The current state of the oil and gas industry, which is experiencing its worst downturn since the energy crisis of the 1970s, is necessitating powerful innovation in how it produces and develops oil and gas reserves. No longer will the maxim “We’ve always done it this way, so it must be right” suffice when breakeven prices often are significantly higher than the cost of a barrel of oil. With the need to increase drilling efficiency mounting, operators are seeking out new solutions to an old problem, looking to service companies to assist them in making their operation economically feasible. Among the innovations in optimization that are currently driving positive change in the industry is a new offering from NOV, the eVolve Optimization Service. The service’s four-tiered approach ranges from surface data-based optimization to full closed-loop downhole drilling automation. Through these tiers, the service equips existing rigs and rig crews with an advanced toolkit to improve performance, enable real-time decision-making and enhance analytics capabilities.

The eVolve service’s second tier, ADVISE, is a data-driven optimization service that incorporates NOV’s BlackBox memory-mode logging tools to enable improvements in drilling efficiency that drive substantial savings. The BlackBox tools capture data with a variety of sensors and can be placed in the drillbit, bottomhole assembly (BHA) and/or drillstring. The tools enable a better understanding of true downhole events such as pressure, vibration, weight transfer and torque reactions while drilling. When combined with data acquired at surface, the tools provide a comprehensive overview of the downhole environment and how drilling practices affect performance and reliability.

The integrated approach of the ADVISE tier builds on this optimization foundation by combining surface data with downhole data obtained from the BlackBox tools to analyze dynamic behavior of drilling activities, enabling better design and component selection for the BHA. Software identifies harmful vibration and evaluates rock properties and formation characteristics, alerting the driller to potential risks and dysfunctions. Torque and drag, mechanical-specific energy, buckling and other dynamic behaviors are assessed to provide a clearer overall picture of the drilling environment. In addition, real-time remote monitoring ensures that the rig crew is always well informed with respect to current conditions on the rig and that it has around-the-clock access to technical expertise.

NOV was tasked with increasing performance on several global shale projects to maintain their viability in this difficult economic environment. Drilling dysfunctions such as stick/slip and torsional and lateral vibration were resulting in nonproductive time, equipment damage and overall below-average performance across the clients’ operations. Increases in ROP, decreases in destructive vibration modes and reductions in drilling time were the major successes from using downhole drilling dynamics to drive enhancements in performance in these projects. The first three, referenced below, took place in the Haynesville Shale, while the final project took place in the Permian Basin.

In this example, a high-density surface and downhole dataset from BlackBox tools reveals the correlation between a spike in downhole torque and an area of high lateral vibration. Access to this level of granular detail enables creation of a driller’s roadmap for application in future wells, ultimately allowing operators to avoid issues such as reduced ROP and significant equipment damage. (Source: NOV)

BlackBox tools are an important part of the eVolve optimization process. This memory-mode logging tool, which records parameters such as RPM, weight, torque and vibration, is available in various sizes and configurations to allow flexible placement in the BHA or drillstring. The tools facilitate the identification of drilling inefficiencies such as lateral downhole vibration, weight transfer issues and stick/slip. (Source: NOV)

Vibrations causing bit damage
The eVolve team used a combination of BlackBox tools on two offset wells to record and study vibrations that were inducing severe bit damage and causing low ROP and discovered that severe torsional vibration was the most problematic aspect, leading to reduced performance for the client. An analysis and evaluation of the downhole data from the tools enabled the creation of new parameter guidelines to increase drilling efficiency and reduce that damaging vibration. In addition, the introduction of the more durable Helios thermostable cutters extended bit life and enhanced overall performance. The implemented changes led to a reduction in the average number of bits used, an increase in average ROP of about 32% and a reduction in average drilling time of about 37%.

Dysfunctions causing below-average performance
The eVolve team analyzed downhole drilling dynamics using BlackBox tools, which determined that the primary causes of reduced performance were stick/slip and lateral vibration. The tools experienced about 13 hours of extreme vibration in the 2,195-m (7,200-ft) interval of the well, which included the Massive Anhydrite, Travis Peak and Cotton Valley formations. This high-frequency vibration was causing the problematic decreases in overall performance. After accurately monitoring drilling dynamics, specific formation-based surface parameter changes were suggested to mitigate the damaging vibration; implementation of these changes allowed the client to increase ROP by about 33% and decrease vibration by about 85%, which reduced its total drilling time from eight to six days.

Revising BHA parameters
NOV deployed BlackBox tools in the 9 7⁄8-in. section of the client’s first well to observe surface and downhole drilling dynamics parameters and establish a benchmark, with the eVolve team noting that the primary drilling dysfunction was severe torsional vibration in the BHA. After making specific BHA and drilling parameter recommendations to address loss of energy at the bit and bit damage, the client was able to drill the section it had previously drilled in 112 hours in 90 hours, a reduction in drilling time of 20%. The client was able to successfully drill the section, which had previously taken up to three bits, in a single bit run, which translated to further increases in operational cost-effectiveness through the reduction or elimination of the equipment damage caused by drilling dysfunctions.

Avoiding cutter damage
The eVolve team observed drilling practices and used BlackBox tools located in multiple positions in the BHA to analyze the operation, revealing that poor connection and slide-to-rotate procedures were causing harmful vibrations, in turn leading to cutter damage. This analysis also identified problematic BHA components that were causing poor weight transfer and reducing overall performance. After the benchmark well was drilled at 14.8 m/hr (48 ft/hr), the client used NOV’s recommendations to correct drilling practices, reduce cutter damage and optimize BHA design. This led to increased ROP in the next two wells of 60% and 164%, respectively—and a consequent reduction in time to total depth of 1.5 days and 2.5 days in the same two wells. Assuming a spread rate per day of $100,000, this saved the client $400,000.

The oil and gas industry is currently in a position to drive enormous advancements in wellbore technologies, with increases in drilling efficiency becoming more and more critical moving forward. This need will allow the type of optimization service that NOV has developed to see broader application in the types of shale environments detailed in these projects and beyond. The value that these projects provided clients is just one example of how services like this can be utilized to create more efficient and cost-effective solutions to the global drilling industry’s challenges. The ADVISE tier is an integral piece of the optimization puzzle, and through a commitment to continuous improvement, the eVolve service and the software and processes that support it will ensure that the industry at large is poised to confidently move forward.