Good Vibrations: How Upending Convention Led to a Game-Changing Drilling Innovation

This article is reprinted with permission from ExxonMobil. 

In 2009, ExxonMobil engineers drilling into deep offshore oil deposits in the Gulf of Mexico unexpectedly encountered a particularly hard and abrasive rock formation. Instead of taking the drill bit half a day to drill through this formation, it ultimately took four runs, or trips in and out of the hole, and three weeks.

Yet just four years later, engineers were able to drill through the same formation in only one run and about a day.

The difference? An innovative approach to drilling that turned conventional industry wisdom on its head and is now reducing time, money and the environmental impact of oil and gas exploration and development.

For nearly a century, drilling engineers grappled with the challenges associated with vibrations along the drill string, which connects the drill bit to the rig at the surface. As the drill bit penetrates rock, the incredible force exerted on the system can cause the drill string to vibrate violently, which sometimes causes the tool to stop drilling, losing precious time.

The traditional approach to researching this problem was to focus on extreme scenarios. Scientists believed that by analyzing the large shocks and intense vibrations associated with extreme events, they would be able to figure out how to minimize damage. However, a team of ExxonMobil engineers and scientists broke new ground by upending that convention, convinced that the solution would come from preventing large vibrations from ever getting started in the first place. Instead of focusing on large vibration events, they developed drilling processes to mitigate vibrations when they are still small and manageable.

ExxonMobil engineers now tune the bottom part of the drill string, known as the bottom hole assembly, using proprietary modeling technology. Jeffrey Bailey, drilling mechanics advisor with ExxonMobil Development Company, compares the upgrade to making music.

ExxonMobil researchers Vishwas Paul Gupta, Jeffrey Bailey, Erika A.O. Biediger and M. Deniz Ertas at the Edison Award ceremony in 2015.

ExxonMobil researchers Vishwas Paul Gupta, Jeffrey Bailey, Erika A.O. Biediger and M. Deniz Ertas at the Edison Award ceremony in 2015. Photo via ExxonMobil.

“We now approach bottom hole assembly design in an analogous way to playing a stringed instrument,” he said.

“We now approach bottom hole assembly design in an analogous way to playing a stringed instrument,” he said. “If we need to modify the design to run at a higher rotational speed, then we shorten the length of the pipe between contact points, just as a musician moves his or her finger closer to the bridge to play a higher note.”

The research team also figured out how to identify and measure vibrations happening at the drill bit, using only measurements recorded by the rig equipment at the surface. This method is applicable to every well that we drill, is less expensive than measurements recorded at the bit, provides real-time data, and enables further optimization methods. The patent describing this methodology was recognized with an Edison Patent Award in 2015 by the Research & Development Council of New Jersey.

Bailey and his colleague Deniz Ertas aren’t new to drilling vibrations. They first developed the models that helped inform their winning approach to vibration mitigation two decades ago. Today that patient research is steadily proving its effectiveness in places like Qatar, Abu Dhabi and the Gulf of Mexico. The technology is also helping drillers reach incredible depths. In 2015, ExxonMobil and its partners drilled a 13,500 meter extended-reach well at the Chayvo field, which lies in Pacific Ocean waters off the eastern coastline of Russia’s Sakhalin Island.

“It took several years to build up to the point where we have the amount of confidence in the method that we do today,” said Bailey. “It’s just been a matter of conviction that the technology works and then persistence and seeing it to completion.”

 

Exxon Launches Multi-Pronged Approach to Reducing Methane Emissions

ExxonMobil is taking fugitive methane emissions seriously with a program designed to lower the volume of the greenhouse gas that is released from the company’s production and midstream sites across the US.

The program, launched in September, prioritizes actions at US sites operated by the company’s shale-focused subsidiary XTO Energy. The effort includes phasing out high-bleed pneumatic devices, research into new technologies designed to detect and reduce facility emissions, staff training, and a leak detection and repair program.

“We are implementing an enhanced leak detection and repair program across our production and midstream sites to continually reduce methane emissions, and are also evaluating opportunities to upgrade facilities and improve efficiency at both current and future sites,” XTO President Sara Ortwein said in a press release.

The program goes beyond measures required by federal and state laws and represents a substantial move by Exxon — the largest natural gas producer in the US — to set a higher bar for the entire industry.

Plan Details

The multi-pronged approach to reducing methane emissions begins with a focus on the wellhead and associated midstream infrastructure; The leak detection and repair program requirse every XTO division to survey production and midstream sites with optical gas imaging camera technology for leaks. Data collected by these surveys will then analyzed for frequency, trends and patterns with facilities and equipment that are found to be more prone to leaking becoming top repair priorities.

XTO is also starting a three-year plan to phase out the use of 1,250 high-bleed pneumatic devices across its US operations. The valves, which are typically found at older sites, are designed to periodically vent pressure buildup to maintain safety, system integrity and efficient operations. The ones considered ‘high bleed’ vent more often and at higher volume

The practice of addressing the most leak-prone equipment and high-bleed pneumatic devices first suggests that XTO’s program could yield notable improvements early on. That’s because the largest portion of methane emissions appears to come from a small number of sources, in much the same way that a small percentage of older cars is responsible for the largest share of automotive-exhaust pollution, according to a 2014 study published by the University of Texas and the Environmental Defense Fund, with participation from Exxon.

The new program also calls for managing planned events in ways that are designed to reduce the release of methane emissions into the atmosphere. For instance, field personal will now monitor and remain nearby during the manual liquid unloading process at well sites to close off all wellhead vents to the atmosphere. Liquid unloading is a process that involves removing liquid that has collected in equipment tubing and prevents natural gas from flowing up through the well.

In addition, a training effort focused on management approaches to overall fugitive emissions is being launched and will consider topics like pneumatic device integrity, leak detection and repair practices, and the sharing of best practices across the company.

XTO will also continue its practice of using green completions to minimize methane emissions at wells during the completion process by capturing or burning off flowback emissions instead of venting them into the atmosphere. It is also working to minimize the need to burn off or flare this gas by maximizing gas capture via pipeline, although some flaring will still happen at new developments where infrastructure investments are contingent on successful hydrocarbon development.

West Texas and New Mexico

XTO has already begun putting some of these practices to use in prolific fields in West Texas and New Mexico. Last year, the company completed a pilot project in the Midland Basin that tested new low-emission designs that use compressed air instead of natural gas to operate the pneumatic equipment that helps to regulate conditions such as level, flow, pressure and temperature. It said the results demonstrated the feasibility of using similar designs for new and existing central tank batteries to further eliminate methane emissions.

The company is also collaborating with ExxonMobil Upstream Research Company and third-party equipment manufacturers to develop state-of-the-art, low-cost, minimum-emissions equipment that could be used for future developments, particularly in the Delaware Basin. Parent company Exxon is also participating in a methane measurement reconciliation study with the Department of Energy’s National Renewable Energy Laboratory, and supporting research underway at Harvard, the University of Texas Energy Initiative, and Stanford University’s Natural Gas Initiative.

Legal Battles

Exxon’s expanded commitment to the environment comes as the company is facing an environmental legal battle in California. In July 2017, seven coastal communities filed suits in their local Superior Court systems alleging greenhouse gas emissions caused by Exxon and 17 other energy companies contributed to a warming planet, leading to coastal flooding, beach erosion and rising infrastructure costs. New York City followed California’s lead in January by filing its own lawsuit against the oil major and four other fossil fuel companies that seeks billions in damages to fund “climate change resiliency measures that the city needs to implement.”

Exxon’s Vice President of Public and Government Affairs for Suzanne McCarron addressed these global warming concerns in a January post on the company’s Energy Factor blog, saying “We believe the risk of climate change is real and we are committed to being part of the solution. That is why we have invested $8 billion since 2000 on energy efficiency and emissions reduction.”

In the meantime, the effort by these governmental bodies to wring money from the oil supermajor may ultimately be distracting from the bigger, overarching challenge we all face — that of securing energy to power a hungry world while coming up with technological solutions to reduce the risks posed by climate change.

The methane emissions reduction effort represents a step in the right direction for Exxon and serves as the latest indication that momentum to develop more sustainable oilfield practices is building across the industry.

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