Exploration & Production Geology
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Modelling of tidal flats
http://www.epgeology.com/sedimentology-f19/modelling-tidal-flats-t2804.html
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Author:  Petsavvy [ Thu Aug 23, 2012 4:20 pm ]
Post subject:  Modelling of tidal flats

Can some body tell me how to model tidal flats region.what should be the basic concept taken into consideration before modeling

Author:  O_Stevens [ Thu Aug 23, 2012 8:39 pm ]
Post subject:  Re: Modelling of tidal flats

I think that very mucht depends on your objective. For volumetrics you are fine with a general understanding of N/G and porosity. These can be field averages or based on your facies model, upscaled cells and geostatiscal interpolations (kriging or SGS). Run this in a stochastic way though, potentially with the uncertainty manager in petrel to get the full range of volumetric outcomes.

For dynamic simulation you will need to think a lot about vertical permeability when upscalling logs into the model and further down the line into the dynamic simulator grid. Tidal flats can have a lot of horizontal shale barriers (deposited when the tide turns), which hamper flow. When in doubt upscale and model at highest resolution in the static modeling package, as upscaling in most dynamic software packages is better at assessing permeability when upscaling small cells into larger ones.

Through the more laterally continuous beds of sands and shale streaks you could find distributary (diverging inland) channels that form during both rising and falling tide. These channels can contain good sands, but may also be disconnected from the bounding strata by shale drapes at the base of the channels (are pretty common). You could capture these features in your facies model and model the shale drapes by applying transmissibility multipliers at the base of channels.

In the end I think you need to study outcrops and other analogues to build your conceptual models and always construct more than one realization/conceptual model. And remember that the software is just a tool to get your conceptual model into something you can do calculations on, never let it depict your geology...

...hope this helps.

Author:  Petsavvy [ Fri Aug 24, 2012 5:28 pm ]
Post subject:  Re: Modelling of tidal flats

thanks O_Stevens for your valuable inputs.Can u tell me which is the best book or literature for tidal flats.

Author:  O_Stevens [ Fri Aug 24, 2012 7:11 pm ]
Post subject:  Re: Modelling of tidal flats

I am not too familiar on literature about this subject. Why not start of with Google earth. Zoom into the Wadden Zee in Holland or other tide dominated areas. Or these other sites grabbed from wiki:

Selected example areas:

Arcachon Bay, France
Banc d'Arguin, Mauritania
Great Rann of Kutch, India
Belhaven, East Lothian Scotland, United Kingdom
Bridgwater Bay and Morecambe Bay, United Kingdom
Cape Cod Bay, Massachusetts, United States
Cook Inlet, Alaska, United States
Koojosee Inlet, Nunavut, Canada
Lindisfarne Island, England, United Kingdom
Minas Basin, Nova Scotia, Canada
Padilla Bay, Washington, United States
Plymouth Bay, Massachusetts, United States
Port of Tacoma, Washington
Skagit Bay, Washington
Snettisham Norfolk England, United Kingdom
Wadden Sea: Netherlands, Germany, Denmark
West coast of Andros Island, Bahamas
Yellow Sea, China, Korea


but for books, no, sorry can't help you there.

Author:  kathi [ Fri Nov 28, 2014 10:41 am ]
Post subject:  Re: Modelling of tidal flats

Anyway, disconformities mark the contact between two sedimentary units that are quite different in age but have parallel layers. Whenever the younger overlying sedimentary rocks fill channels eroded into the older sedimentary layers, the contact can more easily be identified. Sometimes, paleosol formation can alos be recognized if prolonged exposure to the atmosphere/environment has caused leaching weathering of the subsoil. If however, no significant topographic highs and lows or soil horizons are preserved at the top of the underlying older sedimentary rocks, the contact can usually only be recognized by a gap in the paleontologic record (dating (micro) fossils and checking whether a gap is present).

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