The methodology for all the forecasts involves, wherever possible, bottom-up analysis of individual field profiles. Otherwise wells, fields, plays, basins, countries and/or regions are modelled using extrapolation, interpolation and educated analysis based on experience of geology, engineering, and economics in each area.


A more detailed description of the oil forecasting model can be downloaded as a .pdf file. Click here to download.


More information on forecasting and global oil and gas definitions can be found in our public domain publications. Please click articles to access some of these.


Energyfiles forecasts are, of course, based on many assumptions. All forecasts assume a generally stable global political environment, unrestricted (except by economic conditions) worldwide growth in oil and gas demand to their peaks and continuing steady improvements in technology. Production, reserves and recoverable resources for each country are independently assessed based on global data and expert judgement.


Geographic scope

At the last count there were 232 independent countries (including semi-independent territories). Ninety six of these currently produce oil, condensate, natural gas liquids and/or gas at significant rates.


Several further countries have produced oil in the past but are now producing either no oil and/or gas or very little. Others are believed to have the potential to produce oil and/or gas at significant rates but have not yet done so. For forecasting purposes all countries have been included in the analysis.


Fluid scope

All forms of oil and gas are included in global data sets.

Any hydrocarbon production from wells that remains naturally a liquid at surface temperatures and pressures is included as oil even if it has to be artificially recovered from gas. Thus natural gas liquids (NGLs) are included as oil, even though they must be refined from gas, whilst liquefied natural gas (LNG) and gas-to-liquids (GTLs) are not included since they have to be converted. They are included in the gas figures (volumes prior to conversion).


Most extra-heavy oils (unconventional oils) that are extractable under a different economic model and time scale to conventional oils are not directly included in the remaining reserves and resources numbers. However bitumen (specifically that contained in the oil (tar) sand belt of Canada and extra-heavy oils located in the Orinoco Belt of Venezuela), where production may be converted by refining into liquid synthetic oil (synfuel) are individually analysed and included in global production and cumulative production figures. Unconventional oils such as GTLs, coal-to-liquids (CTLs), oil from shales and biofuels are considered separately.


All gas production from conventional oil fields, including from tight gas reservoirs that has been marketed as free gas or LNG has been included. Production of flared and re-injected gas has not been included directly. Unconventional gases such as Coal Bed Methane (CBM) are considered separately.



It has been shown both theoretically and empirically that oil and gas production, freely extracted from a sedimentary basin, rises to a peak at a roughly steady rate as new fields come onstream then begins to decline at a roughly steady hyperbolic rate as the first fields begin to deplete and the last few are unable to make up the difference.


Oil production has a relatively sharp peak whilst, in the past, gas production has tended to form a plateau due to its different marketing system. Pricing adjustments, technology and the use of earlier infrastructure that subsidises later output, all act to stretch decline out creating a skewed distribution. Economic conditions have a profound affect on the actual shape of the curve with former Soviet countries, for example, having volatile production histories as their economies fluctuated.


Production capacity

Production capacity is the volume of oil and/or gas a field, basin, country, region or the world can produce in a given time period. Most countries try to produce as much as they can as quickly as possible. OPEC countries have intermittently artificially restricted oil production to conserve resources and prop up and stabilise the oil price. The speed at which new oil is extracted is increasing rapidly under the influence of new and improved technologies.


Cumulative production is the total volume of oil or gas up to a given year that has been produced. Numbers for cumulative production are taken from the source believed to be most reliable. In most cases this is directly from government figures although uncertainties arise from different modes of measurement, inclusion of different fluids and mixed conversions. All uncertainties have been minimised wherever possible.



Although reserves must always be economic for them to be recovered estimated remaining reserves are taken to be the most likely amount of oil or gas that has been discovered but not yet produced, and will be recovered under economic conditions that could exist in the future if the world remained a stable, comfortable place to live in. If the world becomes unstable then all economic forecasts, and indeed most other forecasts become meaningless.


There will always be additional remaining reserves that will be recovered but such volumes will be insignificant in world terms and recovered far in the future. There are large uncertainties in remaining reserves due to conservative, optimistic and poor reporting by many countries. In a market environment (especially in the USA) proven reserves are artificially constrained by economics. Proven reserves are not used in the analysis. Most likely reserves numbers have been independently assessed by Energyfiles.


Yet -to find resources are estimated here and are coincident with the views of most major oil companies. However some analysts believe that the world’s yet-to-find totals are much greater. The United States Geological Survey (USGS) in particular, report large oil values, with most of this extra oil available in remote regions with none or little current production.


In the view of Energyfiles companies have struggled to find global reserves outside traditional producing regions for good geological reasons. They have explored almost everywhere that it is possible to explore. Deep waters and neglected regions in OPEC and former communist countries provide much of the yet-to-find oil and gas resources included in the analyses with some additional oil and gas available in polar regions.


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