October 2019 /// Vol 240 No. 10

Special Focus

Innovation is key to drilling longer laterals

Innovative drilling solutions must use specific combinations of high-performance drilling motors, RSS and MWD to accurately and efficiently drill significantly longer laterals.

John Evans, Catherine Sampson, Gyrodata

The most recent downturn still haunts operators who continue to strive to optimize drilling operations, reduce costs and drive efficiencies. The idea that “time is money” certainly is at the forefront, as operators continue to push for operational efficiencies.

Operators remain focused on increasing the productivity of new producing wells while also remaining cost conscious. In various shales, operators are meeting their goals by taking advantage of innovative directional drilling technologies that help improve operating efficiencies. For example, they have used more robust and reliable directional tools to drill significantly longer laterals as a way to deliver greater production from a single well. A result is the use of more intricate well completion designs, with the aim of reaching higher initial production rates.

Drilling longer laterals requires robust, highly reliable directional drilling tools that are very accurate and efficient, and easily applied to meet specific drilling objectives. The solution may replace conventional tools (such as mud motors) with upgraded RSS tools; in other cases, a combination of tools may be used to reach the targets. An innovative approach to the application of high-performance technology is necessary to optimizing the application.

A suite of Gyrodata tools, including rotary steerable systems, mud motors and MWD systems, along with well planning, engineering and optimization, is providing a flexible solution that has helped operators in the Permian basin and Anadarko basin drill on-target, record-length laterals.

GROWING LATERAL DEMAND

The shift towards increasingly longer laterals in shale development is clear. In the Permian basin, from 2016 to 2017, well lateral lengths increased by more than 1,500 ft, to an average length of about 7,500 ft. Since then, lateral lengths beyond 10,000 ft have become more common. In the Marcellus play in early 2018, an operator drilled two lateral wells that hit lengths of 17,875 ft and 18,129 ft., breaking area records. The first quarter of this year saw an operator drill the longest known lateral in the Permian basin’s Midland sub basin, with a horizontal displacement of 17,935 ft (3.4 mi).

Although drilling a long lateral can cost significantly more than a conventional vertical well, experts argue that one horizontal well can replace as many as six vertical wells. In tight shale formations, longer laterals allow operators to access more oil and gas than vertical wells. With longer laterals, two to six horizontal wells can be drilled next to each other on the same strategically located pad. Wells drilled from these pads may replace more than 20 vertical wells, significantly reducing drilling operations and expense, and the associated environmental footprint. These longer laterals are helping operators optimize drilling operations. The efficiency of this process is so significant it has challenged the traditional rig count as a measure of drilling activity in favor of lateral footage drilled.

Experts attribute the ability to drill longer laterals to many factors, including best operating practices, rig selection, efficient directional drilling tools, casing running techniques and advanced drilling fluids. Key to the advance is the ability to accurately drill extended laterals in one trip. This is being accomplished through greater reliability of directional drilling tools, including motors, MWD and rotary steerable systems (RSS).

RSS PRECISION AND EFFICIENCY

RSS tools allow operators to precisely steer longer laterals through shale formations while also improving drilling efficiency. In various plays, operators are using RSS and other drilling tools to optimize performance by shortening the rig time to reach total depth. Many RSS technologies have been designed specifically for land wells that need higher build rates and smoother wellbores. Today, closed-loop RSS tools now incorporate a number of design features that deliver less tortuous well paths, as well as tighter curves. Consequently, these tools provide maximum contact with pay zones.

Over the years, RSS technology has matured, and operators have maximized its value and cost-savings for onshore drilling operations, especially for those that occur in horizontal unconventional plays. As RSS technology has provided the more precise directional steering needed to drill challenging target windows, operators have tried to combine the vertical, curve and horizontal sections in one run.

In these long applications, the ability of RSS systems to allow rotation of the drillstring throughout the drilling process reduces friction between the drill pipe and wellbore, which lowers critical torque and drag forces in the extended lateral. Importantly, drillstring rotation enhances hole cleaning during drilling operations and improves the rate of penetration (ROP) achieved with RSS systems. By combining RSS tools with an effective well design and drilling fluid, operators drilling 14,000-plus-ft laterals have been able to reduce tortuosity and keep the wellbores in target zones for almost 100% of the lateral footage.

Gyrodata’s closed-loop, fully automated, point-the-bit WellGuide RSS is designed specifically for highly accurate steering in complex environments, so operators can reach their targets in one run. The RSS has a proven track record of maintaining inclination and azimuth control by using a closed-loop communication system with real-time feedback for wellbore placement. A flexible technology, it allows for multiple hole sizes and all types of drilling fluids; it is also compatible with Gyrodata’s GyroDrill mud motor, MagGuide MWD and GyroGuide GWD tool, as well as other directional providers’ equipment. The WellGuide RSS enables improved directional control for a higher rate of ROP and longer laterals, as well as a smoother borehole.

ANADARKO BASIN EXTREMES

Fig. 1. Actual drilling days track closely with plan. Source: Gyrodata.
Fig. 1. Actual drilling days track closely with plan. Source: Gyrodata.

 

For example, in 2019, an operator needed to drill two directional wells in the Anadarko basin’s Granite Wash play. The firm was experiencing challenges drilling lateral sections greater than 7,500 ft with conventional directional drilling assemblies. The operator asked Gyrodata to provide an RSS solution that could handle a high-volume lost-circulation material (LCM) and low flowrates required to quickly drill each lateral section to nearly 9,500 ft. An optimized bottomhole assembly (BHA) design was recommended that used a 4¾-in. RSS and motor with electromagnetic MWD for precise steering control and survey validation. Gyrodata helped the operator to achieve the planned 8,653 ft in Well 1 and 9,475 ft in Well 2, Fig. 1 and Fig. 2.

Fig. 2. Drilling targets and actual performance in both wells show close correlation. Source: Gyrodata.
Fig. 2. Drilling targets and actual performance in both wells show close correlation. Source: Gyrodata.

Gyrodata’s RSS completed both laterals under a strict timeline and has since contributed to several other drilling applications with the operator, regularly drilling extended-reach laterals for approximately 2,500 ft of additional production hole. The RSS was able to maintain directional accuracy while also enabling increased LCM volume and lower flowrates. As a result, a smooth wellbore at a controlled ROP of approximately 50 ft/hr was delivered. Since working with this operator, Gyrodata has helped various customers regularly drill extended-reach laterals that frequently add approximately 2,500 ft of additional production hole.

THE DRILLING MOTOR FACTOR

To produce longer laterals, drilling motors also have become more durable and efficient. They can now be rotated in laterals with bent housings of up to 2.12° for over 200 hours. Previously, the maximum allowable bent housing that was rotated was 1.5°, and the life expectancy of the mud motors ranged between 100 and 120 hr. These drilling motor innovations have helped oilfield service providers drill longer laterals. For example, in the Midland basin earlier this year, a Gyrodata GyroDrill performance mud motor drilled a 14,201-ft curve-to-lateral section in one run in 226 drilling hr. A new record for the operator, the run was achieved while drilling its longest horizontal well in the area. The well was drilled with one BHA that deployed Gyrodata’s mud motor along with an MWD mud pulse system. The increased battery life that benefits the mud motor also allows MWD tool configuration with batteries that last over 200 hr.

COMBINED SOLUTIONS

Fig. 3. An advanced modeling system was used to optimize the BHA to mitigate downhole vibrations and identify ROP limiters before drilling commenced. Source: Gyrodata.
Fig. 3. An advanced modeling system was used to optimize the BHA to mitigate downhole vibrations and identify ROP limiters before drilling commenced. Source: Gyrodata.

Oilfield service companies have been using a variety of tools, including RSS, MWD systems and performance motors to drill longer laterals in one run. Earlier this year in the Midland basin, Gyrodata helped an operator drill an extended-reach well to 17,665-ft, MD, with a 9,015-ft lateral in one run. The operator planned to drill an extended-reach lateral well with an estimated two-mile lateral section. They needed a solution that would offer automated directional steering with limited surface interaction. They also needed real-time, high-accuracy surveys to confirm the bottomhole location. Experts from Gyrodata’s Guide Center utilized a historical database to determine an effective well plan, the BHA design and drilling parameters that would enhance drilling performance, Fig. 3. The Guide Center provides well planning, well engineering and real-time optimization services for most active directional drilling operations.

Fig. 4. Improvements in the lateral section significantly reduced planned drilling time. Source: Gyrodata.
Fig. 4. Improvements in the lateral section significantly reduced planned drilling time. Source: Gyrodata.

The Guide Center recommended the operator run the MWD surveying technology along with the 6¾-in. mud motor to drill the surface-to-curve section to 8,203 ft, MD. For the lateral section to target, a 7-in. RSS was specified to provide near-bit surveys and auto-steering of the programmed path to 17,677 ft, MD. RSS technology was used to drill a 9,473-ft lateral section in one run in 43.83 drilling hours with an average ROP of 216.13 ft/hr. The RSS kept an 89.99° average inclination and a median dogleg severity of 0.79° per 100 ft. The RSS tool had a steering accuracy that exceeded 99% to the programmed course, resulting in low tortuosity throughout the lateral section. During the lateral section, the operator ended up saving eight days of drilling time, and was able to drill the entire well in 11 days. Gyrodata helped the operator save nine days of rig time and more than $580,000 in drilling costs, Fig. 4.

CONCLUSION

There’s no denying that longer laterals have become a big deal for the industry. Wells with longer laterals have become more common in the drilling industry, because they have additional contact with hydrocarbon producing formations with resultant increased productivity per well. Innovative drilling tools are behind this trend of extended lateral lengths. Applied to replace conventional systems or in combination with them, efficiencies achieved with these drilling tools have led to longer laterals, which have had a significant impact on production rates. 

The Authors ///

John Evans JOHN EVANS is Gyrodata’s product line manager for rotary steerable system (RSS) and measurement-while-drilling (MWD) services. He has over 30 years of experience in the oil and gas industry. Mr. Evans manages the technology portfolio and operations technical support, plus the remote operations Guide Center. His primary areas of expertise include RSS, drill bits and drilling technologies, MWD, logging-while-drilling, as well as drilling engineering and optimization.
Catherine Sampson CATHERINE SAMPSON is Gyrodata’s marketing materials specialist. She has more than ten years of business communication experience. She holds an MS in technical communications from the University of Houston.

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