[allenwrench]

On a talk show one commentator said that 25% of the US has been closed to oil exploration due to environmentalist. Is 25% a good estimate?

[RdSnt]

In the simplest terms the ban on oil exploration in parts of the US has been exclusively that of invasive exploration; physical drilling and digging.
All parts of the US have been explored electronically, from fly overs and satellite. This process gives a very good general indication of what is potentially available.

[aahala2]

$this->bbcode_second_pass_quote('allenwrench', 'O')n a talk show one commentator said that 25% of the US has been closed to oil exploration due to environmentalist. Is 25% a good estimate?

[KingM]

$this->bbcode_second_pass_quote('aahala2', '
')If the percentage refers to the land mass of the US, it's
hardly even an estimate. 2.5% would be much closer, and without
actual calculation on my part, .25% might be closer still.

The only major land excluded from oil due to environmental
concerns(and where oil might be found) is ANWAR.

There are areas off shore the feds prohibit, but how much
area is off limits is not likely to raise the percentage to anything
close to 25%.

[joeltrout]

$this->bbcode_second_pass_quote('RdSnt', '
')All parts of the US have been explored electronically, from fly overs and satellite. This process gives a very good general indication of what is potentially available.

[RdSnt]

What rock have you been living under the past few decades?

http://www.zeenews.com/articles.asp?aid=348055&sid=REG

http://www.satimagingcorp.com/svc/exploration.html

http://www.gulfoilandgas.com/webpro1/pr ... asp?id=755

http://www.sciencedaily.com/releases/20 ... 152025.htm

Enough references?

$this->bbcode_second_pass_quote('joeltrout', '')$this->bbcode_second_pass_quote('RdSnt', '
')All parts of the US have been explored electronically, from fly overs and satellite. This process gives a very good general indication of what is potentially available.

[copious.abundance]

Define "explored."

If some oil company(s) digs a few wells in a few spots in Nevada, for example, and maybe takes some seismic readings here and there, does that mean all of Nevada has been "explored" for oil? Not really.

Or, what if some county in Kansas has had 400 oil wells drilled over the past 5 decades, but none of them have gone deeper than 6,000 feet. Does this mean that this county has been thoroughly "explored?" Not really, there might be deposits deeper than 6,000 feet which no one bothered to look for because it wasn't economic to do so, and/or because they didn't think there would be anything down that far (and they might be wrong).

There's no clear line between being "explored" and being "not explored."

[rockdoc123]

everyones a little bit right and a little bit wrong.

Aeromag and gravity as well as remote sensing are "tools" that explorers use. The aeromag in conjuction with gravity can help to identify potential structural traps in the subsurface whereas the remote sensing can be used to identify surface oil seeps (Nigel Press does a lot of this) and plant growth that might be related to shallow hydrocarbon seepage. Surface features from lidar or radar can also be used to infer subsurface structuring.
That being said it would be very, very unusual for someone to drill a well based on that information alone. Usually 2D seismic would be acquired and for specific playtypes possibly 3D seismic. The only case where someone might drill a well with aerial surveys alone is if seismic is prohibitively expensive compared to a well. The problem with this approach is that once you've drilled your dry hole there is no way of telling if you missed a structure that could have been identified on seismic.

[allenwrench]

$this->bbcode_second_pass_quote('OilFinder2', 'D')efine "explored."

If some oil company(s) digs a few wells in a few spots in Nevada, for example, and maybe takes some seismic readings here and there, does that mean all of Nevada has been "explored" for oil? Not really.

Or, what if some county in Kansas has had 400 oil wells drilled over the past 5 decades, but none of them have gone deeper than 6,000 feet. Does this mean that this county has been thoroughly "explored?" Not really, there might be deposits deeper than 6,000 feet which no one bothered to look for because it wasn't economic to do so, and/or because they didn't think there would be anything down that far (and they might be wrong).

There's no clear line between being "explored" and being "not explored."

[aahala2]

$this->bbcode_second_pass_quote('KingM', '')$this->bbcode_second_pass_quote('aahala2', '
')If the percentage refers to the land mass of the US, it's
hardly even an estimate. 2.5% would be much closer, and without
actual calculation on my part, .25% might be closer still.

The only major land excluded from oil due to environmental
concerns(and where oil might be found) is ANWAR.

There are areas off shore the feds prohibit, but how much
area is off limits is not likely to raise the percentage to anything
close to 25%.

[joeltrout]

$this->bbcode_second_pass_quote('aahala2', '
')
However, I don't believe I'm "talking out my ass" of this. Please
identify any large track, say 100,000 acres or more in the lower
48, that barrs oil exploration for envirnomental purposes.

[RdSnt]

I completely agree with your assessment and I wasn't suggesting that aerial analysis was a complete exploration process. It is however a very effective and valuable first step in evaluating where to put down hardware.
Considering exploration is becoming increasingly expensive and drilling in particular requires huge amounts of many and constitutes the biggest financial risk, aerial surveys can effectively eliminate large areas of the country where there is no chance to find oil. It can then narrow down the prospective areas to a higher tolerance, thus reducing risk.
We can't be poking holes in every square foot of ground, not even every square mile.


$this->bbcode_second_pass_quote('rockdoc123', 'e')veryones a little bit right and a little bit wrong.

Aeromag and gravity as well as remote sensing are "tools" that explorers use. The aeromag in conjuction with gravity can help to identify potential structural traps in the subsurface whereas the remote sensing can be used to identify surface oil seeps (Nigel Press does a lot of this) and plant growth that might be related to shallow hydrocarbon seepage. Surface features from lidar or radar can also be used to infer subsurface structuring.
That being said it would be very, very unusual for someone to drill a well based on that information alone. Usually 2D seismic would be acquired and for specific playtypes possibly 3D seismic. The only case where someone might drill a well with aerial surveys alone is if seismic is prohibitively expensive compared to a well. The problem with this approach is that once you've drilled your dry hole there is no way of telling if you missed a structure that could have been identified on seismic.

[rockdoc123]

$this->bbcode_second_pass_quote('', 'a')erial surveys can effectively eliminate large areas of the country where there is no chance to find oil.

[TheDude]

$this->bbcode_second_pass_quote('allenwrench', 'T')his brings up another question - depth.

I was told that at deep depths crude becomes nat gas from high pressure. Is this true?

If so, some of the people claiming to get more oil we just drill deeper may not have it all right?

[joeltrout]

$this->bbcode_second_pass_quote('rockdoc123', 'e')veryones a little bit right and a little bit wrong.

Aeromag and gravity as well as remote sensing are "tools" that explorers use. The aeromag in conjuction with gravity can help to identify potential structural traps in the subsurface whereas the remote sensing can be used to identify surface oil seeps (Nigel Press does a lot of this) and plant growth that might be related to shallow hydrocarbon seepage. Surface features from lidar or radar can also be used to infer subsurface structuring.
That being said it would be very, very unusual for someone to drill a well based on that information alone. Usually 2D seismic would be acquired and for specific playtypes possibly 3D seismic. The only case where someone might drill a well with aerial surveys alone is if seismic is prohibitively expensive compared to a well. The problem with this approach is that once you've drilled your dry hole there is no way of telling if you missed a structure that could have been identified on seismic.

[rockdoc123]

aeromag and satellite are still used as part of the toolset for some areas such as the overthrust, Appalachia. It isn't an exclusive piece of information but then neither is 3D. 3D is shot in many places but I reiterate that most exploration is done on 2D data and 3D is acquired later as an appraisal tool. There are spots where 3D is used out of the gate but usually that's because there is a fair bit of older 2D data available through seismic brokerage houses or company trades and/or there is already a fair bit of well information.
The fact that all the 3D crews are busy does not say what they are working on, could be appraisal work or could be development work. In some cases those crews might be conducting production 4D which is starting to get some traction in North America.
I reiterate 3D is not a panacea. If I had a nickel for every dry hole that has been drilled on 3D data I could have retired a long, long time ago.
If you want to know what percentage of the US still remains to be explored the USGS reports are the best place to go for the actual science. They outline the basins and speak to some degree on the level of previous activity and the potential YTF.

[copious.abundance]

$this->bbcode_second_pass_quote('allenwrench', '
')This brings up another question - depth.

I was told that at deep depths crude becomes nat gas from high pressure. Is this true?

If so, some of the people claiming to get more oil we just drill deeper may not have it all right?

[SoylentGreen]

Exxon's Russian subsidary drilled a record 37100 ft. last year in Siberia. (Almost 10km! )

[ROCKMAN]

SoylentGreen

You have to be careful with those press releases that don't give all the details. The "Exxon's Russian subsidary drilled a record 37100 ft. last year in Siberia. (Almost 10km! )" didn't actually drill that deep. In the drilling world there's the measured depth of the hole (how much hole you actually drilled) and the true vertical depth (how deep into the earth you drill). The well you reference is what's called an extended reach well. It started drilling verically straight down but quickly started to change course to drill more sideways then vertical. Eventually it was drilling almost horizontally. I'm not sure but I think the true verical depth of the well was close to 8000'. They drilled it this way so they could hit a target that was offshore. It was apparently cheaper to drill more hole from a land location then to drill with an offshore rig.

But there are very deep holes out there. Just last fall I was on a drilling rig in the Gulf of Mexico that drilled over 34,000' true vertical depth...and that was in 7000' of water. The operator gave up before reaching the proposed depth of 37,000'. That would have made it the deepest well drilled in the western hemisphere.