LOW-VISCOSITY, LOW-TEMPERATURE FRACTURE FLUIDS

The liquid carbon dioxide (CO2) fracturing process was studied recentl y during the completion of a 19-well shallow gas project for Crestar E nergy Inc. in southeastern Alberta. The project involved mini fracture treatments that used special tools to record bottomhole pressure, tem perature, and density conditions at the perforations. The analysis of the data gathered during this study has shown some surprising results, and has led to the development of a new technique that may enhance th e characteristics of the liquid CO2 fracturing process, and lower the overall costs associated with this type of treatment. This paper discu sses the uses of low-viscosity, low-temperature fracturing fluids, and the ways in which they differ from conventional fracturing fluids. Ca se studies from the Crestar Energy shallow gas project are used to dem onstrate the cost savings realized by combining liquid CO2( )with nitr ogen (N-2) during the fracturing process.