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Baez F.,NOV Downhole | Barton S.,NOV Downhole
SPE/IADC Drilling Conference, Proceedings | Year: 2011

This paper focuses on technology development for improving drilling performance in natural shale gas plays. These wells involve long horizontal laterals with frequent problems in controlling tool face and maintaining ROP. This results from a number of factors including, high tortuosity through the build section, use of high bend settings on directional motor assemblies, sub-optimal hydraulics, and drill bits with compromised aggressivity. A combination of technologies can be used to dramatically increase performance in these challenging sections by limiting resistive torque, maximizing bit hydraulics, and improving weight transfer. In each example, a separate engineered solution is introduced. These include; • A novel tool that vibrates the drill string with low frequency, low amplitude axial vibrations to reduce drag and dramatically improve weight transfer to the bit. This tool has been used successfully in hundreds of horizontal wells • A specific sealed bearing, motor technology that delivers 100% of the mud flow to the bit. Advantages of full flow include increased bit hydraulics (improved ROP in Shale), and no detriment in response when using tools below the motor that rely on pressure or flow to activate. Run data demonstrates a 37% average increase in ROP compared to conventional sealed bearing motors that rely on flow restrictor bypass leakage for seal performance • Development of a unique flexible bit design, specifically for directional applications. These bits contain novel features that allow rapid design modifications to be performed locally, significantly reducing response time, and allowing the drilling program to proceed at a much faster pace than previously possible Case studies are documented where these solutions have proven extremely successful in gas shale plays. The savings produced by the improvement in drilling performance has greatly assisted the economic viability of continued development in these applications. Copyright 2011, SPE/IADC Drilling Conference and Exhibition.

Berkman S.,NOV Downhole | Stokes T.,NOV Downhole
World Oil | Year: 2011

The NOV Down-hole's 58th annual rig census reports that the total available rig counts for both the US and Canada receded in 2011 despite of an increase in activity for both markets. The statistics from the 2011 census include that the US rig fleet had a net decline of 72 units in 2011, causing the total available count to fall about 2%. There were 262 rig additions and 334 rig deletions during the year 2010. The census report that a number of the US rigs, 315 units, were retired from active service over the year 2010. ODS-Petrodata, which assists in compiling the offshore census data, reports that another 55 units are scheduled for worldwide delivery by the time the 2012 census, is taken next spring. The available count for global offshore mobile units is now 794 units, a net increase of 49 rigs, or 7%. The worldwide offshore fleet is widely distributed, with the US and the Middle East in the lead, followed closely by Southeast Asia and South America.

Barton S.P.,NOV Downhole | Lockley J.R.,NOV Downhole | MacLeod A.M.,NOV Downhole
Society of Petroleum Engineers - Canadian Unconventional Resources and International Petroleum Conference 2010 | Year: 2010

The Horn River Basin is a natural shale gas play located in North Eastern British Columbia, Canada. However, these wells require advanced horizontal drilling techniques and extensive hydraulic fracturing to make them economically attractive. This paper details how a major operator, working in cooperation with a key drill bit supplier, has been able to make radical improvements in drilling performance in this area, leading to significant cost reductions. A typical well consists of a main hole interval that has a vertical section, build section (taking the bore from vertical to horizontal), and a final horizontal leg. When the operator started this project in 2008, the objective was to drill this entire main hole in just three bit runs; one for each directional leg described prior. In actuality, twelve to fourteen bits were utilized, averaging over forty days from drill-out to section TD. This made the economic viability of further development questionable. The team approach of operator and bit supplier enabled bit design modifications and improvements to be implemented in a controlled, continuous, and closely monitored program. A key component of this was the development of a unique flexible bit design developed specifically for directional applications in coordination with a leading supplier of motors. These bits contain novel features that allow rapid design modifications to be performed locally, significantly reducing response time, and allowing the program to proceed at a much faster pace than previously possible. Prior to any alterations, a full analysis of the drilling data of the previous iteration was undertaken. Any proposed changes were then discussed in detail with the drilling operations team, prior to implementation. By July 2009, this systematic cooperative approach enabled the operator to achieve the initial objective of drilling the interval in 3 bit runs, but also their subsequent objective of drilling the interval in just two bit runs. Days to drill this section were drastically reduced from over forty to less than twelve days. The savings produced by this huge improvement in drilling performance has greatly assisted the economic viability of continued Horn River Basin development. Copyright 2010, Society of Petroleum Engineers.

Barton S.,NOV Downhole | Weeden R.,NOV Downhole
Society of Petroleum Engineers - International Oil and Gas Conference and Exhibition in China 2010, IOGCEC | Year: 2010

The increased use of hole opening tools remote from the drill bit has led to a critical need to understand the interaction between the drill bit and the hole opening tool itself. Problems that can result from improper matching include vibration, inability to open hole, mechanical damage to string tools or to the bit, and sub-optimal drilling performance. This paper explores the theoretical relationship between bit and reamer and modeling the relative aggressivity and stability of both tools, building on already established indices for predicting and comparing the performance of bits. It reviews the calculations and methodology of placement and development of both the bit and reamer for optimal interaction and performance. It also considers stabilization of the hole opening tool using both concentric and eccentric devices. The paper also reveals the development of an interactive, intranet tool. This software incorporates logic regarding the configuration of the reamer and assesses these against key characteristics of the drill bit. The tool enables the user to accurately select the drill bit that best complements the reamer that will be utilized. A number of examples from global applications are presented. These demonstrate reduced vibration, improved hole quality and hole opening performance, superior penetration rates, and overall significantly reduced drilling costs. Copyright 2010, Society of Petroleum Engineers.

Raymond D.,Sandia National Laboratories | Knudsen S.,Sandia National Laboratories | Blankenship D.,Sandia National Laboratories | Bjornstad S.,USN Geothermal Program Office | And 2 more authors.
Transactions - Geothermal Resources Council | Year: 2012

Geothermal drilling is hampered by the challenges of hard rock, fractured formations, and high temperatures. This drilling difficulty has traditionally been a point of distinction between geothermal and oil and gas applications yet recently this difference is less pronounced as the oil and gas industry targets more challenging formations for sustained production. This synergy can benefit the geothermal industry as technology developed for oil and gas, backed by significant research and testing, can be adapted for use in geothermal drilling. The work described herein demonstrates the use of mature oil and gas drilling technologies on an actual geothermal well construction project. The principal objective is to develop and demonstrate Enhanced Geothermal Systems (EGS) drilling solutions based upon mature, proven rock penetration systems that have been used in the oil and gas industries to penetrate hard rock formations. Polycrystalline diamond compact (PDC) bits are routinely used in the oil and gas industry for drilling medium to hard rock but have not been adopted for geothermal drilling, largely due to past reliability issues and higher purchase costs. The Sandia Geothermal Research Department has recently completed a field demonstration of the applicability of advanced synthetic diamond drill bits for production geothermal drilling. Two commercially-available PDC bits were tested in a geothermal drilling program in the Chocolate Mountains in Southern California. These bits drilled the granitic formations with significantly better Rate of Penetration (ROP) and bit life than the roller cone bit they are compared with. Drilling records and bit performance data along with associated drilling cost savings are presented herein. The drilling trials have demonstrated PDC bit drilling technology has matured for applicability and improvements to geothermal drilling. This will be especially beneficial for development of Enhanced Geothermal Systems whereby resources can be accessed anywhere within the continental US by drilling to deep, hot resources in hard, basement rock formations.

Pendley M.,NOV Downhole
Materials Science and Technology Conference and Exhibition 2010, MS and T'10 | Year: 2010

Sulfide stress cracking (SSC) has been the subject of investigation since the late 1940's, when a mysterious form of brittle failure began to be observed in steel equipment used to produce oil and gas containing hydrogen sulfide. While the role of hydrogen sulfide in promoting increased levels of hydrogen in steels was recognized early on, researchers disagreed on the mechanism responsible for SSC. Initial theories that SSC was a form of stress corrosion cracking eventually gave way to the current understanding that the phenomenon is caused by hydrogen embrittlement. Research into the effects of hardness, microstructure, chemical composition, and other factors in determining the susceptibility of steels to SSC led to the establishment of industry standards for SSC-resistant materials. Copyright ©2010 MS&T'10®.

Barton S.,NOV Downhole | Baez F.,NOV Downhole | Gee R.,NOV Downhole
Society of Petroleum Engineers - SPE Asia Pacific Oil and Gas Conference and Exhibition 2011 | Year: 2011

Selecting the correct motor and bit combination to drill specific formations is critical to efficiently attain the desired performance through a vertical, directional or lateral application. If the bit is too aggressive, it can stall the motor and significantly reduce the average rate of penetration (ROP). It will also increase the likelihood of premature failure of the elastomeric liner of the motor power section, or twist-off of internal components. If the bit is not aggressive enough, it will not make full use of the available motor power and the ROP will be sub-optimal. A new generation of an intranet system matching tool has been developed, which enables the user to accurately match a drill bit to a specific motor design, in order to deliver a more reliable and greater degree of drilling efficiency. This new software tool incorporates an advanced logic regarding the configuration of the motor power section selected, and assesses this against the bit design based on the four fundamental bit performance indices: Aggressivity, Stability, Durability and Steerability. It also reviews key features of the bit, including length, gauge geometry, cutting structure and torque control component configuration. This software comprises of an interface that uses an extensive database that contains logic tables which describe the multi-dimensional characteristics of the motor and the bit, combining two phases of the tool: first a selection of the ideal bit for an specific application, whether vertical, directional or lateral and secondly a matched configuration of the desired motor. The software also includes, a build-up rate predictor and interference fit guide. A range of case studies have been compiled and clearly demonstrate the accuracy and versatility of this tool to allow improved drilling efficiency. This initiates the implementation of more advanced motor technologies. Copyright 2011, Society of Petroleum Engineers.

D'Ambrosio P.,British Petroleum | Hart S.,British Petroleum | Prochaska E.,NOV Downhole | Bouska R.,NOV Downhole | Tinsley D.,DMTJ Energy Consulting
SPE Drilling and Completion | Year: 2014

Ultralarge-diameter polycrystalline-diamond-compact (PDC)-bit drilling is a fast-growing cost-effective solution in high-tier deep-water drilling operations in the US Gulf of Mexico (GOM) where salt is encountered in the shallow part of the wellbore. Conventional design called for roller-cone (RC) (IADC Code 111-115) drill bits on positive-displacement motors (PDMs) in these ultra-large-diameter intervals. Cost savings on drilling fluid alone, in the form of rate-of-penetration (ROP) gains through the salt interval, has the industry trending to drill these riserless sections with the use of PDC drill bits on rotary-steerable-system (RSS) drilling assemblies. New robust high-torque-capacity topdrives, stronger drillpipe (DP) connections, larger-diameter RSS tools, and improved mud programs have all largely contributed to this step change in drilling performance. In addition, evolved bit and bottomhole-assembly (BHA) design, efficient operating parameters, improved hydraulics, and vibration-prediction modeling have all aided in the success of these runs. Although this emerging new trend reduces drilling times and associated cost, experience has shown there are multiple challenges that must be overcome to complete a successful run in a single trip. These challenges vary from well to well and include, but are not limited to, BHA steerability, rig-equipment limitations, efficient operating parameters, identification of both sediment and salt formations, hole cleaning and hydraulics, salt creep, drilling-fluid displacement, DP torque limitations, stabilization placement, lateral/torsional BHA vibrations, and others. This paper will concentrate on the multiple aspects of ultra-large-diameter riserless PDC-bit drilling applications and the considerations that have been used to optimize them. Prior SPE papers and data from previous deepwater GOM case histories were heavily researched and scrutinized to support the conclusions provided within the body of this paper. Together with industry experience available, these findings have resulted in a set of defined recommendations, providing operators with a guide to justify a lower-cost-per-foot approach through the potential reduction of drilling time in these challenging applications. Copyright © 2014 Society of Petroleum Engineers.

Berkman S.,NOV Downhole | Stokes T.,NOV Downhole
World Oil | Year: 2010

The total available rig count was effectively a wash for 2010 despite a dynamic US rig fleet. RigData and ODSPetrodata provide detailed information regarding the US land and global offshore mobile rig fleets. The Canadian figures are provided by NOV Downhole personnel in Calgary along with Nickle's Energy Group. The US fleet has been experiencing a building boom for the last several years, which has diminished the demand for many of the older units. Rig-building programs continue to turn out new units that increase the size of the US available fleet. The number of US rigs brought back into service jumped this year to 87 units. This is more than double the 36 units that were reactivated in the 2009 census. Note that each of these reactivations had been counted in previous census tabulations, but had been subsequently removed due to becoming inactive or inoperable.

Barton S.,NOV Downhole | Weeden R.,NOV Downhole
Society of Petroleum Engineers - SPE Deepwater Drilling and Completions Conference 2010 | Year: 2010

There is a critical need to understand the interaction between a drill bit and underreaming tool in hole opening assemblies. Problems that can result from improper matching include vibration, inability to open hole, mechanical damage to string tools or to the bit, and sub-optimal drilling performance. Matching of the bit and reamer to avoid these dysfunctions is not a simple process, and certainly is not resultant from simply having a similar cutter size in both cutting structures, or from compromising the rate of penetration potential of the bit. There are four indices that substantially describe the performance of a bit and reamer system: Aggressivity; Stability; Durability; and Steerability. A tool that is capable of calculating the four indices for a bit and reamer allows optimal solutions to be developed for an application once the importance of the rankings are defined for that application. Accurate modeling of bit and reamer solutions must investigate the torque and weight balance in a number of different lithology scenarios. This must take into account the range of compressive strengths plus the type of transition encountered. Suitability of bits for specific reamers can be assessed using a sophisticated and novel reamer matcher tool. These can be tailored, via user input, to the specific parameters of the application. This matching tool uses logic tables based on theory, modeling, and field experience to provide a consistent, logical and quantitative approach to bit selection for reamers. Case studies are presented from deepwater applications that clearly demonstrate the value of the use of indices and reamer matching tool. In combination, these have enabled high efficiency drilling performance, reducing cost per foot to the operator. Copyright 2010, Society of Petroleum Engineers.

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