Uni-Bayreuth

Sprungmarken

 

Development of Shale Gas by Hydraulic Fracturing - Risk Assessment for Surface and Groundwater

Martin Sauter1, T, Lange2, R. Helmig3, A. Kissinger3, M. Heitfeld4, J. Klünker4
1 Lehrstuhl Angewandte Geologie, Universität Göttingen
2 Landesamt für Geologie, Rohstoffe und Bergbau im Regierungspräsidium Freiburg, Freiburg, Deutschland
3 Institut für Institut für Wasser- und Umweltsystemmodellierung, Stuttgart, Deutschland
4 Ingenieurbüro Heitfeld-Schetelig GmbH, Aachen, Deutschland

O 14.2 in Fracking for energy and its role for groundwater and soils

30.05.2014, 15:20-15:40, H18, NW II

Within the context of the assessment of the risks involved in the development of unconventional natural gas resources several expert opinions were formulated during the last three years in Germany (Umweltbundesamt, Umweltministerium Nordrhein-Westfalen, ExxonMobil-Dialogstudie). All of the reports come to the conclusion that hydraulic fracturing measures area controllable. The contamination risk to groundwater by fracking fluids is mainly posed by the “classical” contamination risk scenarios from the surface, resulting from the handling of the various chemical compounds and increased activity (truck traffic, pipelines) rather than from the subsurface transport between the injection location and the shallow groundwater systems.

The paper presents an approach for the assessment of the potentials risks of fracking measures, developed within the ExxonMobil Information and dialogue process (www.dialog-erdgasundfrac.de)  and specifies recommendations for the further procedure. Because of the shallower depth and the large number of boreholes and frack-operations required, the scientists come to the conclusions that development of shale gas resources by fracking poses a new dimension of risks compared to the earlier fracking procedures within the context of tight gas development and well rehabilitation and stimulation.

Should politics decide to develop these resources with fracking technologies, a stepwise approach is recommended: This comprises industrial scale demonstration projects, designed together with scientists, accompanied by communication and public acceptance measures. Before any fracking activities are being started, detailed site investigation will have to be carried out subject to the following aspects:

  • Avoiding areas with gradients directed towards shallow aquifers (water supply) and deep aquifers (spa, health and recreational use)
  • Avoiding areas of tectonically critically stressed conditions not to trigger large scale earth quakes
  • Avoiding wellhead protection areas.

Furthermore:

  • Newest standards for well completion have to be adhered to (well integrity) to prevent leakage along the annulus,
  • Adapted monitoring networks and sampling schedules have to be set up to provide a-priori baseline information and early warning infrastructure.

Research can further contribute in the following areas (selection):

  • Development of methodologies for the characterisation of the hydrogeological function of fault zones (pathway)
  • Investigation of the genesis of fracture networks in claystones (pathway)
  • Investigation of migration and reactive transport of frack-fluids in deep environments (processes)
  • Quantification of methane release from tight clay and marlstones (source term)
  • Development of modelling techniques of density-dependent, multiphase flow and reactive transport of complex fluids in the fractured porous subsurface (modelling)
  • Identification of thermogenic methane gas in well and the surrounding areas (monitoring)
  • Identification of indicator parameters for the detection of migration of frack-fluids (monitoring)


Export as iCal: Export iCal

Letzte Änderung 04.02.2014