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  • Product Sheet: Fault Identification

FAULT IDENTIFICATION AND REACTIVATION

Fault identification (source: TRE)

PRODUCT DESCRIPTION

Category

Component products

 

☒ Surface Motion

  • N/A

 

Uses

  • Subsidence monitoring - Land motion relating to fault lines or other causes
  • Surface Geology Mapping - Structural interpretation

Geo-information requirements

  •  Surface and ground motion
  • Terrain information

Description

Faults, both natural and re-activated through reservoir depletion, can be identified and quantified by interpreting surface movement above a producing reservoir. Maps of surface movement are produced by processing SAR imagery with advanced interferometric techniques. Both historically acquired SAR datasets and actively tasked imagery can be processed to determine ground movement over an area of interest. Surface movement information is typically visualised using ground movement maps or in GIS systems.

By determining the characteristics of abrupt changes in the surface movement profile, faults can be identified, analysed and with advanced processing techniques, and subsequently their locations and movements quantified.

Surface movement is identified for the entire period of SAR acquisitions and displacement measurements are provided along the satellite’s line-of-sight. With the availability of both ascending and descending geometry SAR datasets, movement information is also provided along 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

Pre-licensing

Exploration

Development

Production

Decommissioning

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Pre-licensing:

  • Identification of past ground movement and fault locations

Development:

  • Monitoring of fault movement throughout the construction phase of site facilities and well drilling.

Production:

  • Baseline mapping of natural ground movement pre-production phase and ground movement related to production activities for improved reservoir management.
    Analyses of surface movement to provide information on subsurface features including compartmentalisation, fault reactivation, fluid dynamics, etc.

Decommissioning:

  • Seismicity can be induced after project completion. Fault activity should be monitored as part of the decommissioning phase before transfer to regulator/Crown.

Geographic coverage and demand

Demand and coverage is globally onshore or on offshore platforms.

CHALLENGES ADDRESSED

OTM:001 Identifying effect of fault reactivation
OTM:005 Monitoring natural fault movement
OTM:051 Identification of fault lines

HC:3101 Baseline and monitoring of areas with active faults and subsidence
HC:4301 Map and monitor induced seismic hazards

PRODUCT SPECIFICATIONS

Input data sources

Radar: VHR2, HR1, HR2

Spatial resolution and coverage

Spatial resolution: 20x5 m / 3x3 m / 1x1 m 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 can be identified in each SAR image pixel.

Accuracy assessment approach & quality control measures

MonteCarlo statistical approach

Frequency / timeliness

Observation frequency: Constrained by 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.

Availability

Basic analysis can be performed quickly (24-48 hours) whilst integrated products require detailed analysis (2 weeks).

Delivery / output format

Data type:

  • Vector formats
  • Raster formats (depending on client needs)

File format:

  • Geotiff or shapefile (standard - any other OGC standard file formats)
         

Download Product Sheet

 

Lead Author:TRE
Peer Reviewer:Hatfield Consultants

Author(s):

Alastair Belson

Document Title:

Fault identification and reactivation

# of Pages:

4

Circulation:

Internal – Project consortium and science partners

 

External – ESA

 

 

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