Self-Contained, Rigid-Foam Placement Tool for Plugging Lost-Circulation Zones

Abstract

A solution to the lost circulation problem in well drilling operations has been sought for years without establishing a universally satisfactory technique or material. Recently, laboratory investigations of polyurethane foams examined their potential for plugging loss zones in geothermal wells. The data from these tests indicated that rigid foams with excellent properties for use in plugging operations could be produced under geothermal conditions. Subsequently, a concept for a family of tools of in hole mixing and a placement of rigid foams was designed, and in 1984, a prototype tool was fabricated and successfully demonstrated. After the demonstration, specifications were established for a field prototype tool of ruse in geothermal wells along with the development of suitable high temperature chemical formulations. Field application of the tool began in a Known Geothermal Resource Area in the Spring of 1985.