A semi-analytical workflow to study dimethyl ether improved water flooding; a fractional flow study

Abstract

This paper introduces a semi-analytical procedure to study fractional flow (fw) and performance of dimethyl ether improved water flooding (DEW). To this end, the fw-curve of DME/water-oil is discussed and the effect of the K-value on the fractional flow and the oil recovery curve is studied. To achieve proper fw-curves, governing equations are solved using a finite difference approach, and saturation and concentrations are obtained in every time step. Therefore, numerous fw-curves are found; we select a DME-free and a DME-rich fw-curve. Then, an initial point, which is determined using the partition coefficient value (K-value), is chosen to plot a tangential line on the fw-curve. The intercept of the tangential line and the horizontal axis is named pseudo-adsorption point. Upon increase of K-value, the intercept moves toward the origin of the plot. Moreover, results show that with the increase of K-value, the DME-rich fw-curve moves to the right side, which makes a larger horizontal distance between DME-free and DME-rich fw-curves. In addition results indicate that at small K-values, the increase of K-value significantly improves oil recovery, but the further increase does not lead to significant recovery improvements. This workflow can be considered useful to analyze DME-improved water flooding in different conditions.