Temperature and heat-flow techniques in the exploration of Enhanced - - PowerPoint PPT Presentation

▶
temperature and heat flow techniques in the exploration
SMART_READER_LITE
LIVE PREVIEW

Temperature and heat-flow techniques in the exploration of Enhanced - - PowerPoint PPT Presentation

Aug 23, 2022 272 likes •517 views

ENGINE WP 3 Workshop, Potsdam, 06-08 November 2006 Temperature and heat-flow techniques in the exploration of Enhanced Geothermal Systems (EGS): an overview from the shallow surface to deep into the lithosphere Frster, A., Lenkey, L.,

slide-1
SLIDE 1

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Temperature and heat-flow techniques in the exploration of Enhanced Geothermal Systems (EGS): an overview from the shallow surface to deep into the lithosphere

Förster, A., Lenkey, L., Schellschmidt, R., VanWees, J.-D., Cloetingh, S.A.P.L.

slide-2
SLIDE 2

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

  • Evaluation of the thermal state of

subsurface formations at drillable depth

  • Deciphering of processes responsible

for temperatures appropriate for EGS development

slide-3
SLIDE 3

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Surface Heat Flow

(Haenel and Hurter, 2002)

slide-4
SLIDE 4

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Basic Data

  • temperature values/profiles
  • temperature gradient
  • thermal conductivity (core/cuttings)
  • terrain effects incl.

topography, paleoclimate etc.

slide-5
SLIDE 5

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

shl

sst

salt

BSMT Temperature Depth heat flow q = k dT/dz

q=60 q=80

dT/dz = q / k

slide-6
SLIDE 6

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

T at z = 2000 m T at z = 1000 m

(Haenel and Hurter, 2002)

Surface heat flow is an important thermal parameter to characterize thermal potentials Strong resemblance between surface heat flow and subsurface temperature

slide-7
SLIDE 7

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Geodynamic processes in lithosphere and asthenosphere Heat generation and thermal conductivity of crust Heat distribution by fluids

slide-8
SLIDE 8

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006 Babuska & Plomerova (2006)

High amplitude / small wavelength anomalies, where and why ?

(Cloetingh et al., 2005)

slide-9
SLIDE 9

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Transient heat flow

crust mantle 1/β Lithospheric thickness McKenzie (1978) Normal geotherm dT/dz stretched geotherm dT/dz

slide-10
SLIDE 10

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

slide-11
SLIDE 11

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Larderello Field Rhine Valley NGB Pannonian B.

slide-12
SLIDE 12

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

North German Basin

North German Basin

  • Heat flow by conduction
  • High heat flow (70-90 mW/m²) as a result of

lithosphere thickness and crustal composition

(Norden and Förster, submitted)

slide-13
SLIDE 13

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Different temperature qualities BHTs (DSTs) T-Logs Different mapping scale/detail Heat refraction at salt structures

slide-14
SLIDE 14

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Tuscan Geothermal Fields

  • Mass and heat flux from the mantle in an

extensional setting

  • Emplacement of granite magmas (3.8-1.3 Ma)
  • Extensional shear zone as main pathways

for flow of hot fluids towards superficial reservoir Heat Flow Anomalies Shear Zone Heat Flow

(Bellani et al., 2004)

slide-15
SLIDE 15

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

The Rhine Graben

Temperature at 800 m

  • Thermal anomalies are not correlated to

crustal thickness

  • Heat transfer is as combination of

conduction and convection

(Pribnow and Schellschmidt, 2000)

slide-16
SLIDE 16

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

GPK2 borehole

conduction convection convection convection conduction

BHTs versus Temperature Logs

(Pribnow and Schellschmidt, 2000)

slide-17
SLIDE 17

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 50 100 150 200

Depth (m)

Friedland 1/71 48h BHT

  • Equ. BHT

19900h

Temperature (°C)

BASIC TEMPERATURE DATA:

Temperature log (steady-state conditions) Temperature log plus multiple BHTs Temperature log Temperature log plus single BHT Multiple BHTs at different depths - no log Single BHT - no log

Empirical Numerical

CORRECTION VALID TEMPERATURE-DEPTH DISTRIBUTION

(Förster, 2001)

slide-18
SLIDE 18

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

  • Raw temperatures deviate by as much as

22 ± 10°C (1δ) from the true formation temperature

  • Corrected temperatures underestimate

formation temperatures by as much as 8 – 9°C.

  • Large standard deviations indicate that

corrected BHTs (with 2δ confidence) reflect formation temperatures not better than ± 16°C.

slide-19
SLIDE 19

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

BHTs vs. Temperature Log

(Blackwell and Steele, 1988)

slide-20
SLIDE 20

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Internal thermal properties

  • f sedimentary basins
  • ften unknown locally and regionally
slide-21
SLIDE 21

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

More data are needed Data banking is rudimentary yet

Thermal Conductivity

Laboratory Measurements Well-Log Approaches

PHIe: “effective” porosity

“PETROPHYSICAL DESCRIPTORS”:

Vsh : proportional volume of shale RHOmaa : apparent matrix density Dtmaa : apparent matrix transit time

PETROPHYSICAL WIRELINE LOGS:

Gamma-ray Density Sonic Neutron porosity (API units) (g/cm ) (msec/ft) (limestone-equiv. units)

3

slide-22
SLIDE 22

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Estimated Accuracy of Heat-Flow Determination

(based on methodology)

slide-23
SLIDE 23

ENGINE – WP 3 Workshop, Potsdam, 06-08 November 2006

Signatures of Temperature Field EGS Concept Phase EGS Exploration Phase EGS Development Phase