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Estimated Ultimate Recovery (EUR) Study of 5,000 Marcellus Shale Wells in Pennsylvania. February 2018 Update (pdf)

Gary S. Swindell, P.E., Consulting Petroleum Engineer, Dallas, Texas

Copyright 2018, Gary S. Swindell, P.E.


This study summarizes the results of an updated and expanded evaluation of the estimated ultimate recovery (EUR) for all horizontal Marcellus Shale completions from 2008 through 2014 in Pennsylvania. Individual well rate vs. time plots using publically available production data through June 2017 were used to forecast the EUR of 4,936 wells. The primary objective was to determine the distribution of EUR. Although data is also available for the 2015-2017 well completions, the decline behavior is not believed to be sufficiently established for reliable projections.

For 4,936 horizontal wells with enough history to forecast a decline profile, the estimated ultimate recovery across the whole state averages 6.2 billion cubic feet equivalent (Bcfe) per well with a median of 5.0 Bcfe. The results vary considerably by region - in six counties in the Northeast part of Pennsylvania, the average is 7.2 Bcfe per well and in Wyoming County the mean EUR is 12 Bcfe. In that Northeast region there are a number of wells exceeding 20 Bcfe EUR. (Lease condensate was converted to an equivalent gas volume using a price ratio of 20 thousand cubic feet (Mcf) per barrel).

The data shows that apparent operational changes across the area, primarily added take-away capacity and compression, have significantly improved well performance since the last study in early 2016. Furthermore, many wells have shown more hyperbolic behavior than forecast in the earlier studies.

A regional breakdown, dividing the state into six areas, Northeast, Northwest, West Central, Mountain, Green-Fayette, and Washington, was made to analyze well performance in a more local way. (Fig. 3 in the appendix shows the location of the wells in the study and the regional divisions.)

Charts and tables are used to show the results rather than a paragraph format.

Summary of Projected EUR by County

Fig. 3 - The wells and the regions used in the study.


NORTHEAST REGION - Bradford, Lycoming, Sullivan, Susquehanna, Tioga, Wyoming counties

NORTHWEST REGION - Cameron, Elk, Forest, McKean and Potter counties

WEST CENTRAL REGION - Allegheny, Armstrong, Beaver, Butler, Clarion, Indiana, Jefferson, Westmoreland

MOUNTAIN REGION - Blair, Centre, Clearfield, Clinton, Somerset counties

GREEN-FAYETTE REGION - Greene and Fayette counties



For about 2,200 wells of the almost 5,000 wells in the study there was readily available perforation information. The perforated interval was used as a proxy for horizontal length. Correlations of EUR to this "horizontal length" proxy are below by region.

Copyright 2018, Gary S. Swindell, PE

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