Efficiently drilling the lateral hole section through the abrasive Granite Wash reservoir sands in western Oklahoma and the Texas Panhandle creates a unique challenge. The highly heterogeneous formation was causing inconsistent PDC bit performance while constructing the 6-1/8" horizontal and thus damaging project economics. A study determined that improved ROI could be achieved by extending bit life in areas where poor drilling performance is expected. A detailed forensic analysis showed extensive cutter damage with abrasive wear being the most common dull characteristic. The cutter wear was causing short runs and frequent trips for bit change-out. To solve the problem required a new approach. A fixed PDC element creates an inherent limitation because only a small portion of the cutter contacts formation and as the cutter wears, drilling efficiency declines. The resulting wear flat generates a high degree of frictional heat which breaks the diamond-to-diamond bond leading to accelerated cutter degradation. The situation is exacerbated by difficulty transferring weight-on-bit due to extended length lateral drilling. An R&D initiative was launched to investigate different methods to enable a PDC shearing element to fully rotate while drilling to increase overall cutting efficiency and bit life. Engineers investigated several different retention methods and developed a specialized fixed housing which is brazed into the bit blade. The PDC cutter is mounted on a circular shaft and fitted within the housing allowing 360° cutter rotation. The robust system holds the cutter/shaft assembly securely in the housing for superior reliability. The rolling cutter assembly has essentially the same OD as a standard PDC cutter for superior design flexibility and cutter placement options. A new-style 6-1/8" PDC (MSiR613/MSiR713) was manufactured with rolling cutters strategically positioned in the shoulder area. It has been run over 45 times in the Granite Wash formation and is delivering positive results. On a steerable motor, the RC equipped bit has increased total footage, hours on bottom and ROP compared to direct offsets drilled with fixed cutter PDC.

Improvements in drilling performance in key applications around the world continue to focus on reducing vibrations of the system consisting of the drill bit, bottomhole assembly (BHA) and drillstring. These vibrations can take the form of whirl, stick-slip, bit bounce or combinations of these, leading to drilling inefficiencies. Many efforts are under way to control and manage these vibrations and develop tools that can withstand the higher vibrations seen in today's drilling environment.Introduction of the most-recent design of a hybrid drill bit took place in 2009 with the presentation of IADC/SPE paper 128741. It was shown to be a viable drilling tool for potentially difficult or problem-prone applications. This paper covers the ongoing development work on the hybrid bit technology which combines elements of polycrystalline diamond compact (PDC) and tungsten carbide insert (TCI) bits. Testing is now taking place on a large scale and the results confirm the potential benefits revealed in the early prototype testing.Early tests of the hybrid bits were designed to show that it is sufficiently robust to drill and hold up under normal drilling. The next 100+ runs were targeted at areas where both traditional PDC and TCI drill bits struggle and the hybrid bit proved to be both faster and more durable than the conventional bits. This was achieved through the synergy of the smooth running action of the rolling cutters with the sharp cutting elements on the fixed PDC bit blades. This paper details the knowledge gained in drilling over 167,000 feet just over 10,100 hours that has led to further design improvements and a better definition of the applications in which a hybrid bit can deliver superior performance. These applications are generally in the harder and hard-interbedded formations. The targeting of the hybrid technology is enabling problem wells to be finished sooner and at lower cost while still avoiding dynamic dysfunctions commonly seen. Results of all hybrid runs in a wide range of applications will be compared and recommendations will be made on where this technology can provide the most significant improvements.

Drilling the difficult build section in the Granite Wash play in Washita County, Oklahoma can present a number of challenges. The formation contains multiple reservoirs within complex sequences of sandstone, siltstone and shale interbedded with granite/limestone wash. This hard and abrasive matrix is uniquely challenging and unpredictable which makes conventional drilling with positive displacement motors (PDM) combined with rollercone TCIs and/or PDC bits difficult due to the lack of desired durability. The operator required a new technological solution to minimize the flat time in this particular section by reducing bit trips and/or improving penetration rates (ROP). In normal situations, a turbodrill paired with a diamond impregnated bit is a viable option to tackle this challenge. However, the conventional steerable turbodrill BHA was incapable of achieving the target build rates required by the customer in their deviated section. The challenges in the build section of the well were evaluated by the engineering team. A review of the run data and use of mathematical-based predictive analysis software identified the changes needed to achieve the required doglegs needed to meet the challenge. The study indicated that using a steerable turbodrill with two bends and a specific stabilization setup coupled with a diamond impregnated bit with a shorter gauge length could yield up to 65% higher build rates. This new turbodrill BHA has been successfully field trialed in numerous wells in Washita County, Oklahoma and surrounding areas and has achieved the goal of consistently building a curve with a plan of 14°/100ft and has set numerous new field performance records. Drilling time has been consistently reduced by 45% (from 8.0 to 4.3 days) and bit runs reduced from 2.5 to 1.0 while achieving 40% higher ROP. The authors will present case histories that illustrate performance achievements in the build sections and provide details that contributed to the success of this unique BHA.

The Granite Wash formation in Beckham County, Oklahoma and surrounding areas presents a number of unique challenges in drilling the build section from a vertical openhole to form a horizontal lateral in the productive zone. The formation is hard and abrasive and it is difficult to anticipate rock properties downhole from one well to the next. The erratic nature of the formation results in unpredictable performance by the steerable drilling assembly and drill bits particularly in the build section below 12,000 ft. In most cases, the target build rates are not achieved forcing multiple trips and undesirable cost overruns. To remedy the issue, an innovative drilling system was developed which provides a dependable kick-off ramp and a firm beginning in initiating the build section without having to rely on the drilling BHA's fulcrum point. From the bottom, the drilling system consists of hydraulically set openhole anchor, a whipstock, an impregnated drill bit mechanically attached to the top of the whipstock, a double bend turbodrill section and the rest of the BHA. The procedure includes positioning the drilling system in the hole at kick-off point, orienting the whipstock face with MWD in a desired direction, anchoring the whipstock by hydraulically setting the anchor, disengaging the BHA from the whipstock and commencing drilling operations. All of these steps take place in a single trip downhole. Once the impregnated bit and the turbine assembly pass the whipstock, the sliding and the rotating phase begins to achieve the target build rate. The authors will describe the system's components and the running procedure. They will also discuss system performance, realized benefits to the operator, lesson learned and planned improvements going forward.