Is there a geologic/depositional reason for the seeming lack of unconventional plays in South Louisiana

This is a question that has been on my mind for some time and I thought I would seek some replies from our industry/geologist members.  Over the years of reading the weekly rig report it has been obvious that there is much less activity in South LA and the shallow water GOM.  And that activity is totally vertical or directional drills, no horizontals that I can recall.  I assume from this that the exploration and development is confined to traditional conventional targets.  How deep is worth the expense and is there likely to be any economic pay at extreme depths?

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Lack of unconventional  (or "shale") plays in S Louisiana is tied directly to the subsurface geology in that area. And one can extend this "lack of unconventionals" comment all the way down the Texas Gulf Coast to Mexico (and beyond).

One could write volumes on the "why" behind this, but in summary, the depositional environments that "create" unconventional reservoirs do not exist in these areas. All unconventional reservoir areas have limited extents - especially in terms of moving downdip (toward the coast). As one moves in this direction, any unconventional target (e.g. TMS) gets deeper. And more gas prone. And thinner as that reservoir / rock section pinches out.

So chasing TMS or Eagle Ford in far downdip areas is both economically non viable as well as ultra expensive. And totally irrational and illogical from a geological standpoint.

It is difficult to lump all unconventionals into a single bucket as to economic criteria and factors. But the above comments are a good mantra to follow.

The S Louisiana and Texas Gulf Coast areas are "Tertiary" aged rocks  - Wilcox, Yegua, Frio, Vicksburg, Miocene to name a few major stratigraphic members. These intervals are part of the "sand box" that has filled up these areas over time, i.e. predominantly clastic (sand) reservoirs that have been shifted and tectonically adjusted (faulted) over time to create the complex system that is present today.

These zones are the exact opposite of unconventional reservoir in that they are associated with finite, areally limited O&G traps. Horizontal drilling and frac stimulation is NOT the approach to chase these reservoirs.

The organic rich zones that generate the O&G that charges these traps in the "sand box" are ultra deep and totally inaccessible by today's technology (and most probably the technologies that will be present in the next several hundred years).

So getting back to the topic - "It's all about the rock!"

May need to ask Jim Bob Moffett about the cost and risk of going deep in that area of coonass country.

And all those ultra deep McMoran wells are chasing finite (albeit large) finite reservoir targets. 

Thanks, Rock Man and TD,P. 


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