More Oil Using Downhole Water-Sink Technology: A Feasibility Study

Abstract

Summary In this paper we report on recent R&D progress in downhole water sink (DWS) technology resulting in the establishment of a joint industry/Louisiana State U. (LSU) project-DWS Initiative. Presented are recent case histories of DWS design and successful field trials. The results are then analyzed comparatively in view of the superiority of DWS over single conventional completions. The analysis shows that, although DWS increases production of oil, its potential for reducing production of water is unknown and remains a controversial issue among operators. The case history analysis is followed by results from the authors' theoretical and experimental study on water-cut (WC) suppression with DWS. The study was performed by comparing WC development in single (conventional) and dual (DWS) well completions for a broad range of oil reservoirs with bottom water columns. These theoretical results are supported with experiments conducted using a laboratory physical model of a dual/single completed well-reservoir system. The results included in this paper demonstrate the persistence and irreversible nature of water cut in conventional wells compared to its flexibility and easy control in DWS completions. Defined is the range of production rates where DWS may give a sizable, up to 40%, reduction of WC. It is also shown, with calculations, how to determine the expected WC reduction for a given reservoir and well-completion design.