Investigating the Effect of Polymer/Low Saline Water Injection on the Recovery of Medium/Heavy Oil Reservoirs

在许多油田成功地实施了数千个注水工程。这是一项成熟的技术，即使在低采收率水平下也是可靠的，低风险的，经济上有利的。自20世纪90年代以来，这项技术的大部分知识空白已经填补。然而，优化其性能和扩大其应用，特别是在中稠油油藏，是重要的研究领域，尚未得到足够的重视。本研究建议着眼于加拿大中/稠油碳酸盐岩油藏的烃类工艺“聚合物/低盐水注入”的应用和回收（低盐水与聚合物驱相结合非常有趣）。这项研究的好处是，它可以显着提高石油采收率，特别是中/稠油采收率，同时减少进入系统设施的过量水的产生。该项目具体涉及水库工程。提高石油采收率的一个有希望的趋势是低矿化度注水。低矿化度水驱油是近年来研究的热点。近年来的室内和现场研究表明，低矿化度注水对提高轻质油藏的采收率有显著的作用。虽然提出了许多恢复机制，但仍存在许多问题和不确定性。这项研究计划的重点是解决由水盐度引起的恢复机制。这将需要进行基础研究工作，从加拿大中/稠油油藏的角度研究这一过程（聚合物/盐水）的影响，可能包括对排液和渗吸毛细管压力、岩石润湿性变化和有效渗透率的影响。也有迫切需要有一个更好的理解的恢复机制，改变孔隙尺度水平的盐度，在这种情况下，我们的建议将解决盐度对水和岩石表面之间的表面张力的影响，并研究不同盐度的沃茨和不同的岩石表面之间的粘附力。此外，还将研究水矿化度对聚合物流变性的影响。另一个与水本身有关的有希望的趋势最近得到了报道。对于相对高盐度的盐水，也观察到油回收率的大变化。为了实现这些目标，拟议项目将调查以下因素的影响：（离子浓度和阳离子类型：钠、钙和钾）对采油的影响（最佳矿化度）;注入水矿化度温度;硬石膏和白垩的溶解; pH;矿物表面对润湿性的影响;粘土含量;表面电荷的电位离子;注入水矿化度对聚合物流变性的影响;注入水矿化度对聚合物稳定性的影响;注入水矿化度对聚合物流动性的影响;阴离子类型;酸值;不同的流体注入策略（同时/交替注入）和聚合物段塞尺寸。

Thousands of successful water flood projects are operated in many oil fields. It is a proven technology that is reliable, low-risk, and economically favorable even at low recovery levels. Most of the knowledge gaps with this technology since the 1990's have been filled. However, optimizing its performance and extending its application, specifically to medium and heavy oil reservoirs, are important research areas which have not received adequate attention. This research proposal looks at the application and recovery of the hydrocarbons process "Polymer/Low Saline Water Injection" for Canadian medium/heavy oil carbonate reservoirs (low salinity water in combination with polymer flooding is of great interest). The benefit of this research is that it could significantly improve oil recovery, especially medium/heavy oil recovery, while reducing the excessive water production into the system facilities. This project relates specifically to reservoir engineering. One promising trend for increasing oil recovery is low salinity waterflooding. Low salinity in waterfloods has become an active research area in recent years. Recent lab and fieldwork have illustrated that low salinity water injection for light oil reservoirs can significantly improve oil recovery. While many recovery mechanisms are proposed, many questions and uncertainties still remain. This research proposal focuses on addressing the recovery mechanisms caused by water salinity. This will require conducting fundamental research work to study the effects of this process (polymer/saline water) from the standpoint of Canadian medium/heavy oil reservoirs, and may include the impact on drainage and imbibition capillary pressures, rock wettability alternation, and effective permeability. There is also urgency to have a better understanding of the recovery mechanisms of changing the salinity at pore scale level; in this case, our proposal will address the salinity effect on surface tension between water and rock surface and study of the adhesion forces between different salinity waters and different rock surfaces. Furthermore, the effect of water salinity on polymers rheology will be studied. Another promising trend related to the water itself has recently been reported. Large variation in oil recovery has also been observed for brine of comparatively high salinity. To achieve these objectives, the proposed project will investigate the effect of: injected water salinity (ion concentration and cation type: sodium, calcium and potassium) on oil recovery (optimum salinity); injected water salinity's temperature; dissolution of anhydrite and chalk; pH; mineral surface on wettability; clay content; potential ions on surface charge; injected water salinity on polymer rheology; injected water salinity on polymer stability; injected water salinity on polymer mobility; anion type; acid number; different fluid injection strategies (simultaneous/alternate injection) and polymer slug size.