Influence of heterogeneous permeability distribution on filtration processes around the acting gas production horizontal well

Abstract

Purpose. Investigate the influence of heterogeneous permeability distribution of a porous medium on the reservoir pressures distribution around the horizontal well. The methodology of research. To assess the influence of the porous medium anisotropy on the reservoir pressures distribution, theoretical research methods were used, containing a systematic analysis of the obtained information, numerical modeling based on a combined finite-element-difference method used and methods of visual presentation of the obtained information. Findings. The analysis of the obtained results showed the dependence of the reservoir pressure distribution (hence, the activity of the filtration process) on the length and location of a horizontal well in a porous medium with a heterogeneous permeability. We have sowed that the activity of the filtration process is directly proportional to the length of the horizontal well. The obtained results show for effective exploitation of anisotropic reservoirs it is necessary to place producing wells into the local areas with relatively low anisotropy of the gas reservoir permeability, especially to avoid places with shear anisotropy. Before installation of production wells in anisotropic gas reservoirs, it is necessary to carry out a systematic analysis of the surrounding anisotropy of the reservoirs with the purpose to ensure effective filtration processes around these wells. We have sowed that installation of productive wells in diagonal direction relatively the main anisotropy axes of the gas reservoir permeability improve gas filtration processes. Obviously, the best conditions for gas production processes in any practical case we can achieve due to optimal selection of all anisotropic filtration parameters of the gas reservoir. The originality. The influence of the heterogeneous permeability distribution of the porous medium on the reservoir pressures distribution around the horizontal well was investigated by using the modeling of filtration processes based on a combined finite-element-difference method. Practical implications. The results of the study confirmed the close relationship between the heterogeneity of the porous medium and the reservoir pressures distribution around the acting production well. The combined finite-element-difference method used in this work can be used to solve other filtration problems (for example, to calculate the gas saturation of a reservoir, create a method for calculating well flow rates, assess the effect of injection wells on filtration processes).