Nav: Home

Solving the salt problem for seismic imaging

July 22, 2019

The efficient extraction of oil and gas from within the Earth's crust requires accurate images of subsurface rock structures. Some materials are hard to capture, so KAUST researchers have developed a computational method for modeling large accumulations of subsurface salt, a challenging material to derive accurately from seismic imaging data.

Seismic imaging involves sending soundwaves into the ground, where they will be reflected at boundaries between rock structures. Scientists analyze the reflected soundwaves to determine subsurface rock types and formations, and to pinpoint fossil fuel reservoirs.

However, in some regions, such as the Gulf of Mexico, the subsurface is peppered with salt bodies, which are huge accumulations of salt formed millions of years ago deep inside the Earth. Salt is a low-density, buoyant substance, meaning that salt bodies gradually rise through the Earth's crust over time. This causes stress-related complexities between the salt and the surrounding rock layers. Furthermore, the salt's crystal structure means that soundwaves are reflected at random, and there are no useable low frequencies retained in the seismic data.

"Data from salt zones are presently analyzed by highly trained experts rather than modeled by a computer," explains Mahesh Kalita, a KAUST Ph.D. student in Tariq Alkhalifah's group. "This is a time-consuming and expensive process that carries the risk of human error. We've developed a robust computational method for interpreting seismic data from salt bodies quickly and more accurately."

Existing models use a technique called full waveform inversion (FWI) to minimize the disparity between observed and modeled data. However, the lack of low frequencies in soundwave data from salt bodies means that a traditional FWI fails. Kalita and the team developed a two-part optimization process to refine FWI for salt body imaging.

"For the topmost layer of salt, we get a good enough signal to determine where the salt body begins, but then the soundwave energy rapidly disperses," says Kalita. "Our technique takes the initial data from this top layer and 'smears' it across the most likely area that the salt body encompasses. We call this technique 'flooding'."

The resulting model is then tested alongside observed data to check that the surrounding rock structures match up and to ensure the model has not been "over-flooded." Initial trials using a 1990s dataset from the Gulf of Mexico showed promise, with the new technique generating an accurate representation of local salt bodies.

"We will next trial our automated technique on recent, high-quality datasets that incorporate more three-dimensional details," says Kalita.

King Abdullah University of Science & Technology (KAUST)

Related Salt Articles:

Salt helps proteins move on down the road
Rice chemists match models and experiments to see how salt modifies surface interactions in chromatography used to separate valuable drug proteins.
Mars once had salt lakes similar to Earth
Mars once had salt lakes that are similar to those on Earth and has gone through wet and dry periods, according to an international team of scientists that includes a Texas A&M University College of Geosciences researcher.
Marathoners, take your marks...and fluid and salt!
Legend states that after the Greek army defeated the invading Persian forces near the city of Marathon in 490 B.C.E., the courier Pheidippides ran to Athens to report the victory and then immediately dropped dead.
Water solutions without a grain of salt
Monash University researchers have developed technology that can deliver clean water to thousands of communities worldwide.
Solving the salt problem for seismic imaging
Automated imaging of underground salt bodies from seismic data could help streamline oil and gas exploration.
Higher salt intake can cause gastrointestinal bloating
A study led by researchers at the Johns Hopkins Bloomberg School of Public Health found that individuals reported more gastrointestinal bloating when they ate a diet high in salt.
Table salt compound spotted on Europa
New insight on Europa's geochemistry was hiding in the visible spectrum.
New findings on the effect of Epsom salt -- Epsom salt receptor identified
A team of scientists headed by Maik Behrens from the Leibniz-Institute for Food Systems Biology at the Technical University of Munich has identified the receptor responsible for the bitter taste of various salts.
High-tech material in a salt crust
MAX phases unite the positive properties of ceramics and metals.
The salt-craving neurons
Pass the potato chips, please! New research discovers neural circuits that regulate craving and satiation for salty tastes.
More Salt News and Salt Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at