Whether it is deepwater drilling in the Gulf of Mexico (GoM) or 3,000-m (9,840-ft) laterals in North American shale plays, the ability to more efficiently perform operations from opening sliding sleeves to landing casing at the shoe is critical to lowering costs and increasing production.

Frac systems

Dart-activated system deployed at record depth in GoM. Churchill Drilling Tools deployed its dart-activated DAV MX circulating valve at a record measured depth of 7,930 m (26,012 ft) in a development well off Louisiana in the GoM. The circulating valve system, which includes metal Smart Dart activation technology, enabled rapid and assured reamer bypass in a sidetrack operation and exploited the deepwater capability of the Smart Dart to withstand rapid delivery speeds and HP/HT variations.

Using its multicycle capability, bypass deactivation was equally simple as the assembly was pulled from hole. This proved the capability of the system to give the operator total control over both the fluid path directions and the drilling equipment while maintaining the well control flow-rate objectives set out in the program.

In each bypass application a Smart Dart is used to set the valve quickly into the right mode, while in the closing cycle a universal closing dart is rapidly deployed to allow drilling to resume quickly with no loss of hydraulic performance. Multiple Smart Dart cycles can be performed in any sequence.

In the record depth run, which was delivered out of Churchill’s recently opened Houston base, the DAV MX circulation sub was activated with a 2¼ -in. Smart Dart pumped in to the valve seat in less than 30 minutes and at a flow rate of 170 gpm. With the valve open and reamer disabled, the assembly was pumped out through the window at 300 gpm/2,800 psi and showed no signs of drag or overpull. After passing through the window, the well was circulated before pumping out of hole to 5,030 m (16,500 ft) at 425 gpm/3,800 psi. The valve was then deactivated with a universal closing dart being pumped into place in less than 15 minutes and at a flow rate of 250 gpm.

The DAV MX is used across a range of drilling environments including deepwater, HP/HT, and high-angle extended-reach drilling. The mechanical extrusion system is significantly more reliable, faster, and more cost-effective than polymer extrusion, the process used for traditional ball-activated systems.

Simple casing buoyancy system reduces running time. Operators around the world are taking advantage of horizontal drilling and completion technology to profitably develop low-permeability formations, especially shales. One drawback to horizontal wells, however, is the difficulty of running production casing around the radius and to the toe of the well because of high frictional drag in the lateral section.

As lateral sections increase in length, lateral drag frequently exceeds the driving force provided by the weight of the vertical pipe. Operators often resort to rotating the casing string, but that requires expensive premium connections. The AirLock casing buoyancy system from NCS Energy Services facilitates landing casing without casing rotation, without interrupting casing and cementing operations, and at nominal cost.

The exclusive AirLock seal allows the vertical casing section to be filled with fluid as casing is run, while the lateral section remains air-filled and buoyant. The enhanced lateral buoyancy reduces sliding friction more than 50%, while the weight of the vertical section provides additional force to push the string all the way to the toe of the well.

The simple and passive system has only two components: a seal collar installed in the casing string just above the radius section and a debris-trap collar installed just above the float shoe. Both collars are made up in the casing string during run-in. The seal collar contains a pressure-calibrated breakable seal that locks air in the lower section while the upper section is run and filled with fluid. After the casing is landed, surface pressure is increased to fragment the disc, leaving an unrestricted casing bore. Seal fragments are collected by the AirLock debris trap, and cementing operations proceed as usual.

To date, all casing strings run using the casing buoyancy system have been landed and cemented successfully, NCS Energy Services said.

Ball-actuated frac sleeve provides 62 stages. The Super-Port ball-actuated fracturing sleeve from Peak Completions provides operators with up to 62 independently treated stages using reduced increment ball seats. A single ball is dropped for each stage, and hydraulic pressure shifts the sleeve open to expose stimulation ports. The Super-Port maintains a true 10,000-psi differential rating that offers a solution for stimulation and high frac-pressure capabilities, according to the company. The Super-Port uses standard frac balls that are easy to mill out and offer low costs.

By using the additional number of large ball sizes, operators can significantly increase the minimum inside diameter (ID) of the system, making it suitable for extended-reach wells with high stage counts, the company said. In addition, a larger minimum ID reduces the pressure drop across the system, providing more flexibility in operations.

Dissolvable frac balls can eliminate drill-outs. The Magnum Fastball from Magnum Oil Tools International dissolves on its own under heat, which can eliminate the need for drill-outs, according to the company. This also can eliminate the necessity of well intervention for stuck frac balls or loose frac ball fragments.

These dissolvable frac balls can be used with sliding-sleeve systems or composite frac plugs and, once dissolved, allow free flow of hydrocarbons. The frac balls have been field-tested at 20 bbl/min, according to the company, and come in sizes ranging from ¾ in. to 4.6 in. The environmentally friendly chemical composition also prevents the frac balls from getting stuck in the ball seat.

Hydraulic toe valves designed for cemented applications. An innovative and economical multizone well completion system designed for both open-hole and cemented fracing operations includes the ORIO Toe Valve, which provides a method for performing a high-pressure casing test prior to establishing injection into the formation.

The hydrostatically operated sliding sleeve is part of Team Oil Tools’ T-Frac System. The patented ORIO Toe Valve is run at the bottom of the completion string in horizontal wells. The tool is specifically designed to work in a cemented environment. After completion of the test, excess pressure is applied to open the valve and allow immediate injection to commence fracing operations, including the traditional plug-and-perf method.

The toe valve’s design ensures that the sleeve will open even if excess cement is left in the wellbore. The inner piston is the only moving part in the tool and is completely isolated from the cement. There are no moving parts on the ID or outside diameter of the tool. The ORIO’s unique three layers enable it to function as required.

The toe valve specifications include a rupture disk with ratings up to 20,000 psi that allows pressure-testing of the casing in excess of 15,000 psi and a temperature rating of 177°C (350°F). The certified rupture disks allow the valve to be opened within 2% of design.

Traditional toe valves yield higher failure rates due to the necessity for the sleeve to “crush” any excess cement. The use of an atmospheric chamber means the valve can remain fully open with hydrostatic pressure alone. This particular feature allows higher injection rates as the tool fully opens once activated.

Once the rupture disk has burst, hydrostatic pressure continues to drive the sleeve fully open and maintains it by acting against an atmospheric chamber that allows maximum flow area throughout. Shouldered connections allow rotation while running in the hole or during cementing.

Interventionless toe initiation not only provides an operational cost reduction but also serves as a technology enabler for the cemented ball-activated frac sleeves. Without an interventionless toe initiation, ball-activated frac sleeves cannot be used in a cemented lateral.


Conical diamond technology, rolling PDC cutter introduced. A unique conical diamond element was introduced by Schlumberger’s Smith Bits to enhance polycrystalline diamond compact (PDC) drillbits for improved drilling performance along with a new PDC cutter for improved drillbit durability.

The conical Stinger PDC element enables high-point loading to fracture rock more efficiently during drilling for increased ROP and durability. The diamond element has an ultra-thick polycrystalline diamond layer that is significantly thicker than conventional PDC cutters. The element’s shape is optimized for strength in axial compression. When centrally positioned in a PDC drillbit cutting structure, the Stinger element improves performance by crushing formation core at the borehole center, increasing drilling speed.

At the same time, the Stinger technology also delivers a more stable bit with less vibration to reduce stress on drillstring components and improve the reliability of downhole tools.

In the Williston basin an 8¾-in. PDC bit is typically used to drill the vertical hole before the curve and lateral section in the Bakken oil-bearing sands. In field tests centrally placed Stinger element technology was added to the baseline vertical section drillbit design. Average ROP was increased by more than 46% when compared to the next best performance in offset wells, with a record ROP increase of 77%.

In another development Smith Bits introduced its ONYX 360 rolling PDC cutter. An industry first, this unique technology enables a PDC cutter to rotate 360° while drilling, significantly improving drillbit durability in abrasive formations and extending drillbit life and footage drilled per run.

Strategically positioned in the highest wear areas of a drillbit’s cutting structure, the rolling cutter uses its entire diamond edge to shear the formation as the bit rotates, thereby distributing wear over its full circumference. This rotation allows the cutter’s diamond edge to stay sharp longer, increasing penetration rates and extending drillbit life. The 360° rotation also reduces frictional heat buildup, resulting in less wear and fewer bit replacement trips.

During field testing, more than 80 runs and 39,634 m (130,000 ft) were drilled. In the US Midcontinent Granite Wash, PDC drillbits were fitted with the rolling cutters to increase the amount of footage drilled. In one field test footage was extended by 57% in the abrasive sandstone formation while ROP increased 26%. The new rolling cutters also exhibited uniform wear with no cutter loss and 100% cutter rotation compared to premium PDC fixed cutters that showed greater wear with less footage drilled.

PDC drillbit can increase stability, ROP. Ulterra introduced its CounterForce PDC bit design technology. The tool can lower bit torque and vibration and create more efficient failure of rock, the company said. The technology is designed to increase stability and ROP by maintaining a consistent torque signature with cutters that work to increase crack propagation and lower lateral vibration.

In a case study from the Permian basin, the company noted how the technology was used to finish a Wolfcamp lateral, with the operator reporting a 42% faster ROP than with direct offsets. The operator saved a day of drilling using the technology, according to Ulterra.

Multidimensional cutter can improve drilling performance. The StayCool multidimensional cutter can help operators drill to total depth faster and more cost-effectively by extending cutter life and footage per run. Used exclusively on the Hughes Christensen Talon platform of PDC bits, these cutters incorporate a contoured diamond table, wear-resistant diamond materials, and new interface designs, according to Baker Hughes.

In challenging environments such as interbedded sandstones and carbonates, bit performance is directly related to cutters and the ability to withstand heat. Overheated cutters experience abrasive wear faster, which can lead to lower ROP and higher mechanical specific energy or wasted energy that is not directly transferred into removing rock. The StayCool cutter’s patent-pending contoured design can reduce friction, maintain a sharper cutting edge throughout the bit run, and reduce mechanical specific energy, the company said.

Laboratory testing has shown that the cutters generate 20% less heat on the cutter face than conventional flat-surface cutters. Less heat minimizes cracking tendencies on the diamond table that can lead to failures and shorten run life.

Rotary steerable system

A new rotary steerable system (RSS) can deliver build rates of up to 18°/30 m (100 ft) with full directional control and dogleg assurance for complex 3-D well profiles and multilateral well designs in carbonate, sand, and unconventional reservoirs, according to Schlumberger.

The company introduced its slimhole PowerDrive Archer high build-rate RSS, which can drill well profiles previously only possible with motors in one run with the ROP and wellbore quality of a fully rotating RSS.

Built on the reliability of the PowerDrive X6 system, the slimhole RSS uses a combination of push- and point-the-bit technologies. The geosteering and openhole sidetrack applications were proven in more than 130 field test runs in North America, the Middle East, West Africa, Europe, and Asia.

In the Permian basin, Cimarex Energy needed to drill a 6?-in. horizontal section within a 2.1-m (7-ft) thick true vertical depth zone in the Bone Spring shale formation. The well design included high dogleg severity with a 10°/30-m curve. The slimhole high build-rate RSS was selected to eliminate additional trips downhole, and the challenging curve and lateral were drilled in one run, saving 26 hours of drilling time.

Surface drilling equipment

New top-drive casing drive system built for horizontal wells. Tesco Corp. introduced the HXI 150-ton top drive and hydraulic compact casing drive system (HCCDS) for extended-reach horizontal wells, the company said. The top drive is a lighter, more compact version of the company’s HXI 250-ton model and generates 24,000 ft-lb of drilling torque. The technology allows the transition of the top drive between mobile rigs and includes a safety interlock of the process logic controller system and driller’s control panel. The company also designed the HCCDS to be light and compact. The system can allow circulation, rotation, and reciprocation of the casing, which can ensure it reaches casing point. In addition, the system can replace conventional power tongs, traveling elevators, and the stabbing board.

Downhole solutions

Dogleg reamer solves lateral drilling issues. Although the drilling of extended lateral sections has become relatively routine, wellbore quality issues such as microdoglegs and efficient hole-cleaning significantly increase operator risk and expense. National Oilwell Varco’s Borehole Enlargement Group developed its newest premium string tool, the Dog Leg (DL) Reamer, to help avoid and solve problematic lateral drilling issues.

The DL Reamer has a slight eccentric profile, allowing the tool to pass through a smaller restriction than its actual drill size. As a result, the tool will slide efficiently, even if the pilot bit becomes slightly under gauge. The reamer also has two distinct cutting structures – one for minimizing microdoglegs while drilling ahead and the other offering an uphole cutting structure to allow back-reaming while pulling out of the hole or while pulling up to make connections. Designed for maximum toughness, the DL Reamer has resulted in reduced trip time and proven success in shale laterals, extended-reach wells, creeping salts, and swelling shales. It cleans the wellbore before expandable packer completions or running production casing with added stability and protection while stirring cutting beds and eliminating dedicated wiper trips. The reamer also features torque-control components, resulting in a maintained ROP, over-engagement of cutters in formation, controlled lateral engagement, and stability.

During the testing phase in extended Bakken shale applications, the DL Reamer proved extremely successful in cleaning the wellbore and eliminating dedicated post-well reamer runs. The reamer has been successfully deployed in Wyoming, Oklahoma, and Latin America and is available for pilot bit sizes ranging from 5¾ in. to 12¼ in.

Multiple product solution solves wellbore instability. A client in South America had unsuccessfully tried to drill two critical wells at a cost of more than US $80 million each. The client’s failed attempts were due primarily to uncontrollable annular pressures that resulted from large losses of drilling fluid and wellbore instability during the drilling processes.

Weatherford was asked to step in and recommended a set of technology solutions that would allow for safe and effective drilling of this horizon. Weatherford proposed and successfully implemented a multiple product solution comprised of its Microflux Control System, reaming liner services, and solid expandable systems. As a result, as many as 40 wells will now be drilled using this process.

Lost circulation pill designed for drilling, production, completion. Multi Squeeze is a blend of customized lost circulation material and new proprietary crosslinked polymer that provides a highly effective, pliable plug that will penetrate fractured zones and form a solid seal in the formation, according to Circulation Solutions LLC.

Multi Squeeze has no activators, retarders, or additives other than salt water, fresh water, sea water, brine, or production water to activate the pill, which eliminates any risk of premature activation. The blend can be used in any application where a squeeze plug is beneficial to stop losses and increase the integrity of the formation. Product can be specially blended to protect and improve wellbore integrity based upon the formation and drilling fluids in use and can stop losses and seepage in both drilling and recompletion applications, the company explained.

The product will form a solid seal in the loss zone, not in the well bore. Once the pill is properly mixed and weighted to the required density (up to 18 ppg), it is spotted across the loss zone. The pipe is then pulled 61 m (200 ft) above the top of the pill. Squeeze pressure of 100 psi to 150 psi (higher pressure may be used in certain situations) forces the pill to compress and penetrate the problem zone. The product is effective at temperatures up to 204°C (400°F).

Multi Squeeze has proved to be useful in improving wellbore integrity, cement enhancement, severe and total circulation loss, formation stability, depleted zones, reentries, workovers, completions, and producing formations. The product reduces cost associated with expandable liners, slimhole tool rentals, rig time, coiled tubing, and cement, Circulation Solutions said. The blend is environmentally friendly with no contamination of the pay zone. The product is acid soluble and compatible with all water-based, oil-based, and synthetic-based drilling muds. It can also be blended with fiber to maximize results.

RFID-actuated drilling circulation sub. Weatherford has developed the latest addition to its portfolio of radio frequency identification (RFID) technology, the JetStream drilling circulation sub. Used to simplify drilling and hole cleanup operations, this device features an RFID-actuated circulating valve for unlimited opening/closing capability.

To communicate open and close commands, a surface-level RFID tag is dropped and circulated internally through the sub. A built-in antenna receives the RFID signal, and a battery-powered electric motor operates a hydraulic pump, which moves the valve from the closed position to either the open or diverted position.

If pumping an RFID tag is not possible, additional technology embedded in the sub enables pressure-cycle or mechanical-dart actuation as contingencies.

The RFID sub transforms conventional circulation devices with a design that eliminates ball seats and the associated ID reductions. This is especially advantageous when multiple tools are run, in which case the lowermost ball seat would pose a major restriction in a conventional tool.

Full through-bore diameter provides access to a series of up to 16 RFID-actuated tools. Activations can occur in any order and simultaneously. This increased control facilitates zone selection to enhance annular flow for optimal wellbore cleaning.

Sensors on the RFID-activated circulating valve log all downhole events in the sub’s unique internal memory. Performance data can be downloaded and accessed in less than an hour of retrieval via a close-proximity communication device. Data – including time, drillpipe pressure, hydraulic micropump pressure (inside the sub), temperature, and battery capacity – are automatically converted and displayed on a vertical strip chart.

The circulation sub includes a range of additional improvements that encourage productivity and reliability for operators. It averages 750 hours per major service interval to enhance operational efficiency and reduce nonproductive time.