Noman et al. analyzed the multi-rate welltests of over one hundred high rate gas wells in the southern North Sea, and determined the inertial flow coefficient for the formation matrix. The beta factor of consolidated sandstone was found to be an order of magnitude higher than predicted with correlations for unconsolidated porous media. Fracture stimulating these formations was subsequently shown to reduce the matrix velocities by increasing the effective wellbore radius.
The pressure drop due to non-Darcy flow in a gas well producing at high rates can be determined from analysis of multi-rate pressure test data. In the absence of such data, calculation of the non-Darcy term requires a knowledge of the coefficient of inertial resistance.
This paper presents correlations for estimating the coefficient of inertial resistance from reservoir porosity, permeability and gas saturation. These correlations were derived from analysis of multi-rate pressure tests conducted in over one hundred gas wells and are supported by experimental data using core plugs. They are found to be better than other published relationships in predicting observed performance.
Author(s): R. Noman, Imperial C.; N. Shrimanker, British Gas Corp.; J.S. Archer, Imperial C.
Paper Number: SPE 14207