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Description:
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The increasing interest and focus on unconventional reservoirs is a result of the
industry's direction toward exploring alternative energy sources . It is due to the fact that
conventional reservoirs are being depleted at a fast pace . Shale gas reservoirs are a very
favorable type of energy sources due to their low cost and long -lasting gas supply . In
general , according to Ausubel (1996 ) , natural gas serves as a transition stage to move
from the current oil -based energy sources to future more stable and environment -friendly
ones .
By looking through production history in the U .S Historical Production Database ,
HPDI (2009 ) , we learn that the Barnett Shale reservoir in Newark East Field has been
producing since the early 90's and contributing a fraction of the U .S daily gas production .
Zhao et al . (2007 ) estimated the Barnett Shale to be producing 1 .97 Bcf /day of gas in
2007 . It is considered the most productive unconventional gas shale reservoir in Texas .
By 2004 and in terms of annual gas production volume , Pollastro (2007 ) considered the
Barnett Shale as the second largest unconventional gas reservoir in the United States . Many studies have been conducted to understand better the production controls in
Barnett Shale . However , this giant shale gas reservoir is still ambiguous . Some parts of
this puzzle are still missing . It is not fully clear what makes the Barnett well produce high
or low amounts of gas . Barnett operating companies are still trying to answer these
questions . This study adds to the Barnett chain of studies . It tests the effects of the
following on Barnett gas production in the core area (Denton , Wise , and Tarrant
counties ) :
* Barnett gross thickness , including the Forestburg formation that divides
Barnett Shale .
* Perforation footage .
* Perforated zones of Barnett Shale .
Instead of testing these parameters on each well production decline curve individually ,
this study uses a new technique to simplify this process . Decline Map Analysis (DMA ) is
introduced to measure the effects of these parameters on all production decline curves at
the same time .
Through this study , Barnett gross thickness and perforation footage are found not
to have any definite effects on Barnett gas production . However , zone 3 (Top of Lower
Barnett ) and zone 1 (Bottom of Lower Barnett ) are found to contribute to cumulative
production . Zone 2 (Middle of Lower Barnett ) and zone 4 (Upper Barnett ) , on the other
hand , did not show any correlation or influence on production through their thicknesses . |