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: http://www.flawofaverages.com/

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

Bad

Good

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

1 second

LVEW December 2007 swarm on borehole seismograph

- Surface network picked up only M > 1

M~ 1M~ -1

1 MIN

ON LINE AT: http://quake.wr.usgs.gov/cgi-bin/heliexp.pl

Common interpretation

How is IESE trying to avoid this problem? Hi-res electromagnetic profiling

Common setup

Depth

EW

NS

Res

ista

nce

Common data

Heat Source

Clay Cap

Static shiftR

esis

tanc

e

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

Normalpath

“split” paths

Normalpath

These “image” the fractures

These . do not

Microearthquake

Magnetotelluric Recorder

Lower Lower ResistanceResistance

These “image” the fractures

Higher Higher ResistanceResistance

These do not

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 array@

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 = 0.128 sec

Orientation69 degrees

0

2

4

6

8

0 .0 1 0 0 .1 0 00 .50 km

0

2

4

6

8

0 .0 1 0 0 .1 0 01 .50 km

0

2

4

6

8

0 .0 1 0 0 .1 0 02 .50 km

0

2

4

6

8

0 .0 1 0 0 .1 0 03 .50 km

0

2

4

6

8

0 2 4 6 8 10 12

0 .0 1 0 0 .1 0 04 .50 km

0

2

4

6

8

0 2 4 6 8 10 12

0 .0 1 0 0 .1 0 05 .50 km

F ig . 8 . T h re e d im e n s io n a l t o m o g rap h ic re s u lts o f th e s p lits h ea r-w a v e in v e rs io nd is p la y e d as h o r i zo n ta l sl ice s 1 .0 k m a p a r t. T h e m o d e l is rep re se n ted b y t h e v a lu e o f t h ed im e n sio n les s c ra ck -d e n s it y p a ra m ete r C D = N a3 /N , w h ere o ran g e a n d re d re g io n sre p re s en t h ig h e r c ra c k -d en s ity an d b lu e reg io n s re p re s e n t l o w e r c ra c k -d en s ity. B la c ktr ia n g le s re p re s en t s ta tio n l o c a t io n s .

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

Fractures

Time difference

PGV Seismic Network

Seismic Velocitymapping

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 0.065 crack density surface from Fig. 1, looking from the southeast direction.

All values of crack density greater than 0.065 are inside the plotted surface and values below 0.065 are

outside the plotted surface. The PGV lease boundary is plotted at the bottom for orientation.

4 1 2 0 0 0 4 1 4 0 0 0 4 1 6 0 0 0 4 1 8 0 0 0 4 2 0 0 0 0 4 2 2 0 0 0 4 2 4 0 0 0

4 1 2 0 0 0 4 1 4 0 0 0 4 1 6 0 0 0 4 1 8 0 0 0 4 2 0 0 0 0 4 2 2 0 0 0 4 2 4 0 0 0

7 2 9 4 0 0 0

7 2 9 2 0 0 0

7 2 9 0 0 0 0

7 2 8 8 0 0 0

7 2 8 6 0 0 0

7 2 8 4 0 0 0

7 2 9 4 0 0 0

7 2 9 2 0 0 0

7 2 9 0 0 0 0

7 2 8 8 0 0 0

7 2 8 6 0 0 0

7 2 8 4 0 0 0

r o a d

V i t i

l av a

f i el d

M T S o u n d i n g

M E Q 0 5

T E M s t a t i o n s

O l d T E M

S c a l e 1 : 7 5 0 0 0

m

0 5 0 0 1 0 0 0 1 5 0 0

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.

K 2 0

K 2 1

K 2 2

K 2 3

K 2 5

K 2 6

K 2 7

K 3 0

K 3 2

K 3 3

K 3 4

K 3 5

K 3 7

K 3 8

K 3 9

K 2 3 b

4 1 6 0 0 0 4 1 8 0 0 0 4 2 0 0 0 0 4 2 2 0 0 0

4 1 6 0 0 0 4 1 8 0 0 0 4 2 0 0 0 0 4 2 2 0 0 0

7 2 9 2 0 0 0

7 2 9 0 0 0 0

7 2 8 8 0 0 0

7 2 8 6 0 0 0

7 2 9 2 0 0 0

7 2 9 0 0 0 0

7 2 8 8 0 0 0

7 2 8 6 0 0 0

V i t i

Tra

i l

M T S o u n d i n g

W e l l S i t e

M E Q S t a t i o n

S c a l e 1 : 5 0 0 0 0

m

0 1 0 0 0 2 0 0 0 3 0 0 0

41

Areas of Aligned and No Aligned Fractures!

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

5 15 25 35 45 55 65 75 85 95 105 115 125 135 145 155 165 175

Median Polarization Direction

Norm

aliz

ed n

um

ber

of Shea

r W

aves

/MT F

requen

cies

MT Strike Direction

Fast Shear Wave Polarization Direction

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

5 15 25 35 45 55 65 75 85 95 105115 125135145 155165 175

Polarization Direction

Norm

alize

d Spl

ittin

g eve

ts/ M

T fre

quen

cies

MT Strike DirectionFast S-wave Splitting Direction

0

0.05

0.1

0.15

0.2

0.25

0.3

5 15 25 35 45 55 65 75 85 95 105115125135145155165175

Polarization Direction

Nor

mal

ized

No.

of S

-wav

e ev

ents

/ M

T fr

eque

ncie

s

MT Strike DirectionFast S-Wave Direction

MT Polarization

S-wave split

N E SSplitting direction

N E SSplitting direction

N E SSplitting direction

Num

ber

of

Ob

serv

atio

ns

Num

ber

of

Ob

serv

atio

ns

Num

ber

of

Ob

serv

atio

ns

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