Oil reserves 1

Oil reserves

Proven Oil Reserves, as published by the CIA Factbook, 2009

The total estimated amount of oil in anoil reservoir, including both producibleand non-producible oil, is called oil inplace. However, because of reservoircharacteristics and limitations inpetroleum extraction technologies,only a fraction of this oil can bebrought to the surface, and it is onlythis producible fraction that isconsidered to be reserves. The ratio ofproducible oil reserves to total oil inplace for a given field is often referredto as the recovery factor. Recovery factors vary greatly among oil fields. The recovery factor of any particular fieldmay change over time based on operating history and in response to changes in technology and economics. Therecovery factor may also rise over time if additional investment is made in enhanced oil recovery techniques such asgas injection, surfactants injection, water-flooding,[1] or microbial enhanced oil recovery.

Based on data from OPEC at the begging of 2011 the highest proved oil reserves including non-conventional oildeposits are in Venezuela (20 per cent of global reserves), Saudi Arabia (18 %,of global reserves), Iran (9 %).[2]

Because the geology of the subsurface cannot be examined directly, indirect techniques must be used to estimate thesize and recoverability of the resource. While new technologies have increased the accuracy of these techniques,significant uncertainties still remain. In general, most early estimates of the reserves of an oil field are conservativeand tend to grow with time. This phenomenon is called reserves growth.[3]

Many oil-producing nations do not reveal their reservoir engineering field data and instead provide unaudited claimsfor their oil reserves. The numbers disclosed by some national governments are suspected of being manipulated forpolitical reasons.[4]

Classifications[[Image:Petroleum probabilities.JPG|thumb|Schematic graph illustrating petroleum volumes and probabilities.Curves represent categories of oil in assessment. There is a 95% chance (i.e., probability, F95) of at least volume V1of economically recoverable oil, and there is a 5% chance (F05)• remaining in the ground[5]

All reserve estimates involve uncertainty, depending on the amount of reliable geologic and engineering dataavailable and the interpretation of those data. The relative degree of uncertainty can be expressed by dividingreserves into two principal classifications—"proven" (or "proved") and "unproven" (or "unproved").[5] Unprovenreserves can further be divided into two subcategories—"probable" and "possible"—to indicate the relative degree ofuncertainty about their existence.[5] The most commonly accepted definitions of these are based on those approvedby the Society of Petroleum Engineers (SPE) and the World Petroleum Council (WPC) in 1997.[6]

Oil reserves 2

Proven reservesProven reserves are those reserves claimed to have a reasonable certainty (normally at least 90% confidence) ofbeing recoverable under existing economic and political conditions, with existing technology. Industry specialistsrefer to this as P90 (i.e., having a 90% certainty of being produced). Proven reserves are also known in the industryas 1P.[7] [8]

Proven reserves are further subdivided into "proven developed" (PD) and "proven undeveloped" (PUD).[8] [9] PDreserves are reserves that can be produced with existing wells and perforations, or from additional reservoirs whereminimal additional investment (operating expense) is required.[9] PUD reserves require additional capital investment(e.g., drilling new wells) to bring the oil to the surface.[7] [9]

Until December 2009 "1P" proven reserves were the only type the U.S. Securities and Exchange Commissionallowed oil companies to report to investors. Companies listed on U.S. stock exchanges must substantiate theirclaims, but many governments and national oil companies do not disclose verifying data to support their claims.Since January 2010 the SEC now allows companies to also provide additional optional information declaring "2P"(both proven and probable) and "3P" (proven + probable + possible) provided the evaluation is verified by qualifiedthird party consultants, though many companies choose to use 2P and 3P estimates only for internal purposes.

Unproven reserves

An oil well in Canada, which has the world's third largest oil reserves]]Unproven reserves are based on geological and/or engineering datasimilar to that used in estimates of proven reserves, but technical,contractual, or regulatory uncertainties preclude such reserves beingclassified as proven.[10] Unproven reserves may be used internally byoil companies and government agencies for future planning purposesbut are not routinely compiled. They are sub-classified as probable andpossible.[10]

Probable reserves are attributed to known accumulations and claim a 50% confidence level of recovery. Industryspecialists refer to them as P50 (i.e., having a 50% certainty of being produced). These reserves are also referred toin the industry as 2P (proven plus probable).[7]

Possible reserves are attributed to known accumulations that have a less likely chance of being recovered thanprobable reserves. This term is often used for reserves which are claimed to have at least a 10% certainty of beingproduced (P10). Reasons for classifying reserves as possible include varying interpretations of geology, reserves notproducible at commercial rates, uncertainty due to reserve infill (seepage from adjacent areas) and projected reservesbased on future recovery methods. They are referred to in the industry as 3P (proven plus probable plus possible).[7]

Oil reserves 3

Strategic petroleum reservesMany countries maintain government-controlled oil reserves for both economic and national security reasons.According to the United States Energy Information Administration, approximately 4.1 billion barrels ( m3) of oil areheld in strategic reserves, of which 1.4 billion is government-controlled. These reserves are generally not countedwhen computing a nation's oil reserves.

Resources

Unconventional oil resources are greater thanconventional ones.[11]

Cumulative oil production plus remainingreserves and undiscovered resources. United

States not included.

A more sophisticated system of evaluating petroleum accumulationswas adopted in 2007 by the Society of Petroleum Engineers (SPE),World Petroleum Council (WPC), American Association of PetroleumGeologists (AAPG), and Society of Petroleum Evaluation Engineers(SPEE). It incorporates the 1997 definitions for reserves, but addscategories for contingent resources and prospective resources.[5]

Contingent resources are those quantities of petroleum estimated, as ofa given date, to be potentially recoverable from known accumulations,but the applied project(s) are not yet considered mature enough forcommercial development due to one or more contingencies. Contingentresources may include, for example, projects for which there arecurrently no viable markets, or where commercial recovery isdependent on technology under development, or where evaluation ofthe accumulation is insufficient to clearly assess commerciality.

Prospective resources are those quantities of petroleum estimated, as ofa given date, to be potentially recoverable from undiscoveredaccumulations by application of future development projects.Prospective resources have both an associated chance of discovery anda chance of development.

The United States Geological Survey uses the terms technically andeconomically recoverable resources when making its petroleumresource assessments. Technically recoverable resources represent that proportion of assessed in-place petroleumthat may be recoverable using current recovery technology, without regard to cost. Economically recoverableresources are technically recoverable petroleum for which the costs of discovery, development, production, andtransport, including a return to capital, can be recovered at a given market price.

Unconventional resources exist in petroleum accumulations that are pervasive throughout a large area. Examplesinclude extra heavy oil, natural bitumen, and oil shale deposits. Unlike conventional resources, in which thepetroleum is recovered through wellbores and typically requires minimal processing prior to sale, unconventionalresources require specialized extraction technology to produce. For example, steam and/or solvents are used tomobilize bitumen for in-situ recovery. Moreover, the extracted petroleum may require significant processing prior tosale (e.g., bitumen upgraders).[5] The total amount of unconventional oil resources in the world considerably exceedsthe amount of conventional oil reserves, but are much more difficult and expensive to develop.

Oil reserves 4

Estimation techniques

Example of a production decline curve for anindividual well

The amount of oil in a subsurface reservoir is called oil in place(OIP).[9] Only a fraction of this oil can be recovered from a reservoir.This fraction is called the recovery factor.[9] The portion that can berecovered is considered to be a reserve. The portion that is notrecoverable is not included unless and until methods are implementedto produce it.

There are a number of different methods of calculating oil reserves.These methods can be grouped into three general categories:volumetric, material balance, and production performance. Eachmethod has its advantages and drawbacks.[9] [10]

Volumetric method

Further information: Extraction of petroleum, Oil in place

Volumetric methods attempt to determine the amount of oil in place by using the size of the reservoir as well as thephysical properties of its rocks and fluids. Then a recovery factor is assumed, using assumptions from fields withsimilar characteristics. OIP is multiplied by the recovery factor to arrive at a reserve number. Current recoveryfactors for oil fields around the world typically range between 10 and 60 percent; some are over 80 percent. Thewide variance is due largely to the diversity of fluid and reservoir characteristics for different deposits.[12] [13] [14]

The method is most useful early in the life of the reservoir, before significant production has occurred.

Materials balance methodThe materials balance method for an oil field uses an equation that relates the volume of oil, water and gas that hasbeen produced from a reservoir and the change in reservoir pressure to calculate the remaining oil. It assumes that, asfluids from the reservoir are produced, there will be a change in the reservoir pressure that depends on the remainingvolume of oil and gas. The method requires extensive pressure-volume-temperature analysis and an accuratepressure history of the field. It requires some production to occur (typically 5% to 10% of ultimate recovery), unlessreliable pressure history can be used from a field with similar rock and fluid characteristics.[10]

Production decline curve methodThe decline curve method uses production data to fit a decline curve and estimate future oil production. The threemost common forms of decline curves are exponential, hyperbolic, and harmonic. It is assumed that the productionwill decline on a reasonably smooth curve, and so allowances must be made for wells shut in and productionrestrictions. The curve can be expressed mathematically or plotted on a graph to estimate future production. It hasthe advantage of (implicitly) including all reservoir characteristics. It requires a sufficient history to establish astatistically significant trend, ideally when production is not curtailed by regulatory or other artificial conditions.[10]

Oil reserves 5

Reserves growthExperience shows that initial estimates of the size of newly discovered oil fields are usually too low. As years pass,successive estimates of the ultimate recovery of fields tend to increase. The term reserve growth refers to the typicalincreases in estimated ultimate recovery that occur as oil fields are developed and produced.[3]

Estimated reserves by country[15]

Countries with largest oil reservesMost of the world's oil reserves are in the Middle

East.[16]

Summary of Reserve Data as of 2011

Country Reserves[17]

Production[18]

Reserve life 1

109 bbl 109 m3 106 bbl/d 103 m3/d years

Saudi Arabia 264.52 42.055 8.9 1410 81

Venezuela 211.5 33.63 2.1 330 129

Canada 175 27.8 2.7 430 178

Iran 151.2 24.04 4.1 650 101

Iraq 143.1 22.75 2.4 380 163

Kuwait 101.5 16.14 2.3 370 121

United Arab Emirates 97.8 15.55 2.4 380 112

Russia 74.2 11.80 9.7 1540 21

Libya 47 7.5 1.7 270 76

Nigeria 37 5.9 2.5 400 41

Kazakhstan 30 4.8 1.5 240 55

Qatar 25.41 4.040 1.1 170 63

China 20.35 3.235 4.1 650 14

United States 19.12 3.040 5.5 870 10

Angola 13.5 2.15 1.9 300 19

Oil reserves 6

Algeria 13.42 2.134 1.7 270 22

Brazil 13.2 2.10 2.1 330 17

Total of top seventeenreserves

1324 210.5 56.7 9010 64

Notes:

1 Reserve to Production ratio (in years), calculated as reserves / annual production. (from above)

2 Although the IEA insists on Canada's Reserves as being listed as 178 billion barrels, many experts including CEO of Shell Canada, CliveMather estimate it to actually be 2 Trillion barrels or more, essentially 8 times more than Saudi Arabia.[19]

3 Iraq is estimated to be the first oil reserve in the world with more than 360 billion barrels.

4 Most of oil reserves on Venezuela are extra-heaby petrolium, with high amounts of sulfer.

OPEC countriesThere are doubts about the reliability of official OPEC reserves estimates, which are not provided with any form ofaudit or verification that meet external reporting standards.[20]

Since a system of country production quotas was introduced in the 1980s, partly based on reserves levels, there havebeen dramatic increases in reported reserves among OPEC producers. In 1983, Kuwait increased its proven reservesfrom 67 Gbbl (10.7×109 m3) to 92 Gbbl (14.6×109 m3). In 1985–86, the UAE almost tripled its reserves from33 Gbbl (5.2×109 m3) to 97 Gbbl (15.4×109 m3). Saudi Arabia raised its reported reserve number in 1988 by 50%. In2001–02, Iran raised its proven reserves by some 30% to 130 Gbbl (21×109 m3), which advanced it to second placein reserves and ahead of Iraq. Iran denied accusations of a political motive behind the readjustment, attributing theincrease instead to a combination of new discoveries and improved recovery. No details were offered of how any ofthe upgrades were arrived at.[20] [21]

The following table illustrates these rises.

OPEC countries oil reserves of OPEC 1980–2005

Declared reserves of major Opec Producers (billion of barrels)

BP Statistical Review - June 2009 [22]

OPEC Annual Statistical Bulletin 2010/2011 [23]

Year Iran Iraq Kuwait Saudi Arabia UAE Venezuela Libya Nigeria

1980 58.3 30.0 67.9 168.0 30.4 19.5 20.3 16.7

1981 57.0 32.0 67.7 167.9 32.2 19.9 22.6 16.5

1982 56.1 59.0 67.2 165.5 32.4 24.9 22.2 16.8

Oil reserves 7

1983 55.3 65.0 67.0 168.8 32.3 25.9 21.8 16.6

1984 58.9 65.0 92.7 171.7 32.5 28.0 21.4 16.7

1985 59.0 65.0 92.5 171.5 33.0 54.5 21.3 16.6

1986 92.9 72.0 94.5 169.7 97.2 55.5 22.8 16.1

1987 92.9 100.0 94.5 169.6 98.1 58.1 22.8 16.0

1988 92.9 100.0 94.5 255.0 98.1 58.5 22.8 16.0

1989 92.9 100.0 97.1 260.1 98.1 59.0 22.8 16.0

1990 92.9 100.0 97.0 260.3 98.1 60.1 22.8 17.1

1991 92.9 100.0 96.5 260.9 98.1 62.6 22.8 20.0

1992 92.9 100.0 96.5 261.2 98.1 63.3 22.8 21.0

1993 92.9 100.0 96.5 261.4 98.1 64.4 22.8 21.0

1994 94.3 100.0 96.5 261.4 98.1 64.9 22.8 21.0

1995 93.7 100.0 96.5 261.5 98.1 66.3 29.5 20.8

1996 92.6 112.0 96.5 261.4 97.8 72.7 29.5 20.8

1997 92.6 112.5 96.5 261.5 97.8 74.9 29.5 20.8

1998 93.7 112.5 96.5 261.5 97.8 76.1 29.5 22.5

1999 93.1 112.5 96.5 262.8 97.8 76.8 29.5 29.0

2000 99.5 112.5 96.5 262.8 97.8 76.8 36.0 29.0

2001 99.1 115.0 96.5 262.7 97.8 77.7 36.0 31.5

2002 130.7 115.0 96.5 262.8 97.8 77.3 36.0 34.3

2003 133.3 115.0 99.0 262.7 97.8 77.2 39.1 35.3

2004 132.7 115.0 101.5 264.3 97.8 79.7 39.1 35.9

2005 137.5 115.0 101.5 264.2 97.8 80.0 41.5 36.2

2006 138.4 115.0 101.5 264.3 97.8 87.3 41.5 36.2

2007 138.2 115.0 101.5 264.2 97.8 99.4 43.7 36.2

2008 137.6 115.0 101.5 264.1 97.8 172.3 43.7 36.2

2009 137.0 115.0 101.5 264.6 97.8 211.1 46.4 36.2

2010 151.2 143.1 101.5 264.5 97.8 296.5 47.1 36.2

The sudden revisions in OPEC reserves, totaling nearly 300 bn barrels, have been much debated.[24] Some of it isdefended partly by the shift in ownership of reserves away from international oil companies, some of whom wereobliged to report reserves under conservative US Securities and Exchange Commission rules.[20] [25] The mostprominent explanation of the revisions is prompted by a change in OPEC rules which set production quotas (partly)on reserves. In any event, the revisions in official data had little to do with the actual discovery of new reserves.[20]

Total reserves in many OPEC countries hardly changed in the 1990s.[20] Official reserves in Kuwait, for example,were unchanged at 96.5 Gbbl (15.34×109 m3) (including its share of the Neutral Zone) from 1991 to 2002, eventhough the country produced more than 8 Gbbl (1.3×109 m3) and did not make any important new discoveries duringthat period.[20] The case of Saudi Arabia is also striking, with proven reserves estimated at between 260 and 264billion barrels (4.20×1010 m3) in the past 18 years, a variation of less than 2%,[20] while extracting approximately 60billion barrels (9.5×109 m3) during this period.Sadad al-Huseini, former head of exploration and production at Saudi Aramco, estimates 300 Gbbl (48×109 m3) of the world's 1200 Gbbl (190×109 m3) of proven reserves should be recategorized as speculative resources, though he

Oil reserves 8

did not specify which countries had inflated their reserves.[26] Dr. Ali Samsam Bakhtiari, a former senior expert ofthe National Iranian Oil Company, has estimated that Iran, Iraq, Kuwait, Saudi Arabia and the United Arab Emirateshave overstated reserves by a combined 320–390bn barrels and has said, "As for Iran, the usually accepted official132 billion barrels (2.10×1010 m3) is almost one hundred billion over any realistic assay."[27] Petroleum IntelligenceWeekly reported that official confidential Kuwaiti documents estimate reserves of Kuwait were only 48 billionbarrels (7.6×109 m3), of which half were proven and half were possible. The combined value of proven and possibleis half of the official public estimate of proven reserves.[21]

In July 2011, OPEC's Annual Statistical Review showed Venezuela's reserves to be larger than Saudi Arabia's.[28]

Prospective resources

Arctic prospective resources

Location of Arctic Basins assessed by the USGS

A 2008 United States Geological Survey estimates that areas north ofthe Arctic Circle have 90 billion barrels (1.4×1010 m3) ofundiscovered, technically recoverable oil and 44 billion barrels(7.0×109 m3) of natural gas liquids in 25 geologically defined areasthought to have potential for petroleum. This represented 13% of theexpected undiscovered oil in the world. Of the estimated totals, morethan half of the undiscovered oil resources were estimated to occur injust three geologic provinces—Arctic Alaska, the Amerasia Basin, andthe East Greenland Rift Basins. More than 70% of the meanundiscovered oil resources was estimated to occur in five provinces:Arctic Alaska, Amerasia Basin, East Greenland Rift Basins, EastBarents Basins, and West Greenland–East Canada. It was furtherestimated that approximately 84% of the oil and gas would occuroffshore. The USGS did not consider economic factors such as the effects of permanent sea ice or oceanic waterdepth in its assessment of undiscovered oil and gas resources. This assessment was lower than a 2000 survey, whichhad included lands south of the Arctic Circle.[29] [30] [31]

Miscellaneous prospective resourcesIn October 2009, the USGS updated the Orinoco tar sands (Venezuela) value to 513 billion barrels (8.16×1010

m3).[32]

The Exclusive Economic Zone is a delineated offshore area, mostly to the west and north of Cuba, which, underinternational agreements, is owned by Cuba. This 112,000-square-kilometer zone has been divided into 59exploration blocks. A 2004 joint partnership between a Spanish oil company and Cuba's state oil company (CUPET)estimated Cuba's off-shore reserves to be able to produce ultimately between 4.6 and 9.3 billion barrels of crudeoil.[33]

The US Geological Survey (USGS) estimates that Cuba has resources up to 9 billion barrels (1.4×109 m3) of oil. InOctober 2008, the Cuban government announced that it had discovered oil basins that would double its total oilresources to 20 billion barrels (3.2×109 m3).[34] Note that, consistent with the definitions of reserves and resources asgiven in the above sections, at this stage (June 2009), given no commercial discoveries to date, all recoverable oilestimates in the Exclusive Economic Zone (EEZ) are prospective resources estimates and not reserves estimates.

Oil reserves 9

References[1] "Oil Reserves" (http:/ / www. bp. com/ sectiongenericarticle. do?categoryId=9023799& contentId=7044111). BP Global. 2008. . Retrieved

2009-05-16.[2] "OPEC Share of World Oil Reserves 2010" (http:/ / www. opec. org/ opec_web/ en/ data_graphs/ 330. htm). OPEC. 2011. .[3] David F. Morehouse (1997) (PDF). The Intricate Puzzle of Oil and Gas Reserves Growth (http:/ / tonto. eia. doe. gov/ ftproot/ features/

morhouse. pdf). U.S. Energy Information Administration. . Retrieved 2008-04-17.[4] "Proven Oil Reserves" (http:/ / moneyterms. co. uk/ proven-oil-reserves/ ). moneyterms.co.uk. 2008. . Retrieved 2008-04-17.[5] "Petroleum Resources Management System" (http:/ / www. spe. org/ spe-app/ spe/ industry/ reserves/ prms. htm). Society of Petroleum

Engineers. 2007. . Retrieved 2008-04-20.[6] "Petroleum Reserves Definitions" (http:/ / www. spe. org/ spe-site/ spe/ spe/ industry/ reserves/ Petroleum_Reserves_Definitions_1997. pdf)

(PDF). Petroleum Resources Management System. Society of Petroleum Engineers. 1997. . Retrieved 2008-04-20.[7] "Glossary of Terms Used in Petroleum Reserves/Resources" (http:/ / www. spe. org/ spe-site/ spe/ spe/ industry/ reserves/

GlossaryPetroleumReserves-ResourcesDefinitions_2005. pdf) (PDF). Society of Petroleum Engineers. 2005. . Retrieved 2008-04-20.[8] Wright, Charlotte J.; Rebecca A Gallun (2008). Fundamentals of Oil & Gas Accounting (5 ed.). PenWell Books. pp. 750. ISBN 1593701373,

9781593701376.[9] Hyne, Norman J. (2001). Nontechnical Guide to Petroleum Geology, Exploration, Drilling and Production. PennWell Corporation.

pp. 431–449. ISBN 918-0-87814-823-3.[10] Lyons, William C. (2005). Standard Handbook Of Petroleum & Natural Gas Engineering. Gulf Professional Publishing. pp. 5–6.

ISBN 0750677856, 9780750677851.[11] Alboudwarej et al. (Summer 2006) (PDF). Highlighting Heavy Oil (http:/ / www. slb. com/ media/ services/ resources/ oilfieldreview/ ors06/

sum06/ heavy_oil. pdf). Oilfield Review. . Retrieved 2008-05-24.[12] "Defining the Limits of Oil Production" (http:/ / www. eia. doe. gov/ oiaf/ ieo/ oilproduction. html). International Energy Outlook 2008.

U.S. Department of Energy. June 2008. . Retrieved 2008-11-22.[13] E. Tzimas, (2005) (PDF). Enhanced Oil Recovery using Carbon Dioxide in the European Energy System (http:/ / ie. jrc. ec. europa. eu/

publications/ scientific_publications/ 2005/ EUR21895EN. pdf). European Commission Joint Research Center. . Retrieved 2008-08-23.[14] Green.[15] "OPEC Share of World Oil Reserves 2010" (http:/ / www. opec. org/ opec_web/ en/ data_graphs/ 330. htm). OPEC. 2011. .[16] "World Proved Reserves of Oil and Natural Gas" (http:/ / www. eia. doe. gov/ emeu/ international/ reserves. html). US Energy Information

Administration. 2007. . Retrieved 2008-08-19.[17] PennWell Corporation, Oil & Gas Journal, Vol. 105.48 (December 24, 2007), except United States. Oil includes crude oil and condensate.

Data for the United States are from the Energy Information Administration, U.S. Crude Oil, Natural Gas, and Natural Gas Liquids Reserves,2006 Annual Report, DOE/EIA-0216(2007) (November 2007). Oil & Gas Journal's oil reserve estimate for Canada includes 5.392 billionbarrels ( m3) of conventional crude oil and condensate reserves and 173.2 billion barrels (2.754×1010 m3) of oil sands reserves. Informationcollated by EIA (http:/ / www. eia. doe. gov/ emeu/ international/ oilreserves. html)

[18] U.S. Energy Information Administration (EIA) – U.S. Government – U.S. Dept. of Energy, September, 2011 EIA - International EnergyStatistics (http:/ / www. eia. gov/ cfapps/ ipdbproject/ iedindex3. cfm?tid=5& pid=57& aid=1& cid=regions,& syid=2010& eyid=2010&unit=TBPD)

[19] Mather, Clive "The Oil Sands of Alberta" (http:/ / www. youtube. com/ watch?v=86NG0j0wi1s), Canada Broadcasting Corporation,[20] (PDF) WORLD ENERGY OUTLOOK 2005:Middle East and North Africa Insights (http:/ / www. iea. org/ textbase/ nppdf/ free/ 2005/

weo2005. pdf). INTERNATIONAL ENERGY AGENCY. 2005. pp. 125–126. .[21] "Oil Reserves Accounting: The Case Of Kuwait" (http:/ / www. energyintel. com/ DocumentDetail. asp?document_id=167229). Petroleum

Intelligence Weekly. January 30, 2006. . Retrieved 2008-08-23.[22] http:/ / www. bp. com/ liveassets/ bp_internet/ globalbp/ globalbp_uk_english/ reports_and_publications/ statistical_energy_review_2008/

STAGING/ local_assets/ 2009_downloads/ statistical_review_of_world_energy_full_report_2009. xls[23] http:/ / www. opec. org/ opec_web/ static_files_project/ media/ downloads/ publications/ ASB2010_2011. pdf[24] Adam, Porter (15 July 2005). "How much oil do we really have?" (http:/ / news. bbc. co. uk/ 2/ hi/ business/ 4681935. stm). BBC News. .[25] Maugeri, Leonardo (January 23, 2006). "The Saudis May Have Enough Oil" (http:/ / www. newsweek. com/ id/ 47484). Newsweek. .[26] "Oil reserves over-inflated by 300bn barrels – al-Huseini" (http:/ / www. davidstrahan. com/ blog/ ?p=68). October 30, 2007. . Retrieved

2008-08-23.[27] "On Middle Eastern Oil Reserves" (http:/ / www. energybulletin. net/ node/ 13009). ASPO-USA's Peak Oil Review. February 20, 2006. .

Retrieved 2008-08-20.[28] Faucon, Benoit (18 July 2011). "Venezuela Oil Reserves Surpassed Saudi Arabia In 2010-OPEC" (http:/ / www. foxbusiness. com/ markets/

2011/ 07/ 18/ venezuela-oil-reserves-surpassed-saudi-arabia-in-2010-opec/ ). Fox Business. . Retrieved 18 July 2011.[29] United States Geological Survey, (USGS) (July 27, 2008). "90 Billion Barrels of Oil and 1,670 Trillion Cubic Feet of Natural Gas Assessed

in the Arctic" (http:/ / www. usgs. gov/ newsroom/ article. asp?ID=1980). USGS. . Retrieved 2008-08-12.[30] MOUAWAD, JAD (July 24, 2008). "Oil Survey Says Arctic Has Riches" (http:/ / www. nytimes. com/ 2008/ 07/ 24/ business/ 24arctic.

html). New York Times. .

Oil reserves 10

[31] Alan Bailey (October 21, 2007). "USGS: 25% Arctic oil, gas estimate a reporter's mistake" (http:/ / www. petroleumnews. com/ pntruncate/347702651. shtml). Vol. 12, No. 42. Petroleum News. . Retrieved 2008-07-24.

[32] "An Estimate of Recoverable Heavy Oil Resources of the Orinoco Oil Belt, Venezuela" (http:/ / pubs. usgs. gov/ fs/ 2009/ 3028/ pdf/FS09-3028. pdf) (in en). USGS. 11 January 2010. . Retrieved 23 January 2010.

[33] Lorca-Susino, Maria. "A Brief Energy Outlook for the XXI Century" (http:/ / mpra. ub. uni-muenchen. de/ 9557/ 1/ MPRA_paper_9557.pdf) (pdf). Munich Personal RePEc Archive. . Retrieved 2008-10-17.

[34] BBC: Cuba claims massive oil reserves (http:/ / news. bbc. co. uk/ 2/ hi/ americas/ 7675234. stm)

• http:/ / www. opec. org/ opec_web/ en/ data_graphs/ 330. htm

External links• OPEC Annual Statistical Bulletin (http:/ / www. opec. org/ opec_web/ static_files_project/ media/ downloads/

publications/ ASB2010_2011. pdf)• Energy Supply page on the Global Education Project web site (http:/ / www. theglobaleducationproject. org/

earth/ energy-supply. php), including many charts and graphs on the world's energy supply and use• Oil reserves (most recent) by country (http:/ / www. nationmaster. com/ graph/ ene_oil_res-energy-oil-reserves)

Article Sources and Contributors 11

Article Sources and ContributorsOil reserves  Source: http://en.wikipedia.org/w/index.php?oldid=457666350  Contributors: .V., 2D, 790, A i s h2000, Adso, Afrique, After Midnight, Ala.foum, Alex.tan, Alfio, Alinor,Andryuha, Angrypinkcat, Antandrus, Anubis-SG, Art LaPella, Arthena, Ashdod, Astrometrics, Atlant, Auntof6, Av0id3r, Beagel, Beland, Belligero, BenB4, Bevo, Bfgoobla, Bingo7, BlueZenith,Bobo159, Brekass, Brendanconway, CLW, Can't sleep, clown will eat me, CanisRufus, Carbonate, Cdp1jmp2, Chairboy, Chaser, CiudadanoGlobal, Claygate, Closedmouth, Copana2002,Cpp02jeh, Crissidancer88, Crubins, Cyfal, DGJM, DMCer, Dar-Ape, Darth Panda, Darth Sidious, Davidusb, Dawnseeker2000, Dblord, Desertpad, Dialectric, Doseiai2, Dracken,Driftwoodzebulin, Duivesteyn, Dumpydooby, Dzhim, Ed Poor, Edward, Environnement2100, Eric76, Ericnelson1, Eyreland, FAH1223, FCYTravis, Feezo, Firemantod, Flcelloguy, Francbo,Frank Duurvoort, Fredhutter, FreplySpang, Fushigi-kun, Gaius Cornelius, Gary King, Geografisica, Geologyguy, Gilliam, Gini1, Gralo, Green caterpillar, GreenReaper, Gurch, Gus8591, Gwib,Hanchen, Happydaysyes, Harryboyles, Hongshi, Hu12, Huaiwei, Ilikeflylady, In ictu oculi, Indianstar, Iorsh, Iridescent, IsambardBrunel, Ixfd64, JaGa, Jac16888, Jakob mark, Jeff3000,Jimmy4567654, Jimp, Joema, Jonkerz, Joseph Solis in Australia, Josh Parris, Kamo zilla, Karl Meier, Kessy628, Kevin701, Kgrr, Khukri, Klassica, Knotnic, Konman72, Kurdo777, Lackett,Lamro, LeadSongDog, Legis, Lightmouse, Loonymonkey, Lumidek, MLRoach, Markhu, Maxis ftw, Mayurchanakya, Mazzawi, Mboverload, Mckillingking-rom, Melaen, Merlyn644, MichaelDevore, Micov, Mierlo, Mihai, Miyokan, Monkeyman, Monteitho, Mr shadows1982, Mr. Lefty, Mr.Z-man, MrVoluntarist, Mrubx, Muse1989, N328KF, NHMoldPro, NJGW, Nagle,NathanHurst, NavajoDutchman, NawlinWiki, Nick Mulder, Nick-D, Nirvana2013, Njoedits, Njreader101, Nogwa, Noommos, Noosentaal, NuttyJay, Occamschainsaw, Ohnoitsjamie, Oviguan,P3x1187, PJM, Parhamr, Parnell88, Peterbmoorman, Phoenix2, Pinethicket, Pioneeranomoly, Pixel ;-), Praveen Bhojwani, Prunesqualer, Psy guy, Publicus, Quamaretto, Quercusrobur,RHaworth, RJHall, Random User 937494, Razorflame, Reaper Eternal, Reflecting Pool, Rich Farmbrough, Richhoncho, Rjwilmsi, Rlu, Robertbaertsch, Roberts83, Robjlucas, Robsavoie,RockyMtnGuy, Roke, Rosaura Silva, Rrloomis1, Ruber chiken, Rujholla, Runningonbrains, Samy23, Sasper, Savedthat, Savidan, Scott.medling, Scroner, SeventyThree, Sfoucher, ShalomYechiel, Sir Vicious, Skyemoor, Sleibhine, Smithfarm, Smithpeters, Snow storm in Eastern Asia, Squash Racket, Squids and Chips, Stenge, Steve Casburn, Steve Hart, Struct18, Struway,SuperFlanker, TMLutas, TRosenbaum, Talrias, TashaOak, TastyCakes, Teratornis, The Thing That Should Not Be, Tillman, Timc, Timeshifter, Timharwoodx, Titus III, Tom harrison, TonySidaway, Trefork, Tregoweth, TulsaGeologist, Ufwuct, Ulysses31, Uris, Valentinian, Vexorg, VictorAnyakin, Vince.g.m.y, Vsmith, Wackymacs, Walloon, WaseemM, Watti Renew, Webaware,WikHead, Wikipedia brown, WildWeathel, Work permit, Yamamoto Ichiro, Ynhockey, Yug, Z.E.R.O., Zamp m, Zondor, 558 ,الشبح العربي anonymous edits

Image Sources, Licenses and ContributorsFile:Oil Reserves.png  Source: http://en.wikipedia.org/w/index.php?title=File:Oil_Reserves.png  License: Public Domain  Contributors: Emilfaro, JonkerzImage:Oil well3419.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Oil_well3419.jpg  License: GNU Free Documentation License  Contributors: Helix84, Knutux, Ranveig, Solon,Themightyquill, Verne EquinoxImage:Total World Oil Reserves.PNG  Source: http://en.wikipedia.org/w/index.php?title=File:Total_World_Oil_Reserves.PNG  License: Creative Commons Attribution-Sharealike 3.0 Contributors: RockyMtnGuy (talk). Original uploader was RockyMtnGuy at en.wikipediaFile:USGS world oil endowment.png  Source: http://en.wikipedia.org/w/index.php?title=File:USGS_world_oil_endowment.png  License: Public Domain  Contributors: Jonkerz, SEWilco, 1anonymous editsImage:GlennPool.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:GlennPool.jpg  License: Public Domain  Contributors: US Dept of InteriorImage:Top ten largest oil reserves by country.GIF  Source: http://en.wikipedia.org/w/index.php?title=File:Top_ten_largest_oil_reserves_by_country.GIF  License: GNU Free DocumentationLicense  Contributors: David Kernow, Remi, Roke, Timeshifter, 15 anonymous editsImage:World Oil Reserves by Region.PNG  Source: http://en.wikipedia.org/w/index.php?title=File:World_Oil_Reserves_by_Region.PNG  License: Creative Commons Attribution-Sharealike3.0  Contributors: RockyMtnGuyImage:OPEC.svg  Source: http://en.wikipedia.org/w/index.php?title=File:OPEC.svg  License: Public Domain  Contributors: BourgeoisImage:OPEC declared reserves 1980-now BP.svg  Source: http://en.wikipedia.org/w/index.php?title=File:OPEC_declared_reserves_1980-now_BP.svg  License: Public Domain  Contributors:IorshImage:ArcticLocationMap2.gif  Source: http://en.wikipedia.org/w/index.php?title=File:ArcticLocationMap2.gif  License: Public Domain  Contributors: USGS

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