Meeting today’s exploration, surveying and monitoring challenges with satellite images and services
Sourced from Michael Hall, Airbus Defence & Space
Images taken from hundreds of miles above the earth’s surface, of features such as well sites, damaged pipelines or remote rock outcrops are providing oil and gas engineers and geoscientists with a unique insight throughout the lifecycle of oil and gas projects, whilst also boosting asset security. Here, Michael Hall, Airbus Defence and Space’s Senior Geologist, considers how the latest generation of satellites are delivering new capabilities and greater efficiencies to aid exploration, target development and protect assets in remote, often inhospitable locations around the world.
Satellites have a range of applications including positioning systems and telecommunications. In relation to earth observation, or remote sensing, satellite technology is being increasingly focussed on rapidly delivering up-to-date high resolution images, supported by expert processing and analysis back on earth.
Identifying prospective locations and bringing them into profitable and secure production, requires the integration of a range of data sources. Whether it is in the rainforests of central Africa, remote coastal waters offshore Western Australia or in the barren deserts of the Middle East, satellite technology allows high resolution images to be captured, processed and delivered to enhance this decision making process.
The Airbus Defence and Space satellite constellation provides a comprehensive selection of multi-source and multi-resolution satellite imagery. Leading optical (Pléiades and SPOT) and radar (TerraSAR-X and TanDEM-X) sensors offer highly flexible acquisition capacities. They are capable to cover any point on Earth at least once per day and with 24/7 availability secures near real time data processing and delivery for time-critical requests. In terms of typical imagery resolution specifications, the Pléiades sensors provide imagery product at 0.5m resolution and the TerraSAR-X and TanDEM-X radar sensors down to 0.25m, allowing detailed analysis and interpretation.
Energy and engineering companies can either obtain archive imagery for a particular location or asset, or commission satellites to obtain the freshest imagery to meet their required application. The information gathered by these satellites is then studied independently or cross-referenced with archived data - or imagery acquired by regular acquisitions - to monitor changes over time.
In order to maximise the value of satellite derived imagery, image interpretation and analysis is undertaken by experts who are able detect, identify and determine an objects relevance through an assessment of characteristics and context.
Applications of this geo-intelligence to the oil and gas related sector may include the following areas: Seismic planning. Geological interpretation and analysis. Offshore identification and classification of hydrocarbon seeps. Environmental baseline assessment. Pre-acquisition site analysis. Pipeline and infrastructure planning. Site monitoring. Nearshore bathymetry. Offshore oil spill detection. Surface movement monitoring.
Supporting remote exploration and development
Oil and gas operations are increasingly moving into remote, frontier locations seeking hydrocarbon resources in countries with complex political landscapes, ongoing security concerns and demanding environmental conditions. Due to the efficiency benefits, associated with remote assessment and largely unrestricted data access, satellite imagery and analysis can assist in overcoming many of the constraints associated with these challenges, particularly with falling oil prices.
Onshore, satellite derived data is an established source of supporting information for the oil and gas sector and is frequently used alongside 2D and 3D seismic, and other geo-science datasets to develop a rounded geological understanding of a licence block. Furthermore, satellite data is being used to obtain an accurate and up-to-date assessment of ground conditions, including terrain, geology and access prior to field activity and seismic acquisition. One key contributor to understanding terrain characteristics is using satellite imagery to generate digital elevation models, effectively 3D topographic representations of the earth’s surface, which as well as being used for exploration can be applied to engineering projects associated with facility and pipeline planning during field development.
Figure 1. SPOT 6 satellite image, Algeria. By interpretation of geomorphical, textural and spectral variations, satellite imagery can provide a rich information source to assist in assessing surface geology.
When Austria-based ILF Consulting Engineers required contemporary data to calculate the optimum route for a portion of the South Caspian pipeline, located in Georgia and Azerbaijan, Airbus Defence and Space contributed by providing a variety of satellite derived datasets along the pipeline corridor:First, SPOTMaps (seamless orthorectified mosaic derived from SPOT imagery) and Elevation30 data supported the rapid implementation of a preparatory study of the pipeline corridor.Then, Elevation1, a Digital Terrain Model derived from Pléiades and orthomosaic for in-detail modelling for final analysis and potential re-routing. For a subset of the corridor, 3D vector maps were extracted.Finally, Ground Control Points (GCPs) were captured and used to increase absolute accuracy in plan and elevation.
When the Pléiades derived elevation model was compared to highly precise in situ-measurements, over 80% of the evaluated area showed an accuracy of 50cm to 60cm in the vertical component, exceeding requested specifications.
Looking offshore, due to the high costs associated with exploration, supporting information to help target these activities is of particular value. Airbus Defence and Space has been using satellite radar data for over 20 years to identify the location of sea surface slicks associated with natural oil seeps emanating from the seafloor. As this Global Seeps Database continues to develop, new frontier basins are being assessed and in parallel, as the archive of imagery over a particular location builds over time, increased confidence can be placed on slicks identified by the analysis.
Reducing exploration risk offshore
Additional value can be obtained when the location of hydrocarbon seeps are compared to other datasets such as geophysical information. For example, exploration efforts are gearing up around the Adriatic coast of Croatia, with recent licencing rounds. In the Drava river basin onshore and in several offshore blocks along the country’s Adriatic coastline, exploration licences have been awarded to a number of international oil companies, with further rounds expected in the future.
Airbus Defence and Space and seismic multi-client acquisition and imaging specialists Spectrum Geo, collaborated to produce a joint study correlating natural oil seeps identified from radar and optical satellites with 2D seismic data to assist hydrocarbon exploration in the Adriatic Basin. Assessment of the hydrocarbon systems present in the region is based on combining Spectrum Geo’s sub-surface seismic information with Airbus Defence and Space’s surface seeps data. Results suggested a strong correlation between higher confidence slicks and structural features interpreted from a Spectrum Geo’s 2D seismic survey acquired offshore Croatia in 2013, allowing the targeting of further exploration work.
Remote access to inaccessible areas
Monitoring remote oil and gas installations is a complex process, but viewed from hundreds of kilometres above the earth’s surface, such data offers a fresh and revealing perspective. From a satellite’s eye-view improved understanding can be gained on an asset’s operational activity, potential security risks and any immediate environmental issues.
The US government’s Energy Information Administration estimates the South China Sea holds 11 billion bbls and 190 trillion cubic feet of natural gas. However, the sea’s maritime boundaries are disputed by several regional powers including China, Vietnam and the Philippines making it vital for political and diplomatic reasons that all parties have access to relevant geo-spatial data. Here, Pléiades satellite imagery is monitoring the development of newly created man-made islands around the strategically located, but disputed, Spratly Islands, information that would be difficult to acquires using more traditional means.
Unintentional pipeline breaches, equipment failure or illegal tapping can present a hazard to personnel and the release of oil into the local area. Other consequences of such spills may include a loss of revenue, clean-up costs and impact the local environment, together with reputational damage. Following the 2010 Macondo disaster in the Gulf of Mexico, BP has reportedly paid out in excess of US$13 billion in fines, lawyers’ fees and environmental remediation. In this offshore location satellite imagery, including TerraSAR-X and SPOT 5, supported the clean-up operation through tracking the spill and as an input into predictive models, helping guide the spill response fleet to place booms, skimmers and dispersants.
Looking further back in the oil and gas project lifecycle, when exploration is initiated in an area, satellite data can be used to identify any natural oil seeps, establishing the baseline oil presence on the sea surface in order to be able to rapidly differentiate any spill related to exploration and production.
Figure 2. TerraSAR-X Acquisition- Gulf of Mexico, US acquired October 2010. Darker areas indicate possible oil on the sea surface.
While illegal tapping onshore is largely caused by deliberate intervention, pipeline integrity is also at risk from accidental damage through human activity and pipeline corridors may undergo encroachment due to agriculture or unlicensed construction. In this instance, satellite imagery has a role in identifying oil impacted ground post-event, or pre-event to assess changes which may indicate preparations for pipeline tapping or damage, such as unplanned access roads or other activity in the vicinity, complementing traditional methods of pipeline monitoring. Due to the data volumes involved with modern high resolution satellite imagery, change detection methods are being developed to automatically identify change associated with human activity.
Satellite tasking during a crisis
Due to the Airbus Defence and Space Pléiades and SPOT constellations being each formed of two identical satellites and the agility of the on-board sensors it is possible to obtain daily revisit of any point on the globe, having the capability to secure required images within a matter of hours at high and very high-resolution.
Should existing archive data not meet a client’s remit, the satellites can be tasked to image a target location, with the capability for the client to task the satellite directly through the online Airbus Defence and Space GeoStore service. This is a particularly valuable capability in cases of emergency or when the nature of significant change in local conditions needs to be established, whether man-made or naturally occurring.
For example, when a fire broke out in two fuel tanks sited in Tripoli, one of Libya’s largest fuel storage facilities ground access to the site to assess the situation was considered too dangerous with rival Libyan militia fighting across the city. News reports warned that the fire was threatening to cause a humanitarian and environmental disaster, making the need for a fast response essential. In response, Airbus Defence and Space’s Instant Tasking service and online imagery portal, GeoStore, was requested to task a satellite, and a Pléiades high-resolution imagery of the fire was acquired, showing the affected area.
Figure 3: Satellite Image- Tripoli, Libya, showing smoke from a fire at an oil storage facility.
Following tasking and the satellite passing over the location, the fully processed image product was available for download just 1h 35min after acquisition, allowing an up to date assessment of the situation.
Satellite’s changing perspective
Both archive and freshly acquired, high-resolution satellite imagery is changing the way energy and engineering companies see the world. The ability to task satellites and then rapidly view up-to-date images taken of anywhere in the world is a highly valuable capability. From assessing geological structures in remote locations, guiding exploration in the Adriatic Sea, or obtaining situational awareness during a fire at a fuel storage depot in Tripoli, Airbus Defence and Space satellite imagery and derived services are contributing to the decision making capabilities of a wide array of organisations from oil and gas and engineering companies to environmental specialists.
Adapted by Louise Mulhall