A rigorous engineering and research effort combined with targeted field testing has delivered a new generation of PDC technology. This technology is intended to be utilized for the most technically challenging drilling applications across the globe. One of the first applications identified for this new technology was at the Pinedale anticline field in Sublette County, Wyoming. At Pinedale, the operator's directionally drilled development wells target interbedded fluvial sandstones and shales of the Lance Pool (Lance and Upper Mesaverde formations). Due to surface constraints, all wells are drilled directionally from centralized surface pads. To achieve uniform subsurface well-spacing, well trajectory is S-shaped, with all directional work occurring before the pay interval is encountered at approximately 8,500 ft MD. The pay interval is then drilled vertically utilizing 6 1/2-in. PDC bits to approximately 13,400 ft MD, with the final 1,000 ft frequently drilled with diamond-impregnated bits. The sequence of interbedded fluvial sandstones and shale comprising the Lance Pool presents a difficult drilling environment. The interval is characterized by moderate but erratic unconfined compressive strengths ranging from 10 to 20 ksi exacerbated by high overburden pressures and increased hydrostatic pressures from mud weights exceeding 15 lb/gal to control pore pressure and maintain formation stability. Confining compressive strengths approaching 100 ksi (excluding formation pressures) are not uncommon. These harsh drilling conditions have led to slow penetration rates and short bit runs utilizing conventional PDC designs. The authors will describe the technologies developed and included in the new PDC bits. These new technologies have reduced the time in this interval by more than 100 hours per well, a 25% improvement over previous designs. With eight rigs running, each rig drilling one well/month, the operator is seeing productivity gains worth 308 days of drilling time over a year's time. Introduction Design principles and material technology for PDC bits has improved significantly over the last 10 years. However, the following industry challenges continue to drive the need for improved product performance:Operational costs are high as compared to historical norms.Tripping is unproductive time that increases worker exposure to potentially dangerous operations, so increased bit durability reduces both cost and exposure.Deeper more challenging wells are requiring more durable products.Steerability requirements are increasing as more challenging directional profiles are required.

The development of improved synthesis techniques for polycrystalline diamond compacts (PDC) positively impacted fixed cutter drill bit performance. Coupled with these advances, recent developments in cutter geometry show improved cutter performance in many applications. Laboratory and field testing has demonstrated that modifying the face geometry of the PDC cutter used in a fixed cutter bit is one of the most direct ways to affect the efficiency and longevity of the bit's cutting structure. This paper describes a new non-planar cutter face geometry that has increased footage drilled, rate of penetration (ROP), and improved the bit dull condition in the Meramec formation in western Oklahoma's STACK play. A drilling mechanics focused team created a finite element analysis (FEA) model of the rock cutting process to optimize cutter face geometry for improved cutting efficiency. The new non-planar geometry enabled better cutting efficiency and improved cutter cooling. Multiple lab tests were then used to verify the model's predictions. Results from single cutter lab tests showed an 11% increase in cutting distance as measured in a vertical turret lathe test, a 30% decrease in cutting edge temperature from a pressurized cutting test, and a 10% increase in load capacity compared to a previous non-planar geometry in a face load test. Full-scale pressurized drilling tests in the lab showed that a PDC bit with the new geometry was 15% less aggressive with equivalent-to-lower mechanical specific energy (MSE) when compared to the same PDC bit with a previous generation non-planar cutter. Field tests were conducted with the new non-planar geometry applied to a commercial 0.529 inch [13mm] cutter on a standard 8-1/2 in. drill bit design used in the Meramec Lateral application. The paper reviews in detail three test cases in this multiple bit lateral section using the same bit design with and without the new non-planar cutters. In two test wells, we saw direct improvement of 185% distance drilled on average and an18.3% boost in ROP. At least 17 bit runs have been completed in this application using the new non-planar feature, proving it to be a beneficial enhancement. Similar performance improvement has been observed in other applications as well. The optimized cutter geometry has led to further and faster runs, resulting in significant time savings and improved consistency. The use of advanced cutter geometries provides a significant boost in drilling performance beyond that normally achieved through fixed cutter bit design optimization and materials improvements.

Drilling operations in the Middle East contain many applications where extended reach laterals target hard and interbedded carbonate reservoirs. Such applications are associated with elevated levels of drilling dysfunctions resulting in tool reliability and bit durability issues. These challenges include lateral and torsional vibrations that impact the drilling system longevity and premature cutting structure damage resulting in multiple drilling trips and an increase of nonproductive time (NPT). To address the lateral stability and loss of drilling efficiency challenges of drilling hard carbonates, this paper explores three new concepts applied to drill polycrystalline diamond compact (PDC) bit design. The 5.875′ Slimhole section through hard carbonate of the Middle East was identified as the target application. A study of existing PDC drill bit performance in this section was conducted to determine current design limitations and set objectives. After optimizing the cutting structure and overall PDC bit frame, three new design concepts were also incorporated. Targeting lateral stability, a "chisel" shaped diamond element (SDE) was placed trailing the cutting structure to provide a stable drilling response. Multiple iterations were studied to optimize the bit lateral stability without compromising bit efficiency. The iterations included changing the radial position, the count and orientation angle of these elements. Non-planar faced PDC inserts were strategically placed on the bit cutting structure to reduce the cutting temperatures during rock cutting, and increase the drilling efficiency. Depth of cut control (DOCC) rubbing elements are commonly used to mitigate stick-slip dysfunctions, but standard DOCC elements wore down too quickly to maintain their function. An impregnated blade based DOCC rubbing element was implemented to maintain the stick-slip protection throughout the length of the run. The new PDC bit design completed six successful field trials in the target section and achieved an average increase of 39% in footage and 11% in rate of penetration. Validation of the design concepts via comparing surface data, downhole vibrations data and the bit dull condition showed marked improvements in the desired metrics. A step change improvement of 50% in the level of lateral vibrations and torsional stability was achieved due to the combination of the SDE and the impregnated DOCC elements. The bit drilled consistently smoother protecting the bit & BHA. Final dull conditions also improved with a reduction in broken or chipped cutters across the cutting structure due to MCE inserts. Combination of innovative geometries and materials targeting stability and efficiency significantly increased performance, reduced NPT and lowered tool maintenance costs in one iteration.

Since the late 1970's, research on the efficiency and cutting life of polycrystalline diamond compact (PDC) cutters identified elevated temperature due to frictional heating as one of the primary accelerants of wear to the diamond cutting edge. Temperatures as low as 700 °C activate the back-conversion process, whereby diamond transforms into graphite, due to the presence of catalytic metal in the diamond structure. The Oil and Gas industry responded by investing years developing technologies to reduce the temperatures that PDC's experience in application via improved hydraulics for cooling, higher quality surface finishes to reduce friction, and improved thermal stability via material structure and chemical treatments. PDC cutter technology has progressed substantially in the last 30+ years, but the challenge of synthesizing a perfectly thermally stable PDC still remains unmet until now. Recently, Zhan (2018, 2020, 2021a and 2021b) first developed a new strategy to synthesize ultrastrong and catalyst-free polycrystalline diamond (CFPCD) or binderless PDC cutters with a new world record as the hardest and tough diamond material and the highest thermal stability up to 1,400°C via his invented ultra-high pressure and ultra-high temperature (UHPHT) technology, which is three to seven times higher than conventional PDC cutters used in the industry. An initial laboratory study of a new catalyst-free extreme high pressure, high temperature CFPCD material provides the first instance of a catalyst metal free polycrystalline diamond structure that actually boosts rock cutting performance above and beyond that of the current state-of-the-art PDCs. Proof of concept CFPCD specimens were evaluated against commercial, state-of-the-art non-leached (NL) and deep leached (DL) PDC cutters in the lab. Two CFPCD grades, A & B, were run through a series of tests to evaluate their potential for rock cutting and, ultimately, for use in oil & gas drilling applications. Laboratory testing was conducted on vertical borer wear tests, KIC fracture toughness tests, and thermal degradation monitoring tests. Lab results reveal a threshold that must be exceeded in the synthesis of catalyst-free CFPCDs to achieve sufficient diamond intergrowth and structural integrity to surpass the current state-of-the-art DL PDCs. CFPCD grade A wore equivalently to a commercially available NL cutter and exhibited a toughness comparable to that of commercially available DL PDC material. Grade B, synthesized at a significantly higher pressure than grade A, cut 5.7 times the distance of a commercial NL PDC for an equivalent wearscar volume, and exhibited a 160 % reduction in wear volume comparing volume of diamond worn to volume of rock cut (or G ratios) to DL PDC after cutting the equivalent of roughly 50 miles of rock. The wearscar surface of Grade B also exhibited excellent integrity with no cracking or chipping damage compared to Grade A and commercial PDC grades. This is the first documented instance of a catalyst-free PDC achieving the best wear performance and integrity (fracture toughness) than the current PDC cutters offering on the market. Thermal stability limits of PDC cutters has greatly improved in the past 20 years, but the best commercial PDC's still rely on extending leach depths with certain performance limits. For the first time in the industry, there is a PDC material than shifts this boundary without the use of catalysts and leaching technology, producing a truly differentiable PDC cutter.