OVERVIEW

Deep drilling operations with air and gas drilling technology are used in the recovery of oil and natural gas and in the recovery of geothermal steam and hot water. In the late 1970s, it was estimated that air and gas drilling technology was being used on only about 10% of the deep wells drilled and completed [1, 2]. Today, most of the world's oil and natural gas producing fields are in mature sedimentary basins. The application of air and gas drilling technology is usually limited to either (1) performance drilling operations in competent rock formations or (2) underbalanced drilling operations in low pressure reservoirs (i.e., in-fill operations). In the latter operations, the reservoirs are usually sensitive to formation damage caused by traditional mud drilling operations. The advantage of air and gas drilling operations is that the bottom hole annulus pressures can be designed to be below the reservoir bottom hole pressure. The existence of extensive formation damage using traditional drilling technology has led to the development of underbalanced drilling and completion technology. Even though underbalanced drilling and completion operations have applications in low mud weight drilling operations, the vast majority of these operations utilize air and gas drilling technology. Currently, it is estimated that approximately 30% of land-based oil and natural gas recovery drilling and completion operations utilize some form of air and gas drilling technology (either as a performance drilling operation or as an underbalanced drilling operation). As more oil and natural gas producing fields mature throughout the...