The advent of new technology in 2011 brings about a positive outlook for 2012.

Advances in rotary tool technology, casing drilling, and multistage hydraulic fracturing are just a few of the areas that have enhanced the industry as a whole this year.

Deepwater operations have held the offshore spotlight for most of the year. In Brazil and – despite a slow resurgence – the US Gulf of Mexico, the industry has seen a wide range of new vessels and investment being applied to ramp up exploration activity beginning early next year.

For the onshore market, shale remains the persistent buzz word that drives most of the latest R&D efforts. Horizontal drilling and hydraulic fracturing have been at the forefront of the success in shale exploration in part because the tools and systems applied to these processes are continually being refined, identifying new challenges along the way.

With its small footprint, Nabors’ MAAC Rig 702 is designed to move rapidly from well-to-well on tight locations and to operate at high altitudes. A unique feature is that the MAAC’s rig floor has been rotated 90 degrees. This orientation relocates the catwalk away from wellheads for a safe working environment. The wide open substructure design allows for easy moving over existing wellheads of any height and simultaneous production/workover operations on adjacent wells during drilling or rig moving. Nabors premiered the new design in 2011. (Image courtesy of Nabors Drilling USA)

RSS performance

One of the biggest advances for overall drilling performance in the shales is improved rotary steerable system (RSS) performance. Earlier this year, Schlumberger released its PowerDrive Archer RSS tool, which is helping operators achieve faster build rates.

For any horizontal well, the pay zone begins after the curve is built. Achieving a successful, efficient high dogleg severity (DLS) can exponentially improve the performance and payout of an individual well. Limitations to high build rates include increased friction, bending of tools, and added stress on costly bottomhole assemblies (BHAs).

When being rotated through these high build rate sections, BHAs experience large bending moments. Fatigue life reduces exponentially with increasing build rate. This can reduce the life of standard BHA components to a matter of hours. Fatigue, catastrophic failure, and twist-off of BHA components can occur without a method of modeling and tracking.

Schlumberger’s RSS provides a way to drill well profiles with high dogleg severity to maximize reservoir exposure and increase the potential for hydrocarbon recovery and to combine this with the traditional RSS benefits of increased effective drilling efficiency and superior wellbore quality.

Field trials in 2008 proved the functionality and reliability of the service. Because of this system’s unique capability in terms of dogleg provision, a second stage of field testing was necessary. This supplementary stage was to ensure any BHA used did not impact the build rate capabilities of the PowerDrive Archer system and that any extra fatigue generated through rotating a drillstring through a high dogleg wellbore could be managed.

The tool’s rotation reduces drag, improves ROP, decreases the risk of differential mechanical sticking, and achieves superior borehole cleaning and conditioning. Reducing friction is especially important when drilling horizontal sections, as the drilling can potentially be extended. Running casing also is significantly less problematic due to a smoother and cleaner wellbore.

Borehole quality is fundamental for drilling optimization. This includes borehole cleaning, tortuosity, and wash-outs. With openhole completions, a smooth borehole leads to less chance of borehole problems and key seating. Casing drilling

Drilling with casing also has made a step-change with new technology in 2011. This approach can provide significant advantages to ensure high-integrity casing strings are installed at the required depth in difficult drilling environments.

Weatherford International’s OverDrive system, which uses drilling-with-casing (DwC) methodologies, has enabled several operators to drill and run, set, and cement casing in a single trip, both improving drilling efficiency and reducing costs.

Large tidal changes, strong currents, and poor visibility in the Bonaparte basin offshore Australia made multiple trips for one operator’s surface hole problematic. Weatherford’s OverDrive system was deployed to avoid lost time while finding and reentering the well to drill the surface hole section. (Image courtesy of Weatherford International)

Aside from its seamless approach, an effective DwC tool can add value to operations drilling through potential hazards management, addressing lost-circulation zones, pressure transitions, and unstable formations.

In Oman, an operator experienced severe losses in formation. The challenge was compounded by hole stability issues, and the lack of available fresh water for drilling fluid made onsite mitigation nearly impossible.

Weatherford engineers collaborated with the client to devise a more involved plan to help drill the difficult formation. It was decided to test out the installation of a drillable casing bit on the bottom of the casing string to ream through any obstructions and drill an additional 10 m (33 ft) at total depth. The plan was a success.

After the initial application, the client sanctioned a complete total depth study, including torque-and-drag analysis and cement placement. In subsequent wells, drilling the entire hole section with the casing string using the OverDrive system and a drillable casing bit has become the standard.

Hydraulic fracturing

Completions technology has continued to advance throughout the year as well. Baker Hughes performed the first 40-stage frac job earlier this year in North America’s Williston basin.

The company’s FracPoint EX-C provides the ability to fracture up to 40 stages in series with continuous pumping operations using 1/ 16 -in. increments in ball and seat sizes. In addition, the FracPoint EX-C system does more than just increase the number of available stages; it also allows the use of larger ball seats on wells that do not require a full 40-stage system, which allows for increased pump rates during the frac and reduced pressure losses during production.

The company’s initial 40-stage FracPoint jobs have saved an estimated five days per completion over a 40-stage plug and perf job.

Even though every shale formation is different, there is a growing consensus in the industry that more stages equal more production, so operators are continually requesting increasing numbers of stages per well to shorten the frac spacing interval, improve fracture efficiency, and increase production on a per well basis.

Looking ahead

Closed-loop drilling and drilling automation are two areas that will likely see the majority of new development within the next few years. With the wide range of benefits inherent to both of these technologies, any innovation that is applied will enhance operations both offshore and on land.