Gas Filtration in Reservoir Conditions Taking into Account the Skin Factor

Abstract

This article investigates the gas filtration under reservoir conditions with particular emphasis on the influence of the skin factor on the gas well productivity. The study focuses on the physical and chemical properties of the drilling muds and the well killing fluids, as well as the processes occurring in the bottomhole zone during the drilling and well operation. Unlike the oil wells, the bottomhole zone in the gas wells is characterized by more complex filtration conditions, where the formation of a skin zone creates additional hydraulic resistance and reduces the permeability of the near-wellbore region. The imperfect completion of gas wells leads to non-uniform flow caused by deformation of both the reservoir and the filtration stream, while the physical properties of the skin zone differ significantly from those of the undisturbed formation. The partial or complete contam-ination of the bottomhole zone results in the deterioration of filtration characteristics and consider-able reservoir energy losses. To account for these effects, a method for calculating the skin factor during gas well operation is proposed. The relationship between the well flow rate and the skin factor is established, providing a basis for selecting appropriate treatment methods for the bottom-hole zone in order to improve gas well productivity.