Inverted-ESP Completion Boosts Oil Rate While Disposing of Produced Water
Authors: Wilson Adam 
Published: December 2018

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 187624, “Subsurface Disposal of Produced Water and Simultaneous Increased Oil Production Achieved Within the Same Wellbore Using Inverted ESP—North Kuwait Case Study,” by Shamseldin Z. Elaila, Elred Anthony, Nora H. Al Maqsseed, Mohammad K. Al-Banai, and Sara N. Al-Mutairi, KOC, prepared for the 2017 SPE Kuwait Oil and Gas Show and Conference, Kuwait City, Kuwait, 15–18 October. The paper has not been peer reviewed.

This paper aims to provide an introduction to the early management of downhole produced water in strong waterdrive reservoirs using inverted electrical-submersible-pump (ESP) technology. This technology facilitates a method of downhole water disposal within the same wellbore and, therefore, reduces the costs associated with bringing water to the surface or subsurface for treatment. The technique also saves the costs needed for drilling disposal wells.

Problems Associated With Produced Water

Water produced with petroleum is growing in importance from an industrial and environmental standpoint. In the past, this water was considered to be waste and required disposal. Early on, little attention was paid to the fate of the produced water in the environment. Later, it became clear that possible contamination from produced-water disposal, especially on the surface, needed to be considered.

This unwanted water is also a limiting factor in the productive life of the well. Many factors influence the drive for improved water control—loss of hydrocarbon production, environmental effect of disposal, government regulations, and public opinion. The environmental issues and costs related to produced water and its disposal are becoming major considerations for producers. The economic factors of reducing water production far outweigh the cost of typical water-control treatments. Historically, water-control treatments have often failed because of one or more of the following problems: the source of the problem was not properly identified, the wrong treatment was carried out, or the correct treatment was performed improperly.

For disposal or injection into reservoir rocks, this water must be processed and treated through a series of time-intensive and costly operations. Suspended solids and oil must be removed to an appropriate degree to reduce oil losses and prevent plugging of the disposal formation. Also, increasingly stringent regulations on the entrained and dissolved oil and other chemicals in the produced water must be met.

Economics of Produced Water

Except in the case of gas production from coal seams, water-production rates usually start slowly from the initial development of a property. Facility designers may forestall construction and installation of water-handling equipment deliberately at the beginning of a project to reduce initial capital costs. The eventual appearance of water production requires the addition of capital investment and operational expense to handle the growing water rates, which do not generate revenue to offset the cost. The natural tendency for companies is to minimize the immediate expense; as a result, companies often underdesign the equipment or fail to budget properly for operational expenses.