Production Analysis in the Barnett Shale - Field Example for Reservoir Characterization Using Public Data

Pratikno, H. (ConocoPhillips) | Reese, D.E. (Dave E Reese Consulting LLC) | Maguire, M.M. (ConocoPhillips)


Development of unconventional reservoirs continues to expand in North America and has gained interest worldwide. The first unconventional play to be rapidly developed is the Barnett Shale located in North Central Texas. As of July 2012, the Barnett Shale had more than 13,000 multi-staged fractured horizontal wells (MFHW) with approximately 2,500 of these wells with over five-plus years of production history. In addition to these MFHW, there are approximately 3,000 vertical wells in the Barnett Shale.

Well spacing is a key value driver for field development and needs to be addressed early in the appraisal process. Interpretation of early production analysis from MFHW can provide many insights into the reservoir and fracture characteristics of these wells. However, these interpretations are non-unique until end of linear flow (ELF) is reached. This study used public production data that lacks wellhead flowing pressures. For this study the wells that did see end of linear flow did so in a time period where flowing pressures are expected to be relatively constant and therefore having measured pressures was not deemed necessary. Reservoir permeability, fracture half-length, and original-gas-in-place of the area contacted by the created hydraulic fracture network can be determined once end of linear flow is reached. Once fracture half-length and permeability have been determined, the appropriate well spacing can be estimated using simulation and economics.

A comprehensive review of approximately 2,500 MFHW using public data within two Northern counties of the Barnett Shale found more than 100 wells where end of linear flow could be clearly observed in production characteristics. With the end of linear flow determined for these wells, estimates of permeability and fracture half-length were determined. A single well simulation study feeding an economic evaluation was then used to study well spacing and yield suggested optimum development spacing. This paper will review all of this work, the results and conclusions, and provide observations of some of the trends.