Working on a high-risk subsurface project without clear visibility can put you in a critical situation. It is not just a technical challenge but a decision-making risk. Tomography provides insight into how seismic waves propagate through the subsurface, revealing changes in rock properties.
When drilling, mining, or constructing, continuous seismic monitoring is essential for accurate geophysical analysis of the subsurface. The biggest uncertainties are not on the surface but beneath it. Relying solely on surface or indirect physical signs may not provide a complete picture of subsurface conditions.

If subsurface decisions are based only on surface observations, critical underground conditions can easily be overlooked; hidden conditions underground like water pockets, weak zones, fractures, and more can lead to costly delays, poor decisions, and even increased safety risks.

At Sintela, our borehole seismic tomography can save you from making costly mistakes that could hinder your work. We reduce uncertainty by delivering high-accuracy, high-resolution subsurface imaging.

Turning Fiber Cable Into a Continuous Sensor For Borehole Seismic Tomography

Classical borehole measurements are based on discrete sensors, which are installed at intervals. Anyone who has worked with such systems understands their limitations; what comes between such points is frequently only guessed at, not quantified. This is where fiber optic sensing, powered by advanced DAS technology, comes to the rescue of this approach with essential changes.

The fiber itself is the sensing element instead of the medium of communication. The whole fiber acts as a series of receivers with Distributed Acoustic Sensing (DAS). Each meter of the cable acts as a sensing point, recording strain responses associated with seismic wave propagation in the surrounding formation.

Operationally, this significantly reduces one of the largest issues of subsurface imaging data gaps. Instead of the small points being processed, you have dense and continuous measurements. This not only enhances coverage but also provides assurance in interpretation, particularly in complex geologic contexts, and a minor change can lead to major consequences.

The DAS Benefit: What Does it Help With?

If you have used traditional geophone systems, you might be aware of the advantages and limitations as well. The following factors can impact the quality and practicality of data acquisition:

Limited receiver spacing
Deployment complexity
High costs of repeat surveys

This is where Distributed Acoustic Sensing (DAS) comes into play:

DAS addresses many of these challenges in a way that directly enhances borehole seismic tomography results
Sensing is no longer limited to discrete points but becomes a continuous process, enabling higher spatial resolution
The data density increases significantly without the need to deploy extra hardware. It results in less uncertainty because of improved wavefield sampling. However, it is the interpretation that makes the actual gain visible.
DAS not only records seismic waves, but it also records the behavior of the seismic waves over the whole wellbore. This allows more effective monitoring of wave propagation and analysis of travel times, providing more stable inversion results.
This results in better‑constrained models and decisions grounded in more representative subsurface data

What Insights You Actually Get From Borehole Seismic Tomography

Borehole seismic tomography is a technique to map how seismic energy propagates beneath the surface. Borehole seismic tomography tells you about the propagation and the material in which it propagates.

As a result, you will get:

2D/3D subsurface images
Color maps :

High‑velocity areas often indicate more competent, dense rock
Lower‑velocity zones can be associated with fractures, fluids, or weaker formations

Fractures, voids, or fluid presence are commonly indicated by lower-velocity areas. With visualization, interpretation is the real value. These understandings aid in the identification of the following:

Stability or flow fracture networks
Structural threatening cavities or voids
Areas where water cavities are found can affect the excavation or drilling

Real-World Applications of Borehole Seismic Tomography

Borehole seismic tomography does not belong to a single industry: it is used everywhere where the uncertainty in the area of performance or safety is in the ground. The value does not change; it is only the context.

Mining

Ground conditions in underground mining may change rapidly. Tomography is used to locate fractured areas and weak rock prior to drilling, which ensures that the planning of tunnels is safer and the chances of collapse are minimized.

Oil & Gas

To characterize the reservoir, it is important to know about the heterogeneity. Tomographic imaging enhances visualization of the formation variations, fluid positions, and location of the fractures, which helps in enhancing drilling and completion choices.

Infrastructure and Civil Engineering

Tunnelling and foundation work when voids or fault zones are not detected, they can cause serious problems. The high-resolution imaging enables mapping these risks beforehand to have a more stable design and construction.

GE Environmental and Groundwater

Tomography assists in mapping aquifers and determining flow paths. It is especially helpful for understanding water movement and environmental impact management.

Energy (Geothermal & CCS)

Geothermal as well as carbon storage projects require monitoring of the changes in the subsurface over time. Tomography offers an understanding of the way the reservoir changes in operation.

ONYX™Advantage: What Sets Our Solution Apart

The Sintela ONYX™ system is designed to convert existing fibre-optic cables into a dense array of vibro-acoustic sensors that detect naturally occurring acoustic and seismic signals.

Sintela offers the next-generation fibre sensing solution called ONYX™, which is customizable, simple, and cost-effective. Here’s our range to explore:

ONYX™ Nano

Best suited for: Localized monitoring, boreholes, pilot projects, and cost‑sensitive deployments
Ideal for short-range sensing solutions up to 20 km.
With an integrated processor
19-inch 1U enclosure
40W power consumption, making it energy-efficient
Supports 1 or 2 fibers, with optional redundancy and cut‑resilience configurations
High sensitivity and low noise floor, enabling detection of subtle vibro‑acoustic signals relevant to geotechnical and seismic applications

ONYX™ Peta

Best suited for: Large‑scale mining, infrastructure, energy, and multi‑borehole or extended area monitoring
Ideal of a standard range to 130 km (both the fibres)
Quantitative DAS with integrated processor
19-inch 3U enclosure
110W power consumption
Sub‑meter spatial resolution with industry‑leading sensitivity and dynamic range
Flat noise floor performance maintained over tens of kilometers, supporting stable and repeatable measurements
L‑band sensing option, allowing operation on active or shared telecom fibers without service interruption

Can monitor on 1 or 2 fibers depending on deployment configuration ONYX™ Peta EX

Best suited for: Regional‑scale monitoring, deep mines, long linear assets, and shared telecom infrastructure
Ultra‑long‑range quantitative DAS platform with monitoring distances of up to 200 km on a single fiber
Maintains high sensitivity and dynamic range over extended distances, enabling monitoring where repeaterless operation is required
Quantitative DAS with integrated processor
19-inch 3U enclosure
110W power consumption
L‑band capability supports sensing on live telecommunications networks

Why Sintela is a Trusted Partner for Advanced Subsurface Monitoring

When working underground, the value of the tools is almost determined by the consistency of the data they generate. The veterans do not merely seek new technology but seek systems that will fit best in their work processes and produce results without unnecessary complexity.

Here’s why Sintela is a trusted choice:

They use existing fiber network
Covers huge distances
Real-time monitoring
AI‑assisted processing to support event detection and reduce false alerts
Improves safety and efficiency

Ready to Make Confident Subsurface Decisions?

There will always be a certain degree of subsurface uncertainty, but the amount of uncertainty you have to deal with is manageable. Fiber optic sensing, when used together with borehole seismic tomography, allows a better and more accurate idea of what is further beneath. In applications where precise results are required, this transparency may deliver a quantifiable difference in results.

When considering how to enhance subsurface visibility, minimize risk, and advance your data-driven decisions, it can be worthwhile to think about DAS-enabled tomography from Sintela to fit into your workflow. Contact us today to discuss your requirements and get customized solutions.