On-site fracturing disposal of oilfield-waste solids in Wilmington field, California

With an active drilling program that was generating over 90,000 barrels of drilling waste each year, the THUMS Long Beach Unit in Wilmington Field, Ca lifornia, was spending over 3.5 million dollars per year to dewater and shi p these solid wastes to on-shore landfills for disposal. In 1994, THUMS imp lemented an environmentally safe and economic program of hydraulic fracturi ng for the long-term, onsite disposal of drilling mud, drill cuttings, and tank bottoms. By reinjecting the drill cuttings downhole, transportation, t he major portion of drilling waste disposal costs, was eliminated. This pap er reviews the regulatory permitting process and addresses injection interv al assessment, well candidate selection, fracture containment, and offset w ell seismic monitoring. The equipment, injection history, and economics of disposing over one million barrels of slurry over a 3-yr period are detaile d.