How to optimize drilling strategies and reservoir management: - PowerPoint PPT Presentation

How to optimize drilling strategies and reservoir management: lessons learned from the Soultz EGS project? Leiden, The Netherlands 7-9 November 2007 Risk Analysis for Development of Geothermal Energy Cuenot N., Genter A., Naville Ch. ENGINE WORKSHOP 7 07-09 November 2007, Leiden

Exploration: Challenges > How Exploration can contribute to a better Exploitation of the geothermal reservoir > Unconventional Geothermal Reservoirs No trace on surface (fumaroles, hot soil, thermal springs, altered zone) • > EGS Enhanced Geothermal Systems • • Engineered Geothermal Systems Soultz 3D organisation of the faults and the flow channels 07-09 November 2007, Leiden > 2

Best practices for exploration EGS fractured reservoirs > Based on Soultz experience: high quality datasets but Soultz horst partial vision (borehole wall) flow l/s -20 -10 0 10 20 30 40 > Fractured zones controlled production the flow test Injection > Low natural permeability test associated with fracture zone (brines, 100g/L) > Hydrothermal alteration Image logs GPK1 related to (paleo)fluid circulations are related to natural permeability EPS1 Core Conceptual model 2555 m 07-09 November 2007, Leiden > 3

Best practices in oil industry from exploration to exploitation 2D/3D seismics well data multiwell - oil field Reservoir exploitation From Oil field review, 2005/2006 07-09 November 2007, Leiden > 4

Best practices for EGS reconnaissance at concessionnal scale 2D/3D geophysics Local field mapping Local outcrop analysis Well analysis -Seismic -Fractures/faults geometry -Fractures/faults -Cuttings/cores -Gravi-mag methods -Geological interfaces -Rock petrography -Fractures/faults vs depth -EM, MT Methods -Volcanoes -Mineralogy -Rock Petrography -Other methods -Rock dating -Hydrothermal alteration -Hydrothermal alteration -Thermal spring location -Petrophysics (porosity) -Fumaroles -Geophysical logging -Borehole image logs -Vertical Seismic Profile 3D conceptual model 07-09 November 2007, Leiden

Geology and EGS: Coupled C - THM processes CHEMICAL THERMAL HYDRAULIC MECHANICAL Lithology Mineralogical Lithology, (U, Th, K) rock-matrix Matrix K, Φ Alteration composition (drilling) Rock-matrix Fracture K, Φ composition Hydrothermal Fracture Alteration Fracture Properties Thermal network properties Fracture filling In situ Stress Chemical Drilling Thermal stimulation Hydraulic Hydraulic Scaling, Tracing stimulation stimulation stimulation W-R interaction Rock composition, Fracture, Stress 07-09 November 2007, Leiden > 6

EGS drilling reconnaissance Standart GR Smoothed HAC Potassium Thorium Uranium Depth (m) 100 150 200 250 300 0.02 0.04 0.06 20 40 10 0 1600 Core 1800 2000 2200 2400 2600 2800 Fracture 3000 filling 3200 3400 3600 Stress 3800 Lithology 4000 Field 4200 4400 4600 Fracture 4800 Cuttings Filling 5000 Geophysical logs Fractures 07-09 November 2007, Leiden > 7

Fault network at Soultz derived from 2D seismics Sediments Granite Large-scale faults versus local-scale faults Relationship between basement faults and sediments faults Need for imaging deep fractured crystalline rocks 3D model from Renard & Courrioux, 1994; Valley, 2007 07-09 November 2007, Leiden > 8

Fault network at well scale 14 km length of borehole image logs >> 800 m length of cores in the upper reservoir 1,2 m of core in the lower reservoir FMS, FMI, ARI Amplitude Transit time BHTV, UBI Cores Cuttings Geophysical logs 07-09 November 2007, Leiden > 9

Fracture zones along the well bore From Valley, 2007 07-09 November 2007, Leiden > 10

How to get the 3D fracture network from well only 07-09 November 2007, Leiden > 11

Fracture network: from 1D to 3D 07-09 November 2007, Leiden > 12

07-09 November 2007, Leiden > 13

3D modelling procedure GPK2 GPK3 BRGM, 2006 Sausse et al., 2007 07-09 November 2007, Leiden > 14

AE reflection method Basic concept Using AE/MS waveform as a wavesource 3D imaging like a reflection survey Advantages High energy, robustness, Resistant to surface condition, Simple & easy, low costs - Available for inside basement rock or highly attenuated media in geothermal fields - Detection of sub-vertical structures - Sensitivity to fractured zone (S-wave) from Soma 07-09 November 2007, Leiden > 15

GPK3-GPK4: AE and structures (from Soma et al., 2004) High-f Low-f 07-09 November 2007, Leiden > 16

Vertical Seismic Profile (VSP): better characterisation of fracture zone network? GPK1 Horizontal distance (m) Depth Permeable fracture (dip 60° ) Observed in the well 07-09 November 2007, Leiden > 17

Characterization of permeable fracture zone in drillhole 300 Cross Section Area cm2 Bulk density g/cm3 Gamma Ray GAPI Production log 8l/s DT Shear µs/feet DT Comp µs/feet Injection log 18 l/s Permeable fracture Potassium % Caliper inch UBI Transit Time Thorium ppm Uranium ppm Depth (m) Depth (m) Dip Facies UBI Amplitude 12.25 1.70 2.20 2.70 0.04 0.08 6.25 9.25 100 200 100 125 200 -0.5 0.5 10 25 40 45 60 75 75 45 90 1 3 0 0 2 3482 3482 3483 3483 3484 3484 3485 3485 3486 3486 3487 3487 3488 3488 Flow 3489 3489 F-ma F-ma 3490 3490 3491 3491 Quartz 3492 3492 veins 3493 3493 3494 3494 F-ma Flow F-ma 3495 3495 3496 3496 3497 3497 3498 3498 Soultz, GPK1 3500 m, Natural brine outflow 07-09 November 2007, Leiden > 18

VSP Survey: April 2007 Cra nes 7 conductors cables Recording unit Vibrator Truck EEIG EEIG : 2 cranes + 1 Cable/ winch unit : 2 cranes + 1 Cable/ winch unit M M ESY: 1 Cable/ winch unit ESY: 1 Cable/ winch unit LANTECH: LANTECH: H H recorder + 2 vibrators recorder + 2 vibrators C C 1 1 H H E E T T r r C C o o radio link radio link 2 2 D D E E t t N N a a T T r r r r o o A A b b D D t t a a L L V V i i N N r r A A b b L L i i V V EEIG winch: MeSy winch: radio link radio link GPK4 GPK3 3 surface 3 surface BAK BAK E E R-H R-H UG UG UE UE S S m m onitor geophones onitor geophones downhole tool downhole tool control boxes control boxes 7-conductor cable 7-conductor cable connection connection BAK BAK E E R ASR R ASR 4C 4C -VSP tools -VSP tools 3 geophone 3 geophone + 1 hydrophone, + 1 hydrophone, Tm Tm ax: 200°C ax: 200°C IPP : Technical coordination IPP : Technical coordination EEIG EEIG : global organisation : global organisation IFP, EEIG, EOST, MeSy, Baker Hughes, Landtech, VSFusion 07-09 November 2007, Leiden > 19

VSP preliminary results in GPK4 Direct arrival Refracted arrival PP reflected arrival 3900 m depth: complex damaged zone Image log at 3900 m 4380 m depth: permeable fracture zone 07-09 November 2007, Leiden > 20

Conclusion > Exploration: hierarchy between faults > Regional scale compilation at regional scale (seismics, old wells) • Integration by producing conceptual model • > Local scale 3D/2D seismics (25 km²) • Drill an exploration well • Geophysical logging, borehole image, core, cuttings,… • > VSP survey Top basement fault map • Locate major faults in the basement • > Target new wells Optimize well trajectories (inclined/deviated wells) • Secure well design and thus future exploitation • 07-09 November 2007, Leiden > 21