The need for and the development of surfactant muds is briefly discussed. The components, preparation and application of four types of surfactant muds are given. Case histories of both calcium and sodium surfactant muds are traced. Incidental to the problems occurring, the calcium surfactant mud was successfully converted to a low sodium system. In another well, a low sodium system was successfully converted to saturated salt surfactant mud and desired total depth was reached. Because of their flexibility and stability under severe conditions, these muds should find wide application in future deep drilling operations. They have proved to be a practical solution of many of the shale problems; stable at high temperature; and an excellent completion fluid.
Drilling operations to greater depths and in areas of complex drilling problems have often been handicapped or halted because of the inability of conventional drilling fluids to remain stable under the severe conditions encountered. Elevated bore-hole temperatures, solids build-up, and contamination greatly unbalance conventional drilling fluids, causing excessive viscosities, gel strengths, and fluid losses. These abnormal physical properties in turn contribute to more severe problems, such as lost circulation, blow outs, salt-water flows, and stuck pipe or casing strings. The result of these problems may be either a loss of time, expensive fishing jobs, or a complete failure of the drilling operation to reach the desired objective. Surfactant muds are a new concept in drilling fluids designed to eliminate some of the problems associated with deep drilling. These muds were originally developed for high temperature stability. However, field experience with surfactant muds has demonstrated their capacity to resist solids build-up, severe contamination from salt or anhydrite, and maintain excellent viscosity, gel strength and fluid loss properties under very difficult drilling conditions.