Several mechanical and chemical methods are available for water shut-off treatments in the hydrocarbon wells. Various chemicals have been used as blocking and diverting agents to treat injection and production wells for more than six decades. Several factors determine the success of a chemical treatment in the field, including: candidate selection, identification of the source water, proper choice of the chemical system, and placement of the chemicals into the target zone. Mechanical methods include drilling horizontal or multi-lateral wells, and down hole separation equipment such as hydro cyclones. Another group of mechanical methods are cement squeeze water shut off treatments, primarily by squeezing off perforations or by breaking down the formation rock and placing the cement into the newly formed reservoir partings. The advantage of mechanical water shut off methods are them being conventional, simple and straightforward, though workover rigs are required, and they are more expensive than chemical methods.
Today, gel polymer treatment is one of the most useful chemical methods to reduce water production. Gel polymer systems have a penetration property greater than the mechanical methods and cement to provide a deeper barrier against the excess water. Any plugging due to gel polymers can also be removed unlike physical cement plugging which leads to a permanent plug in the porous media so that the residual oil cannot be produced from the treated region by cementing method after decreasing of excess water production.
As with all production optimization treatments, thorough data analysis, proper candidate recognition processes, and additive selection should be carried out, with appropriate laboratory testing to ensure required performance and compatibility, before treatments are delivered.