Modelling and Simulation of Foam Assisted Water-Alternating-Gas Injection in Naturally Fractured Carbonate Reservoirs
在这项研究中，使用CMG软件数值模拟了三种不同增油方法的碳酸盐岩心浸润实验结果，以研究提高碳酸盐岩裂缝储层中气体侵入区的油藏采收率。
实验结果来自于伊朗低温碳酸盐岩裂缝岩心进行的二次和三次采油条件下的二氧化碳注入、水气交替注入（WAG）和泡沫辅助水气交替注入（FAWAG）实验。利用CMG推导出了岩心的相对渗透曲线和泡沫参数拟合。
然后将这些发现应用于一个由四分之一五点井网和一个由双五点井网组成的区域模型中，前者作为主要的油藏开采方法。此外，这些模型首先模拟了未脱气油和束缚水，然后再模拟了40%的现有气体侵入区域，其中包括甲烷。
泡沫辅助采油过程被发现是增加气体侵入裂缝储层采收率的非常有用的方法，它使试验模型的采收率提高了惊人的20%，在区域模型中提高了超过2%。通过调节注入水和气体的比例，可在三次采油阶段后将采收率提高至多达7%。
Abstract
In this research, carbonate core flooding experimental results of three different EOR methods were replicated numerically using CMG to study the enhancement of oil recovery in the gas invaded zone of carbonate fractured reservoirs. Experimental results for carbon dioxide injection, Water-alternating-gas injection [WAG], and foam-assisted water-alternating-gas injection [FAWAG] that were conducted in Iranian low-temperature fractured carbonate cores under both secondary and tertiary recovery conditions were used for this purpose. From these experiments, the relative permeability curves of the cores and the fitting foam parameters were derived using CMG.
These findings were then used in a pilot model, that consists of a quarter five-spot pattern, and in a sector model where a double five-spot setup was used as the primary method of oil extraction. Additionally, all these models were first simulated, having been saturated by live-oil and connate water and secondly with a present gas invaded zone of 40% consisting out of methane. The foam-assisted recovery process was found to be a very useful aid in the recovery of gas invaded fractured reservoirs increasing the recovery factor in the pilot model by an astonishing twenty percent and in the sector model by more than two percent. By tuning the ratio of injected water and gas the recovery can be raised to as far as 7% additional recovery after 1 PVI for a tertiary stage.
