Evaluation of Blast Furnace Slag Slurries for Oilfield Application

Abstract

Abstract This paper presents an investigation of several slurries using field and laboratory prepared drilling fluids solidified with Blast Furnace Slag. The data presented includes base mud properties, final slurry composition, and slurry properties. This investigation includes measurements of the common properties of thickening time, compressive strength, free water, etc. It also includes an evaluation of the bulk shrinkage of the set material, shear bond, etc., as well as rheological compatibility studies of the finished slurries with the base muds. These additional tests are considered critical in the potential application of this process under field conditions. Results of large scale bond log tests are included. One of the main benefits from any mud solidification process is the reduction in the environmental impact. The benefit is due solely to the reduction of the volume of mud disposal requirements. Due to the dilution requirements of the mud for the incorporation of the Blast Furnace Slag, the actual volume of mud that can be "saved" from disposal may be considerably less than that reported. This study evaluates the actual reductions in disposal volumes while accounting for the dilution volumes. Economic comparisons from field operations are included as well as a theoretical comparison for zero discharge areas like Mobile Bay. Operational considerations and the economics of required mud isolation and storage are reviewed. From the laboratory data evaluated, environmental, and economic evaluations, it is apparent the use of Blast Furnace Slag slurries for oil field applications must be carefully evaluated on a per case basis. While the process may be a viable mud solidification process, the replacement of Portland cement by this material may compromise some properties considered essential in a cementing operation.