Welcome to the forum Hybrid....
This is really interesting. Hope you don't mind me taking you into the realm of economics:
There ought to be a way to model the cost of maintaining the pressure of the vessel at P sub 0, that is, as a little fluid is extracted, the pressure can be brought back up to P sub O at some cost. In the real world, this would represent the injection of water or CO2 or something to maintain the flow rate. Obviously, as the fluid is extracted, the cost of maintaining the pressure at some rate will increase. Also, increasing the diameter of the hole (or drilling more holes) will make necessary an even greater increase in cost to maintain the pressure.
What I am thinking is at some point after the peak, the incremental cost of maintaining the pressure at a given rate can be pretty close to asymptotic, which is to say, at some point, you reach "the wall" and the incremental cost of maintaining the flow rate will exceed the incremental benefit of extracting the fluid. There is an economic breakeven rate, and also, an energy breakeven rate (EROEI).
It would be interesting to know how far to the right of the peak that will occur. From that, you could make some estimates for a given field as to the point at which you would abandon production, and therefore, get some understanding of how much of the "proven reserves" in a given field might be unrecoverable.
The reason that this is interesting to us, is the historical data for production and consumption of NGl in Saudi Arabia.
- Code: Select all
Prod oil cons gas cons ratio
1999 8911 1455 4.5 1980.222222
2000 9511 1485 4.8 1981.458333
2001 9263 1500 5.2 1781.346154
2002 8970 1522 5.5 1630.909091
2003 10222 1629 5.8 1762.413793
2004 10584 1728 6.2 1707.096774
Presumably Saudi is using natural gas or some oil-derivative to pump seawater down into their holes to keep the pressure stable on their small number of oilfields. As you can see, over the past five or six years, the amount of oil extracted per BCF of gas has been getting lower and lower every year. This suggests that they are having to pump the hell out of water into their holes to keep production constant.
Using the above equations, along with a cost factor, you should be able to estimate how close Saudi is to "peak" and also model how many years they have until it becomes too costly to pump the incremental amount.
It would be really interesting to know this.