Decline Curve

What is a Decline Curve?

The decline curve is a method for assessing reserves and foreseeing the rate of oil or gas production. It regularly shows the pace at which production is expected to decline over the lifetime of an energy asset.

Realizing the decline curve can assist a producer with assessing the quantity of oil reserves that can emerge out of a well over its lifetime, the present and future value of a well, and the rate at which assets ought to devalue on an organization's books. In aggregate, the decline curve can likewise assist with deciding the rate of production for a total repository or even different supplies.

How a Decline Curve Works

The decline curve is a method used to decide estimated ultimate recovery (EUR) for an oil or gas reserve. This calculation lays on a set of conditions that U.S. geologist J.J. Arps developed in 1945. Of the utmost significance drilling projects meet an acceptable EUR threshold for a project to be viewed as viable and profitable.

In theory, the decline curve can apply to most wells in the industry. Underlying the decline curve conditions is an expectation that well-production commonly follows a three-section pattern.

1. In the initial phase production phase, the flow of oil or gas remains relatively consistent, as pressure remains almost steady.
2. Next is a transient period where the flow of oil or gas declines quickly, as the quantity of recoverable assets and pressure in the wellbore diminishes.
3. In conclusion, assets exhaust to a level at which they approach the clear cut's limits.

Arps' decline curve conditions most frequently apply to the limit defined production phase.

Computing the decline curve includes a curve-fitting exercise to introduce the future rate of production in light of past production levels. Subsequently, a to some degree extended period of time-series data is expected to estimate the projected trend. Likewise, the decline-curve conditions expect that various variables engaged with production and operations stay steady during the lifetime of a well asset. Principally founded on well conditions, three types of decline curves can apply to the future trend: exponential, hyperbolic and harmonic.

Advantages and disadvantages of the Decline Curve

Investigating the decline curve can be a more direct method for assessing production levels relative to more-complex recreations. Nonetheless, utilizing the decline curve likewise can be less accurate than recreations.

Utilizing the decline curve has several deficiencies, including that it can underestimate oil reserves, underestimate production rates, and overestimate reservoir performance. Since it depends on past data, the decline curve doesn't consider the labor, equipment, and technology changes which could influence production rates. It likewise can't account for the probability of geologic changes that more-perplexing models might have the option to incorporate to a degree. Nonetheless, the Arps conditions are still being used today.

Features

• Essentially founded on well conditions, three types of decline curves can apply to the future trend: exponential, hyperbolic and harmonic.
• The decline curve is a method for assessing reserves and foreseeing the rate of oil or gas production.
• The decline curve is a method used to decide estimated ultimate recovery (EUR) for an oil or gas reserve.