The application of gels for the control of excessive water production in oil and gas wells has been a treatment alternative for several years. The success of these treatments; however, has been relatively low. The Talisman Energy Inc. (Talisman)- operated Sukunka, British Columbia field pilot was conducted in conjunction with an ongoing research project at the Petroleum Recovery Institute to improve water abatement techniques in gas reservoirs. Sequentially injecting multiple slugs of gelant followed by gas allows for gel placement in the water conducting fractures or high permeability channels, while the gas overrides and reconnects to the upper gas zone.
A series of technical and economic screening criteria were developed to select suitable target gas wells with water channeling problems. Talisman's British Columbia candidate demonstrated water influx from a complex fracture system. The initial treatment design and sizing of the gel slugs was based on the experience gathered from previous gel applications in gas and oil wells. A high molecular weight polymer crosslinked with chromium acetate1,2 was used in the gelant formulation. In total, 127.5 m3 of gelant and 17,700 scm of nitrogen were injected during the sequential gel/gas slug application.
The gel application on this gas well was successful in several ways:
a relatively large treatment volume was successfully placed
the water/gas ratio was significantly reduced
incremental gas production paid for the treatment costs in 4 months
Identifying the nature of the water influx problem, and using the proper gel and placement technology lead to the success of this field application.