Mining Publication: Drilling a Horizontal Coalbed Methane Drainage System from a Directional Surface Borehole
Original creation date: January 1982
Authors: DC Oyler, WP Diamond
Three long horizontal holes were drilled from a directionally drilled surface hole at the Emerald Mine near Waynesburg, Pennsylvania. The purpose was to adapt the technique of directional drilling for use in draining methane from coalbeds. A 504-m (1,652-ft) long, 76-mm (3-in) diameter, circular arc pilot hole was drilled, using a downhole mud motor, to enter the Pittsburgh coalbed at a vertical depth of 350 m (1,000 ft). The hole was reamed to 222 mm (8-3/4 in) and was cased to a measured depth of 486 m (1,595 ft). Three 76-mm (3-in) diameter horizontal drainage holes were then drilled, totaling 2,909 m (9,544 ft) of horizontal hole. Improvements in drilling methods increased the average drilling rate from 20.4 M (67 ft) to 64.9 M (213 ft) per day. The cost of drilling the directional and horizontal holes (using a government-owned drill rig) was $1,169,530, a figure inflated by inexperience and by delays caused by lost-circulation problems and fishing operations. An estimated total drilling cost of $960,000 (including rental of a drill rig) for an improved system, was determined by a detailed cost analysis. Initial gas and water production from November 1979 through May 1980 was low because of caving of the horizontal holes drilled in shale near the bottom of the casing.
- Cableless Electronic Surveying Systems for Horizontal Holes
- Degasification and Production of Natural Gas From an Air Shaft in the Pittsburgh Coalbed
- Degasification System Selection for U.S. Longwall Mines Using an Expert Classification System
- Directional Drilling For Coalbed Degasification: Program Goals and Progress in 1978
- Directionally Controlled Drilling To Horizontally Intercept Selected Strata, Upper Freeport Coalbed, Greene County, Pa.
- Drainage of Methane From the Overlying Pocahontas No. 4 Coalbed From Workings in the Pocahontas No. 3 Coalbed
- Nature and Cost of Low Back Pain
- Noise Exposure and Overhead Power Line (OPL) Safety Hazards at Surface Drilling Sites
- Rotary Drilling Holes in Coalbeds for Degasification
- Rotary Drilling Techniques Used in the Beckley Coalbed