Flow in Horizontal Wellbores With Influx Through Porous Walls

Abstract

Abstract Experimental investigation is presented on the channel flow with mass transfer through porous walls, which has Continuous influx into a horizontal wellbore configuration from the oil reservoir. This has been recognized as one of the unsolved, yet most important problems in the production operations because of the complicated interaction between the wellbore and the reservoir. The pressure was measured along the test channel with rectangular cross section, when the turbulent single-phase liquid flow was introduced into the channel. The fluid velocity distribution in the rectangular cross section was also measured to investigate the effect of influx on the pressure drop. From comparison with a one-dimensional momentum exchange model, the model agreed with the experimental data for relatively large Reynolds numbers and described reasonably the flow behavior in a horizontal wellbore configuration. Introduction Literature Review Horizontal wells have become attractive for the production of thin layer reservoirs, naturally fractured reservoirs, reservoirs with gas or water coning problems, offshore environments where various wells are drilled from a central platform, and also in enhanced oil recovery practices such as steam injection, because they can improve the inflow performance of these reservoirs and produce more oil with smaller pressure drawdowns as compared with conventional vertical wells due to enhancement of the reservoir contact and negative skin factors. Depending on the completion method used in a horizontal well, fluid may enter the wellbore through perforations at various locations along the wellbore. As the distance between perforations may be insufficient to achieve a stabilized axial velocity profile, the flow pattern and the pressure gradient in a horizontal wellbore are changing along the well length. Although the flow behavior in the horizontal section, with an increasing flow rate along it due to influx, and the relationship between the pressure drop and the influx from the reservoir have been recognized as one of the unsolved, yet most important problems in the production engineering, they have yet been left unclarified. in order to improve the production efficiency of a horizontal well, there are earnest demands for more information on these subjects. Despite of the increasing number of publication pertaining to drilling and reservoir aspects of horizontal wells, a detailed literature search showed that few studies have been conducted on the flow behavior in horizontal wellbores. The flow nature similar to that in horizontal wellbores has been investigated in different disciplines from the petroleum engineering using channels with injection or suction from porous walls. Yuan and Finkelstein performed theoretical investigation of the effect of uniform injection at the wall on two-dimensional, steady laminar flow through a porous-wall pipe by solving the Navier-Stokes equations both for small and large Reynolds numbers. The results showed that the injection at the porous wall increases the friction coefficient due to increased momentum exchange with the main flow. For a velocity ratio of injection to main flow at the center line equal to 0.01, the friction coefficient at the wall is increased by 70 - 80% over that for zero injection when Reynolds number exceeds 500. However, no experimental studies have been conducted on friction factors for laminar flow through porous tubes with fluid injection. P. 225^