From the old to the newer, or a thought for Khurais and its companions
Posted by Heading Out on August 29, 2006 - 11:02am
In terms of major developments Khurais stands out as being considerably bigger than the rest.
Foster Wheeler's scope of work includes a grassroots central processing facility at Khurais, upgrade of support facilities at the Ju'aymah gas plant, inter-field pipelines, utilities and product handling/storage/infrastructure and support facilities. Foster Wheeler will validate the work undertaken to date and will provide overall project management and engineering services for the central processing facility, including certain procurement and construction management services.The thing missing from that list is the drilling of oilwells. And here there will be a little bit of a problem. In discussing the oil production of the fields in Saudi Arabia, Matt Simmons noted, in "Twilight in the Desert,"a quantity that he called the Productivity Index. This is the volume of oil that would flow from different fields as a result of a pressure drop of 1 psi across the rock: well interface. In other words if you divide the amount of oil you are getting from the well by the difference between the pressure in the rock minus the fluid pressure in the rock, you get the production index. For Abqaiq it was 110 barrels per day, per psi, so that a pressure drop of 150 psi across the well boundary would produce a flow of 16,500 barrels a day, diminishing as the pressure drop declined.
It is the control of this differential pressure, and the resulting flows of oil out of the rock into the well, that allows management of the oil flow in the rock, and stops too much preferential flow through larger fractures, to the detriment of long-term oil production. The pressure differential is controlled through valves at the top of the well, throttling which increases the delivery pressure of the oil from the well, and lowers the pressure drop between the pressure of the oil in the rock, and the fluid in the well.
Flow rates for the major fields in KSA per psi are Ghawar (141 bd/psi); Safaniya (136 bd/psi); Zuluf (100 bd/psi) etc. But when we come to the more recent fields to be developed, Haradh and Khurais, the production indices per psi drops to only 31 bd/psi for Haradh. I have not been able to find the production index for Khurais, but looking at the number of wells that will be drilled, together with those already in place, that presumably have been worked over, I get the feeling that it will be around the same number. With that index and under the same pressure differential as Abqaiq, therefore, each well can be anticipated to produce only around 4,500 bd. Given the promise of a 1.2 mbd increment, this would thus require that some 300 wells will need to be drilled into the formation. However, as with the other fields in KSA the field will be produced under simultaneous water injection. Thus the field will need 4.5 million barrels of treated seawater per day to be injected. Needless to say that cannot be all poured down one well, but must be injected through special wells drilled for that purpose around the perimeter of the field. The total number of wells that must be drilled thus must, under the same conditions, exceed 300 wells. The recently awarded drilling contract calls for just 300. The drilling part of the project has been awarded to Halliburton, and some 23 drilling rigs have been assigned to the task. Providing the rigs themselves does not appear to be quite the issue that was once thought. The 100th rig was commissioned recently, although, given where that one came from, they may still have some difficulty in reaching their target of 121 rigs in the Kingdom by the end of the year.
There are, however, several ways in which production can be increased. The most likely will be that, as has been reported the wells will be extensively hydrofracked to increase the flow, and one can also assume that MRC techniques will be used in the field. The one thing that it is unlikely that they will do is to increase the pressure difference across the well wall, which can be achieved by opening the valves wider at the top of the well. The reason for this is that the greater this pressure drop (which can be thought of as sucking harder) then the greater the problem of controlling the flow to ensure that the water:oil interface (and the overlying gas:oil interface) stay relatively flat, and don't cone into the wells. The problem of coning is one that plucky underdog addressed the other day, and I quote
OK, briefly: oil floats on water in the rock. Horizontal interface between the two phases is called the oil water contact (ignore the transition zone). Production wells are drilled down to somewhere above the contact. When production begins, the area of reduced pressure (drawdown) around the wellbore causes the contact surface to be perturbed upwards until it reaches the production well and you start producing water. This is "coning", so called after the shape of the perturbed contact. If you stop production then the pressure disturbance goes away and the cone collapses, in certain rather complex to define circumstances (has to do with "relative permeability hysteresis", which I can't describe compactly, or maybe at all).In other words sucking too hard can be detrimental to longer-term production. Could be an interesting field to watch being produced.Really hard to interpret diagram here http://www.glossary.oilfield.slb.com/search.cfm and search for "coning"
Coning is promoted by:
High production rates
Narrow interval between contact and bottom of well
High oil viscosity (=> high drawdown & adverse mobility ratio)
Low horizontal permeability (ditto)
High vertical permeability (gas moves faster)
High net:gross (no shale stringers to stop water moving vertically)If you know enough about the rock and fluid properties then you can estimate the "coning critical rate", i.e. the rate at which the cone will have grown to the point where it just reaches the bottom of the producing well. You can then choose to limit your production rate to just below this level to avoid water production. It certainly extends DRY production into the future at lower flowrates, but if you are willing to cycle enough water through the reservoir then you'll eventually get all the moveable oil out anyway, up to the economic limit. And sometimes the coning critical rate is so low that you just have to shrug and accept that it will happen at any economically realistic well production rate, and manage the water on the surface.
Remember that if you are injecting water below the oil, or if an aquifer is influxing into the reservoir, then the contact will be moving upwards anyway so the coning critical rate will change with time as the contact gets nearer to the wells and eventually breaks through independent of production rate.
Coning can happen with gas as well, this time coming from above not below - think Cantarell (but unlikely there due to very high horizontal permeability).
Horizontal wells spread production out through a larger volume of reservoir (hand wave) and so reduce drawdown and the propensity for coning. Again this delays water breakthrough but once it happens, it happens. See "cresting" in the Schlumberger glossary linked above.
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But now Saudi Aramco hopes to get 1,200,000 barrels per day when before the very best they could do was 144,000 barrels per day. How do they hope to accomplish this feat? Obviously it is with the aid of massive injections of seawater. Contracts have been let to lay this seawater pipeline from the Persian Gulf.
In 1983 Saudi drilled 50 new gas reinjection wells in the Khurais field to try to get production up. But production kept falling and the field was eventually closed because of low well production and other technical problems. At the price of oil in those days, they probably felt that a seawater pipeline from the gulf was just not economical. Now however, with the price of oil at $70 a barrel, they will try to get more oil from this field. But a jump from its former peak of 144,000 barrels per day to 1.2 million barrels per day seems quite a leap. I would bet a pretty penny that the field will never produce more than half a million barrels per day. In fact, I have serious doubts that it will ever reach that point.
Ron Patterson
If they're investing serious $ in pressure support (water or gas injection) they must think they've got the well productivity end cracked. Maybe complex bottle-brush wells to spread each well's pressure sink across a square kilometre or so rather than hundreds of square metres.
Still an expensive and risky project. If they make it work, no doubt there will be a trickle of technical papers over the next few years.
It seems very wishful thinking / fantasy to beleive that this field may now produce at 1.2 million bpd.
On the technical side, Plucky's notes could be supplimented with a few comments on bubble and dew points of oil. In fields with poor reservoir quality (low porosity and low permeability) fluids (water and gas) may be unable to flow rapidly enough through the rock to replace the produced oil and this may result in rapid pressure decline. Reservoir engineers must maintain pressure above the bubble point of the oil. That is the pressure at which gas starts to come out of the oil solution (think of taking the cork out of a bottle of bubbly). When this happens, the gas occupies some of the pore volume of the rock and reduces the relative permeability to oil. Furthermore, gas is more mobile than oil so you are likely to end up producing gas and not oil when the bubble point is crossed. At the dew point, all the gas is out of solution and you are left with "dead oil" in the reservoir.
One of the aims of injecting water and or gas therefore is to maintain reservoir pressure above the bubble point but if the reservoir is tight these injected fluids can only do their job slowly. This places constraints on the rate that oil can be produced. 1.2 million bpd seems very ambitious for a 50 year old field that seems to have performed like a dog in the past.
Sorry I don't have any expertise to further illuminate this thread, but I just want to say thank you for your efforts as I avidly read everything you write.
Bob Shaw in Phx,Az Are Humans Smarter than Yeast?
Looking at those constantly updated wind speed probability tables offered by the National Hurricane Center made me wonder if the TOD contributors with expertise could offer something similar in this field.
ie. What do they see is the probability that KSA will peak by 2008, 2010, 2015 or even by now?
Same for other oil producing nations.
Simmons has said that much of the debate currently is "theological". i.e. The data is just not available.
It that case, provisional conclusions expressed as probabilities seems to make sense.
Asebius
Insufficient data means you simply don't know. Probabilities based on insufficient data are just swags, have no meaning.
Spoken like an engineer. (Are you one?) But decision makers almost never have the luxury of sufficient data. And so they mentally navigate the "fog of war" with probabilities.
Regarding SA, I agree with simmons that there is not enough data to guess future production, even though the clues seem to point to major problems. Like many, I guess that they will have difficulty getting back to 9.5mm/d regardless of the number of rigs, but moving from an avg of 18 to, say, 180 may be enough to increase production for a time. They have clearly decided to do their best, we will just have to wait and see. I don't see how anybody not closely involved could assign probabilities.
The curious thing about Simmons is that he bases his early-peak pessimistic case to a large extent on an analysis of data provided by the SPE (Society of Petroleum Engineers), whose expertise he greatly admires.
Yet the SPE apparently estimates KSA's capacity to be greater than do the Saudis themselves. This is because the SPE includes reserves attributable to enhanced oil recovery in its standards, but the KSA excludes such reserves. And that makes quite a big difference.
Some mishtake here shurely ...
KSA date of peak? The date that has the very highest probability of being the peak, 1980 when they produced an average of 9.9 million barrels per day, crude + condensate.
Second highest production year would be 1981 when they produced 9.815 million barrels per day, crude + condensate.
Third highest production year? That would likely be 2005 when they produced an average of 9.55 million barrels per day crude + condensate.
So far this year they have produced an average of 9.357 mb/d through May. But that figure is surely to drop to around 9.2 or 9.3 mb/d as the year wears on.
Ron Patterson
so, the table would be something like:
2005 2006 2007 2008 2009
P1 P2 P3 P4 P5
With the sum of the probabilities equaling 100.
If you haven't seen it, the HL case for a (final) Saudi peak in 2005:
http://www.energybulletin.net/16459.html
To summarize :
- it's likely, but unproven, that the Saudis are lying about spare capacity. It's also likely that they could squeeze out a spurt of additional production, but unlikely that they could sustain it.
- they are managing a long plateau of production, which has quite likely masked the "true" peak production rate.
Now, in order to have faith in the Hubbert linearization of the Saudi peak, I guess I need to study how the curve-fitting was done for Saudi -- can someone point me to an article which discusses this in detail, analogous to "Four US Linearizations", i.e. identifying which period is linearized?OK I could hunt for it myself... the smart people already know it by heart anyway... but I'm hoping that by reiterating this crucial point in detail, we can come to a better collective understandings of the underpinnings of the peak.
AlistairC,
"Smile when you say that pardner!"....I recently commented that the Saudi's and other producing countries could be exercising what they like to call "good supply managementl" to (they like this word) "stabilize" the market, and it sent folks into fits of anger and disgust...IT'S A CONSPIRACY THEORY!!
(this from the same folks who accept a massive linkup of the oil, auto, housing, banking industries and press in "misleading the sheepie")
Of course "supply management" has been a part of the long history of the oil and gas industry, from the Texas Railroad days, right up to the
1970's-1980's OPEC "adjusting the tap days. It often greatly confuses the production picture, and it is extremely naive to assume that all oil producers run "wide open" simply for the purpose of keeping American gasoline prices dirt cheap. That is NOT their first priority.
Roger Conner known to you as ThatsItImout
If the Saudis wanted to fine-tune oil prices to keep them at $70, what would they do ?
How about exactly what they are doing now : throttle back just a touch, to counter the easing of the market which results from demand destruction?
I've been reading TOD for a few months now and gradually have become convinced by articles like HeadingOut's that there is very substantial expertise here.
But just how sure are the main contributers? And when new info surfaces, how are views shifting.
It can be quite difficult to piece it all together. Those various probability products at the Hurricane Center's site speak volumns to me. I realize they are derived using a strict methodology. And that anything so strict can't be developed for use with KSA production forcasts.
Asebius.
The truth is they could be doing both. Simmons points out that they frequently have over produced their fields - putting their old marathon runners on short sprints to meet demand peaks. Right now they may be taking the opportunity ro rest but coud conceivably have 1 million bpd+ in the back pocket available for short term production sprints. Tend to agree with Darwian though that they are past peak. The relentless decline of their super giants will inevitably take its toll.
If KSA tank farms are low which I think they are then they are refilling those as opposed to lowering production rates.
They have a fairly large storage capacity which I think throws a major monkey wrench into any monthly Saudi numbers.
I've not seen anyone come up with a way to see when there pulling out of storage. That would be a useful number.
*Russia became the world's top producer, pumping 9.636-million bpd in May. Saudi Arabia's output stood at 8.93-million bpd, sharply lower than the 9.432-million bpd it produced in the same month last year, said the report.
*
Can anyone tell me if they cherry-picked that number? Would the same be true if they talked about 1990 to present, for example?
BTW, I found the level of condescention in the CGES response to be a bit overbearing.
The last time I was in L.A., I got stuck behind a slow-moving beaten-up truck on the I-10. Those things must be hard to push.
Much has been made lately by the minister of energy in my country (New Zealand) of Coal to Liquids technology, so I've been thinking about it quite a lot lately. Now i know that there are people who have much more technical ability than me on this site so I'm going to run an argument through and hope that if it is wrong someone will correct me.
It is my understanding that Coal to Liquids technology has a current EROEI of 1/1.4. (I got this figure from Richard Heinburg, if it is wrong please correct me). That is, for every equivalent barrel of fuel produced 0.6 of a barrel is expended (excluding sequestration costs). It is also my understanding that to produce one barrel of liquid coal fuel (for lack of a more precise term) 3.5 tonnes of coal is needed. So for every barrel of this fuel that is produced about 5 tonnes of coal is used (although if you simply burnt the coal to carry out the gasification and subsequent liquefaction process you may reduce this amount to say 4 tonnes).
So if we apply these figures to a scenario where CTL substitutes US oil consumption, what does the sustainability look like? Well, the US consumes 20 million barrels of oil per day, roughly 8 billion barrels per year. Multiply this by 4 and you get 32 billion tonnes of coal consumed annually. The US has a stock of around 300 billion tonnes of coal http://lsa.colorado.edu/summarystreet/texts/coal.htm , enough to replace oil demand for around 10 years. The US has around 25% of the world's coal reserves, so the US alone could use the entire world's coal reserves in 40 years under this CTL scenario. Anyone for coal to liquids?
In addition, coal burning power plants and sequestration use predominantly electric power. Most fuel use is only for the locomotives that haul the coal, very efficiently. So the energy return on investment is very low, but the liquid fuel return on investment is very high.
Finally, the measured and drilled coal reserves are by definition always less than ten years, how much less being a question of interest costs and drilling costs. That's because drilling to establish where the coal is so you know where to move your mineshafts to next year or the year after is costly and you don't spend the money till you have to.
So we aren't going to run out of economically minable coal till another fifty years, even if we do make all our liquid fuels from coal for the whole world.
"You assume sequestration costs are high because of perfect pollution control, reducing coal pollution to below nuclear pollution levels and coal power costs to above nuclear costs. This has not been mandated anywhere, and is not likely to be mandated."
Actually for this reason and others I exculded sequestration from the equation.
"In addition, coal burning power plants and sequestration use predominantly electric power."
Ok, so we build many more nuclar facilities to source the electricity. Still this doesn't give us a figure of tonnes of coal per barrel of LCF. Perhaps still 3 tonnes per barrel?
BTW, you realise that economically retrievable uranium is not overly plentiful.
"the measured and drilled coal reserves are by definition always less than ten years, how much less being a question of interest costs and drilling costs."
Fine, but that still says relitively little about howmuch coal is actually left, and how long it would take for the production to peak - these are the important questions (not to mention global warming).
Furthermore, what kind of cost are we talking here? I'm thinking that with all the electricity required for the process were talking very high $ per unit of energy.
If you read this, I would like to add:
It has been concluded previously that we will do CTL, big time, GW or not. It is speculation on how the future will unfold but it is not unlikely.
Extraction from a coal deposit follows a bell shaped curve. So it is thus not so relevant to say "we have 10 years worth of coal for CTL" but it will be relevant to say "when will Peak Coal (PC) occur?". ASPO becomes ASPC, theoildrum becomes thecoaldrum, lifeafterthecoalcrash.net and so on, you get the picture.
I am not trying to take away from this interesting discussion of Khurais which, IMHO, will never produce 1.2/mbd. And remember, never suck too hard, you may get less than you thought you would.
Dave
What makes Khurais so fascinating is the extremely, almost fantastic spread between what has been predicted (guessed?) as possible dialy production for it....ranging from bottem side 144,000 bd to a top side of 1.2 mbd per day.
This tells how very little we actually know about the production of oil (and when I say "we" I am being all inclusive, meaning human beings in general!)
Does anyone have numbers indicating OOIP (Original Oil In Place)? I am holding my copy of "Twilight In The Desert" in my hand, and if it's in there I missed in a cursory read of the Khurais related pages (going by the index), and have not been able to find the number anywhere else.
Has anybody given the Khurais complex a URR (Ultimate Recoverable Reserves) number?
It is always interesting to me that these numbers seem to be often given after the fact and are "trailing" not leading indicators, speaking of which...
Has anyone ever done an HL on Khurais? This would be interesting, given it's extremely erratic history....if one accepts that production over time from a field of X size and from a beginning Quantity (Q) peak would be reached at half of Qt (total Quantity, or possibly earlier, given local conditions, but almost NEVER later than half Qt, how would one factor the "time" variable on a field that has off and on, started and stopped, promising, and then declared hopeless....but as Simmons himself says in "Twilight", now a field that the Saudi's are willing to spend billions on (!!)
Lastly, there seems to be no better field in the world to watch for the dreaded "rate sensitivity" issue. The "coning" issues and other difficulties make me think that even if the field could "possibly" produce 1.2 mbd a day, it would never be pressed to do so for more than a very, very short time, and the Saudi's would be idiots to even try that....why would they risk damage to a potential gem, a potentially large light sweet crude oil field (and my horrible fear is that it will be wasted with no thought, it's almost like shooting one of the last, (maybe the last?) great African elephants just to get to hear how one sounds when it falls....:-( :-(
As of this evening, crude oil prices fell back into the $60's, an ASTOUNDING price, ALMOST AN OIL GIVAWAY, given the instability, logistical problems, political strains, terror attacks, horrendous weather hits, personel and equipment shortages, known depletion in the North Sea, catastrophic geopolitical failure of the U.S. in Iraq {remember when it was going to be "a war of days, not weeks" per the administration?}, and most of all the continuing ATROCITY OF WASTE of the product worldwide, and particularly in the U.S.
I am going to make some enemies when I say this, but:
(a) The oil producing, distribution and maketing structure of energy, to this point has performed with great and admirable efficiency, dependability, and have far exceeded what would have been expected of them given the events of the past 5 years.
There is no other way to say it....the energy industry has faced one of the most difficult periods in it's history, and DONE THE JOB. They have delivered. "Restructuring" of this industry, which some hold as a great dream, should be done with EXTREME caution. Whoever attempts it would have a tough act to follow.
(b) Frankly, oil in the high $60's, low $70's is as cheap as it needs to be. I think the Saudi's will "manage" supply from Khurais and it's other fields, and they are correct to do so. It will be doing the Saudi's, the U.S., the world, and our future a great service to contain supply and hold the price at about the current level, at lowest. If this field can be run "flat out" to get 1.2 mbd, we should never find out, because it should not be tried. What would be the point, with massive energy waste and lack of investment in real alternatives still huge obstacles to our future security and prosperity?
I would be happy, overjoyed to live out the rest of my natural days with oil at $75 to $80 dollars a barrel, and gasoline at $3.50 to $4.00 per gallon U.S.
At those prices we would still be stealing it!
A push to max out production and drop the price endangers the oil fields, endangers the environment, endangers investment in alternatives and efficiency engineering, and most of all, endangers our future.
Anybody's guess on what Khurais (or any other fields we have not even heard about yet) can deliver, but oil is as cheap now as it should ever be.
This could be our last chance NOT to waste the last of the great natural gems, the last of the large remaining light sweet crude oil fields. These, and the remaining natural gas in the world are as priceless as natural gems as the rain forests and the glaciers.
Thank you.
Roger Conner known to you as ThatsItImout
One comment I'd add, as you look at it, is that none of his calculations include a probability assessment for massive drops in flow from elephant fields, a topic we've been discussing here recently in relation to the technologies being employed to keep the flow of such fields up in recent years. But take a look for yourself. I found it most enlightening and frankly would love to see a thread devoted just to the Skrebowski numbers with an analysis by someone more expert than I am.
Since the subject at hand is Khurais, what I would really like to see is a URR stat and an OOIP stat for this mystery field...in fact, let's really make it fun and have someone run a Hubbert Linearization on it...since it was pilot drilled in 1963, it has a long history, and since I am assured that an accurate URR can be gotten by way of Hubbert Linearization, we should be able to get a URR, and a peak date for the field, and this as a leading accurate indicator, right...what do you think, anybody up to the job?
As pointed out by copelch earlier in this string:
Yet the SPE apparently estimates KSA's capacity to be greater than do the Saudis themselves. This is because the SPE includes reserves attributable to enhanced oil recovery in its standards, but the KSA excludes such reserves. And that makes quite a big difference.
And as I quoted Leharrere in another thread, the fields that are hardest to do a Linearization on are the ones that have been influenced by "political" interventions...(??)
Roger Conner known to you as ThatsItImout