The Three Forks First Bench (TF1) in the Williston Basin is attractive to operators for its production qualities; however, the formation is problematic for drlling with polycrystalline diamond compact (PDC) bits. TF1 is an interbedded dolostone, 30 to 40 ft thick, capped by the abrasive Pronghorn/Sanish formation with high stress variations/spikes and laminations. These formation characteristics lead to cutter damage and vibration, which cause slow rates of penetration (ROP) and additional tips due to bit/bottomhole assembly (BHA) failure.
In response to these challenges, a revolutionary rock-removal system has been designed. The system implements conical diamond elements (CDE) to work in unison with the PDC cutters. Conventional PDC bits complete a typical 10,000-ft TF1 lateral in a one-bit/BHA in only one out of five wells. The most common reason for tripping is bit/BHA failure do to the harsh characteristics of the TF1. The CDE's unique geometry applies a concentrated point load to fracture formation more efficiently, and its ultra-thick diamond layer provides superior impact strength and wear resistance. Bits utilizing CDE's in conjunction with PDC cutters are known as CDE bits. They are able to withstand the demands of the application where conventional PDC bits cannot.