Geophysics Analysis & Interpretation

Magnetic Gravity  - Geophysics airborne surveys for oil and gas, mine exploration

​MAGNETIC & GRAVITY DATA

Deliverables


We produce up to 130 maps for a traditional airborne aeromagnetic survey. None of the map is redundant. Each map provides quantitative or visual nuances that enhance the interpretation.

Besides performing traditional filtering we will also apply more advanced maps using our technologies. Some of the technologies include the following:


Accurate Gridding
To achieve the high resolution mapping that we produce, traditional commercially available gridding techniques (Least square, linear, nearest neighbour, or kriging, etc) do not suffice. Our proprietary techniques have the ability to emphasize very small, local vs regional anomalies.


STRUCTURES & FAULTS.  We produce advanced maps of the network of faults and fractures at multiple depths. 


















Traditional "Colour Blobs" produced by standard processing are fuzzy. The TerraNotes processing goes beyond those color blobs and produces more precise maps of the anomalies.  The map above (right) shows the zones where the magnetic properties change, their intensity of change, their edges are precise and their center axes are clearly visible. No guess work anymore. TerraNotes produces such maps as slices at different depth. For instance, the map above (right) is a slice taken at ~400 m below ground level - while the traditional map on the left (blobs) is NOT a depth slice and represents the total magnetic field at all depths.)  


BASEMENT TOPOGRAPHY MAPPING IN 3D. We produce maps of the crystalline basement topography plus over 20 maps including integration of fault networks over basement topography. The maps below show the basement topography with lineaments, 3D, contacts of geostructures, edges of geostructures.











The 3 maps above show the topography of the crystalline basement of an exploration zone. The depth of each survey datapoint is calculated to produce a map in 3D, i.e. this is not an inversion scheme.  


FIELD DECOMPOSITION. Traditional RMI maps (Residual Magnetic Intensity) contain a lot of signal that is largely irrelevant for exploration of economic deposits. TerraNotes has researched and developed geophysics technologies to process the magnetic field into its components. These maps are used to achieve greater accuracy in exploration targeting. They show greater details of the anomalies and often hidden anomalies. The anomalies have better defined contours and their contact zones are more precise for target or drilling accuracy. 



















The map on the left above was produced using standard processing and shows a big blue blow supposedly representing a mag low. The map on the right was produced with TerraNotes GRIDFIT processing. Both maps are using the same airborne magnetic data. The map on the right has extracted magnetic anomalies blinded by the big blue blob on the left maps. Also, the map on the right shows more precisely the relation of the magnetic anomalies to the lineaments nearby.


MODELING, SIMULATION, INVERSION

TerraNotes uses the results of its Magnetic Field Decomposition technology to produce much more precise and reliable models and inversions than with conventional magnetic or gravity data and commercial modeling packages.


We use a number of classic as well as some innovative techniques to establish the relationship between the anomalies and the size, depth and shape of their causative source; thickness of layers, extension of faults and fractures; and better characterization of some alterations zones. All these results can then be integrated into geological models. 


Deliverables for each modeled zone may include the following:

  • Detailed Susceptibility Inversion Map
  • Map of lithologies and alterations
  • Location and shape of each modeled units 
  • Modeled cross sections for blocks of units (depth, thickness, lateral extent of the block of units)
  • Models of structures (contacts, faults, fractures, shear zones)
  • Geological and geophysical structural interpretation and structural relation to geochemical interpretations
  • 1D, 2D and 3D visualization of the geological units and integration to your geological model



Modeling Using the Field Decomposition DataAnother example: The 3 comparative maps below represent the same exploration anomaly. Notice that Map C on the right is more accurate that the RMI map using traditional standard processing or map B. ON map C, the size of the magnetic high anomaly is much smaller than on the other 2 maps. Its shape is also more precise, which allows for more accurate drilling.


On the central panel B below, the modelled structure was generated through inverse modelling of the RTP-RMI data.

On the right panel C, the modelled structure was generated through inverse modelling of the TerraNotes Decomposed RMI data (as discussed in the previous paragraph above).

It is obvious in the figure that the model generated from the TerraNotes Decomposed RMI data is a much more accurate model. It reproduces its source data with a high degree of accuracy. The model generated from the unprocessed RTP-RMI data is significantly less successful in reproducing its source data.

















Another set of examples:


















The panel on the left shows the Magnetic Inversion based on the RTP (Reduced-To-The-Pole) data.

The panel on the right shows the same Magnetic Inversion but this time it is based on the TerraNotes Magnetic Field Decomposition technique. 


These profiles exclude all cells above the elevation displayed on each picture.

Notice that the high susceptibilitycells are much more evenly distributed throughout the body (in right panel) than they are in the RTP results.


The shape of this model (right panel) is similar to that of the produced by intensive drilling the client conducted in that exploration zone.



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Applications for oil and gas exploration, mine exploration, groundwater and environmental applications. 
TerraNotes geophysics provices airborne surveys advanced data analysis, imaging, and interpretation.