Revolutionizing Drilling Efficiency in Highly Interbedded Formations Using A Sustainable Approach Through A Cutting-Edge Pdc Bit Design

Abstract Drilling large diameter boreholes through highly interbedded formations presents significant challenges such as torsional instability that potentially leads to a drill string twist-off or a premature Polycrystalline Diamond Compact (PDC) bit damage. This paper introduces a novel solution to overcome these challenges by utilizing an innovative PDC bit that uses active cutting elements across the bit cutting structure to control the Depth Of Cut (DOC) while improving the performance and reducing the risk of twist-off. A conceptual development project was established with the objective to replace multiple bits with a single PDC bit. The design engineering team have identified the application challenges and have designed an advanced PDC bit with an alternative cutters configuration to drill through interbedded formations more effectively. The unique PDC bit has a strategic cutters arrangement distributed across the bit face with alternating aggressive and passive back rake angles that enables the bit to shear the formation from various points of contact, control the DOC and improve Rate of Penetration (ROP). The field test demonstrates the result of deploying the new concept in drilling transitional formations that generate significant torsional vibrations. Historically, several PDC and roller cone bits designs approaches have been unsuccessful to overcome the challenge of drilling interbedded formations in 22-inch section. The bits have been pulled out of hole prematurely due to bit damage or twist-off incidents. The advanced PDC design was tested in an established field with more than 1000 wells, where the operator typically completes the section with at least two bits, either roller cone or conventional PDC bits. The new bit successfully drilled the entire section through interbedded formations and has achieved the best ROP in the field with 49.56 % improvement over the previous ROP record. Subsequent testing in another field shows unprecedented achievement, the bit has drilled the whole section in a single run with 70% ROP improvement. It has been proven that the new approach has reduced harmful torque fluctuations by 25 % while drilling through transitional zones. The innovative PDC bit resulted in a smoother torque response, an improved PDC bit dull condition, and a significant drilling cost savings by eliminating bit trips and new bits cost. This paper addresses a typical torsional instability issue that many operators encounter in large diameter sections, and it presents a viable solution that can potentially improve performance in variety of transitional applications. The new PDC bit can create more opportunities to enhance drilling performance and reduce drilling costs. In addition, the results of the real-time downhole vibrations analysis can be used to improve future design iterations, optimize drilling parameters and thus improve drilling performance.