2D seismic is back – but why did it leave? In this first article, based on a discussion with Lee Hunt, Geoscience Technical Advisor, and Eric Street, Director of Geosciences at Carbon Alpha, we discuss why 2D seismic went away, why it’s back again, and why it has now become indispensable for carbon capture and storage (CCS).
Watch the full interview here or keep reading below.
As it turns out 2D seismic didn’t disappear, but rather a preference for—and capability to acquire—3D blossomed. The evolution to 3D seismic involved overcoming some hefty technical challenges.
“Part of [2D seismic] going out of style was that we finally achieved the ability to commercially shoot 3D,” explains Lee. The development of instruments and algorithms, noise attenuation, and the growing computational power required for processing complex 3D datasets were all significant hurdles to the development of 3D seismic.
“Originally the very first 3D’s didn’t have channel capacity – not just channels in the field, but instrumentation that could have a big recording system,” recalls Lee. “So that channel count had to change. We needed new instruments. Eventually we started getting those things, and that led to the arguing and debating over 3D designs, which is still going on today and is quite fun,” says Lee with a playful smile.
“We also had to learn to process this data, and that meant developing algorithms that could manage and take advantage of the new higher domains that exist in a 3D survey. Initially, we weren’t very good at those things, but we had to get there. We had to learn how to attenuate noise in 3D domains to both find and emphasize signal. But also, to do all those things, we had to develop computational power to process that data.”
Moreover, Lee explains that software development was also needed to facilitate interpretation. Working on paper was fine at the time for 2D, but with the development of 3D data, geoscientists relied on software for understanding the subsurface. “We’ve learned how to interpret 3D data. And that included visualization techniques. Computational capability, again, comes back into this. We had to develop and learn to use graphical handling for the information.”
With the technological development of computers and field equipment, prices for 3D seismic began to come down, making it a more widely popular option. “It was found to be worthwhile to use 3D to solve certain problems and we could solve them more cheaply than before. So, we became motivated to shoot 3D as soon as we could,” explains Lee. “…through those early years, we spent a lot of time justifying 3D economically. Even though in many cases there was an economic reason, you still had to prove it.”
The shift from 2D to 3D seismic surveys is also deeply tied to the unique nature of subsurface geology. “There’s no single answer to the question of why 2D went out of style. But I think something that we can’t forget is that we have geology, we have a subsurface, and it’s unique and distinct,” explains Eric.
The evolution from 2D to 3D seismic surveys aligns with the natural progression of basin exploration. Eric explains that while 2D is great for greenfield exploration, this invariably gives way to 3D models as targets get smaller and more resolution is needed. On a small scale, more factors need assessment, like potential for carbon storage or hydrocarbon extraction, and risk. Drawing from his oil and gas experience, Eric explains, “If we’re steering horizontal wells and we’re avoiding features which might intersect with those wells, say fracture systems where you lose mud and, in the worst cases, even entire wellbores, that requires 3D in that level of imaging…3D is a tool that we use to answer the smaller scale geologic considerations in a basin.”
Our early work to justify 3D seismic data unintentionally cemented a strong bias against 2D seismic. According to Lee, we have ourselves to blame. “A lot of times we would invest great effort trying to study or demonstrate how the 3D worked better than the 2D. We hammered this home everywhere we could because we really wanted to be able to shoot that 3D. It wasn’t a foregone conclusion at the time. But the very nature of undertaking this effort, this evolution, probably developed a huge bias towards 3D seismic and against 2D. It was an inevitable result of going through that process.”
Today, this affects geoscientists who are transitioning into the CCS industry, where 2D is a necessity. New geophysicists tend to be inexperienced with 2D – something we’ll expand on in future articles.
Technological development, economics, and geological needs pushed geophysicists toward 3D seismic. But old technology is becoming new again. In our next article, we explore what drove the resurgence of 2D seismic, and why it is playing such a big role in CCS project development. Stay tuned!
Eric Street, P.Geo. serves as Director, Geosciences at Carbon Alpha.
He holds a Bachelor of Science in Earth Sciences from Simon Fraser University. His career has included exploration and development roles in the upstream energy industry for both domestic and international projects. Eric’s international experience in multiple basins worldwide has been of particular value in CCS projects, specifically his expertise with 2D seismic, play-based exploration and common risk segment mapping, and the use of GIS and public data systems.
In his role, Eric is responsible for ensuring a rigorous, risk-based, methodical geoscience workflow is applied to all Carbon Alpha projects. His work helps build stakeholder confidence in subsurface storage attributes to enable project advancement safely and on schedule.
Lee Hunt is a professional geophysicist with 3 decades of experience working virtually every play in the WCSB and many other basins. He has drilled over 400 horizontal and vertical wells, using 2D and 3D seismic, and has experience with the oldest, most primitive techniques as well as the newest, most advanced ones. And he has catalogued the value of these experiences in some 50 conference presentations and journal publications. Lee was appointed as the 2012 CSEG Distinguished Lecturer, a national lecture tour where he spoke about AVO analysis, fracture and hazard detection and the economic value of processing and interpretive techniques. In 2020, he was chosen as the 2020 CSEG Symposium Honoree, the ninth such honoree in the history of the society. Lee and his co-authors won Excellence of Oral Presentation for the 1997 SEPM Convention, the 2000 CSEG Convention Best Paper Award, the 2008 CSEG Convention Best Geophysical Abstract, the 2008 CSEG Best Technical Luncheon Talk, the 2010 CSEG Convention Best Geophysical Oral Presentation, the Best Exploration Paper at VII INGPET in 2011, Honorable Mention for Best Paper in The Leading Edge in 2011, and Best Paper in the CSEG Recorder in 2011. He was a participant in the creation of the CSEG MLA, APEGA’s Q.I. Practice Standard, as well as APEGA’s Guideline for the Ethical Use of Geophysical Data. He was also one of the principal designers of the first CSEG Value of Geophysics with Case Histories course.
Lee currently works as Principal, Geophysics for Carbon Alpha, a Carbon Capture and Sequestration company. On the personal side, Lee Hunt is an Ironman Triathlete, an enthusiastic sport rock climber and an author. His published works of fiction include the novels Dynamicist, Herald, Knight in Retrograde, Last Worst Hopes, and Bed of Rose and Thorns. Lee is also a contributing journalist for Big-Media.ca when time allows.
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