Wettability Studies and Estimation of Capillary Pressure on Heterogeneous Bioturbated Sandstones from Kachchh Basin, India

Abstract

Reservoir characterisation for modelling and flow simulation is done assuming the homogenous nature of the rock. Heterogeneity is overlooked to prevent occurrences of reserve management complexities. Bioturbated sandstone reservoirs are heterogeneous and prominently found in many petroleum producing basins. Studying the fluid characteristics of these heterogeneous systems is essential, as with changing characters will affect the resulting wettability behaviour. Thus, in a bioturbated heterogeneous reservoir, estimation of the wettability will help in estimating the flow behaviour and possible outcomes of hydrocarbon oil and gas recovery from such formations. With this background, a collective approach has been designed to understand the reservoir behaviour of bioturbated sandstones from Kachchh Basin. The samples are from outcrop, and the analysis includes established standard experimental procedures of core/rock analysis for estimating wettability. The paper explores the experimental analysis of the measuring contract angle in various bioturbated samples. Contact angles of both oil-wet and water-wet cores were measured considering time and gradient factors. Capillary pressure of the various grades of bioturbated sandstones was calculated combining obtained data on contact angle values along with the pore size (radius) and interfacial tension data. The results suggest that the final model can be designed and proposed for the characterisation of bioturbated heterogeneous sandstones using the Capillary pressure behaviour of rocks along with hysteresis trend of imbibition and drainage flows.