Date of Award

Spring 2021

Degree Type

Thesis

Committee Chair

B. Todd Hoffman

First Advisor

David Reichhardt

Second Advisor

Richard Rossi

Abstract

The need for accurate reserve estimation is apparent, however, forecasting production from unconventional reservoirs is challenging. Intricate fracture networks, complex transport mechanisms, and convoluted flow configurations associated with unconventional reservoirs cause complications with current decline curve analysis methods. Though the hyperbolic decline curve analysis method is a reliable production forecasting method for conventional reservoirs, the accuracy of the hyperbolic method for unconventional reservoirs has been questioned due to the limited amount of long-term production data available. Nonetheless, some unconventional reservoirs, such as the Bakken and the Barnett, have produced long enough to establish the hyperbolic method’s effectiveness for unconventional reservoirs. To test this, an extensive and versatile, nonlinear regression analysis model was built in Python using the method of least squares to match specific durations of production data – first 6 months, first year, first two years, etc. To understand how accurately the models predict production, the evaluation cases were validated against the most recent 5 years of data. From these evaluations, at least 4 years of flow data must be available to have confidence in the model’s ability to predict production. If 4 years of production data is not available, the hyperbolic exponent, b, should be fixed between 0.9 and 1.1 for oil wells and between 1.1 and 1.2 for gas wells. The initial nominal decline rate, Di, should be determined in association with b. Not only do these guidelines result in satisfactory, long-term predictions, but they mitigate any significant error influenced by the underlying implications of and relationships between b and Di. With a better understanding of the effects that b and Di have on production forecast accuracy, companies can better allocate capital to maximize their abilities.

Comments

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Petroleum Engineering

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