Quantitative characterization of interlayer interference and productivity prediction of directional wells in the multilayer commingled production of ordinary offshore heavy oil reservoirs

Abstract

Based on the physical experiment of visible multi-tube water flooding, in combination with field production data, the interlayer interference in multilayer commingled production of ordinary offshore heavy oil reservoirs is quantitatively characterized and an appropriate productivity prediction method of directional wells is established for multilayer commingled production of ordinary heavy oil reservoirs. The dynamic relationship of interference coefficients between fluid and oil production indexes is obtained for the multilayer commingled production of ordinary heavy oil reservoirs. The Vandervlis directional well productivity equation is revised by introducing interference coefficient with consideration of starting pressure gradient and a dynamic productivity prediction equation is finally established suitable for multilayer commingled production of ordinary heavy oil reservoirs. Interlayer interference is mainly controlled by vertical reservoir permeability difference, which can be comprehensively characterized by reservoir reference permeability, permeability contrast and permeability deviation. The productivity of wells with different water-cut stages is variously affected by interlayer interference. This influence will be intensified in high water-cut situation, which needs appropriate adjustment measures. The productivity can be more accurately predicted by considering interlayer interference, and the revised directional well deliverability equation can be well applied to field production. Key words: offshore oil field, ordinary heavy oil reservoir, multilayer commingled production, interlayer interference, interference coefficient, directional well, productivity prediction