Abstract
The most effective approach to reduce the cost of drilling oil and gas wells is to increase penetration rates. Researchers have investigated means to drill rock faster for many years, and jet-assisted drilling is one approach that has been considered various times. While incorporating various jetting techniques into the drilling process has been found to be effective in increasing penetration rates, problems with leaks, system reliability, and high costs have prevented widespread application of high-pressure (HP) jetting technology.
An R&D project[1] sponsored by the U.S. Department of Energy was undertaken to develop and field test a HP drilling system based on employing specially designed jet bits to erode radial kerfs (grooves) in the rock which are then broken off by the mechanical cutters. Tools required for jet kerf drilling (JKD) were successfully developed and tested in the laboratory and field.
This project's original concept was to employ coiled tubing (CT) to convey the BHA into the well. Later in the effort, rotary drilling with jointed pipe was also investigated and successfully implemented using an upgraded conventional rig and commercial double-shouldered drill pipe.
Project highlights include development and testing of HP motors and jet kerfing bits, a field test using a CT-based drilling system, and a second field test using conventional rotary drilling equipment. Based on these successes, JKD is now highlighted as a technology that has potential to increase penetration rates while remaining reliable and economic.
Implementation of JKD tools and techniques within the USA gas and oil industry is now feasible. However, it will not be a simple process, with the current business environment remaining the most challenging hurdle. Successful implementation will require close cooperation from drilling contractors, operators, and bit manufacturers.
