Water Control in High-Water-Cut Oil Wells using Relative Permeability Modifiers: A Saudi Lab Study

Abstract

Abstract Water production in a hydrocarbon-producing well greatly affects the economic feasibility of a well, in worst cases, resulting in the well being shut in. Therefore, an effective water-control treatment program is important to help control water production and maintain or increase hydrocarbon production. Relative permeability modifiers (RPM) can be implemented in some high-water-cut wells as a chemical treatment to selectively reduce water production. The study in this paper introduces an RPM system that is a hydrophobically modified, water-soluble polymer. This polymer is adsorbed on the rock surface, resulting in the alteration of the characteristics of rock surfaces. The unique polymer chemistry selectively reduces the water's effective permeability in the reservoir, impeding water flow and facilitating increased hydrocarbon flow. It can also help enhance the reservoir drainage area. Core-flooding experiments were conducted in the laboratory to assess the performance of the RPM system. Experiments were conducted on synthetic cores and formation cores from a well in the Central Arabia field. The laboratory experiments showed that the RPM system can drastically help decrease water permeability, with low regained water permeability and high regained oil permeability in a synthetic core. The water regained permeability was 17% (i.e. 93% reduction in water permeability) in a formation core using formation oil and water. High-permeability core plugs were used in the laboratory to determine the effectiveness of the RPM system. A detailed procedure was followed, including repetitive oil and formation water cycles, to determine core permeabilities. The results demonstrate that the RPM system is effective in the Central Arabia sandstone formation. This paper discusses the study performed to implement an RPM system in a Saudi formation, where the treatment can effectively reduce water flow in the treated area with minimum damage to hydrocarbon flow. The RPM system can be customized based on the temperature and permeability of the treatment zones to achieve maximum reduction in water production.