Abstract

When it comes to decline analysis, very little has changed since Arps’ "Analysis of Decline Curve" paper published in 1945. An evaluator tries to visually match a production profile with either an exponential, harmonic or hyperbolic equation. Certainly, French Curves have been replaced by computers that quickly reflect our best guess, but for hyperbolic wells where the profile cannot be represented by a straight line it’s still a guess, granted it’s an educated guess based on experience. This paper will propose that in many instances, automatic forecasting, using an accurate tool, can replace manual forecasting.

A common problem faced by all evaluators is how to forecast new wells with little production history. In this paper, an analog forecasting method is proposed that yields excellent results both in predicting budget volumes and matching future production profiles. This method will be demonstrated using back casting studies on real world examples.

In SPE 147059, Haskett indicated that the production forecast represented sixty seven percent of the NPV uncertainty in resource play development. Type wells are the primary technique used to generate production forecasts for these new wells. Hence you would expect the oil and gas industry to devote significant research on this topic. When the authors performed a search on SPE One Petro® and Google® for papers about type wells, they only found their two previous papers (SPE 158867 and SPE 162630). In an informal survey of the industry, the authors found that the time slice method of creating type wells was widely accepted. In SPE 158867, Russell et al recommended that the selected well method of creating percentile type wells was preferred over the time slice method. Further research, presented in this paper recommends that the time slice method should be avoided.

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