There have been numerous reports in recent times, of oil and gas fields not running out at the expected time, but instead showing a higher content of hydrocarbons after they had already produced more than the initially estimated amount. This has been seen in the Middle East, in the deep gas wells of Oklahoma, on the Gulf of Mexico coast, and in other places. It is this apparent refilling during production that has been responsible for the series of gross underestimate of reserves that have been published time and again, the most memorable being the one in the early seventies that firmly predicted the end of oil and gas globally by 1987, a prediction which produced an energy crisis and with that a huge shift in the wealth of nations. Refilling is an item of the greatest economic significance, and also a key to understanding what the sources of all this petroleum had been. It is also of practical engineering importance, since we may be able to exercise some control over the refilling process.Recharging of Oil & Gas Fields
Of course we all understand the concept of "re-pressurising oil fields" using gas injection and other means.
As the oil or natural gas in a formation is produced, the hydrocarbons remaining in the reservoir may become trapped because the pressure in the formation has lessened, making production either slow dramatically or stop altogether.
...gas injection is used on a well to enhance waning pressure within the formation. Systematically spread throughout the field, gas-injection wells are used to inject gas and effectively sweep the formation for remaining petroleum, boosting production.... gas injection can serve as an economical way to dispose of uneconomical gas production on an oil reservoir. While in the past, low levels of natural gas that were produced from oil fields were flared or burned off, that practice is discouraged in some countries and against the law in others.
...Gas Injection, Gas Lift & Gas Miscible Process
Although the terms are sometimes interchanged, gas injection and gas lift are two separate processes that are used to increase production. While gas injection is a secondary production method, gas lift is a type of artificial lift.
Artificial lift is another way to increase production from a well by increasing pressure within the reservoir. The main types of artificial lift include gas lift and pumping systems, such as beam pumps, hydraulic pumps and electric submersible pumps.
While gas injection is achieved by injecting gas through its own injection well, gas lift occurs through the production wells. In gas lift, compressed gas is injected down the casing tubing annulus of a production well, entering the well at numerous entry points called gas-lift valves. As the gas enters the tubing at these different stages, it forms bubbles, lightens the fluids and lowers the pressure, thus increasing the production rate of the well.
Furthermore, a type of EOR employed on a well in the tertiary production process, a gas miscible process can be used to increase production. The difference in this recovery method is that the gases introduced into the reservoir are not naturally occurring. In a gas miscible process, carbon dioxide, nitrogen and LPG are injected into the reservoir. _Rigzone Gas Injection
Most of the oil in existing wells remains underground, waiting for people to become smart enough to retrieve it. Better enhanced oil recovery techniques will inevitably be developed to extract more and more of the residual hydrocarbon -- until it is no longer economical to do so. Then the remaining oil will wait for further developments.
Thomas Gold argues (here and here for example) that oil wells are charged and re-charged with new oil & gas from below. He claimed that most new hydrocarbons are generated deep in the crust, rising into geological traps at several different depths for particular parts of the crust. That is the abiogenic theory of hydrocarbon production, which is supported by astronomical data and by lab data simulating conditions in the deep crust and upper mantle.
Rapid charging of oil fields -- such as is suggested here -- would require deeper secondary reservoirs under pressure, feeding into the primary reservoirs as they are depleted.
There is another way in which oil & gas fields are re-charged -- via the biogenic production of oil & gas. But biogenic production via geologic heat and pressure is generally a much slower method of re-charging than Gold's abiogenic method. But it inevitably occurs all the same. Biogenic oil is a renewable resource, but it is renewable on a different time scale than humans generally use.
And yet, there is a way in which biogenic oil can "rapidly" recharge a depleted oil field. In the case of multiple communicating oil reservoirs at different depths, heat, and pressure, a deeper biogenic reservoir could re-fill a more superficial reservoir at variable rates, depending upon a number of factors. Oil & gas migrate upwardly, when given the opportunity. In this case, instead of "turtles all the way down," it is "oil & gas reservoirs all the way down." ;-)
Biogenic Oil Formation
This image illustrates the conventional idea of biogenic formation of oil. Imagine it taking place over and over again, during the 3 billion + years that photosynthetic life has been converting CO2 into various biological carbon polymers, layer stacked upon layer etc etc . . . . .
Abiogenic Hydrocarbons Forming in the Mantle
This image illustrates the likely abiogenic formation of hydrocarbons in the upper mantle. These hydrocarbons then can migrate upward into the crust, and become trapped under impermeable minerals. Abiogenic hydrocarbons almost certainly mix with biogenic hydrocarbons.
Abiogenic hydrocarbons are also modified in various ways by deep crust microbial populations. In other words, the predominately short-chain abiogenic hydrocarbons from the mantle can be converted to longer chain hydrocarbons on the way up.
Finally, there is the ocean crustal tectonic activity which feeds a constant supply of partially processed organic material to the deep crust and mantle via constant subduction of ocean crust beneath continental crust. This is a slow but steady pipeline which supplies feedstock for production of oil & gas on a constant basis. The Earth's huge gas hydrate resource likely owes a great deal to this tectonic process.
By. Al Fin
Al Fin runs a number of very successful blogs that cover, energy, technology, news and politics. More
Comments
Gee, another example of how perfect this world really is.
I suggest we stop cutting down our trees instead of worrying about how much CO2 we are adding.
The single worst day in Yellowstone fire history destroyed 150,000 acres of trees. If we could have controlled that fire, those trees would be removing almost 2 million tons of CO2 PER YEAR, while adding about 11 million tons of O2.
That's just ONE DAY, in ONE FOREST, on one SMALL SPECK on this planet.
or in other words, humans over time developing technology through scientific ingenuity, have ended up using oil which expels Carbons in the air. this carbon is consequently eaten by plants who use photosynthesis. therefore god... still not sure what god created us so we'd use petroleum oil to burn for combustible fuel when there could be less harmful to human ways to utilize energy for a system. in fact this seems in reverse to reality. If any god who creates could see down the cooridoor of time they would more than likely want us to utilize black hole gravitational entropy energy since its 100% clean, lasts for flipping ever, and when used correctly is much more safe and could generate orders of magnitude more energy than this. I can't wait for many years from now when the internet AI compiles a giant joke book of posts like yours so we can all laugh at how primitive our minds are in this age right now even while having the combined knowledge of our species at our fingertips, they still must insert an omni-something creator while calling people like jim "Silly". oh my the irony is so heavy it's hard to carry all by myself. while the article explains that this oil is not some magic source like alot of theists have been claiming, you still somehow find a way to say this is all some elaborate creator who planned it, when the reality of the observation would just further fall in line that everything has evolved and through adaptation/natural selection, you have exactly what you described as "another example of how perfect this world really is" as if you even have a functioning comparable planet that is not as perfect as ours or like you've met this creator when all others before have failed to provide even a shred of actual evidence without twisting the facts like you just did to insert this god who is still unnamed. this science is made from humans working day and night to understand our world and how it works, stop injecting things that need not be, and stop calling people silly, because that IS silly.
also great read, thanks @Al Fin