A PRACTICAL APPROACH FOR FIELD SCALE PERFORMANCE ESTIMATION OF WATER INJECTION IN FRACTURED OIL RESERVOIRS

Abstract

In this study, a practical method is developed to predict the waterflooding performance in naturally fractured reservoirs (NFR) if the production rate is dominated by the capillary imbibition transfer between matrix and fracture. Capillary imbibition transfer rate is defined explicitly as a function of matrix (permeability, wettability, and size), flow (rate or velocity) and reservoir (size) properties. Verification of the formulation is based on previously performed experimental and numerical studies. Then, a correlation between total water injected and total oil produced is developed using the abstract relationship between recovery and time proposed by Aranofsky et al. (1958). A parametric study is performed to obtain a critical (or optimum) injection rate for an efficient recovery of oil. It is shown that a critical injection rate value exists depending on the capillary suction capability of matrix. Beyond the critical rate, the process becomes inefficient as the increasing rate would not yield a faster oil recovery.