FORMATION WATER SIGNATURES OF THE FT WORTH BASIN RELEVANT TO GAS PRODUCTION FROM BARNETT SHALE

One of the critical issues facing production of gas from the Barnett Shale is co-production of excess water from adjacent formations. In order to identify subsurface sources of produced water we combined regional database analysis with new, high resolution sampling program in Parker County, Texas. Resulting water compositions reveal three separate water populations of interest within the Barnett Shale. Two populations related to the Ellenburger Fm can be established and one that has contributions from the Marble Falls and/or Barnett Fms. The difference between Ellenburger and non-Ellenburger formation water can be reasoned from salinity alone although full chemical analysis provides a more robust identification. Based on this analysis it is likely that the recently sampled Kos Beverung 1H well produces some Ellenburger water, whereas the Muir J2H, Stevenson-Langford 1H, RBR H2H, and Grubb 2H all produce water that is indicative of Marble Falls and/or Barnett contributions. Data gathered during sampling are consistent with a) regional field observations and b) well completion results. Information gained from this sampling program can be used to selectively place completions in subsequent wells and to direct near field drilling opportunities.