New Facets of Universal Fluid Usage: Reduction of Hole Wash-Out and Solidification for Environmentally Safe Drilling Waste Disposal

Abstract

Two new benefits derived from the use of a Universal Fluid (UF) have been demonstrated:reduction of the hole washout volume andsolidification of excess drilling fluid and drill cuttings for environmentally acceptable on-site waste disposal. A UF containing about 30 lb/bbl blast furnace slag was used as a drilling fluid while drilling a recent south Louisiana well in an effort to reduce hole washout and to demonstrate that the solidification of the UF and drill cuttings would provide an environmentally safe material which remains on-site and can be used for location maintenance, road construction, and land fill or other uses. The UF was used while drilling a 9 7/8-in. hole from 3,125 ft to the casing depth of 10,600 ft. The slag content ranged between 25 and 30 lb/bbl, while the UF weight was increased slowly from 9.4 lb/gal to 12.2 lb/gal. Caliper logs indicated that the average diameter of the UF-drilled section was 10.88 in., considerably better than the 12.85 in. of the same section of a previously drilled offset well. Of the total 147,000 lb of slag used, about 30% remained in the UF, about 22% was deposited as filtercake, and about 21% was discharged with the cuttings through solids control equipment. A concept of rig-site drilling waste management involving solidification of the UF wastes is elaborated and related lab and field data are presented. The necessary amount of slag for solidification is already in the UF and solid wastes, but additional slag can be added depending on the final product firmness desired. To demonstrate the waste solidification process, an additional 20 lb/bbl slag was mixed with a 40-barrel batch of the excess waste in a "V," -bottomed auger tank. The UF mixture was allowed to harden on location and successfully used for land fill. This paper shows that the UF can protect the drilled wellbore and can be economically treated and used for on-site disposal. P. 785