科研之友
微信
新浪微博
Facebook
分享链接
摘要
Waterflood in a viscous oil reservoir is not very efficient because the water fingers through the oil due to adverse viscosity. Typically, thermal methods are used, to recover viscous (and heavy) oil. However, thermal methods can be inefficient when the depth of the reservoir is high and pay thickness is low. Nonthermal chemical enhanced-oil-recovery (EOR) methods are being developed as alternatives. Recently, a new low-cost chemical EOR technology called alkali-cosolvent-polymer (ACP) flooding has been developed which does not use any synthetic surfactant. In viscous oil reservoirs, the oil recovery in the first 30 years is more important than the ultimate recovery, which may take many hundreds of years. The purpose of this study is to identify the optimum ACP slug viscosity and the optimum timing for the initiation of the ACP process. ACP formulations that achieve ultralow tension were developed. Since the sweep efficiency is challenging in viscous oil reservoirs, ACP floods were performed in a quarter, 5-spot lab model. Experimental results were numerically simulated and matched using an in-house simulator UTCHEM. The results of the experiments indicate that the tertiary ACP flood with the oil to ACP slug viscosity ratio between 2 and 4 could recover more than 80% of the oil with a reasonable pressure gradient. This unfavorable mobility of the chemical slug is beneficial considering both oil recovery and pressure drop. The timing of the start of the tertiary flood did not change the cumulative oil recovery very much. However, a shorter waterflood resulted in an earlier oil recovery.
- 出版日期2017-7
