What are seismic survey locations and what associated data is in Lens Subsurface?
Marine seismic surveys are how companies image what lies beneath the seabed before they drill. Using AIS data from Wood Mackenzie's VesselTracker (VesselTracker.com), offshore live seismic surveys from 2016 are captured. These survey locations are then verified against seismic image providers (e.g. TGS) and displayed on Wood Mackenzie's Lens Subsurface map as a survey area polygon.
Each survey is linked to the blocks, fields, prospects and well activity it covers within the Wood Mackenzie dataset and these associated data sets can be visualised, extracted and analysed easily.
What can seismic surveys be used for?
Seismic activity is one of the earliest signals of what a company, state oil company or government plans to do next, and much of it is never published. Survey locations and associated datasets allow users to:
Capture who is acquiring seismic, where and when, including surveys shot with a company's own vessel that vendors typically do not advertise.
Spot early signs of activity, such as a large survey areas over open acreage ahead of a licensing round.
Compare surveys with the drilling that followed, using well counts and success rates two and five years after a survey ends.
Put exploration activity in context alongside the blocks, fields, prospects, and company ownership data already in Lens.
How are surveys detected?
We detect surveys automatically from vessel movements. Seismic vessels sail slowly and steadily in long, straight, parallel lines, which is a distinctive pattern in AIS data.
Positions are filtered to towing speeds (2 to 7.5 knots) and steady headings.
Nearby points are grouped into survey areas, and sparse points such as sailing to and from port are trimmed away.
A rectangle, lined up with the survey direction, is drawn around what is left. This is the survey area in Lens.
Validation checks reject patterns that are not real surveys and repeat visits by the same vessel within 14 days are merged into one survey.
Only the shooter vessel is published. Escort and guard vessels are excluded.
How are surveys described and enriched?
Survey type: 2D, 3D or undetermined, estimated from the spacing between survey lines. Under 2 km is 3D and over 4 km is 2D. Between 2 and 4 km we also use point density and the number of lines, and vessel descriptions mentioning cables or streamers can override the result. 2D seismic data is often lower resolution, often shot at the basin or sub-basin scale, while 3D seismic data is much higher resolution and often focused on an individual block, prospect, or field.
Status: ongoing, standby or complete, based on how recently the vessel was last seen working.
Blocks, prospects, fields and wells: any block overlapping the survey by at least 5% is linked. For historic surveys we use block ownership as it stood in the quarter the survey started, not today's ownership.
Likely client: if most of the blocks under a survey are open, relinquished or on offer, it is labelled multi-client. Otherwise, it takes the name of the main block operator.
Well activity: wells spudded within two and five years after the survey ended, split by type and outcome, with success rates.
What do the seismic survey datasets in Lens show?
Four data grids appear in Lens once seismic surveys are filtered for or selected on the map. Default columns are shown in this order:
Data Grid | Default Columns |
Seismic survey areas | Survey name, Survey ID, Vessel name, Status, Survey type, Duration, Country name, Basin |
Blocks by seismic survey | Block, Survey ID, Block operator, Block partners, Activity level, Licence status |
Fields by seismic survey | Survey ID, Field name, Field operator |
Prospects by seismic survey | Survey ID, Prospect name |
Survey names follow a set pattern: block, vessel, basin, survey type, month and year.
The dataset also holds further attributes that can be added as columns, including survey direction, line spacing, area, vessel IMO, prospect hydrocarbon type and target reservoir, block water depth category and licensing round and well counts.
Note:
The layer is built on ship tracking data, so vessels that switch off their tracking will not appear.
Survey areas are approximate. They show where the vessel worked, not the exact footprint of the data.
Only offshore surveys that have started are shown. Onshore surveys and planned surveys are not included.
Survey type, likely client and whether a block was a likely survey target are inferred.