New cold-production technique for heavy oil with strong bottomwaterdrive

Document Type

Article

Publication Date

1-1-2014

Abstract

Few heavy-oil reservoirs with strong bottomwaterdrive have been developed successfully, because severe water coning causes low ultimate recovery, low well productivity, and high water production. In these reservoirs, thermal and gravity-assisted methods that could improve recovery are perceived as economically unfavorable or technologically infeasible. In this paper, we propose a new cold-production technique, called the bilateral water sink (BWS), to meet those challenges. The BWS method suppresses water cresting by producing oil and water simultaneously from bilateral horizontal wells completed in the oil and water zones separately. Unlike conventional horizontal-well production, where water cresting causes water to bypass oil, making the waterdrivemechanism ineffective, the BWS prevents water cresting by altering the potential distribution in the near-well region. With cresting suppressed, water drives the oil from the edges of the well drainage area to the well, resulting in high ultimate recovery. By exploiting the natural reservoir energy of the bottomwaterdrive, the BWS becomes economically, technically, and environmentally appealing - especially for offshore fields where cold production is the only option and oil/water separation is a problem. In this paper, new analytical models are derived to design the water and oil rates for the BWS and to quantify the method's effect of avoiding water cresting and improving oil recovery. The analytical models are verified with numerical simulations. The BWS technique is also theoretically demonstrated by use of data from an actual oil field. The results show a considerable increase of oil recovery, from less than 15% for a conventional horizontal well to approximately 40% for a BWS well. Copyright © 2014 Society of Petroleum Engineers.

Publication Source (Journal or Book title)

SPE Journal

First Page

270

Last Page

279

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