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carbon-bearing reservoirs below these displaced salt features. However, the imaging technology allowing geoscientists to plan exploration wells to determine the commercial potential of subsalt prospects was still in very early development. A faint bump That didn’t stop ExxonMobil seismic interpreter Flip Koch from putting pencil to paper to analyze newly acquired seismic data prior to a 1999 Gulf lease sale. Koch detected a structure beneath the subsalt that appeared as a faint “bump” on several seismic lines in an unexplored area that possibly others had not detected. As it turned out, ExxonMobil was the only 7 company to bid on the Keathley Canyon blocks that would eventually yield hundreds of millions of barrels of oil. Ricardo Livieres played a key role on the technical team that followed up Koch’s work to confirm that the Hadrian blocks represented a “good neighborhood” for oil and gas exploration. “We learned that a strong system was present for generating hydrocarbons, a number of reservoirs were available to explore and that the structure covered a large area,” says Livieres. “But you never know for sure until you drill.” Hadrian-1, drilled in 2004- 2005 to a total depth of 27,973 feet, proved dry in the deep objective. However, hydrocarbon-bearing reservoirs were Adrian Foster (left), Stephen Welch (center) and Dennis Brock review how to apply learnings from the Hadrian-area discoveries to future exploration and development in the subsalt trend. found in the shallower formations at about 20,000 feet. “After that first well, we knew we had hydrocarbons present, so we focused our technical work to understand where they went and where we should drill next,” says Nick Way, exploration project manager. Where’s the salt? Expanding on some basic geotechnical observations, Livieres began projecting out the small oil accumulations detected in Hadrian-1. The company also stepped up seismic-processing efforts to better understand the geometry of the overlying salt. “If you can figure out where the salt is, you have a much better chance of developing a clearer image of what’s below it,” says John Emerick, exploration supervisor. “Trouble is, salt significantly distorts seismic reflections. It can require a year or more of processing and interpreting the data to obtain an improved image.” Dennis Brock, current exploration team lead, adds that the image distortion caused by the subsalt is like viewing a pencil in a glass of water. “The bottom looks bent, but you know the pencil extends straight down through the water. When we attempt interpretations around the salt, what we see is that bent image. Things are not where they should be, plus they’re fuzzy.” Good news came in 2008,
when the team’s analysis led to the drilling of Hadrian-2 and the discovery of gas and heavy oil. That work also paved the way for drilling Hadrian-3 in 2009, a well that discovered thick reservoirs filled mostly with oil. On the cutting edge As plans progressed for drilling Hadrian-5, advances in threedimensional seismic surveys had vastly increased the volume of data available for seismic interpreters. The explorers took these data and used new high-speed computers and proprietary seismic-processing tools to generate a much-improved image of the deep, subsalt geology. “We were applying cuttingedge technology that had never been fully vetted in the subsalt,” says interpreter Stephen Welch. “We were pushing the limits of how fast you could apply these interpretation techniques. But it led to images that were superior to anything we could have seen just three years before.” Overcoming moratorium delays Only two days before ExxonMobil was to begin drilling Hadrian-5, the then- U.S. Minerals Management Service (MMS), now known as the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE), suspended Gulf operations following the BP Macondo incident. Late in 2010, with the drilling moratorium lifted and ExxonMobil required to secure new drilling permits, the company assembled a cross-functional team from Exploration, Drilling, Land, Regulatory, Law, and Public & Government Affairs to work with BOEMRE to get the well reapproved. The team’s effectiveness paid off, and Hadrian-5 was the first new-drill well that BOEMRE approved after it lifted the moratorium in March 2011. Only four days after the permit was issued, drilling began. Three months later, the well confirmed a major oil accumulation that would form part of the Lucius field. Continuing Gulf focus With the Hadrian-area discoveries moving into development, exploration activity will continue in the Gulf of Mexico. “Our Gulf exploration team will continue looking at prospects along the subsalt trend,” says Adrian Foster, exploration manager. “We hold a substantial acreage position, and we intend to maintain a very active exploration program in the Gulf.” From an energy-security standpoint, Foster notes that the Gulf also offers an attractive location to bring reliable and needed energy supplies to U.S. markets. “The Gulf will continue to deliver large discoveries, and we look forward to continued success there.” the Lamp Upside down in the subsalt Drilling Manager Mark Moyer has experienced just about every kind of downhole environment possible in managing engineering and operations for ExxonMobil wells around the world. Few have proved as complex as the Gulf’s ultra-deepwater subsalt play, says Moyer. “Rock formations are normally older the deeper you drill. With salt movement, however, things can get turned upside down. For instance, in one well, we encountered an unusually thick section of older rock above salt and then found younger rock below it. “Generally, the older the rock, the harder the rock. Our drilling slowed to about 3 to 5 feet an hour through this thick older section versus an average of 50 feet an hour in the rest of the well.” Very hard rock can also cause vibrations in the drill string, which is filled with expensive electronic equipment to measure downhole conditions and rock properties, he says. “To avoid equipment damage, we applied the latest model of ExxonMobil’s vibration-analysis software. An ExxonMobil Upstream Research scientist was also onboard the rig to make adjustments as needed to provide the smoothest drilling possible. “Despite the subsalt’s complexity and unpredictability, we handled the challenges effectively and reduced both drilling time and costs without compromising safety. Plus, ExxonMobil made a significant discovery. What could be better than that?” ExxonMobil contracted the leading-edge Maersk Developer semi-submersible to drill the Hadrian-5 well. 8
Page 1 and 2: An ExxonMobil publication Inside Pa
Page 3 and 4: In this issue Inside Papua New Guin
Page 5 and 6: must manage a multitude of risks -
Page 7: An ExxonMobil exploration effort mo
Page 11 and 12: Much of Jeff Beck’s career has be
Page 13 and 14: The following ExxonMobil employees
Page 15 and 16: When offshore pipelines needed to b
Page 17 and 18: nology, an innovative approach to b
Page 19 and 20: Construction crews will install mor
Page 21 and 22: To support local education, PNG LNG
Page 23 and 24: Kutubu oil facility (existing) Aust
Page 25 and 26: process safety, product stewardship
Page 27 and 28: Mobil motor oils are made for the w
Page 29 and 30: cial,” says Stewart, whose openwh
Page 31 and 32: tag is thin enough to fit through a
Page 33 and 34: Halobutyl rubber, a high-value poly
Page 35 and 36: Doron Levin honored The Society of

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