Improved Workflow for EUR Prediction in Unconventional Reservoirs

Date
2015-12
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Abstract

Maximizing recovery of hydrocarbons from unconventional reservoirs poses a serious challenge as our understanding of these complex systems is still in a nascent stage. Production forecasting is especially a complication as the degree of uncertainty increases immensely and there is lack of accuracy in the predictions. The degree of heterogeneity in these reservoirs puts to question the use of data and results from other wells in shales. The developed workflow encapsulates various techniques at every stage of the production forecasting process. Incorporating diagnostic plots, hybrid models, improved data smoothing methodologies and cases of multiphase flowing wells as well as scenarios with a transition flow regime between transient and Boundary dominated flow, i.e. “Boundary-Influenced” flow regime. The developed workflow has rigorously tested on multiple shale formations and has proven to be more accurate than conventionally used techniques which are based on modified Arps decline curve models. Validation procedures have been used which support the EUR values generated from the workflow. This final results obtained show the magnitude of possible errors by using older reserve estimation methods. In the current price environment, having reliable and accurate reserve estimates and forecasts is a vital aspect of any company’s decision making process. The proposed workflow attempts to alleviate this concern by providing reliable and tested methodologies to generate EUR evaluations.

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Keywords
Unconventional reservoirs, Decline curve analysis, Shale reservoirs, Reserves estimation, EUR, EUR Workflow, Diagnostic Plots, Hybrid Models, Transient Flow Regimes, Barnett, Fayetteville, Hogshooter, Granite Wash, Cottage Grove, Outlier Removal, Liquid Loading
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