Performance of Horizontal Gas Wells Associated with Non-Darcy Turbulent Flow

Abstract

The non-Darcy flow effect is a phenomenon occurring only in the vicinity of the gas horizontal well and is negligible in the region far away from the wellbore. It is closely related to high gas flow velocity. In the case of high gas flow rate in the porous media, Darcy's law is no longer applicable and has to be modified to allow for the additional pressure loss due to the turbulent flow. The non-Darcy flow appears if the gas flow velocity reaches a value that is large enough and the flow changes from linear flow to nonlinear flow .To describe the nonlinear flow situation, a quadratic term has to be added to the Darcy's flow equation. In recent years, horizontal wells are drilled in gas reservoirs to deal with the water coning as well as to increase the deliverability. However, compared to the numerous researches on the non-Darcy flow of vertical wells, little attention goes to horizontal wells because people assume that the non-Darcy effect will not affect the gas horizontal well deliverability too much. This study is aimed at evaluating the negative effect of non-Darcy flow for horizontal gas well quantitatively by proposing deliverability equations considering turbulent effect. The non-Darcy flow effect is a phenomenon occurring only in the vicinity of the gas horizontal well and the flow model in the area far away from the wellbore is still Darcy's flow. Therefore, a gas reservoir can be divided into two parts: Darcy's flow domain and non-Darcy's flow domain. Two deliverability equations in the two domains are constructed separately and combined together. This research project also presents a simultaneous system of equations to calculate the production rate for horizontal gas wells as well as the non-Darcy radius. The inflow performance of vertical wells and horizontal wells in a cylindrical reservoir with bottom water are compared. The effects of reservoir and wellbore parameters on production performance are also studied, particularly, (1) Pseudo pressure drop ;(2) reservoir permeability;(3) pay zone thickness; (4) Horizontal well length.

Date of Award	2015
Original language	American English
Supervisor	Jing Lu (Supervisor)