Epilogue: The innovative answer to an unimaginable task

SLB operator at a worksite with PPE equipment on

Epilogue

The innovative answer to an unimaginable task.

This is a story of curiosity. The kind of curiosity that empowers you to take a big risk for an even bigger reward. And we’re not talking about just one person—we're talking about many. Many engineers worldwide that came together to do what was previously deemed impossible: check the safety barriers in old oil and gas wells without the risk and cost of taking them apart.

When you consider the millions of wells worldwide that should be checked to ensure they’re in good working order, you can quickly appreciate the challenge…and the incredible commercial opportunity.

At SLB, we live for those.

"This may seem like an energy tech story—which, in part, it is—but as you read on, you’ll see that this is more a story about people. Behind the tech are brave humans who went against the odds to craft something that continues to make a difference for both their industry and their planet."

Kamaljeet Singh, Downhole Surveillance Technical Director

Oftentimes, it takes a global effort to build something truly revolutionary.

Here’s an unexpected question:

How much do you know about telescopes?

The wells we build look very similar, thanks to what we call casing strings. These are steel pipes of decreasing size placed in a well during drilling for additional support and to protect the earth around it. And with average wellbore lengths of 7,000 feet (more than 2 kilometers!), you can imagine how difficult it is to assess the state of those casing strings over time—not to mention the high pressures, corrosive fluids, and heat found deep underground.

It’s even more difficult to assess the well’s safety when there are multiple layers of casing strings around the tubing. We had successfully seen through one layer for decades using sound waves, returning clearer and clearer imagery of the barriers (both metal and cement) around the tubing. But seeing through two layers of steel pipe? They said it couldn’t be done.

Using sound waves to pass through and “paint” the picture of a second, more internal layer of casing is infinitely more complex. People thought it was impossible, so they always pulled the tubing out of the well to look at the remaining single layer directly. Not only does that take time and money—along with being a risk to the environment and safety—but it also produces more carbon emissions. And that’s what got us.

“The first step in any plug and abandon operation is to cut and pull the tubing, and for that, you need a rig. The rig is the highest cost and highest carbon contributor of any offshore operation. So, what we looked at is, how can we eliminate the rig from the equation?”

Omar Mansour , Global Product Manager for Reservoir Performance Intervention

SLB

The objective

Enabling operators to intervene without a rig.

How could we determine the integrity of multiple well barriers without retrieving any tubing? It’s with a difficult question like this that innovation begins.

A combination of physics, sensors, and modeling experts from around the world were brought together to tackle the challenge. Digital, AI, and machine learning (ML) experience were then layered on top of that because, hello, data.

Group of people stood around a screen in a lab

Research program manager, Sandip Bose, presenting the energy tech he helped develop to internal stakeholders, standing next to his experimental setup and above the world-class pool (512 cubic meters!) in which the experiments took place—all in our research center in Boston

The approach

Fair warning, this is the techy bit.

Penetrating through two casing strings was a daunting task because it required going to low sonic frequencies, which even academically-speaking is quite impressive. But we started putting the pieces together, taking inspiration from years of acoustics domain knowledge, and it wasn’t long before we had a solution to field test.

Our team intelligently combined sonic and ultrasonic tech into a novel product, Epilogue™ dual-string barrier evaluation, that could accurately facilitate the probing required. Ultrasonic was used for shallow probing of the 1st casing, followed by sonic imaging for deeper probing of the 2nd casing. The latter was mapped with the assistance of machine learning of the sonic behavior, while additional algorithms were engineered and validated by experiments done at scale and subsequent modeling.

The result

Safe and secure plug and abandonment.

Epilogue (now a multi-award-winning wellbore insight platform) was launched to the industry in 2021, after numerous tests done on real wells thanks to our client partner, Equinor. And its algorithmic tech has been making sense of ultrasound signals from across more than 165 jobs since then.

20
patents

11
journals

165+
jobs

Ultimately, it’s about plugging and abandoning wells with the knowledge that they’re safe and efficient for both the operator and the planet. That’s the beauty of Epilogue—great for them, great for us, great for everyone.