Paper: Stable Foam Used as a Circulating Media in Wellwork Processes

Stable foam meets the need for a light weight, non-polluting, space-saving fluid with the lifting characteristics of a 50 sec viscosity mud. The foam weighs 0.5 lb/gal and has a pressure gradient of 0.026 psi/ft while in circulation. Stable foam has been used successfully in workovers in West Texas, New Mexico, the Rocky Mountains and the West Coast in some 500 wells with high success ratios and a substantial reduction in cost. The application is best suited to deepening, coring, drilling or foamout of obstructions such as sand bridges, scale, cement and junk. A special application is that of liner removal and setting as well as liner cementing. The process adapts itself to a closed circulating system. The injected foam is nonpolluting, removing the hazard of leakage or spills in offshore work. The foam is used one time in circulation and then reduced with defoamers to a small quantity of liquid. These characteristics make it ideal for offshore workover fluid. Progress is being made in high-pressure foam structure for deep well work. Its application can be expected to increase as the industry becomes more familiar with the process.