Abstract
This paper is a comprehensive presentation of ALL the methods available for analyzing production data, highlighting the strengths and limitations of each method. These methods include those developed by Arps, Fetkovich, Blasingame and Agarwal-Gardner, as well as a new method called the Flowing Material Balance. Some methods yield recoverable reserves, while others give hydrocarbons-in-place.
Traditional (Arps) decline analysis (exponential or hyperbolic) gives reasonable answers in many situations, but has its failings, the most important one being that it completely ignores the flowing pressure data. As a result, it can underestimate or overestimate the reserves.
The increase in electronic data measurements has made the flowing pressure as readily available as the flow rate. This enables the use of the more sophisticated methods of analysis, which take into account both the flowing pressure and the production rate.
The sequential and systematic use of all these methods gives a consistent and more reliable answer. The strengths and limitations of each method are reviewed, from the simplest exponential decline to the Flowing Material Balance. Two examples are given, one that overestimates reserves, and one that underestimates them. An additional example illustrates the importance of knowing the dominant flow regime.
