and Subsea

Case Studies Back to All Capabilities
Pipelines <br />
and Subsea

Integrated pipeline services

Our project managers work closely with you during pre-commissioning, commissioning, operations and decommissioning, to deliver tailored, integrated solutions that improve efficiency and reduce costs. Our broad suite of services reduce on-site personnel reducing interfaces and enhancing safety management

Our capabilities include:

  • Subsea flooding and testing using remote technologies and custom downlines
  • Pipeline cleaning using chemical, gel or mechanical methods
  • Conventional flooding and gauging
  • Pressure testing using water, air or nitrogen
  • Dewatering using liquid and membrane nitrogen or air
  • Drying using swabbing, super dry air, nitrogen or vacuum techniques
  • Purging and packing with nitrogen prior to commissioning, capping or abandonment
  • Pipeline decommissioning

Pipeline pre-commissioning and commissioning

A complete suite of pipeline pre-commissioning and commissioning services is delivered under a single project management team to ensure safe and timely delivery of your pipeline construction project. Empowered teams work with bleeding-edge pre-commissioning equipment and technologies to deliver onshore and offshore projects with large and small diameter pipelines. Our services include:

  • landfall civil work and preparation
  • water winning
  • pipeline flooding
  • pipeline gauging
  • pipeline cleaning
  • geometry and caliper survey
  • hydrostatic testing
  • pneumatic testing
  • leak testing
  • dewatering
  • air drying
  • air cleaning and drying
  • nitrogen drying
  • chemical conditioning
  • vacuum drying
  • baseline ILI survey
  • nitrogen packing
  • subsea leak detection
  • turn-key pre-commissioning vessel support

Late life pipeline support and decommissioning

Project managers and skilled personnel work alongside you to maximise the life of your assets, manage assets during late life and prepare your infrastructure for cessation of production. A full range of services during late life or decommissioning includes:

  • Subsea pumping of hydrate inhibitors and production chemicals
  • Pipeline cleaning using chemical, gel or mechanical methods
  • Providing custom pumping / nitrogen solutions to propel ILI tools in low-flow / low pressure situations
  • Revalidation testing using water, air or nitrogen
  • Providing cryogenic or membrane nitrogen to purge the pipeline prior to repair, modification or abandonment
  • Pipeline decommissioning

During the decommissioning phase we can flush and clean your pipelines for in-situ abandonment or removal.

Pipeline maintenance

The efficient operation of pipelines is crucial to your asset and maintaining a clean pipeline helps to maximise flow rates, increases the longevity of the asset, improves reliability and safety and reduces risk. Experienced pipelines teams ensure your pipelines continue to operate at maximum efficiency with minimal downtime using specialist cleaning methods to remove debris with minimal cost and disruption. A wide range of maintenance solutions designed to address common problems includes:

  • Subsea pumping of hydrate inhibitors and production chemicals
  • Pipeline cleaning using chemical, gel or mechanical methods
  • Providing custom pumping / nitrogen solutions to propel ILI tools in low-flow / low pressure situations
  • Revalidation testing using water, air or nitrogen
  • Providing cryogenic or membrane nitrogen to purge the pipeline prior to repair, modification or abandonment
  • Pipeline decommissioning
  • Pipeline turnkey ILI inspection solutions, via our partners
  • Pig tracking

Pressure testing

A critical component of any pipeline pre-commissioning and revalidation operation is the pressure test. This often involves compliance with codes such as DNV OS-F101, or accreditation by local bodies such as NATA.


EnerMech provides a comprehensive pressure testing solution including all necessary equipment , and competent, accredited and experienced personnel.


Whether we are testing a new pipeline prior to pre-commissioning, or an existing pipeline for revalidation, we have the solution.

Membrane nitrogen purging

EnerMech owns and operates a large global fleet of nitrogen pumping and generation equipment. Depending on LN2 availability, and other logistics, we design and deliver nitrogen purging and packing solutions for new and existing pipelines.

For subsea projects, our nitrogen spreads also include downline solutions to connect the vessel based spread, to the subsea pipeline.

Dewatering and drying

Following any hydrostatic test, EnerMech can engineer and provide tailored pipeline dewatering solutions, even overcoming the hydrostatic head in the deepest subsea developments.

Our offshore dewatering spreads offer the smallest footprint, saving you costly vessel space.

Once dewatered, our engineers can then help design and implement a suitable drying / conditioning campaign, tailored to your needs. This may involve:

  • Air drying / air cleaning and drying
  • Vacuum drying
  • Swabbing with glycol or methanol

Umbilical, hydraulic, electrical and fibre optic testing

A highly skilled, expert team and custom equipment fleet, manage the testing of your umbilical, hydraulic, electrical and fiber optic equipment during the pre-commissioning duration, including pre-and-post load out tests, pre-abandonment test, post pull-in and post hook-up tests.


A range of tests is offered to ensure systems and valves controlled by hydraulic umbilicals must use fluid cleaned to the required specification. Umbilicals with different fluid cores and pressure ratings are separated into groups and pressurized through a common manifold to ensure testing is carried out. Calibrated instrumentation and PRVs are routinely used to ensure the correct pressures are adhered to.

Electrical power cables

To help ensure the safe transmission of your crucial data from subsea operations, we carry out reliable testing on electrical power cables in all stages of pre-commissioning activities for continuity resistance (CR), insulation resistance (IR) and time domain reflectometry (TDR).

CR, IR and TDR testing

CR (conductance resistance) testing is carried out on looped quads or umbilicals to ensure there is continuity throughout the length of the conductors. IR (insulation resistance) testing is carried out on individual or looped quads, and can be bundled to save time. In addition, IR testing on a quad can be carried out against other quads or against the cable screen, and voltage used for IR testing can be discussed and tailored to specific projects.

TDR (time-domain reflectometry) testing is used to find faults within a conductor on single or looped conductors. The test uses a high-frequency pulse which is transmitted along the conductor with a reflection signature or trace received back to the TDR test set. Faults will be highlighted on the final trace and can be compared to FAT results.

Fibre optic

Skilled engineers carry out fibre optic testing of both single mode and multi-mode variants of fibres. With demand for fibre optics increasing for several applications across the global energy market, our testing capabilities allow for continued connectivity, ensuring the best possible safety and productivity in the harshest of environments.

Optical Time Domain Reflectometers (OTDR) testing is performed to prove the fibre optic tubes can transmit required levels of light without significant loss in accordance with specifications laid down in BS-EN-50173. An OTDR injects a series of optical pulses into the fibre that is being tested. The OTDR measures the time and intensity of the light reflected and displays a final trace of the attenuation over distance.

Umbilical cleanliness management and flushing

Contamination and debris in umbilical fluids leads to failure in subsea controls and actuation systems. EnerMech can remove this risk by cleaning fluids used within umbilicals to the required specification to the following standards:

  • hydraulic fluid: SAE AS 4059 Class 6 B-F
  • chemical fluids: SAE AS 4059 Class 8 B-F

Cleaning can take place prior to mobilisation or on vessel or platform. Once cleaning is complete, fluid cleanliness certificates are supplied and samples kept for a dedicated period of time. By continuously flushing the fluids through filters, high levels of cleanliness are achieved to ensure standards are maintained throughout the duration of operations.

Wireless monitoring

Pressure and CR wireless monitoring provides efficient and accurate monitoring over manual or wired approaches. Using wireless technology, we support operators to optimise ongoing well production and acquire a better understanding of long-term performance. Dedicated teams carry out pressure monitoring by connecting pressure transducers to umbilical cores or a manifold. A wireless receiver will transfer this data to a laptop which provides a live feed of the pressures within the umbilical. Should the pressure fall below a specified value, we will stop operations to allow topping up operations to be carried out. CR Monitoring is carried out by measuring the continuity resistance of a quad (or group of quads). Conductors will be looped at the second end to allow for successful CR monitoring. A wireless receiver will transfer data to a laptop which can give a live feed of the continuity resistance within the conductors. We are then able to advise you of any spikes in the CR while lay operations are ongoing, indicating possible damage to the umbilical. If this happens, we can carry out further testing.

Using our wireless technology, you can benefit from cost-effective and efficient monitoring to umbilical cores and manifolds, especially those in challenging locations.

Empowered pipeline and subsea experts utilise innovative technologies and practices to deliver a full range of pre-commissioning, commissioning, cleaning and decommissioning solutions to your pipeline and subsea projects. Using industry knowledge and experience, they collaborate closely, listen intently and deliver innovative and cost-effective solutions reducing project risk

  • Project management and engineering
  • Conventional flooding, pigging, gauging and testing
  • Subsea remote pigging and testing and dewatering
  • Gel services and chemical applications
  • Pipeline dewatering, conditioning and drying
  • Nitrogen packing and RFSU pressure equalization
  • Umbilical pre-commissioning including testing of fiber optic and electrical systems
  • Riser annulus testing
  • Pipeline decommissioning

To find out more about our pipeline and subsea capabilities, explore our services here, or for more information about our subsea technologies click here

A sample of our project experience:

  • Kaombo, Angola
  • Egina FPSO, Nigeria
  • Persephone WP3, Australia
  • Prelude FLNG, Australia
  • Flyndre Cawdor, UK / Norway
  • Hejre, Denmark
  • Shah Deniz 2, Azerbaijan
  • Liza, Guyana
  • Appomattox, Gulf of Mexico
  • Thunderhorse, USA
  • Mad Dog, USA
  • Scheihallion Field Suspension, UK
  • Cygnus, UK
  • Kraken, UK
  • Moho Nord, Congo
  • Bahr Essalam, Libya
  • Golden Eagle, phase 1 & 2, UK
  • East & West Hub Development, Angola
  • Gannet Oil Export Replacement, UK


To find our more about EnerMech and our capabilities, please contact us

Contact Us