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MOST FREQUENTLY ASKED QUESTIONS :

Is there a way of ‘blind’ testing the technology on existing wells, dry or HC-bearing?

Yes, we routinely sample near on/offshore existing wells for microbial calibration, either in production or abandoned. Offshore, gravity cores can be dropped from a supply boat or just from a rig platform crane. These well measurements are important to calibrate the microbial survey values and statistically distinguish high/med/low anomalous and background ranges and threshold values.


How does the fact that isotopic ratios above thermogenic HC accumulations tend to go back to purely biogenic values above the shallowest reservoir (as observed in Angola in every well)?

We do not know the offshore Angola HC stacked reservoir distribution in detail. But we guess that it has to do with depletion of the main, deeper thermogenic accummulation(s) over time, after which biogenic values from the shallow reservoir(s) start to become more dominant. Usually we measure evidence of mixing of both from the beginning.


How can you distinguish macroseepage from microseepage?

from several criteria as tabled in the matrix below. The main 4 criteria are 1) difference in microbial index (high vs.  low), 2) HC content (1000’s vs. 10-100’s ppm), 3) heavy HC content (high vs. low C1-5 molecules only), and 4) surface distribution (seep/linear vs. shape). The latter is true because macroseepage is caused by migration deflected along faults/joints, macro-fractures, unconformities, barriers or dipping layers to visible seep points or fault lines at surface.  Whereas microseepage is driven by buoyancy-driven gas flow vertically through natural microfractures to surface geometries which approximate and ‘mimic’ the trap accumulation’s geometry at greater depth. Both processes are not mutually exclusive and can happen simultaneously, but at different speeds and quantities over geological or real time. Macroseepage is accumulative and static (i.e. could have happened in the past), whereas microseepage is ongoing at present, highly dynamic and sensitive!

 

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Does you company also carry out types of geochemical analysis other than SSG from clay minerals or carbonate cement?

Yes, we can take oil/gas samples from surface seeps and mud volcanos for full compositional and isotope analysis.

We do not take Headspace gas or Absorption samples from sediments like other conventional geochemical contractors, as we consider these as much less reliable or representative.

 


What is the 3 key differences between microbial and geochemical SSG hydrocarbon detection?

One is that the first can identify, locate and delineate HC accumulations, whereas the second can only forecast the HC composition and likely fluid fill. The other is that the first is based on ongoing (present) dynamic microseepage, whereas the second measures accumulative (past) static macroseepage and is not necessarily a representation of what is happening today. The last one is that microseepage is apical and near-vertical above HC accumulations, whereas macroseepage is usually deflected and laterally offset.