Alaska geo survey releases annual report
Division of Geological & Geophysical Survey annual report includes 2019 fieldwork on North Slope Nanushuk, Torok, Seabee formations
In mid-January, the Alaska Division of Geological & Geophysical Survey released its annual report, covering agency activities in 2019, such as fieldwork involving the North Slope Nanushuk, Torok, Seabee, Canning, Schrader Bluff, Sagavanirktok and Fortress Mountain formations.
Headed by Steve Masterman, state geologist and director, DGGS is part of the Alaska Department of Natural Resources and a sister agency to the Division of Oil and Gas. Among other things, DGGS provides geologic information to help industry discover and develop Alaska’s energy resources.
According to Masterman, notable 2019 accomplishments related to the oil and gas industry include the following:
* DGGS staff safely completed more than 1,093 days of fieldwork and 2,500 square miles of geologic mapping.
* DGGS petroleum geologists conducted fieldwork in the North Slope foothills and near the 1002 area of Arctic National Wildlife Refuge.
* The Geologic Materials Center, or GMC, in Anchorage held a core-scanning workshop where more than 80 attendees reviewed state-of-the-art scanning technologies and results from vendor scans of GMC samples.
* DGGS conducted auger drilling for sand and gravel resources on the North Slope in a joint effort with the Bureau of Land Management that was partially funded by the Arctic Strategic Transportation and Resources, or ASTAR, project.
ENI-funded project, and moreIn 2019, DGGS’ Energy Resources Section did reservoir archetype summaries on several Brookian formations on the North Slope - Fortress Mountain, Torok, Seabee, and Sagavanirktok - for an ENI-funded project with the Texas Bureau of Economic Geology.
The section also completed 12 days of helicopter-supported fieldwork in the Big Bend area south of Umiat, mapping bedrock formations in outcrop that host large oil accumulations in the subsurface of the eastern National Petroleum Reserve-Alaska and Colville River Delta region.
Another 10 days of helicopter-supported fieldwork done by the section on the North Slope characterized the petroleum reservoir potential of the Nanushuk and Torok formations west of the Dalton Highway; plus, another 10 days were spent evaluating petroleum systems east of the Dalton Highway, including the 1002 area of the Arctic National Wildlife Refuge.
Further, a large structure-from-motion survey was done of the Nanushuk and Torok formations at Slope Mountain for use as a base for mapping reservoir-scale sand bodies, and in modeling their seismic response (seismic forward modeling) to better understand the seismic signature of the Brookian Nanushuk oil reservoir sands in the subsurface at the big Willow and Pikka fields.
Masterman says indications are that 2020 will be another “impactful” year. Among others, projects already in the planning stages include drilling four stratigraphic core holes into Brookian reservoir and source rocks, expansion of data collection under ASTAR, with additional data acquisition for sand and gravel resources, and petroleum geology.
Additional core workshops are planned at the GMC to advance industry understanding of the North Slope’s Brookian reservoir rocks.
Billions of barrels undiscoveredNorthern Alaska continues to garner attention as one of the most prolific hydrocarbon provinces in North America, with 28 billion barrels of oil equivalent discovered to date onshore, and an estimated 30 billion barrels of oil and 181 trillion cubic feet of non-associated gas in undiscovered, but technically recoverable accumulations, said DGGS’ annual report, quoting the U.S. Geological Survey 2012 assessment.
“Understanding the petroleum geology of this region is critically important for making new discoveries. To promote new exploration investment and reduce exploration risk, the Energy Resources Section conducts applied research on North Slope petroleum geology. Results of this work are published as high-quality geological maps and topical research reports that are available to the public at no cost,” said DGGS’ annual report.
The section has a long history of public outreach in the form of core workshops and field tours. In July 2019, it led a two-day-long tour that focused on key outcrops of the Nanushuk, Torok, Seabee, Canning, Schrader Bluff and Sagavanirktok formations in the central foothills that was “well attended by industry petroleum geologists and geophysicists,” DGGS said.
The tour visited outcropping deltaic sand bodies in the Nanushuk and Schrader Bluff formations that “represent valuable analogues for large oil accumulations in the subsurface” and state geologists “discussed key features that influence reservoir quality” with participants.
Oil-stained “sandstones in the Seabee formation and immediately overlying organic-rich clay shales and oil-saturated silicified tuffs in the Hue shale were examined highlighting their function as a reservoir-source couplet,” the report said.
The tours “allow DGGS scientists to share their insights on the region’s petroleum geology, and for a general sharing of information among participating industry representatives,” promoting discovery and production of Alaska’s hydrocarbon resources and spurring exploration investment and development success by “providing unique, high-quality outcrop analogue information that reduces exploration risk,” DGGS said
The survey’s annual report can be viewed online at http://dggs.alaska.gov/webpubs/dggs/ar/text/ar2019.pdf.