油田減退モデルによる世界の大型巨大油田の生産挙動に関する一試算

抄録

Oil production potential could be predicted by an Oil Field Depletion Model. Production calculated by the existing model declines earlier than field cases. Therefore we propose the following new model which is based on reserves and production data of 225 Large Giant Oil Fields (LGO) in the world
(1) LGO can be classified by Production Ratio (PR): Cumulative production/Recoverable reserves, that is, PR>50%: Declining fields, PR=50%-10%: Plateau fields, PR<10%: New fields.
(2) Production Profile ‘Stacking Theory’ can be recognized. A group of LGO sustain production until 60% of reserves have been produced, though single field declines production at 50% of the reserves produced. Plateau rate of the group is 60% of the sum of the peak rates of each oil field. Reserves vs. Production ratio (R/P) of the group is nearly doubled.
(3) Decline curve defined by exponential decline of which rate is reciprocal of R/P at decline started, can be applied.
(4) Build-up production may be assumed 10% of reserves.
The model interprets each LGO groups:
(1) 97 Declining group had declined since 1988 at the decline rate 6.25% per annum and will continue to decline exponentially.
(2) 71 Plateau group will sustain its maximum production potential until the year 2014. Relatively smaller production rate results in slower decline of 3.6% per annum.
(3) 57 New group would start production to fill up reduction of declining group. Ceiling of production rate will be calculated by R/P=16.
A future production profile curve of the world LGO is illustrated by assuming 1.5% per year ascent of world oil demand. The curve may represent the production from the world proved oil reserves because remaining reserves and production rates of LGO are dominant, accounting for 66% and 58% of the world total, respectively.