Well testing interpretation method and application in triple-layer reservoirs by polymer flooding

Abstract

Well testing method has historically been the main source of formation evaluation in oilfields. This work demonstrates well testing analysis for formation evaluation in crossflow triple-layer reservoirs by polymer flooding, and a well testing model is proposed by considering mechanical degradation, dispersion, convection, and shear-thinning of polymer solutions. The type curves, having five segments with different flow regime, are developed based on this model, and parameter sensitivity is analyzed. The typical characteristic is the existence of two ’concaves’ in the type curves, distinguished from one-layer and double-layer reservoirs. A field test validates the proposed well testing model, which can effectively evaluate the layered permeability and skin factor. Furthermore, formation damage due to adsorption of polymers at the rock surface is estimated through comparison of the interpreted parameters with the values prior to polymer flooding, which explores the feasibility of applying this interpretation method in formation evaluation of polymer flooding reservoirs.