ABSTRACT: Close Infill Drilling Through Mine Access Allows Enhanced Recovery
AYLER, MAYNARD F., Hydrocarbon Mining Company, Golden, CO
Close infill drilling is a well-proven method for enhancing oil recovery, but cost has limited its use for deeper reservoirs. The environment is now a major consideration. The potential for close infill drilling from mine workings usually is ignored.
Economics are the governing factor for choosing locations for mine-assisted infill drilling. Those fields with thicker pay zones, good production histories, and good mobile residual reserves of 25,000 bbl or more per acre should be considered. The mine shaft is the most expensive single factor, so only fields of 4 sq mi or more should be targeted. Because all wells are drilled from within the mine workings, well spacing of 1 ac or less is feasible with no surface disturbance. This system permits penetration across the full pay zone, and is not as limited as horizontal drilling from the surface.
Geologic mapping of fracture patterns in the mine passageways should provide excellent data for planning well spacing.
Assuming the needed mobile residual reserve is present, other major limiting factors would be a rock temperature of 110 degrees F or less and a stable, impermeable stratigraphic horizon for mine development. Fields with little or no hydrogen sulfide are preferable. Depending upon these limitations, fields to a depth of 5000 ft could be considered. Production costs ranging from $5.00 to $6.00 per barrel can be attained.
AAPG Search and Discovery Article #91018©1992 AAPG Southwest Section Meeting, Midland, Texas, April 21-24, 1992 (2009)