Excessive water production affects profitability of oil and gas. It reduces hydrocarbons production rates. In addition, it leads to corrosion, scale formation, and extra costs in constructing large water handling facilities. One of the key issues is to correctly identify the source of the excess water and develop the appropriate treatment.1  The targeted reservoir of this study is a naturally fractured carbonate reservoir that displays super K which are areas of extremely high permeability that can produce substantial volumes of both oil and water. Super K zones can significantly enhance recovery per well, however, these zones present significant challenges at the onset of water production because they can dominate the flow in the wellbore resulting in high water loading.

One chemical method to deal with the excessive water production problems is the use of Relative Permeability Modifiers (RPM). It reduces water cut of the produced fluids without significantly damaging hydrocarbon production. Unfortunately, most of the developed RPMs are suitable for Sandston reservoirs rather than carbonate ones. There have been no successful applications of materials that display a relative permeability modification in reservoirs of this type. It is estimated that carbonate reservoirs contain more than 60% of the world’s remaining oil reserves so the development of new technologies that enable these reserves to be tapped are extremely worthwhile.2 

The development of novel materials which could tackle excess water production in carbonate wells would represent a radical, and much needed step-change technology for the extraction of the significant reserves trapped in reservoirs of this type. This paper describes a comprehensive review of different chemical methods for water control and reports on lab tests to examine the performance of several commercially available RPMs to reduce water-cut in carbonate cores. An advanced work to create and develop a relative permeability modifier (RPM) to control water production in naturally fractured carbonate fields with super K permeability is also described in this paper.

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