Effect of Water-Cut on Sandstone Strength and Its Implications in Sand Production Prediction

Abstract

ABSTRACT Production of water is inevitable from reservoirs particularly in aged fields. Water is very useful for efficient reservoir management but could be a nuisance when it does not contribute to hydrocarbon production and cause diverse problems such as corrosion, sand production, etc, in a well. High water cut increases the potential of sand production risks. Several mechanisms of sanding, sand control models and measures exist in the industry to ensure safe operation of facilities. In this work, series of laboratory triaxial compressible strength tests on different core samples was performed to investigate and quantify the effect of water-cut on sandstone strength and sand production. The tri-axial compressive strength tests were performed under in-situ confining pressures. The samples were initially 100% saturated with brine at some time and other times the water-oil saturations were varied. The results showed that the effect of water-cut on sandstone strength and sand production is very significant for all sandstones tested. Also, strength reduction is more significant for 100% water saturated samples than samples with less water saturation for all samples. Hence, water saturation-induced rock strength reduction is the most significant factor governing sand production. Although, failure of rock is pre-requisite for sand production, the failure does not always lead to sand production