199 comments on Extracting Heavy Oil: Using Toe to Heel Air Injection (THAI)
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199 comments on Extracting Heavy Oil: Using Toe to Heel Air Injection (THAI)
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But the doomers told me technology couldn't help us! Anyway, thanks for the post Gail, I really like the future of this technology. My only question is who do I invest in to make some bank on it?
I don't understand the statement "the air flow is controlled"... once the air breaks through in the far end of that horizontal... how do you ever shut it in to eliminate the cycling of compressed air.
All that matters in a combustion process is the air to oil ratio.... injected air costs money.
If you had vertical wells, you could simply shut in the one that breaks through and let the combustion advance to the next closest well.
Some of these horizontal well applications are a mystery to me.
FF
With the horizontal well, there is really no place for breakthrough to take place, except up the pipe where oil is expelled. There is sufficient pressure to prevent this. The only air that needs to be injected is the amount to keep the process going - nothing is lost to the outside.
With the many vertical wells, there was lots of place for air to break through. It was a constant problem (my interpretation) to shut the wells close to the breakthrough.
This is Don's original description of the situation. Perhaps it makes the situation more clear:
"The combustion gasses bring the mobilized oil and vaporized water to the surface, so no pumps are needed."
Still won't these gasses, etc find the easiest route to exit from? I envision bubbling froth of oil, water, and gasses. I must be missing something.
I'm not an oil-guy , forgive my ignorance.
You got it- all that blob of fluid sees is the pressure drop on it. It doesn't care whether the well is vertical, horizontal, or circular helix.
FF
Might I also mention that at shallow depths (above 1,000' let's say)... hydraulic fractures will be induced horizontally such that a cross section can be created which exceeds that of a horizontal 7" well... at probably 2% of the cost.
Gulf oil Company did this in Kentucky in 1960 and achieved a recovery of over 60% of the OOIP from a 150' tar sand.
FF
Fractional_Flow,
You used the one word sure to catch my eye...."Kentucky" :-)
Does anyone have good resourses on how much tar sand/medium/heavy oil may be in the lower 48 states.
I have been watching the various in situ extraction ideas for some time, and most of them have fell down on cost/energy used to energy return issues (EROEI essentially). This one seems promising, but again, we don't want to jump on the bandwagon too quickly.
On a non-technical issue, the type of developments we are seeing is why I have thought that the Saudi's will soon up production IF they can up production. They have almost "flushed up" most of the game (competitors) as the bird hunters would say. But they may want to let a few get fully vested in the new technologies and production areas before they come in and essentially chop the legs out from under them. But they can't risk letting the competing ideas really get momentum and efficiency of scale going or the cat may be out of the bag.
What a game, but a damm hard investing environment to figure out, I will say that! :-)
RC
Colorado has more oil than Saudi Arabia but it is in the form of oil shale. Off the top of my head a trillion barrels of uneconomical rock oil. Just worry about the Green River formation and the other 46 states is a rounding error.
RobertInKyoto
I haven`t escaped from reality. i have a daypass.
Roger,
There's a lot of heavy oil at shallow depths in the lower 48-a hundred billion barrels at least. The oil is under little pressure in the reservoir, and would not pump out at commercial quantities years ago. Modern drilling methods do not detect this oil easily because most states require a driller to set a surface string of pipe which goes through the sands to protect surface water. When the electric well log is run, it starts below this surface casing.The producing level of these wells discussed above is 500 meters, or 1,640 ft.
At Spindletop, the first producing field on the Gulf Coast, the 70,000 barrel a day gusher blew in at 1100' ft, and there were several shows in sands above the production. A few wells have been completed, but never made over 10 to 20 barrels a day. The oil is all 18 gravity or less, and just won't flow into the well quickly enough to be commercial.I think what happened is that the oil close to the surface was degraded by contact with fresh water and possibly microbes, and was passed up for higher gravity crude.
I've got ideas where a number of these shallow oil sand prospects are located, and am certainly willing to help put them together for a share, even have some money of my own and one prospect of 2,000 acres pretty well ready to go
Bob Ebersole
If the scale of that fourth image is to be believed, the combustion zone is involving an area much greater than "10%"
DelusionaL, This might help.
http://www.petrobank.com/hea-faq.html
Don
(I'm not an oil guy OK?)
It looks good but I still think this is fluid dynamics. I get the warm thinner oil and flow but the 1(one) piece of oil reservoir rock I have looked at wasn't uniform in the "empty space". Wouldn't oil like water take the easiest route even if downward in this situation? Wouldn't combustion rates be set by oil makeup to maintain proper heating/self sustaining flame front? A mixture of required flame speed vs rock porosity?
The pictures look like chemical osmosis through a consistent medium, I envision something more like lightning, fractured, fissured, racing ahead and essentially sealing in areas that just burn away as the flame front has past by.
DelusionaL, I'm not an oil guy either. The oil does take the easiest route, downward via gravity into the producer (horizontal) well which is one of the reasons for its effectiveness. The producer is placed at the bottom of the reservoir. The reservoir in this case is sand, not rock. Oil sands are porous, rock is not which is why THAI won't work on shale oil. The fire front is so hot (often over 700 C) that it is incredibly robust but slow moving (10 inches per day) so that it leaves very little behind.
Don
So is it the negative pressure area created by the producer well withdrawing oil that controls the direction of the burn also?
If the producer well was north, and the horizontal portion ran on a north-south axis, I couldn't see what would prevent the combustion front from moving east or west, or even south for that matter. The reservoir is not lined with sides to direct the burn after all. I guess this is apparent to others, so I must be missing something.
Hi doug fir, Yes.
You said it yourself. The horizontal producer evacuates the oil through gravity along the course of the well due to the creation of a low pressure sink and injected air pressure from behind.. It goes east/west only to the extent that the heat in the reservoir goes. Eventually, at some distance (it appears 50 to 60 meters on either side of the producer) a cooling effect takes place and the oil stops mobilizing. I'm sure that there will be oil left behind but it appears that the process is very efficient.
Don
Thanks for the explanation. D
As I understand it, the longest running well is about a year. So technically, they have no idea as of yet when breakthru will occur.
right and when it does do they seal that part of the horz. well and pull back. It states that combustion gases and vaporized water come to the surface. So why shouldn't the gases bypass the oil altogether? Like sucking on a straw at the bottom of a milk shake.
I'm not an oil guy but this doesn't add up to me. Very slow production (better?)
Yes the combustion gases, water AND oil come to the surface together by flowing down via gravity into the horizontal producer well. I believe your straw analogy is more akin to a vertical well? The fluid and gases drain into the horizontal well because the fire front heats and mobilizes the bitumen with the lighter elements mobilizing first. The heavier elements (coke), are deposited at the back of the fire front and provide the fuel for the process. Ergo, the horizontal well is always full of fluid and precedes the fire front at all times. That is why there has been no air breakthrough. The horizontal producer is full and there is no vertical producer to allow air breakthrough either. Again, horizontal wells completely change the nature of fire flood extraction. If there is a flaw in the THAI process, I don't think it resides in this area.
Don
Don, I think I'm missing something or do not understand something.
The gravity drainage/low horz. production well- If the gas(water vapor and exhaust gases(?)) escape like a bubble pump (manometer pump) lifting oil as it rises, then it looks like gas(s) can and do bypass the oil somewhere in the system. Is this just how it is supposed to work? Maybe this is what I'm missing.
You are working very hard and patiently to explain this to me. I might be a lost cause because I grow plants for a living ;)
DelusionaL, This is the first laugh I've had in two days. I wish I could grow plants! OK. If you study the diagram carefully you'll see that the fire front melts the bitumen. As this occurs a low pressure sink is created into which air/oxygen (I'm not sure which but I think it's oxygen) is injected under pressure from the surface. As the bitumen melts, gravity pulls it and water and gases which are co-mingled with the aforementioned fluids into the horizontal producer well. It is impossible for the gases to "escape" or "bypass" the oil while being produced through the horizontal. You should also notice that there is no place for air breakthrough to occur other than through the horizontal and it is in effect a 500 meter long hose full of fluid. Just think of the pressure required to push that out of the way. It won't happen. It might help if you go here
http://www.petrobank.com/hea-thai-image-1.html
and click on animation. The animation goes through the initial steaming high in the reservoir to mobilize the bitumen and then air injection commences. And it is you who are being patient. I wish I were able to explain this better to you and I'm sure you're not alone. Some of the other comments made suggest to me that others do not understand the process very well. You are just not afraid to admit it. So by all means keep asking. If you can grow plants, you can do anything!
Don
Ok now in this diagram at the toe part it looks like at some point you have air on the production pipe. Does it get sealed (moving away from the flame front) as this happens?
The producer gets sealed in two ways.
1. The producer is always full of fluid (oil and water) mixed in with combustion gases because of the mobilizing and draining via gravity of the reservoir through heat.
2. The heavier elements, coke etc., solidify on top of the producer after the fire front has rolled by. Again DelusionaL, the air pressure required to blow 10's or 100's of meters of fluid out the top of the horizontal producer would be immense. It just is not an issue. I'm hopeful that this explanation makes sense to you. And if not, I'm still here. I must say I admire your persistence. Perhaps it's persistence that will help me learn how to grow plants?
Don
I was a reluctant doomer. Been looking for some good news. I'm enjoying my coffee a little more this morning.
And yes, where do I invest?
Arlo, Petrobank trades on the Toronto Stock Exchange as PBG and in Norway on the Oslo Bors as PBG and on the pink sheets in the US as PBEGF
Don
Thank you Don. Much appreciated.
Don't be too smug.
Here's the best reason I can think of to leave the oil sands alone.
Thank you for the link.
What would it be like for humans to think intelligently instead of stupidly? Good overview--very nice!
AntiDoomer,
I am not sure why you take comfort in the thought of increased production from heavy oil. An economy which is constantly striving to increase its short term wealth is sooner or later going to get into trouble with its resource base. If we can leverage heavy oil, tar-sands, and oil shale, along with improved energy efficiency into several more decades of economic growth at the cost of increase carbon emissions is this really a good thing? I understand the temptation to think so as I have succumbed to it myself. Please, Lord, let me have a few more decades of my ‘normal’ life. But in the long (or maybe not so long) run we have to create an economy whose primary purpose is to preserve wealth rather than to constantly increase it. This is not to say that I think scientific and technical progress will come to an end with the end of economic growth. Nor do I think that there will be zero opportunity for wealth increase in the future. It may be that even in the context of an economy which seeks to maintain long term sustainable methods of economic production, opportunities will arise from time to time to increase living standards though increased efficiency. But to make the desire for constant increases in short term output the driving force of our economic system is insanity. In any rational system of economic production developing methods of agricultural production which maintain topsoil and recycle nutrients so that food production is independent of mining finite concentrations of minerals would be a top priority. Such goals are the kindergarten of sustainable economic production and yet they are not even on the radar screen of the current economic system. Clearly a fundamental paradigm shift is needed and not just techno-fixes which will keep the stock market healthy for X-years longer.
Roger K,
I agree with you that over the next two to three decades (just a guess) we have to adopt a new economic model along the lines of Herman Daly's steady state economy in which economic development,ie, improvements in quality replaces economic growth,ie, increases in quantity. But that transition will require overall economic and political stability as we learn to adjust to lower levels of energy consumption and invest more heavily in renewable energy. If we can buy some time to keep the global economy from a hyperinflationary implosion - don't mean to sound apocalyptic - or major resource wars, we have a chance to accomplish a paradigm shift. I understand, however, the danger of the complacency that can be bred by extending our ability to extract FF a little while longer.
Arlo, your reading of the situation is very good, and your closing line the great warning:
"I understand, however, the danger of the complacency that can be bred by extending our ability to extract FF a little while longer."
We do need to buy a little time....the technology on renewables/alternatives are moving very fast....but.....
If we do after 1997 what we did after 1977, and take the fix of "oil from somewhere, anywhere" and throw the renewable alternatives in the garbage, we lose the whole ball game, pure and simple.
RC
Roger K,
I agree. We live in a finite world. Even if we can "fix" our oil problem for a while, we still have the other problems we had before and they are getting worse - climate change, pollution, fresh water shortages, soil problems, plus all the debt -related problems on the financial side (also related to growth). We need to be finding a more sustainable lifestyle and get rid of the growth paradigm.
Well said.
I think the doomers say that technology won't "save" us from our energy predicament it might "help" us. There is a difference :)
Consuming 30 billion bbl of oil per year we need all the THAI we can get. Not to mention on going growth in China, India, Russia, Brazil et.. el..
I wonder if there were a Manhattan style project for THAI if we could get 90-100 million bbl per day production? That would be cool.
I think THAI is a useful, but limited source of non-conventional oil.
It is not a (IMO) a panacea. It may help, but it will not make up for the looming shortfall of conventional, easy to source and extract light , sweet crude.
It is the loss of the flow of light sweet in the coming years that will be the over-arching problem. A few gains from this technology will merely and ever so slightly delay the inevitable.
Doomers frequently get accused of dissing 'technology'. But ANY of these tecnologies, be it THAI, Ethanol, Thermal depolymerisation etc will simply fail to make up for the loss of flow rates from KSA, Kuwait, Mexico, Russia, UKCS , Norway, North Slope etc.
To carry on as normal requires the discovery of between 4 and 6 New KSAs.
By all means, Try everything and anything to avert disaster, but it will not make up for the looming shortfalls in Light Sweet coming this way soon.
Simmons still has it for me: 'The biggest new fields we will find are now conservation'.
THAI:
Looks to me that it may be feasible in Siliclastic reservoirs. It will not mobilise Kerogen in Shales. It will be tough to use in almost all carbonate reservoirs.
Some other aspects bother me as well, and could possibly be best answered by a Chemical Engineer and a Reservoir Engineer:
How do you remove the flu-gases created by combustion of hydrocarbons in Air? Same with water? How do you ensure full combustion and not create Carbon Monoxide?
At the stated depths, will the overburden gradient be sufficient to stop, control or confine fracturing when air is pumped in and oil is then burnt, expanding and then resulting in the expected loss of volume as it is extracted?
How do you guarantee that the water table is not polluted?
No doubt it will form one component of the energy extraction mix. But it will not mean energy independence.
There are limits to technology, and growth.