Introduction of 25mm-PDC Cutters in the Latest Drill Bit Technology Leads to Multiple Drilling Performance Records and Reduces Days to Production in Oman

Abstract

Suppressed oil prices amid a call for increased returns from shareholders has created opportunities for operators and service companies to work closely in developing and deploying new technology in well construction efforts. Under extreme pressure, operators are seeking innovations to reduce drilling time and shorten the time to production. An operator in Oman has tripled output over the last ten years using enhanced oil recovery (EOR) methods, making it the largest independent oil producer in the Sultanate. The development of polycrystalline diamond compacts (PDC) is one of the fastest-evolving technologies for fixed cutter drill bits. The application of PDC bits continues to expand performance by increasing rates of penetration (ROP) to lower drilling costs. The most recent developments in synthetic diamond cutters have been in 25mm-diameter cutters. Although 25mm-PDCs were developed in the mid-1990s, they lacked the necessary durability for demanding drilling applications. Only recently has the technology become available to meet these needs in this size. Several recent tests in Oman have shown the new 25mm-cutter technology drastically improved performance with shoe-to-shoe runs at increased ROP. With the new cutters came the need for paired frame improvements with special considerations for aggressiveness and mechanical limitations for torque, both for the drilling rigs and use with positive displacement motors. During vertical drilling through carbonates and shales in the Diba field, the technology established a new field record ROP of 217 feet per hour—an 80% improvement over the field average ROP. In the Jalal field, 275 feet per hour was achieved—29% higher than the previous best record. The technology was also introduced on a steerable motor in a directional well, delivering improved penetration rates and excellent stability in slide mode. An additional lesson learned was the smooth torque generated by the large cutters. The smooth drilling torque enabled improved directional tool face control. This operator has implemented an aggressive drilling and development program to drill faster and reduce cost per foot in heavy oil sands and fractured carbonates. The authors will present case studies to demonstrate how the latest technology 25mm-cutters and new frame technology helped lowered drilling costs for this operator's drilling program in Oman.