Denver company taking a fresh look at old seismic data
http://www.alaskajournal.com/2019-03-20/denver-company-taking-fresh-look-old-seismic-data
Although the first new oil is yet to flow, the apparent recent successes of several companies exploring on the North Slope has at least a few people looking for new clues in old geologic information that covers a large swath of the oil and gas basin.
Geologist Bill Enyart and his Denver-based company Seismic Strategies have applied modern processing techniques to approximately 1,000 miles of the roughly 15,000 miles of two-dimensional seismic data shot across the National Petroleum Reserve-Alaska.
The 23 million-acre federal NPR-A covers nearly the entire western half of the North Slope. The eastern portion of the reserve nearest to existing oil infrastructure is a focal point for Slope oil exploration after Torok and Nanushuk formation discoveries by ConocoPhillips in the NPR-A and Armstrong Energy and Caelus Energy on adjacent state acreage....
...Enyart said the NPR-A 2D seismic data was shot by federal agencies, including the Navy, in the 1970s and 80s. The NPR-A was first established as a Naval Petroleum Reserve in 1923 and was later transferred from the Navy to BLM.
He described the original seismic as “a very good data set†that would be difficult to duplicate today, primarily because of cost and environmental considerations.
Given that, the mere fact that it exists makes the old information valuable today, he said.
“The signal’s there but since that data was acquired we have seismic data processing routines that can extract additional information and those routines just weren’t available 40 years ago,†Enyart said.
Very simply, when geologic seismic data is shot, sound waves are sent into the depths of the Earth and when those waves return — in a basic sonar process — they provide information about the type and formation of rocks beneath the surface as well as the possibility of hydrocarbon deposits.
New seismic reprocessing technology provides higher resolution images and can better organize old sound signals that were disrupted by permafrost, which can scramble seismic signals.
“The original process was just broad-brush processing looking deep into the section. Historically, a lot of the production was coming from older, deeper formations, so we put a lot of effort looking into the (often shallower) Cretaceous rocks, that would be the Nanushuk and Torok formations,†Enyart said, adding that he’s not aware of anyone else doing this work on the NPR-A data....
