Articles tagged with "ghawar"
Saudi Aramco has stated that it designs the well layouts and extraction patterns from its oil fields so that they effectively decline at a rate of 2% per year.* If one divides 100 by 2 it yields 50. If one subtracts 50 from 2012, one gets the year 1962. Even for those with poor math skills, these are not difficult operations, and they lead to the conclusion that those fields which came into production in the early 1960’s and earlier are now reaching the end of their productive lives. They are not there yet, since production took time to ramp up, and some fields have been rested over the years when production was cut back, or even mothballed. But this gives you some perspective on the overall scope of the situation, without the need for complex mathematical modeling.
(*The IEA apparently believes that the figure is closer to 3.5%) (H/t Matt) Saudi Arabia states that, without using advanced recovery techniques and “maintain potential” drilling sites – often not in the same field as that being depleted – the rate would be 8%.(h/t Darwinian ).
Posted by Heading Out on July 9, 2012 - 9:40am
Tags: abu sa'fah, dorra, ghawar, hawtah, hout, khafji, khurais, khursanuiyah, lulu, najd fields, nuayyim, qatif, saudi arabia [list all tags]
Fom the viewpoint of those who suggest that there is no problem, the discussion that swirls over the future of global oil supplies often seems to focus on the large volumes of oil that still remain in place around the world. The critical point, however, is not that this oil exists, but rather the rate at which it can be recovered. This is perhaps most obviously pertinent to the discussion of oil coming from the Bakken formation in North Dakota, where the rapid decline in individual well performance means that a great many wells must be developed and remain on line in the out years to sustain any significant flow past peak. As I noted last week, it is a point that clearly was missed by Leonardo Maugeri, and equally by George Monbiot, who has finally been swayed to the side of the cornucopians, after years of doubt.
But the issue of individual well flow rates are an increasingly critical factor when future oil production in oilfields around the world are considered, and this holds equally true when the fields in Saudi Arabia are discussed.
The history of oil production from Saudi Arabia has largely come from individual wells that produced in the thousands of barrels a day. In order to sustain that production over decades, it has been necessary to ensure that 1) the pressure differential between the well and the rock are sustained; 2) that the rock has an adequate permeability to ensure that flow continues at a steady state; 3) that the oil itself is of relatively low viscocity and is thus able to easily flow through the rock; and 4) that there is a sufficient thickness and extent in the reservoir to allow such sustained production.
All of those factors came together in the giant fields that provided high levels of production over many decades, most particularly in the northern segments of Ghawar.
Yet those conditions are less commonly congruent in the fields that Aramco must now exploit to address the coming falls in production from the historic sources. These “best of the rest” (as the late Matt Simmons called them) must now increasingly carry the burden of sustaining Saudi production fail, individually, on differing grounds from meeting those earlier parameters. Collectively and in the face of Ghawar’s decline, they will only be able to sustain production to their original targets and will not provide replacement production as the oldest and larger begin to fade. I would remind you of the curve that Euan put up back in 2007.
In recent posts I have been looking at the potential for the historically high-producing Saudi oilfields at Abqaiq, Berri and Ghawar to sustain or even to increase current levels of production into the future. This is particularly important when one considers the historic main oilfields in production within that country. And of these, the largest not yet covered is the offshore field at Safaniya, today's topic.
There is a growing impression being given in the discussion of oil and natural gas supplies that the world is moving into a period where there will soon be such a plentiful sufficiency of crude that the US may consider exporting some of its production (h/t Leanan). But if one looks behind the headlines, and particularly at the current status of the largest oilfield contributing toward this rosy picture - the Ghawar field in Saudi Arabia - that optimism becomes more evidently built on a very transient set of data that, as this series of posts seeks to show, will not be sustainable for any significant period into the future.
The three major oil producers (i.e. those producing more than 5 mbd each) are currently seeing surges in production as the world moves to an overall production of 90 mbd. The OPEC June Monthly Oil Market Report (MOMR) notes that this has brought Russia to 10.33 mbd in May, some 100 kbd over the same period in 2011; and Saudi Arabia is reported to have averaged 9.917 mbd in May, up 40 kbd over April. The United States is running at 6.236 Mbd of crude (from the EIA TWIP), while importing 9.117 mbd. The MOMR reports US oil supply at 9.66 mbd on average, but counts more than just crude in this value. The gain over the past year is around 600 kbd. It is interesting to note, in regard to OPEC production the continued difference between the volumes that OPEC reports from direct contact with the suppliers, and that when the numbers are obtained from “secondary sources.”
Without getting into the discussion of the other aspects of the site, it was interesting to read a post dealing with future oil production on “Watts Up with That” today, in which it is suggested that the forthcoming fall in Saudi oil production will presage the decline in overall global oil production. (The site has won the “Best Science” weblog award the past two years).
The relevant quote is
The next big one to tip over into decline will be Saudi Arabia.
And, if you have been following this series, then you will understand the basis on which I make the observation that this is, in fact, incorrect. The site uses a plot by Euan (without the link) from back in 2007, though it is credited to 2008.
One of the reasons that I am writing the current OGPSS series is to see how the earlier estimates that we made “back when” are playing out, and for reasons I have explained both in earlier posts and below, Saudi Arabia is likely still a couple of years away from peaking. No - to finish the opening thought - the major player who will tip over first is much more likely to be Russia (of which I have written earlier) than the Kingdom of Saudi Arabia (KSA). Very simply, Russian producers will likely yield back global production leadership to the KSA soon, (though presently still slightly ahead). Further, since they run on maximizing current production rather than overall field yield, they are not doing the necessary steps to sustain future production, a growing characteristic of the KSA operations.
Recent Tech Talks have focused on the increased use of novel technology in Saudi Arabia as a means of recovering oil stranded during the waterfloods that have successfully sustained production over the past few decades. That technology is further expanded with the use of carbon dioxide injection as part of an Enhanced Oil Recovery program. The CO2 project has been in the works for some years, with an initial estimate that some 40 million cubic feet of CO2 would be injected daily into flooded areas of the Ghawar field. The gas will come from the Uthmaniyah Injection Plant and will be initially injected into seven wells in the Uthmaniyah section of Ghawar. The initial flood will be monitored, since it is important to ensure that the CO2 finds the oil that it will help flow to production wells.
Aramco has also recently announced success with changing the make-up of the injection water being pumped into the fields to sustain pressure. By altering the ionic composition and salinity of this water, it has been possible to significantly increase the amount of oil that is liberated and thus recovered from the reservoirs.
Ghawar is sufficiently large that it has been divided into different segments, and the conditions vary between them. Because of the differences between the various regions, the overall statement that Ghawar is producing some 5 mbd has to be read with a degree of caution, lest it be presumed that this has continued to be from the same regions of the overall field. (And while this article deals with oil production, it should be noted that Ghawar also produces around 2.5 billion cubic feet (bcf) of natural gas a day.)
There is a real, practical limit to the amount of oil that can be recovered from a reservoir. Depending on the availability and economic viability of different technical approaches, that limit might be less than 25% of the total volume of oil originally in place, or it can be more than 50%, as has been achieved in some of the fields in the Kingdom of Saudi Arabia (KSA). But one cannot get out more oil than is originally there, and in most cases it is difficult to reach even half that value. However, where the volumes of oil that have been left by conventional methods remains high, as it does in the KSA, then the use of advanced technology, as I began to explain last time, become easier to justify.
KSA is now reaching the point where the easy production of oil, as in sink vertical wells at kilometer intervals and watching an average of 10 kbd merrily bubble to the surface, is now largely over. The oilfields are moving increasingly into the more advanced and costly procedures to help sustain a production that would, under earlier production regimes, have long faded into memory. Ghawar, for example, is moving into CO2 injection and some steam assist (likely with the areas with heavier, tar-ier deposits) seeking to maintain an overall 5 mbd production.
But today I want to talk a little about KSA's increasing use of hydraulic fracturing of their horizontal wells, and offer a little more technical detail about growing cracks through rocks. Consider the problem that high production fields have when a horizontal well runs through a high permeability or densely fractured zone. The impact of this on premature water breakthrough is well documented. The relative preferential movement of water along faults, for example, can be seen in this model from Ghawar.
Figure 1, Relative water movement along faults in Ghawar (Dogru et al)
The very size of oil reservoirs in Saudi Arabia means that as the dominant method of water flooding is used to sweep oil to the producing wells, not all the oil in place migrates as hoped. Some remains in place and this makes up a very significant volume of possibly lost production. This is particularly true in reservoirs such as the Hanifa and Hadriya reservoirs at Berri, where water flooding since 1975 has largely obscured the field. Recognizing this problem, Aramco has increasingly used sophisticated mathematical models of various reservoirs to help locate these remaining pools, searching for oil volumes that could be successfully recovered.
As the models were increasingly able to divide the reservoir into smaller and smaller fractions over time, the presence of these pools became increasingly apparent. Definite proof of their existence then came through drilling. Here again, the change in technology in the use of horizontal wells has allowed the recovery of volumes of stranded oil from thin layers that would have been more difficult to recover had technology not advanced. The first test of this was at Berri where the field modeling was changed from a 14-layer to a 128-layer model, revealing accessible "lost" oil. Five wells were drilled into the region and all yielded oil for a total of 17.4 million barrels by 2007, when the wells were still producing. This capability has extended the life of the Berri field, capturing much of the oil that would otherwise have been lost.
One of the problems, however, in changing to the use of the horizontal wells has been that the well diameter is reduced and as a result the ability to do remedial work on those wells as required was limited at first. The three techniques that are now being aggressively used in these cases include acidizing, advanced hydraulic fracturing, and hydrojetting. And since this latter is an area in which I “wrote the book” and controlled crack growth demonstrations led to the only time I was picketed by a union, I thought I would spend today's post explaining a couple of these developments with fluid treatments, which aren't often as simple to apply as they may appear. Next time I'll finish up with some thoughts on improving hydraulic fracturing, and the possible benefits of using carbon dioxide as the fracking medium rather than other fluids.
The problem of scale in the pumping of fluids into the reservoirs and the flow of oil out is that the quantities dealt with are significantly larger than in most other countries. Flow levels are required to reach over 10,000 bd, both in oil recovery and in the relatively precise location of water injection to sustain reservoir pressures. This led Aramco to adopt horizontal well technology, not only for the recovery of oil, but also in the injection wells that are used to inject the seawater.
The Haradh III development at the southern tip of the Ghawar oil field in Saudi Arabia, completed in 2006, has been portrayed by the national oil company Saudi Aramco as the turning point in the battle between geological adversity and engineering prowess. The poorest reservoir rock in Ghawar has succumbed to the latest in well and drilling technology. Aided by 3D Seismic images showing fracture locations, well sites were optimized and drills were guided by remote control from Dhahran. Smart completions were standard (did they ever call them "dumb" completions?), and something called an "iField" was set up. Maximum-reservoir-connectivity wells (MRCs) were fitted with monitoring electronics and valves on individual laterals such that they could be throttled back as needed to minimize water encroachment. Testing was done, adjustments were made as needed, and everything rolled out ahead of schedule. Goals for individual well productivity of 10,000 barrels/day were met, and projections indicated smooth sailing for ten years or more. Lots of glowing articles were published, and the man in charge eventually rode off in glory to solve the rest of the world's oil production problems.
Funny thing, though. When you look at a satellite photo and count the number of producer wells they ended up drilling, it adds up to quite a few more than they have been claiming -- about 60% more.
There must be a reasonable explanation. Perhaps they simply miscounted.
A few months back, Saudi Aramco commissioned a story about the first wells in the Ghawar oil field in Saudi Arabia, the world's largest. With the title "Ghawar's Magnificent Five", it was published first on the Saudi Aramco website but has subsequently appeared elsewhere. Saudi Aramco later published the same article along with the companion piece "Still Going Strong" (subtitled "57-year-old super-giant Ghawar oil field productive as ever") in the Fall 2008 issue of SA Dimensions magazine, also available on their website1. "Magnificent Five" is the newly minted moniker2 for the group of discovery wells, one for each of the five major production areas of Ghawar: 'Ain Dar, Shedgum, Uthmaniyah, Hawiyah, and Haradh. These articles are remarkable in that Saudi Aramco rarely reveals production details for specific wells in Ghawar, but something in this myth-building exercise is amiss -- both in the consistency of the numbers provided and their use as indicators for the state of the wells and the overall field. In this article, I will examine the data provided for these wells and cross check with other available information including satellite imagery available within Google Earth. There is definitely more to the story, and this uncut version is actually more interesting than what Saudi Aramco has released to theaters.
1http://www.saudiaramco.com. Click Newsroom/Publications/Dimensions.
2The wells' new nickname invokes the grandeur of another movie: The Magnificent Seven. It is noteworthy, though, that most of the seven died prematurely.