Geological Mapping Using EO Data for Onshore O&G Exploration Michael Hall ESA Oil and Gas Workshop, Frascati, Italy michael.hall@infoterra-global.com
Why use EO data for Geological Mapping? Availability and suitability of existing mapping Many area of active exploration have a lack of existing geological mapping at a suitable scale or accuracy Spatial Coverage Remote sensing techniques allow the rapid appraisal and interpretation of large geographic areas with difficult field access Context Site specific field based observations can be viewed in their wider spatial context Range of datasets Variety of imagery suitable for different mapping scales, terrain characteristics and vegetation cover Enhanced fieldwork efficiency and seismic targeting Fieldwork and seismic acquisition can be targeted to identified areas of interest 2
Contribution of EO Datasets - Workflow Inputs Processed EO Dataset Optical Imagery Radar Imagery DEM Published Data Geological Mapping Papers Client Supplied Data Field Observations Well data Seismic Sections Image Enhancement Optical Decorrelation Stretching Principal Components Band Ratios DEM Shaded relief Slope/Aspect Contours Interpretation / Analysis Mineral Analysis Interpretation Structural Interpretation Stratigraphical Interpretation Fracture analysis Landcover Classification Products Geological Maps Digital Hardcopy Structure Contours Reports Landsat Data available from U.S. Geological Survey, EROS Data Center Rose Diagrams Cross sections 3
Datasets Project Stage Dependent Available Data Project Stage Scale Image Resolution DEM Resolution Regional Evaluation 1: 500 000 1: 100 000 15m 90m Basin Studies 1 :50 000 1: 10 000 15m 2.5m 30m 20m Licence/Prospect Evaluation Environmental/ Monitoring 1:10 000 1: 500 2.5m 5cm 5m 10cm Various Various Various 4
EO Datasets for Geological Interpretation - Relative Suitability* Landsat/ASTER SPOT GeoEye/WorldView/ QuickBird/Ikonos Airborne SRTM DEM ASTER DEM (excluding GDEM) SPOT HRS DEM WorldView/ GeoEye/ IKONOS Stereo DEM Licence Basin Regional Airborne stereo DEM *Considering pricing and resolution 5
Geological Features from EO Data - Structure BEDDING FAULTS FOLDS Horizontal Unclassified - major Unclassified Shallow Moderate Unclassified - minor Anticline axial surface trace Steep Vertical Thrust steep dipping Syncline axial surface trace Overturned Thrust shallow dipping Overturned anticline axial surface trace STRATIGRAPHIC BOUNDARY Extensional steep dipping Overturned syncline axial surface trace DRAINAGE Extensional shallow dipping River with direction of flow Direction of fold plunge Wadi Channel Strike-slip (showing relative off-set) Outline of fold closure at surface Drainage divide Surface trace of bedding Drainage basin Shear zone (showing relative off-set) Surface trace of foliation TOPOGRAPHIC FEATURES Break-in-slope (teeth face low side) Sub-surface fault structure Landsat Data Courtesy of NASA's Earth Science Enterprise Scientific Data Purchase Program 6
Geological Features from EO Data - Stratigraphy Lithology can be determined by variation: Texture Spectral response Geomorphology Depending on application spectral assessment undertaken at levels ranging from full hyperspectral approach to simple band ratios Field data or existing mapping valuable in the interpretation process Landsat 321 RGB Landsat 742 RGB DC Landsat 742 RGB Landsat Minerals Clay/Ferrous/Iron RGB Landsat Data available from U.S. Geological Survey, EROS Data Center 7
Regional Evaluation Case Study East Africa Rift System Exploration requirement Exploration hot spot Extensive area ~ 4.5 million square km Lack of consistent geological data in digital format EO Contribution SRTM and Landsat study Regional geological understanding (1:100k- 500k) Provides geological context for more focused studies Integration of previous geological mapping Onshore lake and coastal seeps identified using Radar imagery SRTM Data Courtesy of NASA provided by USGS/DLR 8
Regional Evaluation Case Study East Africa Rift System Recent earthquake activity indicates ongoing neotectonic faulting Tertiary fluvio-lacustrine deposits within the rift grabens/half grabens and older Karoo Supergroup deposits are the main Petroleum Systems Several phases of rifting are apparent with significant overprinting between events Frequent lake seeps identified from radar imagery, particularly in the western rift branch Landsat Data Courtesy of NASA's Earth Science Enterprise Scientific Data Purchase Program/ Earthquake localities from USGS Earthquake Hazard Program/ SRTM Data Courtesy of NASA provided by USGS/DLR Lake Oil Seeps 9 NE-SW trending extensional faults within Quaternary deposits
Licence Evaluation Exploration requirement Detailed geological understanding Planning for focused field campaign and seismic acquisition Integration of existing field observations Initial development of subsurface understanding Assessment of fracture characteristics of outcropping reservoir units EO Contribution High resolution imagery Ikonos, Quickbird, WorldView, GeoEye High resolution DEM Stereo Ikonos/WorldView/GeoEye or SPOT HRS Detailed geological interpretation (1:5000-1:10,000) Fracture analysis Thermal identification of possible oil seeps Schematic cross sections Structure contours Fieldwork routes Seismic quality Environmental assessment 10
Climate and Surface Characteristics and EO Data Selection for Geological Mapping Selection of EO dataset needs to be closely linked to surface and climate characteristics Vegetation, cloud and subtle topographic relief limit optical sensors for geological applications. Alternatives: Radar ALOS - L-band PALSAR system 10m resolution Cosmo-Skymed X-band constellation, 1m resolution TerraSAR-X X-band system, 1m resolution Radarsat-2 C-band system, 3m resolution These systems provide: High resolution imaging Flexible imaging modes Multiple polarisations and look angles Interferometric capabilities Thin sand cover ALOS L-band PALSAR system 10m resolution Penetration of the shallow subsurface in dry granular material to ~1m 11
Climate and Surface Characteristics and EO Data Selection - RADAR Relief Enhancement over tropical rainforests in West Africa ASTER data, NASA, METI and ERSDAC TerraSAR-X Infoterra GmbH Aster channels 1,2,3 TerraSAR-X dual polar stripmap 12
Geological Mapping for Pipeline Planning Including L band Radar for Shallow Subsurface Interpretation Proposed Route ASTER DEM Contours JERS SAR ERS SAR Landsat 7ETM+ Russian Mapping Surface and Subsurface Geology Source data Interpretation Landsat Data available from U.S. Geological Survey, EROS Data Center ASTER data, NASA, METI and ERSDAC ERS data ESA Distributed by Eurimage JERS-1 SAR data JAXA 13
Geological Mapping for Pipeline Planning Including L band Radar for Shallow Subsurface Interpretation Landsat JERS ERS JERS SAR Scale 1:100 000 Landsat Data available from U.S. Geological Survey, EROS Data Center/ASTER data, NASA, METI and ERSDAC ERS data ESA Distributed by Eurimage/JERS-1 SAR data JAXA 14
Future EO Systems for Geological Mapping TanDEM X ~12m global elevation model Released 2014 Landsat 8 and Sentinel-2 Landsat 8 launched 2012 Sentinel-2 launched 2014 Multiple SWIR bands offering lithological discrimination Important due to technical issues with Landsat 7 SLC and ASTER SWIR artifacts High resolution sensors Pléiades 1 launched Q1 2011 GeoEye 2 late 2012 SPOT 6 and 7 (2012/2014) 15
Conclusions Earth Observation (EO) data for geological mapping applications is well established and can make a significant contribution to Oil and Gas exploration Applicable from regional scale studies to more focused license block evaluation Range of datasets available suitable for different climate and ground conditions Potential for closer integration of EO based interpretation and 3D modeling Forthcoming sensors offer the potential for continuing and enhancing the role of EO data in exploration applications 16
Contact Michael Hall Infoterra Ltd, UK michael.hall@infoterra.global.com About SPOT Infoterra Spot Infoterra is a global provider of geo-information products and services bringing decision-makers sustainable solutions to increase our security, protect the environment and monitor natural resources. With unique access to SPOT and TerraSAR-X satellites, and a broad range of spaceborne and airborne acquisition capabilities, the group offers an unrivalled combination of Earth imagery. This combination forms the solid base for an extensive portfolio of products and services spanning the entire geo-information value chain 17