Some of the numbers presented in this website may not be the most recent available
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Reserves are analysed in terms of Cumulative production + Remaining production
Ultimate recoverable reserves - are the sum of ‘Cumulative production’ (volume of oil and/or gas up to a given year that has been produced) and ‘Remaining production’ (the volume of oil and/or gas up to a given year that will be produced).
Developed remaining reserves - are defined as that part of Remaining production that will arise from all current producing fields that have entered production but have not yet been abandoned and will continue to produce.
Undeveloped remaining reserves - are defined as that part of ‘Remaining production’ that, most likely, will arise from discrete parts of current producing fields that have not yet been drilled, and all field discoveries and field extensions that have not yet entered production but will be developed.
Undiscovered remaining reserves - are defined as that part of Remaining production that, most likely, will arise from potential field discoveries which have not yet been discovered but will be found and developed.
Cumulative oil - is the total volume of oils produced and consumed up to a given year. Globalshift defines the given year for cumulative oils as the current year minus one. All oil types can be included in ‘Cumulative oil.’
Cumulative gas - is the total volume of sales gases produced and consumed up to a given year. Globalshift defines the given year for cumulative gases as the current year minus one. All gas types can be included in ‘Cumulative gas.’
Remaining oil - is the ‘most likely’ volume of oils that have not yet been produced but will be recovered under economic and other conditions that could exist in the future. They are summed output values over a future period, usually to the year 2100.
Remaining gas - is the ‘most likely’ volume of sales gases that have not yet been produced but will be recovered under economic and other conditions that could exist in the future. They are summed output values over a future period, usually to the year 2100.
More details on reserves and resources
The term reserves has been misunderstood and misused in the oil and gas industry and media. It has multiple meanings. Reserves and recoverable resources are together considered here as Cumulative production plus Remaining production.
Proved, probable and possible reserves (P+P+P) are not used in in this context. They represent the concept of 90% (proved reserves are subject to a 0.9 success risk), 50% (probable reserves are subject to a 0.5 success risk) and 10% (possible reserves are subject to a 0.1 success risk). Note that the volume attributable to ‘Remaining production’, should equal more than proved reserves and could roughly be equated to P+P (2P) reserves.
Remaining reserves equates to most likely remaining reserves and recoverable resources of oil or sales gas that have not yet been produced but will be recovered under economic conditions that could exist in the future. This assumes the world remains a stable, comfortable place to live with a price regime that satisfies demand whilst demand changes in manageable steps and fossil fuels retain market share. They are summed output values over a future period (to the year 2100). Remaining production volumes are not statistically derived and are best thought of as one interpretation of ‘most likely’ numbers.
Developed remaining reserves - represent all current producing fields that have entered production but have not yet been abandoned and will continue to produce. It is an estimate based on objective analysis of past production and depletion rates to assess future production through history matching. It does not include new oil and gas from old fields extracted through new methods or step-out drilling.
Undeveloped remaining reserves - (also known as ‘potential additional resources’ and ‘reserves growth’) are that part of Remaining Production that are attributable to current producing fields and all field discoveries and field extensions that have not yet entered production but will be developed. They are a speculative estimate based on subjective (but educated) examination of the relevant area. The term ‘Reserves Growth’ (not used by Globalshift) has often been used to define these volumes. ‘Reserves growth’ is a confusing term with multiple definitions, including undeveloped fields (or fallow fields) and the use of improved technology to access hitherto un-producible volumes.
Undiscovered remaining reserves - (also known as yet-to-find) are that part of Remaining Production that are attributable to all potential field discoveries which have not yet been discovered but will be found and developed. They are a speculative estimate based on subjective (but educated) examination of the relevant area.
Undeveloped and undiscovered volumes and profiles are estimated based on geology, engineering and economics in each sedimentary basin, allied to past exploration and production histories in the area.
Peak production is the year of maximum output of oil, gas or other hydrocarbons. The peak year will be determined by a combination of actual supply, available capacity, supply restrictions if any, prevailing demand at the current price, and demand restrictions if any.
Resources are all the oils (or gases) that exist in the earth from any source, including developed, undeveloped and undiscovered that, if produced (extracted from the subsurface), could be used for fuel or in the chemical industry.
Resources may be recoverable or not. They are not critical to the forecast production profiles in globalshift.co.uk since a substantial portion of estimated resources will either be produced far in the future, when the world must no longer be dependent on fossil fuels, or will never be produced due to unfavourable economic and/or technological circumstances.