Investigation on flow regimes and non-Darcy effect in pressure test analysis of horizontal gas wells

The results show that the appearance of elliptical and pseudo-radial flow regimes depends on relative well length and formation thickness. In addition, the effect of off-centered wells with respect to upper and lower boundaries in transient pressure data is expressed. The results also show that non-Darcy flow can cause a significant skin in transient data of a horizontal gas well. Magnitude of the skin is mainly affected by reservoir permeability and production rate of the horizontal well. Contrary to the general belief regarding negligible effect of non-Darcy flow in analysis of horizontal gas well test, this study showed that it can cause a significant error in analysis of the well test data.