Repurposing legacy 2D seismic data for Carbon Capture and Storage (CCS) projects comes with its own set of challenges and complexities. In this last article in our Seismic & Carbon Storage series, we explore the challenge of repurposing data that were originally shot for different objectives. This article is based on a fireside chat with Lee Hunt and Eric Street of Carbon Alpha.
Catch up on the series
When we ask Lee and Eric to give us some insight into working with legacy 2D data, both start to laugh. “Often it isn’t very good… it’s bad,” says Lee.
Sometimes the 2D surveys haven’t been reprocessed. They may have insufficient offsets. Often they target reservoirs used for oil and gas exploration and development that are much shallower than the ideal carbon storage reservoir. “Also, and this is just kind of funny,” recalls Lee, “sometimes you run into some really old and esoteric sources. Somebody’s weird rubber band gun was up in the field and you’re trying to decide if there was enough energy in this rubber band.”
Lee adds, “Sometimes we buy data, and very rarely, there’s corruption in the field records… the old tape media actually degraded over time. Most of that has been recopied onto digital media, however, sometimes that didn’t work out”.
Furthermore, vibroseis data may have short sweeps. Or processing may have included notch filters at 60 Hz to eliminate powerline noise.
“This is very problematic,” says Lee, “Old data can have a lot of problems like this, and some of them we can address to a certain degree, completely, or not at all.”
When it comes to dealing with 2D for CCS applications, Lee has some helpful advice. “You definitely want a geophysicist working on it or someone with a lot of experience on that side of the geosciences. It’s very important in making your plans and managing your project that these things are understood and that issues are discussed. And that the interpretive goals of this data are realistic to the quality of the data.”
To mitigate these issues, Carbon Alpha has all legacy data that they license reprocessed to minimize data issues. “We have found that the value in the data is usually there, but sometimes takes a lot of work to dig it out,” says Lee. “We have been keeping track of the statistics of the data that we bought and whether the lines have proven useful to the task. And so far, about 99% of the lines that we bought, even the ones that have at first blush appeared incomprehensibly bad, have actually been useful for our mapping.”
Eric explains that a dose of realism is needed when working with 2D. Geoscientists coming from onshore exploration in North America tend to be biased toward 3D data. Expectations for both datatypes should be different in terms of the questions that each can answer. “We’re really focusing on the suitability criteria for carbon storage complexes,” he adds, alluding to structural complexity and breaches to the seal. “We have to be very realistic with what we hope to achieve from the 2D data that we have.”
Repurposing legacy 2D seismic data for CCS projects is indeed challenging. Quality issues, technical limitations, and the need for realistic goals are things we are learning to work through. However, with meticulous data management, reprocessing efforts, and a clear focus on project-specific objectives, legacy 2D data can continue to play a valuable role in advancing CCS goals.
Are you ready to take on the challenges of 2D seismic data? SeisWare has the tools to help! Connect with us to learn more.
In this first article with Carbon Alpha, we discuss why 2D seismic went away, why it’s back, and why it is indispensable for carbon capture and storage (CCS).
Will 2D be around forever? In part 4 of our series, we explore this question by examining the stages of a CCS project and seismic budgets.
Bias and uncertainty have affected our decision-making and 2D skills. What will it take to bridge the gap in today’s carbon storage workforce?