HISTORICAL SURFACE Deformation
Historical surface deformation (Source: TRE)
☒ Surface Motion
- Subsidence monitoring - Land motion relating to fault lines or other causes
- Subsidence monitoring - Reservoir management
- Subsidence monitoring - Infrastructure monitoring
- Surface Geology Mapping - Structural interpretation
- Logistics planning and operations - Facility siting, pipeline routing and roads development
- Surface and ground motion
Historical surface movement can be accurately determined by processing SAR imagery acquired over an area of interest with advanced interferometric techniques. Surface movement information is typically visualised using ground movement maps or in GIS systems, where movement due to oil & gas production (including related activities) or to natural phenomena can be identified and analysed.
Natural ground movement occurring prior to reservoir production can be identified and quantified in order to accurately determine the impact of eventual production activities on surface movement. Where reservoirs have been developed for a number of years, historical surface movement information can provide a valuable insight into potential future reservoir behaviour, including reservoir compaction, fault reactivation, compartmentalisation, fluid movement, etc.
Where historical SAR imagery is available, surface movement can be identified for the entire period of SAR acquisitions. Surface movement measurements are provided along the satellite’s line-of-sight and, with the availability of both ascending and descending geometry SAR datasets, in the vertical and horizontal directions.
Known restrictions / limitations
- Accuracy and density of measurements dependent on a number of factors, including the wavelength of SAR sensor and repeat time of the satellite
- North-south movement cannot be identified
- Processing for high-accuracy ground movement can be performed only after acquiring a minimum number of SAR images (approximately 15-20 SAR images with same geometry)
- No surface movement information achievable over water bodies
- Density of measurement points identified over vegetated / swampy areas decreases
- Surface movement is a combination of all active layer deformation contributions
- Historical analyses can only be performed where SAR data was acquired with relative high resolution. Although a good coverage exists over many areas worldwide, some areas do not have large historical SAR data archives
Lifecycle stage and demand
- Information on historical ground and fault movement to support decision making on a prospect
- Baseline mapping of natural ground movement pre-production phase for improved reservoir management
Exploration & Development:
- Critical historical ground movement information for the identification of stable ground to support effective and safe land seismic surveys and for the planning of infrastructure, pipelines, wellheads and area development
- Analyses of surface movement to provide information on subsurface features including compartmentalisation, fault reactivation, fluid dynamics, etc.
- Identification of stable ground for the safe and effective planning of ground surveys and infrastructure
- Ground movement over infrastructure, e.g. wellheads, pipelines, etc. can be monitored in order to identify potential issues in advance
- Baseline mapping of ground movement related to production activities for improved reservoir management
- Natural ground movement occurring before production can be determined. For reservoirs where production has occurred for a number of years, historical subsidence maps provide a valuable understanding of reservoir dynamics
- Same as production. Once the site is closed, remediation monitoring will confirm the stabilisation of the site before transfer to regulator/Crown.
Geographic coverage and demand
Demand and coverage is globally onshore or on offshore platforms. No measurements over water bodies.
OTM:001 Identifying effect of fault reactivation
OTM:002 Tracking fluid migration in the subsurface
OTM:003 Subsidence from reservoir draw-down
OTM:004 Regulatory verification relating to injection of fracking fluids
OTM:005 Monitoring natural fault movement
OTM:006 Technical verification relation to injection of fracking fluids
OTM:007 Identify communication between producing zones
OTM:008 Determine historical ground movement for infrastructure planning
OTM:009 Determine historical ground movement for pipeline routing
OTM:011 Surface infrastructure movement relative to sub-surface
OTM:014 Forecasting sand dune migration
OTM:020 Tracking groundwater tables
OTM:051 Identification of fault lines
OTM:060 Forecasting landslide locations
HC:1105 Identify permafrost zone for data analysis
HC:2501 Characterization of surface/near-surface structural geological properties for infrastructure planning
HC:2504 Identification of slope instability
HC:2505 Identify geophysical properties of the subsurface
HC:3101 Baseline and monitoring of areas with active faults and subsidence
HC:3201 Assessment of infrastructure placement and effects to the surrounding environment
HC:3203 Management of surface impacts due to ground deformation from operations
HC:3204 Monitor stability of surface reservoirs such as settling ponds
HC:3302 Assessing ground deformation to support enhanced recovery operations
HC:3303 Monitoring effectiveness of steam assisted gravity drainage (SAGD) operations
HC:4201 Remediation and reclamation monitoring
HC:4208 Identification of groundwater table to reduce potential issues during seismic activity
HC:4301 Map and monitor induced seismic hazards
HC:5102 Assess potential project site for historical use
HC:5201 Monitoring assets for risk management
HC:5306 Assessing terrain stability for infrastructure planning in permafrost environments
Input data sources
Radar: VHR2, HR1, HR2
Spatial resolution and coverage
Spatial resolution: 20x5 m / 3x3 m / 1x1m pixel size
Coverage: 250x150 km / 100x100 km / 40x40 km / 30x50 km / 10x10 km
Minimum Mapping Unit (MMU)
Related to pixel size of satellite imagery used. One ground measurement point can be identified for each pixel in satellite image.
Accuracy / constraints
Thematic accuracy: Ground movement can be determined to millimetre accuracy (with a sufficient number of SAR images).
Spatial accuracy: In ideal conditions, one measurement point is identified in each SAR image pixel.
Accuracy assessment approach & quality control measures
MonteCarlo statistical approach.
Frequency / timeliness
Observation frequency: Constrained by actual satellite repeat cycle, typically 4-24 days. Historical satellite repeat cycle was up to 35 days. Appropriate satellites can be chosen in terms of spatial and temporal resolution.
Timeliness of delivery: Depends on the requirements of the Client and processing required.
Basic analysis can be performed quickly (24-48 hours) whilst integrated products require detailed analysis (2 weeks).
Delivery / output format
- Vector formats
- Raster formats (depending on client requirements)
- Geotiff or shapefile (standard - any other OGC standard file formats)
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