ECONOMIC DISPOSAL OF SOLID OIL-FIELD WASTES

A variety of solid oilfield wastes, including produced sand, tank bott oms, and crude contaminated soils, are generated during drilling, prod uction, and storage processes. Crude oil and crude-contaminated sands or soils are generally designated as nonhazardous wastes. However, the se materials still must be disposed of in an environmentally acceptabl e manner. The problems can become most pressing as oil fields in urban areas reach the end of their productive lives and the properties are redeveloped for residential use. An economically and environmentally s ound solution is to reinject the solid waste into sand formations thro ugh slurry fracture injection. Slurry injection has been used to dispo se of drilling muds and cuttings in Alaska, the Gulf of Mexico, and th e North Sea; naturally occurring radioactive materials in Alaska and t he Gulf of Mexico; and large volumes of produced oily sand in the prov inces of Alberta and Saskatchewan, Canada. The technique offers a numb er of economic and environmental advantages for disposal of solid oilf ield wastes. When reinjecting into depleted oil sands, the crude waste is simply being returned to its place of origin. The long-term liabil ity to the operator is eliminated, in marked contrast to surface stora ge or landfill disposal. Finally, fracture-injection costs are less th an typical transport and landfill disposal costs for moderate to large quantities of solid waste.