Generalized Extreme Value Statistics, Physical Scaling, and Forecasts of Gas Production in the Barnett Shale

Tadeusz W. Patzek*, Wardana Saputra, Wissem Kirati, Michael Marder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

We develop a new method of predicting fieldwide gas or oil production from unconventional reservoirs, using the Barnett shale as an illustration. First, we divide the qualifying 13 141 horizontal gas wells in the Barnett into six static samples in which reservoir quality and completion technologies are similar. These samples contain wells of all ages. The Barnett samples coincide with the main gas producing counties, Tarrant, Johnson, Denton, Wise, Parker, and Hood. Second, for each sample, we use a purely data-driven nonparametric approach to arrive at appropriate generalized extreme value (GEV) distributions of gas production from the sample's dynamic well cohorts with at least 1, 2, 3,..., up to 14 years on production. We now have up to 14 cumulative probability distribution functions (cdfs) of annual well productivity per sample. From these cdfs, we stitch together six P50, P10, and P90 statistical well prototypes, one per sample or county. Our statistical well prototypes are conditioned by well attrition, hydrofracture deterioration, pressure interference, well interference, progress in technology, and so forth. So far, there has been no physical scaling. Third, we fit the parameters of our physical scaling model to the statistical well prototypes and obtain their smooth extrapolations to 30 years on production. At late times, we add radial inflow of gas external to the stimulated reservoir volumes of the mean wells. Fourth, we calculate the number of potential wells per square mile of each Barnett county and schedule future drilling programs. We then stack up the extended well prototypes to obtain the plausible forecasts of gas production in the Barnett until the year 2034. We predict that the six Barnett counties will ultimately produce 24.5 trillion standard cubic feet (Tscf) of gas from the existing wells. On energy equivalent basis, in this "do nothing" scenario, these counties will produce 4.2 billion barrels of oil equivalent, making it one of the top producers of fuel for the US. Finally, we consider a possible addition of 4.5 Tscf from the future 3570 surviving wells or 6800 new wells drilled between 2019 and 2028. On the average, only 1/2 of the current Barnett wells will survive beyond 15 years on production.

Original languageEnglish (US)
JournalEnergy and Fuels
DOIs
StatePublished - 2019

Bibliographical note

Publisher Copyright:
© 2019 American Chemical Society.

ASJC Scopus subject areas

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology

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