Factors affecting gel strength design for conformance control: An integrated investigation

Abstract

In petroleum industry, excessive water production represents a major industry challenge because of its serious economic and environmental impacts. Conformance control gel treatments have been proven to be effective in mitigating this problem and in reactivating oil production in brown fields. Understanding the most important factors that control the performance of gel treatment represents a priority for the optimization process and should be considered during the design of gel treatments. In this study, different scenarios of reservoir simulation models were developed and validated with field data to investigate the most important factors controlling the success and failure of gel treatments. Numerical simulation methods were used to determine how the optimum water residual resistance factor (Frrw) of gels should be changed with different reservoir conditions to achieve the highest oil recovery. Furthermore, the impact of crossflow on gel design was deeply investigated and correlated with the oil recovery improvement and water cut reduction by calling up some of the petroleum engineering basics. Moreover, the relationship between the gel penetration depth and permeability contract has been determined. The results of this research developed a new equation which correlates the optimum Frrw, that should be achieved by gels, with the reservoir candidate properties. However, Design of Experiments (DOE) proved that there are two main parameters which have the dominant role to decide the optimum Frrw. New cut-off values for crossflow and permeability contrast have been determined from this study to provide guidelines on gel treatments selection criteria. This research presents new findings to optimize gel design according to the reservoir conditions. The findings of this study are built on an integrated combination of field data, reservoir simulation, and reservoir engineering basics. • The results of this research developed a new equation correlating the optimum Frrw with reservoir properties. • The optimum value of Frrw is only function of two main parameters which are the permeability contrast and the oil viscosity. • If the crossflow ≥0.1 and the permeability contrast ≤10, there is no benefit from gel treatment regardless of the Frrw used. • There is no effect for the timing of gel treatment on its performance if the high-K streak was already watered out completely. • This study found that as far as the oil viscosity increased the optimum value of Frrw should be increased for better results.