Breaking barriers

Jerry Lee discusses new and improved drill bit designs and technologies with several leading companies.

Rising energy demand has resulted in the need to reach reserves in more complex formations. The more complex the formation, the more issues that arise that must be addressed before production can begin. Those complex challenges must be met by similar caliber innovation and development from the industry. Currently, there are several companies who have introduced or are developing new drill bit technologies and innovations to overcome some of those challenging issues facing the industry today.

The MicroCORE Bit, developed in collaboration with TOTAL, allows the continuous generation of micro-cores, while drilling. The core, broken by the bit, is  carried to the surface through the annulus along with the drilled cuttings.	MicroCORE cuttings are not impacted by the shearing process of the cutters and provide an undisturbed structure for analysis in any formation type. Photos from Tercel Oilfield Products Ltd.

Tercel

Tercel Oilfield Products Ltd. has been testing and qualifying its latest innovation since 4Q 2013. Improving upon their previous MicroCORE designs, Tercel’s product line, featuring the new Phoenix cutters, began commercialization in the last couple of months.

Though the MicroCORE design has been around since 2007, Tercel’s innovation is focused on enhancing the rate of penetration (ROP) performance by optimizing the arrangement of cutters on the face of the bit. By improving the energy distribution to the more efficient cutters, the weight on bit is used more effectively in the cutting process, resulting in an average increase in ROP of 36-40% and up to an 82% increase in recent Bakken shale applications, says David Morrissey, Vice President of Sales and Marketing.

The design may be applied to any fixed cutter drill bit. The MicroCORE cutting structure removes the inefficient center cutters on the bit, develops a core by cutting around the center of the hole, and provides an efficient method of evacuating the undisturbed core fragments to surface. These core fragments never see the shearing action of the cutters and provide a high quality sample for analysis on the surface.

Tercel’s field tests have shown that the process of drilling the core and the more efficient cutting structure work to stabilize the bit in the hole and reduce vibration, increase stability, steerablilty and durability resulting in lower repair charges as well.

With greater energy focused on the cutters they must be able to efficiently manage the influx of energy. Now standard in all Tercel fixed cutter drill bits, the Phoenix premium PDC cutters meets this challenge and improves upon previous standard cutters in both shock and abrasion performance. Operators no longer need to choose between improving impact shock or abrasion resistance. The Phoenix series cutter allows simultaneous improvement of both properties, prompting better ROP performance, longer depth drilled and less repair charges. Produced using “low cobalt content, the [cutters] strength is really in [performing] in a dynamic thermal environment,” Morrissey says.

Application of the new product line has seen success in three subsalt wells in a development project off the coast of Brazil, outperforming competitor drills bits in the same formation. Future application will likely be seen in offshore fields of Malaysia.

Trace of cutter movement during eccentric and off-center drilling. A center cutter is traced in blue, and an outer cutter is traced in red.	Model of a bottom hole assembly with a bent housing motor. Images from NOV.

NOV

At NOV, product development is often an evolutionary process, says Tony Watts, engineering manager. A performance issue is identified, analyzed, and a solution is developed. One problem ReedHycalog has identified facing drilling engineers is the eccentric and off-center drill bit motion on bent housing motor BHA’s when performing directional drilling operations. Not only does this cause the hole to be drilled larger, but also results in the bit cutting unevenly. For over three years, the Bent Housing Motor project engineers have been developing a solution. Understanding the issue, NOV engineers have developed a proactive approach, whereby the bits are designed to adapt to the non-axial rotational movement and cut the formation accordingly. Using NOV’s in-house software, models of how the drill bit rotates are constructed, allowing the path of each cutter to be traced. Individual cutter contact with the formation is then modeled so that the cutter layout is optimized. This produces a directional bit that cuts all portions of the bottom of the well and in a more predictable manner. During tests in the Epping Field, North Dakota, the new design produced more footage than the offset well using a competing bit. The new bit is designed to work with a broad base of motors, however, it may also be customized for a specific motor. If progress continues as expected, commercialization of the new product may begin 4Q 2014.

After continuous improvement, NOV has also re-introduced the FuseTek drill bit. A hybrid that incorporates both PDC and diamond impregnated technology into the same bit, the FuseTek bit is designed to drill zones that are interbedded with hard and soft layers. By combining the two technologies, engineers have increased the durability of the bit. The PDC cutters can cut through the soft layers until they eventually fail as the bit drills hard layers. Then, the diamond impregnated portion continues to drill through the harder lithologies. This will save the driller from unnecessary non-productive time when tripping in and out to replace bits. At an offshore well in the Iwafuneoki Field in Japan, during 4Q 2013, application of the FuseTek drill bit saw a 174% increase over the average interval drilled by competitor bits in the same well, and an 84% increase in footage over the next best performing bit.

The Baker Hughes Kymera FSR directional hybrid drill bit creates fewer torque fluctuations and tolerates more weight on bit for faster drilling.

Baker Hughes

Baker Hughes Inc. (BHI) has been busy this last year introducing and developing new technology for the oil and gas industry.

BHI will add to its unique line of hybrid drill bits with the introduction of the Kymera FSR. The hybrid drill technology was first introduced in 2011 to target hard interbedded formations. Having succeeded in their original goal, the line has expanded its capabilities to drill in medium to soft regions, such as carbonate or sandstone as well. Additionally, success has been realized using Kymera bits as pilot bits for all concentric expandable reamers, including the BHI GaugePro XPR and Echo lines.

Though it may seem counterintuitive to use roller-cone bits in what seems like a fixed cutter situation, test runs have shown increased performance using the Kymera FSR directional hybrid drill bit. Instead of simply having a crushing role, the roller cone portion of the bit increases stability by distributing the weight of the bit and controlling the penetration depth of the cutters. By controlling the bit in such manner, not only is stability increased, but durability also increases by reducing vibration and preventing twist off and downhole tool failure, says Allan Holliday, product manager for Kymera drill bits. Kymera FSR bits also incorporate a new line of tungsten carbide cutters in its design. The new generation of cutters is sharper and up to 30% tougher than the previous lines leading to higher ROP and reduced vibration. Current Kymera FSR bit application has been primarily onshore, however, expansion to commercial offshore application will begin in about six months, Holliday says.

BHI has also recently commercialized a new line of cutters, the StayCool multidimensional cutter. In design for nearly two years, and introduced in October 2013, the StayCool cutters are constructed with a groove in the body. In contrast from the shearing motion of the traditional smooth faced cutter, the grooved contour of the cutter produces a scooping motion. By introducing the groove to the cutter design, the cutter produces less frictional heat which results in less thermal degradation, longer durability, and greater efficiency of the bit. In comparison, the StayCool cutter runs about 50% cooler than its standard counterpart in laboratory testing, and similar results in field applications; increases in average ROP, about 15%, and average footage drilled, about 12%, have also been seen, says Barzin Chiniwala, cutter product manager.

Improvements have been made to BHI’s SlickBit anti-balling coating technology. The coating long ago proved its value in preventing bit balling but was sometimes lacking in durability. Now an enhanced flouropolymer-based compound, maintaining the SlickBit designation, is much tougher and more durable than its predecessor due to the addition of novel reinforcement additives, says Steven Radford, technical advisor. By applying the SlickBit coating to the drill bit, cuttings are less likely to adhere and ball up, allowing the driller to drill faster and longer, reducing bit trips. Application in the Gulf of Mexico has shown increased ROP for one driller by 68% in water-based mud (WBM) over the same bit, uncoated, run on a sidetrack of the same well. They also observed that a coated bit in WBM drilled 72% faster and 3.5 times longer than the average of uncoated bits in OBM in this area. The same operator, in a different area saw bits coated with the improved SlickBit coating drilling 57% faster in WBM without shale balling, compared to offsets in OBM. And in a 54 bit sampling of bits in one area in Alaska, prone to shale balling, the coated bits drilled 45% further. With this new BHI bit coating, BHI says operators are now seeing significant cost saving through fewer bit trips, reduced NPT, faster ROP, and eliminating the cost and challenges of using oil based mud.

Baker Hughes’ StayCool multidimensional cutter technology reduces the drilling day curve and costs. Images courtesy of Baker Hughes.	Baker Hughes’ StayCool multidimensional cutter technology minimizes friction on the cutter face, improving rates of penetration.

Halliburton

Set to launch early in the coming year, Halliburton Drill Bit Services’ new cutter technology will boast higher abrasion resistance, impact resistance, and thermal mechanical properties, according to Brad Dunbar, product manager for Fixed Cutters Drill Bits for HDBS.

With the use of data from offset wells, engineers were able to identify areas of improvement and refine their designs with the ultimate goal of producing more efficient drill bits with the capability to drill longer intervals and a higher rate of penetration.

Changes in the chemistry and manufacturing processes used to develop this new technology have resulted in a number of new patents. Featured alongside proven technology, the new cutters have increased its abrasion resistance by 20-30% as compared to previous products, Dunbar says.

In terms of removing thermal mechanical, abrasion, and impact damage as barriers to performance, “the goal of PDC manufacturing is to push those three boundaries,” Dunbar says.

Development for the yet-to-be-named PDC cutter began nine months to a year ago, and it is currently in the validation and testing phase. For the purpose of collecting larger amounts of data in a shorter amount of time, current application of the new technology is limited to onshore sites. However, when the new product line, featuring the new cutters, is released, interested companies can expect them to be marketed for both onshore and offshore drilling operations.