Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74074, USA.
FEMS Microbiol Ecol. 2012 Jul;81(1):13-25. doi: 10.1111/j.1574-6941.2011.01196.x. Epub 2011 Nov 1.
Hydraulic fracturing is used to increase the permeability of shale gas formations and involves pumping large volumes of fluids into these formations. A portion of the frac fluid remains in the formation after the fracturing process is complete, which could potentially contribute to deleterious microbially induced processes in natural gas wells. Here, we report on the geochemical and microbiological properties of frac and flowback waters from two newly drilled natural gas wells in the Barnett Shale in North Central Texas. Most probable number studies showed that biocide treatments did not kill all the bacteria in the fracturing fluids. Pyrosequencing-based 16S rRNA diversity analyses indicated that the microbial communities in the flowback waters were less diverse and completely distinct from the communities in frac waters. These differences in frac and flowback water communities appeared to reflect changes in the geochemistry of fracturing fluids that occurred during the frac process. The flowback communities also appeared well adapted to survive biocide treatments and the anoxic conditions and high temperatures encountered in the Barnett Shale.
水力压裂用于增加页岩气地层的渗透率，涉及向这些地层中泵送大量流体。压裂过程完成后，一部分压裂液仍留在地层中，这可能会对天然气井中有害的微生物诱导过程产生影响。在这里，我们报告了来自德克萨斯州中北部 Barnett Shale 两口新钻天然气井的压裂和返排水中的地球化学和微生物特性。最大可能数研究表明，杀菌剂处理并没有杀死压裂液中的所有细菌。基于焦磷酸测序的 16S rRNA 多样性分析表明，返排水中的微生物群落多样性较低，与压裂水中的群落完全不同。压裂和返排水群落的这些差异似乎反映了压裂过程中压裂液地球化学性质的变化。返排群落似乎也很好地适应了杀菌剂处理以及 Barnett Shale 中遇到的缺氧条件和高温。
