A Guest Post by George Kaplan
This analysis concerns C&C only. Natural gas production is low and steadily declining with few deep gas-condensate discoveries and the shallow dry gas fields at end of life. I don’t know if lack of gas may affect oil production – e.g. insufficient: flow to allow stable pipeline operation; income to be economic to warrant continuing maintenance; or fuel gas or lift gas supply to surface facilities. Any such issues could influence shutdown timing and hence the possible stranding of assets.
Top Down Production Projections
The chart above shows a Verhulst fit to GoM C&C production using seven curves, three describing shallow production and two each for deep and ultra-deep. A symmetric logistic curve is convenient for manual curve fitting as it allows a linear extrapolation to give the ultimate recovery, but most production curves are not symmetrical – usually the decline is less concave with a thicker tail, especially as the production volume and number of independent producing entities are reduced. With Excel, using least-squares optimisation fitting to any curve(s) is simple and has the benefit of allowing additional constraints to be imposed for sensitivity checks (e.g. total area, equivalent to the ultimate recovery, and position or height of peak), so more general Verhulst curves allow closer fitting.
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