Denver company taking a fresh look at old seismic data

[thackney]

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....

[IsailedawayfromFR]

@Smokin Joe
Give us some comparison of the value of even the best 2D using up-to-date reprocessing vs a new 3D dataset, using a scale of 1 to 10 with 10 being the very best and 1 is crap.

[Smokin Joe]

@Smokin Joe
Give us some comparison of the value of even the best 2D using up-to-date reprocessing vs a new 3D dataset, using a scale of 1 to 10 with 10 being the very best and 1 is crap.

I haven't worked with enough seismic data to be able to make that comparison.

That said, for any data set, the processing is what will reveal more or less information. The reflections, refractions, etc. should all be in the data, and in the days where shothole data was the standard, the signal strength may well have offset differences in the  sensitivity of the recording equipment, developed later to use vibes.
Shothole data vs vibe in permafrost terrain may place the signal source below the permafrost layer, something which could make it better than vibration induced signals.

In this case, part of the problem is that no one is likely to get the permits, even with a sympathetic administration (some judge, somewhere far, far, away will block them, anyway) to perform an extensive modern 3D run over the same terrain. That makes this data important, and reprocessing that data may yield far more than the original data run, especially with the data crunching power of modern computers.