Making the most of it: Combining seismic and electromagnetic observations in complex rock IESE MT Team – J.Peacock, P.Leary, E.Shalev, M.Hasting, J.Pogacnik, & P.Malin NORSAR MEQ Team -- J.Albaric, V.Oye, N.Langet, M.Hasting, I.Lecomte, K.Iranpour, M. Messeiller, & P.Reid AGIS – Karlsruhe Meeting 28/11/2012

3 Part Outline: I. Complex rock a. Coromandel outcrop b. 3 Empirical rule for complex rock c. Well log and core evidence for complex rock d. THM coupling in complex rock – the movies II Combining seismic and electromagnetic observations in complex rock a. The event location conundrum at SAFOD b. The MT coil experiment – needs verification III MEQ and MT at the Paralana HSA site a. The MEQ event cloud b. The continuous and time-lapse MT effect

I. Coromandel NZ outcrop: why we need a new approach to thinking about/modeling fractures Graywacke reservoir exposure Coromandel New Zealand

Coromandel basement metasediments spaced this far apart d flaws this long (strong) l L D The first rule relates spacing and properties Expressed in terms of wavenumber Rule I S(k) ~ 1/k The second rule relates porosity and permeability Expressed in terms of fluctuations Rule II δ ~ δlog( ) The third rule relates fluid flow and Rules I & II 2 m Expressed in terms of a power law Rule III ~ 10 ( - 0 ) 3 Empirical rules for complex rock Coromandel Fractures Compared to flaws this long (strong) spaced this far apart 2 m volume v

Data from Roger Slatt Rule I: reason to believe S(k) ~ 1/k from well logs S(k) = fluctuation power at k k = spatial frequency S(k) ~ 1/k

(blue) log( ) (red) δ ~ δ log( κ ) / ~ 10 ( - 0 ) Sample No. Well No % 92% 86% 69% 94% 87% 87% Rule II: reason to believe δ ~ δlog( ) from well core porosity and permeability

Rules III ~ 10 ( - 0 ) : and injection well flow in complex rock Perm Distribution Pressure Velocity small medium large

HEAT TRANSFER BY FLUID FLOW IN COMPLEX ROCK IS EMERGENT THE HEAT SOURCE IS DOWN HERE THE WATER COMES IN HERE THE WATER COMES IN HERE THE WATER COMES OUT HERE 1 KM What are meant by an emergent phenomena?

The problem: Define drilling target using best 3-D method Mag 2 repeating event ~ 10x10 m. Phase 1: 60 surface stations, 2 years, located within 100 m errors Phase 2: add 32 levels borehole, 1 year, located within 50 m errors moved 800 m Phase 3: add sensor 400 m from target, located within 20 m errors moved 200 m II Combining seismic and electromagnetic observations in complex rock Earthquakes location: a lesson from SAFOD

MEQ and MT: the first test – yet to be repeated (by us anyway)

? Vel Acc Pod 1 Vel Acc Pod 3 Vel Acc Pod 5 MT Low gain Mid High – reversed polarity Oct Event : Vel, Acc, MT

S-P 2 x S-P S-P 2 x S-P Oct Event : Stacked Raw and Low Pass MT Sept Event : Stacked Raw and Low Pass MT

III MEQ and MT at the Paralana HSA site Seismic CMP profile MT profile 11 permanent MT 56 repeat MT profile 8 Borehole MEQ 4-6 Surface MEQ

Paralana: 3D MT, MEQ and Geology from Seismic Reflection E 1km

Paralana: 3D MT and MEQ 1.Km ~NE 1.Km ~NE N E

Paralana: Permanent MT station PB01 differences ~ a few hundred meters from well head Period of ~ sec ~ 1 km; ~ 3-4 sec ~ 3-4 km Begin End

Permanent MT Map Day Period Impedance Tensor min/max ellipse NE directed change Max change ~ 3 – 4 km

Paralana: 3D MT, MEQ and Phase Tensors NE 1km

Paralana: 3D MT and MEQ N E Possible Location Extraction Well Possible Location Extraction Well

Fully coupled Hydro-Thermal-Mechanical model including shear stresses in complex rock