Norwegian energy firm Equinor is to deploy cabled subsea instrumentation from Sonardyne International Ltd. to help increase the accuracy of time-lapse seismic data at the giant Johan Sverdrup oil field.

From first production at the development, Equinor plans to use seafloor based seismic cable permanent reservoir monitoring (PRM) technology to observe what is happening in the reservoir over time to help maximise recovery rates.

While PRM technologies increase the amount and quality of data that operators have about their reservoirs, processing it can sometimes be complicated by changing environmental conditions, such as water velocity and tidal height, at the time each survey is conducted. If those conditions are known, their impact can be readily removed.

To solve this challenge, Equinor has engaged subsea services contractor Subsea 7 to install a Sonardyne Pressure Inverted Echo Sounder (PIES) at 110 – 120 metre water depth at Johan Sverdrup. PIES instruments continuously measure the two-way travel time of sound waves propagated through the water column from the seabed to the sea surface as well as the pressure (depth) at the seabed. This data is then used to calculate a continuous time history of average water velocity and tidal variation throughout the whole water column.

While PIES instruments are already very widely used in marine seismic survey operations, this will be only the second time where PIES units are hardwired into topside power and communication infrastructure, which means Equinor will have instant and continuous access to their data. Conventionally, PIES data is collected acoustically by a passing surface vessel, including unmanned surface vessels.

[blockquote author=” Shaun Dunn, Global Business Manager for Exploration and Surveillance at Sonardyne”]”Time-lapse seismic is a key tool to help operators optimise their recovery rates through improved reservoir visualisation, modelling and eventually also predictive analytics. By using a PIES, Equinor will have higher repeatability in their seismic data which further supports proactive reservoir management.”[/blockquote]

Joint trials by Norwegian research institute SINTEF Ocean and marine resource technology company Sonardyne International Ltd. have proven the ability for an acoustic positioning system to track underwater robots as they move through industrial-scale fish pens.

Being able to accurately track remotely operated vehicles (ROVs) in aquaculture operations, including cage and mooring inspection and removing perished fish, will help operators to increase efficiency and productivity and reduce the need for divers.

Until now, there has been a misperception that acoustic tracking systems do not work in fish farm applications, due to the volume and density of fish within the pens or cages. Fish have an air-filled swim bladder that helps them regulate their buoyancy and this organ can interfere with the transmission and reception of acoustic signals from the surface to an ROV. In a farm with up to 200,000 fish in any one cage, it has been thought that this could pose significant challenges for some acoustic based systems.

In the trials, at the Korsneset SINTEF ACE site near Trondheim, Norway, a Micro-Ranger 2 Ultra-Short BaseLine (USBL) positioning system was used to track an Argus Mini ROV through a pen containing an estimated 150,000-200,000 salmon. Micro-Ranger 2 is Sonardyne’s latest USBL positioning system, designed for users with no previous experience of USBL equipment. It features a small acoustic transceiver deployed from a vessel or pontoon and an acoustic transponder attached to the ROV. Micro-Ranger 2 uses Sonardyne’s Wideband 2 acoustic signals combined with highly sensitive receivers, which can detect the unique acoustic signals, even in challenging acoustic environments.

[blockquote author=”Elizabeth Paull, Business Development Manager at Sonardyne”]“The demonstration, with SINTEF, showed that our systems function to their usual high standards in low to medium fish densities, both inside and outside of the cage, with the ROV being tracked consistently and accurately. When tracking the ROV through the highest density of fish, the frequency of position updates did decrease, but, the positioning of the ROV was still accurate when acoustic paths were available. And, by moving the ROV away from the net, the frequency of updates could be improved.”[/blockquote]

“These positive results mean that those in the aquaculture industry can now use Micro-Ranger 2 for ROV tracking, knowing that the system will track even with high densities of fish,” adds Paull. “This means that items of interest, such as holes or tears in the net, can be located and then relocated quickly and easily, reducing the time needed to make repairs.”

Shell Brasil has agreed a partnership with underwater sensor technology company Sonardyne International Ltd. and Brazilian research institute Senai-Cimatec to develop innovative autonomous technology to make the monitoring of Brazil’s challenging deepwater pre-salt oil fields more efficient.

The new 4D seismic monitoring system, based on so-called On Demand Ocean Bottom Nodes, is being developed under a National Agency of Petroleum, Natural Gas and Biofuels (ANP) promoted programme.

The goal of the project, which Brazilian oil major Petrobras is also a partner in, is to increase the autonomy of ocean bottom nodes, enabling them to be deployed and remain on the seafloor for up to five years, ready to record the seismic and geodetic data on demand. During that period, no interventions, such as connections for data extraction or replacement of batteries, would be required. The nodes would communicate wirelessly with autonomous underwater vehicles (AUV), such as the Shell-funded FlatFish AUV. These capabilities will help to generate operational efficiencies and eliminate the various existing difficulties in deploying current 4D seismic monitoring technology, which is vital to the development and production optimization of oil and gas fields. The new technology will also allow the reduction of both costs and operational safety risks.

[blockquote author=” Jorge Lopez, Shell Research and Development Advisor in Brazil”]”This is a very promising project, fully aligned with the new reality of the oil and gas industry, which seeks to use new technologies to ensure a safer, more efficient operation that has less impact on the environment. For Shell, Brazil is an important centre for attracting partners and technological development, and we are sure that the partnership with Sonardyne and Senai will be very successful.”[/blockquote]

Shaun Dunn, Global Business Manager, Exploration and Surveillance, Sonardyne, says, “We are delighted to be working with Shell Brasil and Senai Cimatec to create this exciting new technology for offshore reservoir surveillance. The project will use our significant expertise in the design of long-endurance battery-powered subsea instrumentation, as well as our wireless through-water acoustic and optical communications technologies. Leveraging these will help to create a unique capability that will greatly enhance the cost effectiveness of on-demand seismic surveys and continuous seafloor deformation monitoring offshore Brazil.”

The project is divided into three main phases: development, including design and initial testing of the new node, including communication with the underwater vehicle; manufacturing of a pilot scale system; and deployment of the pilot system for three years in a pre-salt field.

Petrobras will provide technical advice, aid selection of a pre-salt field for a pilot deployment and support integration of the seismic data into the field’s reservoir management programme.