Abstract

Excessive water production is a serious problem operators face with increasing frequency. Coning due to bottom water drive and production from high permeability, watered-out channels during waterflooding are primary causes contributing to water production problems.

A variety of mechanical and chemical processes have been developed to reduce water production in producing wells. Both types of processes have had various degrees of success when applied. The advantage of a chemical process, such as resin or polymer, is that treatments can be injected deeper into the reservoir matrix. This can have longer lasting effects on water production. The most effective chemical methods involve the crosslinking of water soluble polymers to form gels. Gel systems can be placed either around injection wells or production wells. Injection well treatments are implemented to improve the vertical conformance, while production well treatments are intended to reduce water production while maintaining or increasing oil production.

Most crosslinked polymer treatments for controlling water production have been carried out at low temperatures. The majority of the low temperature processes use polyacrylamide crosslinked with trivalent metal ions, such as chromium. At high temperatures, thermal degradation can occur which is detrimental to gel quality and stability. Temperatures above 170°F dictate the use of polymers with a molecular structure that resists thermal or hydrolytic degradation.

This paper focuses on the results of applying an acrylamide copolymer and organic crosslinker treatment for water control in a high temperature (210°F)sandstone reservoir. Two wells were treated with a substantial decrease in water production and a significant amount of oil recovered.