Successful Sealing of Vent Flows with Ultra-Low-Rate Cement Squeeze Technique

In the western Canadian sedimentary basin, tens-of-thousands of wells currently are leaking gas between the surface and production casings. Often this leakage manifests itself as a surface vent. While much work has gone into preventing gas vents during primary cementing, little has been done to improve the chances of successfully sealing existing leaking wells. The work described in this paper focuses on new materials and techniques that have been developed to seal vent flows. The paper describes the theoretical physics behind the process and gives case histories to demonstrate the successful application of the technology.