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A new approach to exploration led to success for Oxy.
There are many ways to breathe new life into old fields, and in California they’ve tried most of them – waterflooding, steamflooding, etc.
But it’s not been since the 1950s that operators actually started looking for new hydrocarbons.
In a session titled “Discovery Thinking” at the annual meeting of the American Association of Petroleum Geologists, Robert Bridges of Vintage Production, a subsidiary of Oxy, discussed the new thinking that led to Oxy’s Gunslinger discovery in 2009. He characterized California as having a rich history of production dating back to the late 19th century. To date the state has produced 35 billion barrels of oil equivalent (boe), and even the oldest fields are still producing thanks to EOR technologies.
Perhaps exploration is a new concept to California operators because they didn’t have to look very hard at all for those early fields – they were either discovered by oil seeps or by drilling on surface anticlines. When 2-D seismic was introduced in the 1940s, it led to a few smaller discoveries, but the giant fields had already been found.
“There seems to be an overall attitude of pessimism,” Bridges said, “one of, ‘We’ve found it all.’”
Bridges and his team applied Oxy’s version of discovery thinking to the Elk Hills field, which it bought from the US Department of Energy in 1998. Effectively, the team wanted to bypass assumptions made about the field in the past and apply a fresh new approach.
Firstly, this required what Bridges termed “forensic geology.” Part of forensic geology is to separate data -- original paper well files, raw logs, drilling and completion reports, and raw unprocessed seismic data -- from “non-data” -- workstation interpretations, maps and cross-sections, papers and publications, and final seismic volumes. He warned of the “digital format pitfall,” in which an interpretation is mistaken for accurate data.
This approach required that existing data be skeptically reviewed, removing bias and looking for previous interpretations that may or may not be correct. It also required careful integration of different types of data.
Finally, it required a different team format. A typical exploration team, he said, relies on previous interpretations and experts and expertise and is target-focused and management-directed. Oxy’s approach, dubbed “Discovery Skunkworks,” focuses on raw data and data sharing and is opportunity-focused, multidisciplinary, and member-directed.
“The team has the freedom and ability to create a new reality quickly,” he said.
This method does require management’s support and trust, he added.
Both of these were in evidence in the Elk Hills field. The team used near-field analogs from the Cymric Flank to drill a step-out well in 2008. The results were positive enough to gain management’s trust, and the discovery well was drilled the following year. To date, 23 wells have been drilled with IPs in the upper reservoir of 10 to 30 million cubic feet per day (MMcf/d) and lower reservoir IPs of 100 to 2,000 barrels of oil per day and 1 to 3 MMcf/d.
More importantly to Bridges, the field went from zero to 35,000 boe/d in 280 days and created 1,025 jobs at a time when the economy was suffering badly.
“Success like this should inspire us to think about what’s left to find in California,” he said.