T23D-2984
Petrophysical, Structural, and Hydrogeological Characteristics of the Alpine Fault Hanging Wall Based on DFDP-2 Wireline Logging, Temperature, and Hydraulic Measurements
Tuesday, 15 December 2015
Poster Hall (Moscone South)
John Townend1, Rupert Sutherland1,2, Virginia Toy3, Mai-Linh Doan4, Bernard P Celerier5, Cecile Massiot1, Jamie Coussens6, Lucie Capova1, Tamara Jeppson7 and DFDP-2 Science Team, (1)Victoria University of Wellington, Wellington, New Zealand, (2)GNS Science, Lower Hutt, New Zealand, (3)University of Otago, Dunedin, New Zealand, (4)University Joseph Fourier Grenoble, ISTerre, Grenboble, France, (5)University of Montpellier II, Montpellier Cedex 05, France, (6)University of Southampton, Southampton, SO14, United Kingdom, (7)University of Wisconsin Madison, Madison, WI, United States
Abstract:
Fault rock assemblages reflect the combined effects of interaction between deformation, stress, temperature, fluid, and chemical regimes on distinct spatial and temporal scales at various positions in the crust. Here we summarize the petrophysical, structural, and hydrogeological characteristics of the Alpine Fault’s hanging wall based on measurements made during the second stage of the Deep Fault Drilling Project (DFDP-2) in late 2014. In total, more than 19 km of wireline logging data including 4.8 km of borehole televiewer imagery were acquired during the three-month drilling operation, which reached a maximum depth of 893 m (817 m true vertical depth). In conjunction with manual and automatic measurements of hydraulic parameters, on-site analysis of rock cuttings and fluid geochemistry, and post-drilling temperature measurements, the wireline data permit detailed analysis of bulk rock properties, fracturing, and fault zone structure. We focus in particular on understanding how the hydraulic conductivity of individual fractures relates to the high bulk conductivity of the hanging-wall, and thus to the transport of fluids and heat through the shallow crust.
