Plus an Introduction to the: Institute of Earth Science & Engineering RESOURCE INDEX MAPPING: Getting the Right Data for the Right Model

HOW? Seismology Potential Fields Ground penetrating radar Geochemistry & mineralogy What does IESE study? THE EARTH BETWEEN “WELL-WATER AND MAGMA” WHO? 14 PhDs 14 Technical 6 Graduate students UoA Geo & Eng faculty Industry IESE University of Auckland Contract Based Project Based Grant Based Market Driven Balance Knowledge Driven Products & Services Innovations & Training Research & Education How does IESE work ?

Where does IESE work?

From: with apologies to S. L. Savage & text Geophysicist’s prediction Reservoir Engineer’s....experience What is IESE doing at these places? …trying to avoiding the “flaw” of averages….

Why a new conceptual model and data acquisition approach? Drilling cost effectiveness: example of geothermal well outputs – New Zealand Mean=2.6 MWe After deepening

Where would you drill? Example of flaw of averages in geothermal development BadGood Ohaaki geothermal well field fit on to a 1/k resource index map

Surface seismograph Borehole seismograph M ~ 0.5 MEQ Data from 3.3 km deep LVEW How is IESE trying to avoid this problem?...one way: borehole seismology 1 second

LVEW December 2007 swarm on borehole seismograph - Surface network picked up only M > 1 M~ 1 M~ -1 1 MIN ON LINE AT: bin/heliexp.pl

Common interpretation How is IESE trying to avoid this problem? Hi-res electromagnetic profiling Common setup Depth  EW NS Resistance  Common data Heat Source Clay Cap Static shift Resistance  Depth  High Low....Uncommon data Splitting depth Up Flow Electric Field - wire Magnetic Field - coil Recorder Lap top Drill site?

Depth Hi-res electromagnetic profiling with “uncommon” data

How is IESE trying to avoid this problem?...another way: tomography

Microearthquake (MEQ) S-splitting mapping Seismic recorder Normal path “split” paths Normal path These “image” the fractures These. do not Microearthquake What is special about IESE’s approach to these methods? - MEQ & MT based fracture mapping - Time lapse / repeated surveys Magnetotelluric (MT) Polarization mapping Microearthquake

GOES = Geophysical Observatory and Exploration System 32 cm 4 km 100 m delta

Earthquake Shear-wave from below What is shear wave splitting ? Fractures Time difference Shear wave splitting

Identifying S-Wave Splitting P S1 S2 Time delay = sec Orientation 69 degrees

Example - fracture density tomography at Casa Diablo geothermal field, Califronia Fractures Time difference

PGV Seismic Network Seismic Velocity mapping Fracture mapping Resource index mapping: S-wave splitting

Consistent fast polarization direction?

3-D Crack Density-Depth Tomography Map: Red = high crack density Blue = low.

Fig. 2. An isosurface plot of the crack density surface from Fig. 1, looking from the southeast direction. All values of crack density greater than are inside the plotted surface and values below are outside the plotted surface. The PGV lease boundary is plotted at the bottom for orientation.

MT red triangles TEM yellow circles MEQ purple squares Krafla Geothermal Field – Iceland. Map of Seismic & E&M Stations

Fast polarization direction for shear wave splitting

43 MT polarization directions for upper half of cross section.

41 Areas of Aligned and No Aligned Fractures! MT Polarization S-wave split N E S Splitting direction N E S Splitting direction N E S Splitting direction Number of Observations Area 1 Area 2 Area 3

Both S-wave & MT splitting 3 successful wells - one 32 MW Example: successful geothermal wells - Iceland No splitting & polarization 1 dry well drilled Pre – MEQ & MT drilling plan 8 -> 18 -> 32 Mwe (Landsvirkjn, per. com.)

MT site & low resistance direction Earthquake station & fast direction Drill site MT Polarization S-Wave splitting Drilling direction Example: successful geothermal wells - Kenya Wells go from 2  5  7 MW Plant goes from 75 MW  140 MW (UN Press Release)

IESE Project Based Balance of R&D and Service New Practical Knowledge Provides R&D/Training