| Abstract |
While geological formations with high permeability are most desirable within the production zone of a geothermal well, their presence at shallower depths can create a number of problems during well drilling. In conjunction with low formation pressures, high permeability can lead to major losses of the drilling fluid. To overcome this problem and allow drilling to continue with conventional drilling fluids, such as bentonitic mud, losses must be progressively plugged. The use of aerated drilling fluids can effectively eliminate the overpressure between the well bore and the formation, ensuring circulation returns. |