Although the application of statistical techniques to type wells is gaining acceptance, it is often unclear to evaluators how these techniques can be applied to capture accurately the full range of uncertainty in the average single-well estimated ultimate recovery (EUR) for a geologic subset. The objective of the complete paper is to present an integrated work flow that can be used to build P90, mean, and P10 type wells, which represent the range of potential outcomes for the geologic subset in an unconventional resource play.
Introduction
A common challenge that accompanies new technologies dedicated to the discovery of unconventional resources is how to forecast production and quantify EUR. Early in the life of a resource play, it can be difficult to build type wells because of limited production history and a small well count.
Traditional methods would use an analogous-field well model or decline methods to predict future production. Because of unconventionals being a relatively recent development, no late-life fields exist that can be used as direct analogs to understand mid- to late-time horizontal-well behavior in tight unconventional formations. For plays in the early stages of development, because of the relatively small well count and difficulty with a direct analog, the early-time well behavior is also not easily predicted with confidence.
