Passive Seismic Services

Passive Seismic Tomography is the gem in our exploration toolbox . A methodology originating from regional seismology, downscaled after years of experience at an exploration level.  Easily applicable, cost effective and environmentally friendly, it is a robust exploration alternative in cases where conventional practices wouldn’t be an option, either due to block size, penetration issues, budget limitations, accessibility and/or environmental restrictions.

Seismotech has already applied Passive Seismic Tomography in a number of “mission impossible” cases worldwide. In difficult geological settings, from thrust-belt zones and evaporitic environments to massive sedimentary deposits, as well as in extreme morphologies, from tropical jungles to harsh mountainous areas and environmentally sensitive zones. Our clients have acquired impressive results both at a reconnaissance level, where we have delineated the 3D structural image of enormous areas of interest at limited time and budget, as well as at a reservoir scale, where we were able to define productive and non-productive areas around known productive structures.

Having in mind that in order for the methodology to be applied, the area of interest has to be tectonically active, Passive Seismic Tomography is an excellent all-terrain, all-weather exploration tool for those areas, capable of giving answers in difficult exploration problems.

 

Benefits

The benefits of Passive Seismic Tomography are substantial:

Operational

  • It can be applied to the most mountainous and difficult terrains (rain forests, swamps etc.) since we only have to install single seismographs at points spaced a few Km apart and there is no need of dense geophone layouts.
  • There is no need of explosives, vibroseis etc. since we use the natural microseismicity as seismic sources.
  • No day-to-day operations etc.
  • No permits required.

 

Technical

  • Provides 3D geological detail beneath the entire exploration block no matter how big and accessible is (even many thousands Km2).
  • Ideal for regions with seismic penetration problems such as heavily weathered surface layers, basalt barriers, etc. (in Passive Seismic Tomography microearthquakes play the role of seismic sources within or below the target, so we have only 1-way ray paths, crossing the medium of interest, from the source to the sensor at the surface).
  • In many cases (difficult geologies, high topographic reliefs, strongly attenuating media) provide data better than conventional seismic.
  • Provides not only 3D Vp but also and Vs velocity variations beneath the entire exploration block.
  • Provides 3D distribution of Poisson’s ratio which depends upon the kind of fluids in the pore space (water, gas, oil).
  • We can easily obtain 2D horizontal and/or vertical sections whenever we want throughout the exploration block.
  • We can get an animated 3D video of Vp, Vs and Poisson’s ratio parameters below the entire exploration block.
  • We can use the 3D velocity data to reprocess conventional seismic data (post stack depth migration) and increase their resolution.
  • We can get a 3D variation of the seismic attenuation (or rock quality factor) below the entire exploration block. A parameter dependent on fracturing, and the kind of fluids in the pore space.

 

Economic

  • We can explore large areas (many thousands of Km2) at a fraction of the cost of a conventional 2D seismic.
  • No need of explosives vibroseis or expensive seismic gear (e.g. cables, telemetry nodes, geophones).
  • It requires only a fraction of the personnel (seismic crew) required for a conventional seismic survey.

 

Environmental

  • 100% safe to the environment.
  • No explosives, road blocking for vibroseis etc.
  • Uses natural seismicity as a source.
  • Ideal for environmentally sensitive regions (rainforests, national parks etc. tropical forests, swamps etc.).
  • No special permits required even for environmentally sensitive areas.

 

Other

  • Can be used in frontier geopolitical exploration areas to build a pre-project plan at minimum cost.
  • Used to investigate very large areas to define places where to apply conventional seismic (better layout of seismic lines), so reduce the exploration cost.
  • Provide confidence on exploration activities not only by defining an accurate geological setting but also minimizing the investment risk.

 TAVANA provides the best services ,

 

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