Combined Cyclic Solvent Injection and Waterflooding in the Post-Cold Heavy Oil Production with Sand Reservoirs

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• 作者：Hongze Ma ; Desheng Huang ; Gaoming Yu ; Yuehui She ; Yongan Gu
• 刊名：Energy & Fuels
• 出版年：2017
• 出版时间：January 19, 2017
• 年：2017
• 卷：31
• 期：1
• 页码：418-428
• 全文大小：605K
• ISSN：1520-5029

文摘

In this paper, cyclic solvent injection (CSI) and waterflooding (WF) were combined and studied to maximize their technical synergy and optimize the enhanced heavy oil recovery (EHOR) in the post-cold heavy oil production with sand (CHOPS) reservoirs. The original heavy oil sample was collected from the Colony formation in western Canada. The PVT data and viscosities of CH₄/CO₂/C₃H₈-saturated heavy oil were measured at different equilibrium pressures and T_res = 21 °C. A total of eight sandpacked laboratory tests were conducted to study and compare four different EHOR processes after the primary production: CSI, CSI + WF, simultaneous CSI + WF, and WF + CSI. In the last three processes, WF was applied after, simultaneously with, and prior to the CSI production, respectively. Three different pressure drawdown rates (6.8, 12.5, and 25.0 kPa/min) and two different solvents (CO₂ and C₃H₈) were used to determine their specific effects on CSI + WF. The experimental results showed that CSI + WF had the highest heavy oil recovery factor (RF) of 30.1% in comparison with 28.9, 25.9, and 24.3% for WF + CSI, simultaneous CSI + WF, and CSI, respectively, when CO₂ was used in CSI. The intermediate pressure drawdown rate of 12.5 kPa/min resulted in the highest heavy oil RF in CO₂-CSI + WF. In addition, C₃H₈ was found to be a more effective extracting solvent than CO₂ due to its more favorable PVT properties and larger heavy oil viscosity reduction.