The use of horizontal wells for subsurface soil and aquifer remediation

The use of directionally controlled horizontal drilling for environmental restoration had its genesis in 1988 when two horizontal remediation wells were drilled at the Savannah River Nuclear Facility near Aiken, South Carolina. Since that time, horizontal remediation wells have been drilled at several Department of Energy and Department of Defense sites as well as on several commercial sites across the country. Directional drilling technology applied to ''Near Surface Horizontal Environmental Drilling'' comes from the oil and gas industry, the utility/pipeline river crossing industry and to a lesser extent the mining industry. Rig designs vary from very small track or wheel mounted rigs using 10 feet (3 meters) drill pipe and having less than 2,500 ft. lb. (3,400 N-m) of torque and 15,000 lb. (67 kN) of push/pull force to extremely large trailer mounted rigs with torques exceeding 60,000 ft. lb. (81,400 N-m) and over 500,000 lb. (2,200 kN) of pull. Vertical depths of horizontal wells drilled to-date have exceeded 250 feet (75 m), but the great majority of contaminant plumes are located at depths of less than 50 feet (15 m). Horizontal well displacements have exceeded 1000 feet (300 m) but most of the projects cover less than 400 feet (120 m). Wells can be drilled ''blind'' (terminate in the earth) or exit back up the earth on the other side of the plume from the drill rig