The Diamond Drill in Exploration for Oil and Gas

Abstract

Abstract Most wildcat wells are drilled with conventional oil well rigs. To reducecost of non-productive holes there is an increasing trend toward slim holes forexploration. It is suggested that a step further in this direction may be useof diamond drills. In remote areas where cost of transportation is high; when targets, forexample pinnacle reefs, are relatively small and hard to pinpoint; whencontinuous core is an asset, the diamond drill may make economic sense. Onceproductive targets are encountered, conventional rigs become practical. The advantages, disadvantages, limitations, and possible further adaptationof this normally "hard rock" tool in a "soft rock" environment arediscussed. Introduction The purpose of this presentation is to suggest avenues where the diamonddrill might be useful in exploration for oil and natural gas. The diamond drillis primarily a "hard-rock" tool and the problems of a "soft rock" environmentare different from those normally encountered by hard rock drillers.Nevertheless, under certain geological and geographical conditions the diamonddrill offers advantages which can be of economic interest to those engaged inthe search for oil and gas. This is particularly the case for stratigraphictests in remote areas. Exploration for petroleum and natural gas and exploration for metals isconducted along the same general lines though the details vary widely. Photointerpretation, geophysics, and geological investigations indicate targetareas. Testing of these targets ultimately requires the use of drills. Wildcat wells are drilled with essentially the same drill rigs as areproduction wells. Due to the high cost of wildcatting, considerable effort hasbeen expended to effect economies. One approach has been toward slim holedrilling. Realizing fully the limitations, it is suggested that a further stepin this direction might be through use of the diamond drill. Diamond drillshave been used successfully for stratigraphic tests in some areas and withsavings in cost of as much as 50 percent. Features of diamond drills throughwhich economies may be affected, compared to rotary rigs, include lower capitalcost, smaller crews, and lighter overall and unit weights.