Updates
Later, 5:47 p.m. CDT: back to more serious matters. For everyone, quick, what was the estimate for natural gas (dry) in the Bakken in
the USGS Survey of 2013? From the survey:
Gas estimates ranged from 3.43 Tcf (with a 95% chance of production) to
11.25 Tcf (with a 5% chance).
For newbies, the USGS is always considerably conservative.
The Bakken is currently producing 2. 4 billion cubic feet per day (bcfpd). In a year, 365 x 2.4 = 876 billion cubic feet.
Rounding, about 1 trillion cubic feet/year currently? Assuming the math is correct (a huge assumption).
The USGS 2013 Bakken survey:
Gas estimates ranged from 3.43 Tcf (with a 95% chance of production) to
11.25 Tcf (with a 5% chance).
The Zohr? See this post.
Thirty trillion cubic feet. The operator plans to max out at 2.9 billion cubic feet day. That works out to be about thirty years of production. Amazing how the law of large numbers always seems to work out.
Later, 5:29 p.m. CDT: a reader thanked me for clarifying LNG and how it's measured and sold. The reader said, that with regard to angels dancing on the head of a pin, more information was needed --
If
the angels are in Texas doing the Cotton-Eyed Joe, each angel will need her
very own pin (;>) Same would hold true for polkas at a ND wedding
dance.
For less exuberant dancing, more information is needed:
are their wings retracted within the silhouette of their bodies?
ditto haloes?
will
each pin be devoted to a certain type of dance? e.g. couples dancing a
waltz will occupy less room than a bunch of individuals doing a line
dance
if pow-wows are included, where do we put the drum?
inevitably at the end of the evening, somebody's gonna want to limbo, so we'll need specs on the limbo pole.
With regard to the "drum" we need to know the number of angels in the "drum group." Generally there are four members in a drum group but the groups can be far larger -- requiring a second pin, perhaps. As for placement, except in Oklahoma where the drum is in the center of the dance floor, the drum would be on the large circle between the inner circle of dancing angels and the outer perimeter of spectators.
And, once again, down a rabbit hole ...
Original Post
See this post from LinkedIn.
This is a long, long post, but I think the best bit was this, and yes, the writer actually says it ... near the bottom of the post, and I quote verbatim:
The
question I always get is how long does one TCF of gas last? The answer
depends on ... how fast you take the gas out
of the reservoir.
LOL. I haven't had so much fun since I read Art Berman's analysis of the shale revolution.
I may have posted this years ago. I don't know. If not, I should have. From Bharat (Bob) Shah over at LinkedIn, he begins:
If you are associated with any aspect of an LNG plant, you know that the
LNG plant capacity is always specified in tons per year. And that the
LNG onshore storage is always in cubic meters and so is capacity of LNG
carriers. And then LNG is sold on dollars per MMBTU. The heating value
is in BTU/SCF. The gas flow coming in the plant is referenced in MMSCFD
and the reservoir capacity is TCF.
And that's the problem:
- LNG plant capacity: tons per year
- LNG onshore storage: cubic meters
- LNG carriers: cubic meters
- LNG is sold: on dollars per MMBTU
- heating value: BTU/SCF
- gas flow in the plant: MMSCFD
- reservoir capacity: TCF
- size of the head of a pin: measured in the number of dancing angels
So, Bob makes it very, very simple:
- Basis: one train, in his example, has an annualized 5 MPTA or 5,000,000 tons/year or 5 million tons or, I suppose, 5MM tons, or maybe 5 M tons
- So, back to the 5 MPTA = 571 tons / hour (divide 5 million by the number of hours in a full year, 8,760 hours in a full year)
- 571 tons/hour = 1.26 MM (yup, all of a sudden we have switched to "MM") lbs/hour
- 1.26 MM lbs/hour = 75,449 Lb-Moles/Hour (I can't make this stuff up, a quick switch from "lbs" to "Lb-Moles" -- which for a moment I thought was lobster-moles)
I assume we're about to get to the number of angels dancing on the head of a pin.
So, a few more calculations, and we get to, and I can't make this up either,
1TCF approximates (we've been using "equal" signs until now, but now it's an approximation)
18 MM tons of LNG
Why the approximation? Because of the following assumptions:
- feed gas composition, CO2, H2S, N2, H2O content in wellhead gas and efficiency of refrigeration compressor drivers, gas density; etc
- and a bunch of other things
Another assumption: US $8 / MM BTU (this was back in 2016).
Okay, let's move on.
This next comment is refreshing: "
The conversion from tons to cubic meters is simple." Well, perhaps not:
The onshore storage and the LNG carriers have a fixed capacity just as
for any other liquid storage systems. This capacity is always measured
in cubic meters. Why not in barrels or cubic feet, one may argue. It has
always been in cubic meters and majority of LNG customers use metric
measurements. The conversion from tons to cubic meters is simple. (Interestingly enough, I don't think Bob actually shows the "conversion." Instead, he jumps into the issue of shipping).
Let us say one LNG
tank has a capacity of 180,000 cubic meters. So the tank holds 81,000
tons of LNG. [Bob: "You do the math."]
At 571 tons per hour of LNG production per hour per train,
it holds 142 hours of LNG production.
Most LNG plants have at least two
LNG tanks. Some may be a bit smaller in capacity.
Unlike crude oil tank
farms, one can’t justify LNG tank farm as the LNG tanks are very
expensive (LNG is stored at minus 260 deg F).
In order for LNG train(s)
to keep running, the LNG must be loaded into carriers regularly. The
typical LNG customer will be thousands of kilometers away from the LNG
plant. The LNG carriers move slowly at about 20 knots, so several LNG
carriers must be on their way to ensure onshore tanks are available for
continuous LNG production. It is not profitable to curtail LNG
production because the next carrier is still a few days away. The LNG
shipping logistics is very complicated and must be worked out along with
lining up LNG purchasers.
Okay. Now, all of a sudden, a new way to measure LNG: "TCF stands for trillion cubic feet of gas.
BCM is also used and it stands for billion cubic meters."
TCF stands for trillion cubic feet of gas. BCM is also used and it
stands for billion cubic meters. One bcm equals 35.2 bcf or billion
cubic feet.
Gas reservoir capacity is usually referred in TCF.
The
question I always get is how long does one TCF of gas last? The answer
depends on the composition of the gas and how fast you take the gas out
of the reservoir. The heavier components have to be removed before
liquefaction but they count in the reservoir capacity. In addition,
there will be other impurities and gases such as CO2, H2S etc. On my
last project, the reservoir capacity was known to be 120 TCF. Our Hysis
runs for a case indicated that one TCF of wellhead gas produced about 18
million tons of LNG. For the two 5 MPTA trains, the reservoir had
enough gas to last 216 years. So there was plenty of gas for more
trains. And the project did consider plans for future mega trains that
would give total LNG park capacity to 100 MPTA. Without making
adjustment for NPV, the 100 MPTA Park and 120 TCF corresponds to 840
billion dollars of LNG.
In his next post: how many angels dance on a head of a pin? Assumptions:
- the pin is the standard dressmaker / all-purpose pin (not needle)
- length of the pin does not matter
- angels are the standard size as measured before the Fall
- the angels' average separation correlates with "circular" arrangement seen in The Nutcracker and not the linear arrangement patented/trademarked by the Rockettes
