Field Application Results of Water Permeability Modifier in Fracture Stimulation Treatments in Western Siberia

Abstract

Abstract Historically, hydraulic-fracture stimulation of zone zones with directly underlying waters has not been considered a practical method for improved oil recovery. This was because the stimulation treatment could result in water cuts from 90-100%. Many of the oil and gas reservoirs in Western Siberia have production zones that fall into this scenario. The zones contain high-permeability streaks of mobile water and have water bearing layers above and/or below the producing zone. When a hydraulic-fracturing treatment is performed on such production zones, unintentional stimulation of the adjacent water bearing layers occurs. As a result, high water production is observed from the high permeability streaks of water or the adjacent water-bearing layers. Over a period of time, those wells will continue to lose hydrocarbon production rate, while the water cut continues to increase. Water separation and disposal of the produced water is expensive and not always successful. Using recent water permeability modifier (WPM) chemistry advances, the hydraulic-fracture stimulation of such zones has now been shown to be an effective way to stimulate and produce the mature oil and gas fields such as those found in Western Siberia. The incorporation of a water permeability modifier with a hydrophobic backbone containing hydrophilic branches with the hydraulic fracture stimulation has proven to be very effective in obtaining oil production above what was anticipated based upon comparison with offset wells fracture stimulated without the WPM. It was further observed that not only was the produced water rate typically less than previously observed, but that it continues to decline over time instead of increasing. This paper presents the results of the implementation and analysis of 11 WPM fracture-stimulation treatments that were performed in a field in Western Siberia in 2009. Discussed will be the WPM technology, treatment design, post production analysis, and recommendation selection of candidates and successful implementation of the WPM technology in the western Siberian fields.