Directional drilling equipment can be used with magnetic ranging to intercept specific targets such as vertical wells. In this example REI drilled 2 parallel SIS boreholes in advance of a future longwall mine for degasification. Both boreholes intercepted the same 6.75 in (171 mm) diameter vertical well. Water production (to reduce reservoir pressure) was performed from the vertical well as well as gas production. In this case both SIS boreholes were drilled over-balanced with minimal drilling fluids (clean water) and gas production from the vertical well reached 353,000 ft^3/day (10,000 m^3/day). This project was performed with one of REI’s underground drills.
