Challenging application demands durability
The lithology associated with applications in northern Utah's Wasatch formation consists of difficult interbedded sand and shale with a UCS that ranges from 2,000 to 30,000 psi. From 5,900- to 10,500-ft TVD, the formation is characterized by sandstone with a UCS of 10,000 to 15,000 psi. It is interbedded with soft shale that has a UCS of 2,000 to 5,000 psi and hard sandstone stringers with a UCS of 25,000 to 30,000 psi.
To increase drilling performance of the 7 7/8-in Mi616 PDC bits drilling in this area on a directional BHA using a PDM with a 1.5° bend angle, MiZ616 PDC bits with a Stinger element were tried with the following goals: increase ROP, improve cutting structure durability in high weight-on-bit applications (30,000 to 50,000 lbf), and reach section TD in one run.
Innovative cutting element increases cutting structure performance
The Stinger element has twice the diamond thickness of conventional PDC cutters and is manufactured from synthetic diamond material engineered to provide superior resistance to abrasive wear and impact loading. Combining this capability with the Stinger element's unique conical geometry resulted in a cutting element that can significantly enhance a PDC bit's durability.
To ensure that placement of the Stinger element at the PDC bit's center would maximize drilling efficiency, engineers used IDEAS integrated drillbit design platform to further optimize the cutting structure. This effort included selectively abbreviating the blades that held the PDC bit's low-velocity center cutters and placing the Stinger element at the center of the PDC bit's cutting structure.