Drilling advances

As we embark on a new decade, the pressure is on drillers in the deepwater Gulf of Mexico. Indeed, signals arising from the dying embers of 2019 suggest that when, or more appropriately, if Gulf drilling activity returns to a semblance of that seen earlier in the decade past, more attention will be directed to deepwater blocks with downhole pressures of 20,000 psi and greater.

When Chevron gave the thumbs-up to its Anchor development in 5,000 ft of water in the Green Canyon area on Dec. 12, it marked the first deepwater high-pressure development to receive a final investment decision (FID) in the Gulf of Mexico. That same day, but with less fanfare, Chevron’s Anchor partner, Total, said it had begun front-end engineering and design (FEED) for its high-pressure North Platte field, which straddles four blocks in the Garden Banks area, in preparation for a possible FID in 2021. “These two high-pressure, 20K-psi projects will help to unlock the potential of the Central Area of the Gulf of Mexico,” says Arnaud Breuillac, president of Total Exploration and Production.

Only the fittest. In this environment, only the fittest will survive, which is good news for Transocean Ltd, which is set to deliver the industry’s only drillships rated for 20K service. Chevron has signed a five-year contract for the Deepwater Titan, under construction at Singapore’s Jurong shipyard and scheduled to commence drilling in the Gulf of Mexico in the second half of 2021.

“In the U.S. Gulf of Mexico, we continue to have constructive discussions with multiple operators regarding the need for a second 20,000-psi-capable rig,” President and CEO Jeremy Thigpen told analysts on Oct. 29. “And, with some customers indicating a desired commencement of activity in late 2020, it’s not unreasonable to expect a final investment decision to occur in the coming months.” Transocean says the twin floaters will include dual 20,000-psi BOPs, net hook-load capacity of 3 million lb, a 165-ton active heave compensating crane and an enhanced dynamic positioning system.

“In addition to the 20,000-psi opportunity, a number of players continue to inquire about ultra-deepwater rig availability in the Gulf, largely for activity commencing in the first half of 2020,” Thigpen said during the latest earnings season. “Well economics in the Gulf continue to improve, which is driven largely by efficiencies that reduced project cost through short cycle times, thus derisking projects and making them more attractive options in our customers’ respective portfolios.”

Aside from the rig and hardware demands, wells of this geologic and geo-mechanical complexity also heighten the need to go beyond drilling and access real-time data throughout the well construction process, says Andy Hawthorn, director of applications for Baker Hughes’ XACT downhole acoustic telemetry service. “In drilling, we’ve done a fantastic job over the past 30 years. We are now drilling wells that used to be undrillable, and a lot of that is due to the ability to access real-time downhole data. Unfortunately, what we haven’t talked much about is if we’re improving the drilling process, are we also improving well productivity?” he told the IADC Drilling Engineering Committee (DEC) quarterly technology forum last September.

Completing the uncompletable. Hawthorn referenced the results of a Shell investigation of offshore wells released in 2015, which found real-time data were available for only 15% of the total well construction time. “That was for on-bottom drilling,” he said.”If we really want to automate and improve, how do we tackle the other 85% of the time when we don’t have access to real-time data?”

As with drilling, the ultimate objective, Hawthorn said, is accessing real-time data to enable the routine completion of wells once considered uncompletable. “Imagine what you can do with cementing, well completions, slot recovery and P&A, none of which currently have (access to) downhole data, but make up 85% of your rig time,” he said.

With downhole tools rated for up to 30K pressure, Hawthorn went on to say that the inline XCAT service multi-application offers an alternative to restrictive mud pulse telemetry and the like. The bi-directional system operates independently of fluid, flow, formation and depth to deliver real-time data throughout the drilling, cementing, perforating, fishing and completions operations, according to Baker Hughes. The use of applied acoustics provides operators downhole data from previously unavailable environments, the company says.

In one deepwater Gulf of Mexico application, Hawthorn said access to real-time data through the XCAT service enabled an operator to change its production strategy. The well was drilled to 10,000 ft in 8,000 ft of water with a “very tight” mud weight window of 75 psi. “This well was originally thought to be uncompletable and was going to be produced open hole.”

Owing largely to the capacity to continually monitor differential pressures, the operator did an about-face on the initial production scheme and elected to run screens as a prelude to the installation of a gravel pack completion. “Get this wrong and you destroy your well, but we are now running screens in a 4,000-ft horizontal and next year (2020) will gravel pack it,” he said. “So, we’ll go from completely open hole (production), to screens to gravel pack, all because of access to downhole data.”

The drilling of more complex wells with myriad geo-mechanical and well construction issues will intensify the need for real-time data after the programmed depth has been reached. “There has to be a step-change beyond what we’ve been doing to drill more productive wells,” Hawthorn said. “I can drill a 10,000-ft lateral, but if it doesn’t produce, it doesn’t make any difference.”

About the Authors

Jim Redden

Contributing Editor

Jim Redden is a Houston-based consultant and a journalism graduate of Marshall University, has more than 40 years of experience as a writer, editor and corporate communicator, primarily on the upstream oil and gas industry.