There are 11 wells in my 1200+ acre unit and I'm being told that no oil is being captured from the wells. Is this possible?
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Marshall County,WV. It's near Majorsville. CNX / Noble wells. Condensate is being produced. My royalties show it.
Zack,
What county are you in? Low BTU dry gas areas will have wells that produce absolutely 0 oil or condensate. It really depends on the area......
The short answer is NO; for the Marcellus and the Utica, much/most of the areas will yield only dry gas.
A long expiation involves …. Geochemistry 101
How organic material in sediments evolves to produce oil, condensates, natural gas liquids and oil.
As the sediments get buried, the first thing generated is Natural Gas, referred to as Biogenic Gas.
Think of this as ‘swamp gas’; this is Natural Gas produced by biological processes. This tends not to be commercial; produced at shallow depths …. they do capture and use it at large municipal landfills.
As the sediments are further buried, pressures and temperatures increase.
When the pressures and temperatures reach a certain point, oil is generated ….. essentially the conditions in the earth (assisted by time) are acting as a natural refinery. When the conditions have been reached in which oil begins to be generated, we would state that the sediments have entered the ‘Oil Window’.
As the sediments are further buried, pressures and temperatures continue to increase.
Both oil and some natural gas are produced while the sediments are within the ‘Oil Window’ (a range of pressures and temperatures over which the organic material present in the sediments can be altered to produce oil).
It is typical that some natural gas is present with oil (this natural gas is referred to as ‘Associated Gas’ and is present as either dissolved in the oil, or as free gas),
While the sediments are within the range of depths at which the pressures and temperatures are such that oil can be generated, these sediments are referred to as ‘Mature’ for oil generation.
As the sediments are further buried, pressures and temperatures continue to increase; reaching a point at which the sediments are referred to as ‘Over Mature for Oil Generation’. At this point, we have entered what is referred to as the ‘Gas Window’, where the temperatures are so high as to break down the long chain hydrocarbons (oil) into natural gas (methane). The oil is destroyed … and it becomes natural gas.
As the sediments are further buried, pressures and temperatures continue to increase; we reach a point at which the natural gas is destroyed (leaving only carbon). This condition is referred to as ‘Over Mature’.
Between the ‘Oil Window’ and the ‘Gas Window’ is a brief range of depths at which the pressures and temperatures are such that Condensates and Natural Gas Liquids are primarily produced.
The above is a basic and simplistic explanation; like most things in life, there can be exceptions.
A basic rule of thumb would be the greater the depth the sediments have reached (at some point in their burial history) the more likely that only natural gas is present.
JS
Jack; you left out one factor....time. The longer the sediment is under pressure and heat, the more cooked it becomes. The shales of Oh and Pa are very old, 250 million yrs +/- depending on strata. The oil in the Gulf Of Mexico is deeper, under higher pressure and temps but it has been buried for a much shorter time period. Thus it is still mostly in the oil stage and not been converted to gas. Correct me if I am wrong.
One Q I have is in the "over mature" zones there is just carbon left. I have heard that it is in the form of CO2. Where does the O2 come from that deep? Is there that much oxygen trapped in the earth? And if it is pure carbon, what is the form? I don't suspect it is diamond, maybe graphines?
RE: “you left out one factor....time. The longer the sediment is under pressure and heat, the more cooked it becomes.”
That is true …… to a point.
I tried to keep the earlier description simple and basic; thus the characterization of my comments as being Geochemistry 101 ….
I did not want to get into such subjects as heat flow and paleo-heat flow, geothermal gradient and paleo geothermal gradient, burial history, types of kerogens (and their individual propensities to generate different ratios and types of hydrocarbons), markers of thermal maturity (such as conodont color alteration index and vitrinite reflectance), chemistry of connate water, etc.
My skills in explaining do not extend far into Geochemistry 201, and Geochemistry 301; nor do I expect that the bulk of my audience is prepared to subject themselves to such a punishing discussion.
RE: “The shales of Oh and Pa are very old, 250 million yrs +/- depending on strata.”
Time does factor into things; however for the Marcellus and Utica, the movable hydrocarbons were largely generated quite long ago …. and, have been sitting there festering and waiting for us to figure how to exploit. In the Gulf Coast, oil and gas are currently still today being generated in an active ‘kitchen’.
RE: “The oil in the Gulf Of Mexico is deeper, under higher pressure and temps but it has been buried for a much shorter time period.”
Not quite correct; the oil in the GOM has not necessarily been subjected to higher temperatures. For a given current depth; the Marcellus and Utica have been subjected to higher temperatures (due to higher historic heat flow) and potentially to greater pressures (due to their more complex burial history).
Within the Gulf Coast/Mississippi Delta area, heat-flow values are generally quite low, in large part because of the high sedimentation rates and nature of the basement rocks. In the Gulf of Mexico area, sediments are young and tend to currently be at (or near) the deepest depth to which they have ever been buried …. A short and well understood burial history; coupled with low-heat flow and lower geothermal gradient
Within the Marcellus and Utica of the Rome Trough, the sediments have been exposed to a much more complicated burial history with exposure to higher heat flow and a higher geothermal gradient. And, there has been uplift and erosion; their current depth is not the deepest that they have been at during their long history.
RE: “The oil in the Gulf Of Mexico is deeper, under higher pressure and temps but it has been buried for a much shorter time period. Thus it is still mostly in the oil stage and not been converted to gas. Correct me if I am wrong.”
The Oil in the Gulf Coast is there because of its unique situation; likewise the Natural Gas in there because of all the factors which go into its history. As the huge wedge of sediments continues to accumulate as the sediments carried by the Mississippi River (the Big Muddy) continue to accumulate as this mighty river drains much of the North American continent …. more of the existing oil will slowly be converted to natural gas.
One way to look at things:
When we look at the Utica and the Marcellus; we are looking at ‘fossil’ oil and gas ….. created long ago and essentially trapped outside of time.
When we look at the oil and gas of the Gulf Coast, we are looking at a dynamic system that is still evolving.
From a Geochemical perspective, comparing the Utica/Marcellus to the Gulf Coast is not an Apples/Oranges comparison …. more of an Apples/Brazil nut comparison.
RE: “One Q I have is in the "over mature" zones there is just carbon left. I have heard that it is in the form of CO2.”
When we burn (oxidize) natural gas in the atmosphere; free oxygen is required. At depth, in the earth, we are in an anoxic environment (no free oxygen present). The carbon in over-mature natural gas becomes graphite (elemental carbon).
Again, I am simplifying matters (as before); but this time adding an additional bit of what I understand.
All IMHO,
JS
Thank you Jack Straw...... Very Nice Explanation !
I got a dumb question..
Why is there so much "water" ie brine...at such depths....????
and why doesn't it "boil off" ?
I know.. the pressure I guess keeps it from boiling... down there..
but WHY... is it there in the first place with OIL ???
RE: "Why is there so much "water" ie brine...at such depths....????"
The sediments were deposited in an ancient ocean.
The water you refer to is what a petroleum geologist or reservoir engineer would refer to as 'connate water'.
This connate water started out as the sea water trapped in the pores of the rock as and when the rocks were deposited. Through the many millions of years this fluid has festered away, dissolving minerals and likely increasing in salinity as it shared a long and tortured history with the rocks trapping it.
You are looking at a 'fossil water' that has suffered a hard life; a life spent under a lot of heat and pressure .... with no place to go.
JS
OK, thanks,
I guess then the Ocean was at 6000 feet down ? at one time..
I know they say the Gulf was up past Ohio at one time...
But 6000 feet down sure was some change in geology...
thanks, Mike
Zack,
Check with the state agency that keeps track of Oil and Gas production in WV. They will report your wells production at some frequency, typically yearly.
In Ohio we have the ODNR that now requires a Quarterly report of oil and gas production of each well. It's a great way to see how many barrels of oil and MCFs of natural gas your well has been shorted by your producer.
The Natural Gas Liquids are left unaccounted for which is bad for the landowners, great for a get rich quick unethical producer.
They don't do that, do they?
Sure they do. Can you say Theft? I new you could.
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