Replies to This Discussion

Permalink Reply by Gregory Wrightstone on June 5, 2016 at 4:09am

My opinion is that no economic quantities of oil will be produced from the Utica. Bear in mind that the liquids that people call "oil" from the wet gas window of the Utica is really condensate, not true oil

Probably due to a number of factors including lower reservoir pressure. But mostly due to size of the oil molecules, which are much larger than condensate molecules. Imagine trying to move beach ball size oil molecules through volleyball sized pore throats.

The big "shale" oil plays like the Bakken have a layer of rock in the midst of the shale with high perm and porosity and that acts like a French Drain.

• ▶ Reply

Permalink Reply by Joseph-Ohio on June 5, 2016 at 5:32am

Someone (from an E & P entity) posting / replying here, once implied (I inferred at any rate) that reservoir pressure is a function of overburden.   The person also mentioned that his outfit needed minimally 4000' of overburden to entertain developing a horizontal well in the Utica.  

Does molecule size still impact / make things too difficult say with 5500' of  overburden ?  What's your read on that Mr. Wrightstone ?

• ▶ Reply

Permalink Reply by Gregory Wrightstone on June 5, 2016 at 5:53am

Simplistically, if normally pressured, pressure increases with depth at .47 psi per foot. So a 10,000' well would have 4,700 psi. However, all the good shale plays are over-pressured. The more, the better. It is because the organics (TOC) were converted to nat gas with no place to go. So you find the really good Marcellus areas at 4,000' in NEPA may have 3,500 # while underpressured areas at 7,500' may have the same 3,500#.

The oily areas of Utica just didn't get overpressured because they weren't buried deep enough to have high enough heat to convert the TOC to gas, thus significantly underpressured, relative to depth.

• ▶ Reply

Permalink Reply by Joseph-Ohio on June 5, 2016 at 6:47am

So, not 'over pressured' even at 5500' overburden.

But, pressurized enough to lift I'd have to estimate.

However, sweeter cherries in southeast OH right now (but for how long I also wonder) ?

Thanks for your input Mr. Wrightstone - please continue with new info. and any clarifications.

Regards

Permalink Reply by Joseph-Ohio on June 5, 2016 at 11:07am

To expand a few thoughts that came to mind and to inquire :

Considering 5500' of overburden X .47 psi per foot = 2585 psi (further considering 'normal' generated pressure would be the pressure generated absent TOC (the pressure absent the contribution of organics)).

So any psi above 2585 psi would be indicative of TOC (organics) converted to gas (and oil).

Is that interpretation / line of thought correct Mr. Wrightstone ?

Permalink Reply by Joseph-Ohio on June 5, 2016 at 11:19pm

Can you kindly define the meaning of your term 'normally pressured' ? ?

Thinking you mean overburden pressure absent pressure generated by heat and decomposed organics / TOC.

Correct or no ? ?

Permalink Reply by Gregory Wrightstone on June 6, 2016 at 3:01am

Over-pressure means that the reservoir is in excess of 0.47 #/ft. We see the best areas of Utica and Marcellus are >.65/ft. TOC only adds to pressure in areas where it was buried deep and hot enought to convert to nat gas.

• ▶ Reply

Permalink Reply by Joseph-Ohio on June 6, 2016 at 8:15am

As I continue to attempt to understand what's going on within the Utica in my near geography (in terms of 'over-pressure') I'm coming up with the idea that the only way to know for sure how much 'over-pressure' exists here would be via developing more exploratory wells.

However, since an abundance of producing Natural Gas and Oil wells do exist in my near geography in various strata I'm thinking the organics must have been buried deep enough and things got hot enough to generate the production within the Utica Point Pleasant strata.

That's what I'm coming up with anyway.

Thanks for your help Gregory.

Standing by for more / all you can share.

Permalink Reply by Gregory Wrightstone on June 6, 2016 at 11:17am

So don't confuse Utica or Marcellus shale reservoirs with the overlying reservoirs. The Shale hydrocarbons are "in-situ" or the source is the reservoir. As they begin cooking the TOC, most is trapped but a LOT of hydrocarbons are expelled, finding their way to overlying conventional reservoirs where they are trapped. These can migrate many miles.

Utica is likely source for all the shallow zones in Ohio.

• ▶ Reply

Permalink Reply by Joseph-Ohio on June 6, 2016 at 11:43am

Not confusing the Utica shale with the overlying shallower reservoirs but just noting that considering those reservoirs exist and the Utica shale is the source that the organics must have been and are deep enough and things are / were hot enough to produce the gas and oil in those shallower reservoirs (Clinton Sandstone comes to mind as an example).

Wondering still about existing 'over-pressure' and molecule size and their effect on production from the Utica shale  (in my geography).

Permalink Reply by Joseph-Ohio on June 6, 2016 at 11:06pm

Seems to me that a shorter way to say it would be :  If there is Natural Gas and Oil in the Clinton Sandstone (and there is) and the unexplored / undeveloped Utica Point Pleasant (as the source rock) lies below (and a 350' thickness does lie below at an approximate depth of 5500' to it's top) that there would be Natural Gas and Oil to be recovered within that Utica Point Pleasant source rock awaiting recovery / harvest.

Permalink Reply by Gregory Wrightstone on June 7, 2016 at 5:18am

You are assuming vertical migration, which happens, but also the gas migrating can move updip a considerable distance. Many miles, so gas in Wayne County could have migrated from Belmont.

• ▶ Reply

• ‹ Previous
• 1
• 2
• 3
• Next ›
• Page