressure depletion rate on foamy oil flow have been studied sufficiently, but few studies are available on the effect of heavy oil itself. In order to investigate the effect of oil viscosity and the solution gas-oil ratio on foamy oil, 11 tests of solution gas drive through a sandpack were carried out in this work. The results show that a typical foamy oil solution gas drive exists in three stages, which are the oil phase expansion stage, the foamy oil flow stage, and the oil-gas two-phase flow stage. As the oil viscosity decreases, the foamy oil flow stage shortens, resulting in reduced recovery of this stage significantly. In the experiment with an oil viscosity of 200 mPa·s, foamy oil flow was not observed. A lower limit of oil viscosity should exist for steady flow of foamy oil, which is considered to be approximately 600 mPa·s according to the experimental results. As the solution gas-oil ratio increases, the oil recovery first increases and then decreases. Foamy oil flow could be observed clearly when the solution gas-oil ratio was between 10 and 26 Sm/m, which indicates that there is an optimal range of solution gas-oil ratios for foamy oil solution gas drive. The test with a solution gas-oil ratio of 35 Sm/m showed that oil-gas two-phase flow followed the oil phase expansion stage as a result of the production of a quantity of gas, which illustrates that excess solution gas is unbeneficial to foamy oil flow on the contrary. The investigation revealed that oil viscosity and the solution gas-oil ratio are essential for foamy oil flow, which provides theoretical support for foamy oil production.
在一些稠油藏中，溶解气驱采收率异常高与泡沫油有关。温度、渗透率和压力衰竭速率等外部因素对泡沫油流动的影响已得到充分研究，但关于稠油自身影响的研究却很少。为了研究原油粘度和溶解气油比对泡沫油的影响，本文开展了11次通过砂质充填层的溶解气驱试验。结果表明，典型的泡沫油溶解气驱存在三个阶段，即油相膨胀阶段、泡沫油流动阶段和油气两相流动阶段。随着原油粘度降低，泡沫油流动阶段缩短，导致该阶段采收率显著降低。在原油粘度为200 mPa·s的试验中，未观察到泡沫油流动。泡沫油稳定流动应存在一个原油粘度下限，根据试验结果，该下限约为600 mPa·s。随着溶解气油比增加，采收率先升高后降低。当溶解气油比在10至26 Sm/m之间时，可清晰观察到泡沫油流动，这表明泡沫油溶解气驱存在一个最佳溶解气油比范围。溶解气油比为35 Sm/m的试验表明，由于产生了大量气体，油气两相流动跟随油相膨胀阶段之后，这说明过量的溶解气反而不利于泡沫油流动。研究表明，原油粘度和溶解气油比对泡沫油流动至关重要，这为泡沫油开采提供了理论支持。
