When the well goes quiet,
the reservoir speaks

Every operational shut-in is a pressure transient event you’ve already paid for. Andromeda runs automated time-lapse PTA on these transient responses inside your production engineering environment, using the inputs you already trust. The PTA results from these opportunistic shut-ins update your IPRs and feed them directly into your production optimisation workflows within that same ecosystem. The volumes are deferred, the insight is not.

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TIME-LAPSE PTA

Every shut-in becomes a data point

Over the past two decades, continuous pressure measurements from permanent downhole gauges, ESP intake sensors and wellhead instrumentation have enabled PTA to expand from specialist reservoir studies on exploration and appraisal wells into routine reservoir surveillance across development wells.

As operational shut-ins recur on wells across a field, the events accumulate faster than engineers can analyse them.

Andromeda automatically turns successive events from each well into structured PTA analyses, giving engineers a moving picture of how the well and reservoir are changing over time.

Higher PTA utilisation

Analyse more operational shut-ins, making fuller use of the pressure data already recorded.

Reservoir pressure

Monitor volume-averaged reservoir pressure as new PTA results become available.

Skin and mobility

Track skin and near-wellbore mobility to see how conditions around the well are changing.

Mobility fronts

Follow the distance to a mobility front through time, whether it is a flood front, an advancing aquifer or a bank forming near the wellbore.

FIELD CASE · WINTERSHALL NOORDZEE

The well that should have stopped

A late-life gas well with a permanent downhole gauge and a flowmeter. PTA identified halite deposition at the perforations as the cause of impairment.

Direct PI historian connection: pressures and gas rates are streamed live into Andromeda, allowing frequent water-wash events to be monitored as part of routine halite surveillance and water-wash optimisation.

A daily fresh water wash programme followed. Repeated skin estimates helped optimise wash frequency, fresh water volume, soak and gargle time and choke strategy.

Every wash costs production. The automated workflow follows each build-up and identifies when wellbore storage has cleared sufficiently for a reliable skin estimate, so the wash can begin at the earliest technically justified point. That is optimisation at the margins.

Across cycles, the skin trend shows how quickly the impairment returns after each wash.

In effect, a live offshore laboratory. Each production and wash cycle tests the operating strategy, and the analysis is used to adjust the next cycle.

produce

→

↓

halite deposits

→

↓

shut in

→

↓

PTA skin estimate

→

↓

fresh water wash

→

↓

soak and gargle

→

↓

return to production

With Andromeda, this becomes a repeatable, automated workflow, making better use of limited engineering hours and allowing engineers to focus on operating decisions and execution.

PTA DIAGNOSED THE CAUSE

≈0 million Sm³≈100 million Sm³

≈0 million Sm³≈100 million Sm³

≈0 million Sm³≈100 million Sm³

of incremental gas to date

Without the wash programme the well would have ceased production in July 2025

PTA OPTIMISES THE CYCLE

≈0 minutes≈60 minutes

≈0 minutes≈60 minutes

≈0 minutes≈60 minutes

from each daily shutdown

Recovered by starting each wash sooner

ANDROMEDA AUTOMATES PTA

≈0 hours≈25 hours

≈0 hours≈25 hours

≈0 hours≈25 hours

of engineering time per well, per month

25 build-ups, each about an hour for an engineer by hand

More on PTA for reservoir surveillance and production optimisation · July 2026

Nassim Gassabi post on LinkedIn, 13 July 2026: PTA is often treated as a specialist reservoir engineering methodology. Yet much of its practical value lies in production engineering. When well deliverability declines, the challenge is identifying what is driving it. Depletion, changing total mobility and skin may all contribute, and PTA helps distinguish between those effects.

READ ON LINKEDIN

INTEGRATION · TIME-LAPSE PTA AND RTA

Integrated where it’s used

Operators have invested heavily in digitalisation, and data, models, workflows, surveillance and optimisation are increasingly managed within connected systems. Yet the automation of PTA and RTA has grown up alongside that environment, not within it, despite drawing on inputs that already exist there and returning results that feed straight back into surveillance and optimisation. Running alongside has a cost, and the opportunities created by continuous pressure measurement, especially around opportunistic shut-ins, go to waste.

Trusted inputs from the production engineering environment

Bottomhole pressures are acquired from permanent downhole gauges or inferred from ESP intake pressures, and surface measurements can serve where the flow is single-phase. Oil rates, by contrast, depend on workflows for rate allocation, virtual metering, MPFM calibration and well test validation. These workflows already run in the production engineering environment, where PVT and well models are also maintained. Integration lets PTA and RTA reuse the inputs engineers already cross-check for reservoir surveillance and production optimisation.

Assembling those inputs separately, outside the main system, creates greater scope for inconsistency, uncertainty and loss of engineering context.

Results feed the workflows that guide decisions

Volume-average reservoir pressure, drainage area, skin, mobility, the distance to a mobility front and related PTA and RTA outputs are not end points. Because Andromeda operates within the production engineering environment, they feed directly into reservoir surveillance and production optimisation.

Engineers use those results to assess well performance, adjust operating strategy and identify intervention, workover and drilling opportunities. The decisions that follow are evaluated and put into practice in that same environment.

A second ecosystem is a second burden

The production engineering environment already acquires, stores, processes and derives a well’s dynamic data: downhole and surface pressures, temperatures, rates, and the choke and valve positions that explain them. Where a second system holds its own copy of the pressure data, it rebuilds part of that and has to keep the copy in step with the source.

Whether bought or built in house, the second system carries its own storage, maintenance and IT overhead, and rates, PVT and other inputs still have to be brought across from the production engineering environment. Andromeda works directly with the pressure data and these inputs inside the environment that already holds and governs them.

Integration is not only an architectural improvement. It is how proven methods that are too often underused become routine.

FIELD CASE · PETEX DOF INTEGRATION

The intervention that wasn’t needed

A well showed declining productivity. The operational question was whether this was formation damage, which would point to an intervention, or a near-wellbore PVT effect which would point to a change in production strategy.

Time-lapse PTA was run automatically across multiple build-ups in a Petex DOF environment. The early-time pressure derivative indicated a near-wellbore gas-blocking effect in a volatile oil well.

The productivity change was therefore explained by changing near-wellbore effective permeability, not formation damage. No intervention was required; the response was choke management.

Time-lapse PTA was run automatically across multiple build-ups in a Petex DOF environment. The early-time pressure derivative indicated a near-wellbore gas-blocking effect in a volatile oil well.

The productivity change was therefore explained by changing near-wellbore effective permeability, not formation damage. No intervention was required; the response was choke management.

PTA in the DOF workflow environment

The Andromeda PTA workflow sits in the DOF environment beside the workflows that feed it - pressure handling, rate allocation, virtual metering and PVT - and the surveillance workflows its results will eventually feed. Built on an open API architecture, it runs natively inside the Petex environment.

PTA in the DOF workflow environment

Image illustrating the product’s features

Automated shut-in detection

Pressure and rate histories are processed continuously. Andromeda's machine learning shut-in detection algorithm identifies valid build-ups, which are synchronised with rates and prepared for time-lapse PTA, so opportunistic shut-ins are captured and analysed automatically.

Automated shut-in detection

Time-lapse PTA diagnosis

Multiple build-ups showed changes in the early-time derivative consistent with near-wellbore gas blocking rather than formation damage. Mechanical skin stayed low across the three analyses while the estimated effective permeability of the inner zone fell.

Time-lapse PTA diagnosis

Results returned to IVM

PTA outputs are available alongside wider production data, so the diagnosis can feed back into surveillance and operating decisions.

Results returned to IVM

PTA outputs are available alongside wider production data, so the diagnosis can feed back into surveillance and operating decisions.

PETEX IFM CLIENT

ANDROMEDA STUDIO CLIENT

PETEX IVM CLIENT

Announcement of the Petex integration · May 2026

PE Ltd (PETEX) post on LinkedIn, 22 May 2026: BIG! In the run up to the PE Ltd Digital Oil Field #DOF day 2 round up, as promised, a landmark extension to the #PETEX offering! #PETEX DOF can now communicate, end-to-end, seamlessly, and in real time with "Andromeda" #PTA Pressure Transient Analysis, brought to you by Nassim Gassabi, co-founder and Managing Director of Engineering Workflows Ltd!

READ ON LINKEDIN

ARCHITECTURE

The engine is the product

Andromeda is a PTA and RTA engine accessed through a documented REST API. The same engine can run within an existing production engineering platform, on operator-controlled infrastructure or on an engineer’s workstation.

Three kinds of client, Andromeda Studio, software built by the operator, and AI agents, all reach the same Andromeda PTA and RTA engine through one documented REST API. That engine can be deployed in three alternative ways: embedded in an operator's platform, on operator-controlled infrastructure, or on an engineer's workstation.

FOUNDERS

Founded by reservoir engineers

Nassim Gassabi

Managing Director

Nassim sets Andromeda’s product direction and defines its engineering specifications.

Zohrab Dastkhan

Technical Director

Zohrab designs Andromeda’s architecture and develops its analysis engine.

SERVICES · PTA AND RTA

Training, consulting and integration

Training and workshops

PTA and RTA from the fundamentals of fluid flow, with hands-on exercises in Andromeda. Engineers learn to interpret the dynamic response in its geological and operational context, then apply the findings to reservoir characterisation and well performance assessment.

Consulting

Expert consulting services in PTA and RTA cover the interpretation of DSTs on exploration and appraisal wells, and time-lapse PTA on development wells using continuous pressure measurements, including PDG and ESP intake pressures. These studies help engineers diagnose changes in well performance and assess intervention opportunities. They support reservoir characterisation, field development projects and production optimisation.

Workflow development and integration

We develop tailored engineering workflows and software solutions, and integrate Andromeda’s engine with other engineering systems through its documented REST API. Engineers can then use the analysis within their existing engineering environment. The Petex DOF case shows this in practice, with analysis results returned to the operator’s surveillance tool.

Discuss training, consulting and integration requirements.

GET IN TOUCH

When the well goes quiet,the reservoir speaks

When the well goes quiet,the reservoir speaks

When the well goes quiet,the reservoir speaks

Every shut-in becomes a data point

Every shut-in becomes a data point

Higher PTA utilisation

Reservoir pressure

Skin and mobility

Mobility fronts

The well that should have stopped

The well that should have stopped

Integrated where it’s used

Integrated where it’s used

Trusted inputs from the production engineering environment

Results feed the workflows that guide decisions

A second ecosystem is a second burden

The intervention that wasn’t needed

The intervention that wasn’t needed

PTA in the DOF workflow environment

PTA in the DOF workflow environment

Automated shut-in detection

Automated shut-in detection

Automated shut-in detection

Time-lapse PTA diagnosis

Time-lapse PTA diagnosis

Results returned to IVM

Results returned to IVM

The engine is the product

The engine is the product

Founded by reservoir engineers

Nassim Gassabi

Zohrab Dastkhan

Training, consulting and integration

Training and workshops

Consulting

Workflow development and integration

When the well goes quiet,
the reservoir speaks

When the well goes quiet,
the reservoir speaks

When the well goes quiet,
the reservoir speaks