Directional drillers have a new edge for developing deep, long bores of unconventional oil and gas wells. Atlas Copco Secoroc PDC bits feature deep leach cutters created with MegaDiamond’s proprietary, patented deep leaching technology.
Internal lab testing has been confirmed by field tests in such demanding areas as the North Dakota oilfields. “We have been seeing good results from many of our customers after multiple runs in deep drilling applications,” says Curtis Larson, Atlas Copco applications engineer, oil & gas.
In a Williston drill-out between a bit with MegaDiamond cutters and another, the MegaDiamond cutter sharpness outlasted the non-MegaDiamond bit two to one.
The MegaDiamond cutters have also shown similar results in Texas and Oklahoma through additional competitive runs, often outperforming standard deep leach cutters.
Deep Leaching Technology
Deep leach cutters stand up better to drilling the deeper holes at longer intervals due to high thermal resistance.
While other PDC inserts, with their typical, highly abrasion-resistant cutting edge, are ideal bits for oilfield use as a whole, they tend to convert to graphite at a lower temperature than a simple diamond. This is due to the presence of cobalt, which acts as a catalyst to sinter the diamond-to-diamond bond, unitizing the diamond layer to the tungsten carbide substrate.
During heating, cobalt expands at a higher rate than diamond, causing the thermal stress in the diamond table to increase and the structure breaks down. The cobalt between the diamond crystals expands and breaks diamond-to-diamond bonds, resulting in reduced cutter life and cutter failure due to the heat created from the friction on the cutters during drilling.
The deep leaching process selectively removes cobalt from the diamond table of the PDC cutter. Leaching increases cutter thermal stability, which reduces damage and extends bit life in difficult and abrasive formations.
Atlas Copco, based in Stockholm, Sweden, serves segments ranging from compressors and air treatment systems to construction, mining and drilling equipment. The company, founded in 1873, has more than 39,800 employees worldwide, and operates in more than 170 countries. Atlas Copco in North America operates in more than 109 locations and employs more than 4,500 people in the United States. For more information, visit www.atlascopco.us.