[Soft_Landing]

You hear a lot of talk about how technology has increased the rate at which we can extract oil from a reservoir. But i've never seen a quantification of how much this has changed.

The gaussian extrapolation really assumes that the extraction profile for oil wells is not systematically varied through time. But I guess we know that this is happening. This does mean that the overall distribution will not be gaussian, but instead, be skewed to some degree, resulting in a higher peak, and steeper depletion.

The 1850 trillion dollar question is: how much? So if anyone has any quantitive data about the rate of change of the depletion profile over time, it love to know about it. Thanks.

[Whitecrab]

I think this energy forum needs a topic on what new kinds of techniques - if any, can delay the peak. I'm trying to get my uncle, who's a petroleum engineer, onside with me about Peak Oil. However, he shot this back:

It is great that you are interested in the petroleum industry... maybe you can help find a solution!!! ... my personal thoughts are that the problem is probably 50 years out or so.... it is a supply/demand issue.... if the price of oil is higher there will be more production (from any number of sources) brought on stream.... do not disregard the volumes available through EOR (Enhanced Oil Recovery)... we currently recover less than 30% of OOIP so there is still 70% left... we know where it is and at $50/bbl + it will be possible to economically recover more...

I've heard numbers flying around that the recovery % we make today ranges anywhere from 15-20%, to 40-50%, depending on the source I'm reading. Either way, that suggests there's at least double the oil we expect existing, but that we're unable to access.

Can anyone confirm or deny what my uncle is saying? If we get desperate enough, can we start taking desperate and expensive measures to get the oil that's left in some places? If there are some really high cost solutions to get that extra 50%+ out of the ground, that could delay and smooth the peak, giving supply/demand economics more time to adapt. There would be less of a supply shortfall, although price could still be rising to crippling levels and the EROI could drop or even go negative.

[Rod_Cloutier]

I’ve heard in the media that there is a problem with oil drilling operations. When drilling for oil the bit will often break- requiring a new bit to be fitted to the drill shaft. The drilling companies all say there is no way to get around this problem –it is unsolvable. Well I’m in the camp of thinkers like Thomas Edison who said “No problem can withstand the assault of sustained thinking” & I would like to share some ideas I’ve had on this problem.

One solution might be to have a series of drill bits connected in a drill through scheme. IE- you get a master drill bit, a smaller drill bit fitted above or inside it, and then an even smaller drill bit inside or above that one. Each drill bit made of progressively harder material that can simply drill through the old bit once that bit has failed or broken. This would save the time and money of extracting the drill rigging out of the ground, replacing the bit at the surface then having to reinsert the drill rigging back down to where it was.

Another idea along the same lines is to have explosives built into the drill bit & have a drop in bit slide down the drill shaft after. IE- when the drill bit fails the explosives in the bit can be remotely detonated from the surface & then a replacement drill bit slides down a hollow drill shaft from the surface to continue drilling. The replacement drill bit also having explosives built into it so the process could continue thru multiple drill bits till they reach the targeted depth.

Still further if explosives in the drill head are ruled out or unsafe- the drill head could be made of materials that would vaporize when an electric current is applied to it. IE- a very high voltage cord runs down through the drill shaft to the drill bit & when the bit has lost its utility a sufficiently high voltage is passed down the cord to the bit to vaporize it & then a new drill bit can be dropped down the shaft to replace it.

I hope these ideas help someone somewhere!

[smiley]

One solution might be to have a series of drill bits connected in a drill through scheme. IE- you get a master drill bit, a smaller drill bit fitted above or inside it, and then an even smaller drill bit inside or above that one. Each drill bit made of progressively harder material that can simply drill through the old bit once that bit has failed or broken.

I don't think they have that luxury. I'm not an expert in oil drilling, but ordinary drillbits are usually made of a very hard steel or alloy coated with boroncarbide or cubic boron nitride. That's as hard as it gets (one step down from diamond). Even with a diamond blade it takes ages to cut a piece of boron nitride.

In order to increase the lifetime of a drill you use the hardest material possible. I don't believe they have room to increase the hardness of the drills any further.

[Rod_Cloutier]

Sometimes you have to take one step backwards in order to take two steps forward!

If the method I suggested in this article is defeated because we are currently making use of boroncarbide or cubic boron nitrate drill heads; then part of the solution is not to use these super-hard materials.

As suggested in my original article, you begin drilling through soft earth with a soft drill bit, when that has worn down- a harder drill bit drills through it and down into harder Bedrock. When that drill bit is exhaust a further drill bit made of harder stronger material (like the boron carbide bit mentioned) could be used as the last step of the process.

The addition two soft drill bit steps would cut down or eliminate wear & tear of the super-hard bit needed to reach the targeted depth. And the new process would reduce drilling expense & cut drilling times. If more wells could be drilled quicker & cheaper- more and more marginal supplies of oil could be brought economically to the market.

[dmtu]

Oil rigs use reverse circulation. Dual walled drill steel allows mud (mud stabilizes the earth wall and brings cuttings to the surface) to be sent down the outer wall while cuttings come up the center so the progressively smaller bit idea would be tough and undoubtedly more expensive if not technically completely impossible. The drill bit usually a tri-cone or hammer has to be larger than the steel so at the outset you would need an extremely large hole and an extremely large blowout preventer (prevents the steel from being forced out of the hole by high pressure gas). The anhydrous (?) rock that acts as a cap over good oil deposits is very hard, in my personal experience with limestone a bit can be useless in as few as 6 hours of use with as little as vertical 100 feet. Drills are also limited by drawback strength. While I won't claim to be a pro by any means I have worked on exploratory rigs. Tripping steel back out of the hole is just about the most hated task there is on a rig so I imagine if there was a better way one of those guys would have figured it out. I know I certainly gave it some thought. Toughest work I've ever done and I think I would as soon starve as to do it again.

[Grasshopper]

I've heard numbers flying around that the recovery % we make today ranges anywhere from 15-20%, to 40-50%, depending on the source I'm reading. Either way, that suggests there's at least double the oil we expect existing, but that we're unable to access.

The range in recovery of original oil in place (OOIP) that you have noticed is due to different reservoir types, drive mechanisms(eg: water - drive, gas-cap drive, solution gas drive). Your uncle is right about ultimate recovery being dependent on price, higher prices will lower the economic limit of any well in barrels per day. At that stage of development, only tiny increments are possible, though. Higher prices will justify spending more on research and exploration, which will result in more discoveries and enhanced recovery techniques. A promising method is CO2 injection, wherby carbon dioxide is injected to maintain pressure in oilfields or displace methane from coalbeds.
some CO2 sequestration projects which will/are being used to enhance oil & gas production in Canada can be found here:

http://www.encana.com/operations/upstre ... stics.html

http://www.nrcan.gc.ca/es/etb/cetc/comb ... cts_e.html

North America, especially the USA, is more thoroughly explored than other parts of the world due to the presence of independent oil companies which compete for the smaller pools that are left. In the last decade, increased competition and western involvement in the former Soviet Union has increased production in many areas.
Horizontal drilling went from experimental to main-stream in just a couple of years. Production rates are generally higher, with resulting higher decline rates, but increased ultimate recovery from oil pools that are drilled up horizontally.
new enhanced recovery projects will increase ultimate recovery a lot, but much of that last 50% will probably stay underground. I have been reading some threads about diminishing returns regarding alternate energy mostly, but that would ultimately apply in oil production, of course.
The consequent price increase resulting from peak oil will tend to intensify exploration and development and thereby increase ultimate recovery, smoothing out the world-wide decline.

{edited for format error - row}

[Ted]

Humans have removed a fairly large quantity of matter from deep beneath the surface over the past century. The fact that oil and gas rise under pressure implies that stresses in the surrounding rock must change in consequence. Does the ground adjust gradually or are there instances in which the stresses build up in relatively hard formations without much movement until an earthquake relieves it? Does extraction of oil remove an important lubricant and promote uneven stress distribution?

[nailud]

This isn't anything that you need to worry about. Oil and gas are produced from pore spaces in rock (between sand grains or in fractures, for example), and are not (usually) critical to the structural integrity of the rock.

[Ted]

The fact that it's under pressure disproves your contention.

[markcmyers]

I understand that historically, the point at which half the oil has been removed is the same point at which production starts to decline. But why is this? Why can't production be ramped up after the halfway point, so that production continues to increase for a time, postponing the decline (which, of course, will be steeper when it comes)?

[dhickerson]

Why can't production be ramped up after the halfway point, so that production continues to increase for a time, postponing the decline (which, of course, will be steeper when it comes)?

Well, like you said, that would worsen the steepness of the decline when it happens, but even more importantly, to ramp up production you would use more resources getting at the oil and at some point the amount of resources put into the process would be worth more than the oil you'd be getting in return. Steep steep down from that point.... *thud*

[Aaron]

Many factors affect this, but the most important are the extraction rate characteristics of an oil well.

At the beginning of an oil wells life, they are typically under geologic pressure, and flow freely without assistance.

We have discovered that we can insert water (or gas etc) to maintain this positive pressure even after the well no longer "naturally" provides this pumping pressure.

The problem is that either naturally occurring pressure or artificially induced pressure extraction can only go so far. We pressurize the well and it pumps at a given rate... that's it.

If we could find another "giant" field somewhere, we could indeed maintain or increase production. Therein lies the rub.

[markcmyers]

...that would worsen the steepness of the decline when it happens

This might be a reason why it's not wise to increase production after peak, but surely wisdom isn't the mechanism that underlies Hubbert's curve.

...to ramp up production you would use more resources getting at the oil and at some point the amount of resources put into the process would be worth more than the oil you'd be getting in return...

Yes, there is a point at which net energy is 0, but is this point reached whenever you try to flatten out Hubbert's curve, or would it occur sometime later? Is the point of zero returns the controlling mechanism for the curve? If so, who has demonstrated it?

Is it possible that no one fully understands the mechanism that underlies Hubbert's curve?

[markcmyers]

The problem is that either naturally occurring pressure or artificially induced pressure extraction can only go so far.

I guess my question would be: Is the downside of Hubbert's curve fundamentally a description of declining pressure? Is it just physics, or are there other things at play? Has anyone attempted to prove that the downside of Hubbert's curve can be explained primarily by declining pressure?

[Aaron]

No,

The main reason for declining production is the lack of new oil field discoveries.

A given field can produce "X" amount of barrels per day.

Add all the producing fields together... that's the maximum extraction rate.

[markcmyers]

The main reason for declining production is the lack of new oil field discoveries.

A given field can produce "X" amount of barrels per day.

Add all the producing fields together... that's the maximum extraction rate.

You seem to be saying that Hubbert's curve tracks the number of producing fields times their various maximum extraction rates. This would entail that all fields produce at maximum capacity all the time, or perhaps close to it. Is this true? If not, then there are additional variables underlying Hubbert's curve.

[0mar]

In most of the conventional oil field wells/fields, initally oil literally flows free from the pressure. The slightest crack will send it gushing up from the ground. However, as oil is withdrawn, the pressure declines. It becomes increasingly more difficult to recover the oil without secondary and tertirary recovery methods. Most methods are there to help bring the pressure back up to pre-peak periods. However, there are some added risks, one not withstanding is that the 3-D topology of the oil well may not be able to sustain the new source of pressure and it will collapse. Since each field is unique, there needs to be fairly tailored methods used, otherwise one risks damaging the field permentantly.

It is analogous to drinking from a slurpee. If one keeps the straw level (like a pump/drill in an oil field), it becomes harder and harder to drink the slurpee. While not completely perfect as an analogy, it can help convey the picture of reduced fluids and pressure as constraints on extraction.

[markcmyers]

You guys are doing a great job explaining why production inevitably declines
at some point. But nothing you've said is a convincing argument why the decline must follow Hubbert's Curve. Do you see this?

[Aaron]

You seem to be saying that Hubbert's curve tracks the number of producing fields times their various maximum extraction rates. This would entail that all fields produce at maximum capacity all the time, or perhaps close to it. Is this true? If not, then there are additional variables underlying Hubbert's curve.

Many factors affect this, but the most important are the extraction rate characteristics of an oil well.

Agreed... the cumulative extraction rate for all producing fields = maximum current rate.

Although at current prices, it's hard to imagine any producer holding back.