Potential and Challenges of Shale Gas Kurt M. Reinicke Institute of Petroleum Engineering Clausthal University of Technology

Transcription

1 Potential and Challenges of Shale Gas Kurt M. Reinicke Institute of Petroleum Engineering Clausthal University of Technology

2 RESERVOIRS TIGHTER THAN CONCRETE k (md) Permeability (md) Conventional Reservoir k = md Concrete Sidewalk k = md Tight Gas Reservoir k = md Shale Gas Reservoir k = md Conventional Rock Unconventional reservoirs Very low permeabilities Not recoverable without elaborate technology Shale 50 μm 50 μm Source: ITE, ExxonMobil, Source: ITE,

3 (BRITTLE) SHALE ON THE SURFACE Source: USGS, 2011 Shale outcrop in ideal conditions with many natural fractures and fissures 3

4 SHALE IN THE SUBSURFACE Time Scale Lithostratigraphy Shale gas (in Germany) is found in depths of ca m capped by massive impermeable layers Potential shalegas targets Barrier formations North German Basin Lithostratigraphy Source: Walter,

5 SHALE GAS ARE CONTINUOUS DEPOSITS Shale gas deposits have large areal extent (still) difficult to quantify bear large potential despite low recoveries Distribution of Posidonia Shale Source: Doornenbal & Stevenson (edts),

6 EUROPEAN SHALE GAS RESOURCES ARE SIGNIFICANT Denmark (650) U.K. (560) In Mrd. (10 9 ) m 3 Norway (2350) Sweden (1160) France (5100) Netherlands (480) Germany (230) 1300, BGR 6/2012 Shale Gas Resources Mrd. m 3 Source: EIA ARI World Shale Gas Resources, 2011 Conv. Gas Reserves: 4500 Mrd. m 3 Source: EIA,

7 KEY TECHNOLOGIES Source: BGR, 2011 USA 2010: more than shale gas wells ca. 135 Mrd.(10 9 )m 3 /a (consumption Germany 95 Mrd.m 3 ) Initial production from deposits with natural fractures Recent boom technology driven Key Technologies Horizontal/multilateral-drilling Frac/multifrac technology 7

8 SHALE GAS IS DEVELOPED BY WELLS Wells are constructed to provide a tight connection between surface and reservoir Well design with sectional introduction of steel pipes annulus cementation Source: ConocoPhillips Adapted Well Bore Schematic 8

9 FRACKING Fracking Experiments Fracking is the process of initiating and propagating a fracture in a rock layer, by pumping a liquid under high pressure Well Perforations Multiple Fracture Planes Well Source: DGMK, 2003 Frac Simulation Source: Steeb,

10 FRAC FLUIDS Typical frac-fluid composition for proppant frac Water =90,6% Proppants =8,96% Others =0,44% 0,120% 0,100% 0,080% 0,060% 0,040% 0,020% 0,000% Source: Miskimins, SPE,

11 FRACKING IMPROVES WELL PRODUCTIVITY Far reaching fractures penetrating the formation represent highly permeable flow paths, improve well inflow Technology in use since 1949, appllied in >1 million wells 11

12 SHALE GAS DEGASSING Well Frac-fluid Clay particle (mm) Clay layer Source: BGR,

13 SHALE GAS DEGASSING Well Frac-fluid Clay particle (mm) Clay layer Source: BGR,

14 SHALE GAS DEGASSING Well 3: Gas flow in production well 2: Gas flow through fissures 1: Degassing by diffusion Clay layer Source: BGR,

15 SHALE GAS THE CONCERNS Fracturing causing fissures to potable water horizons Leaks along wells Toxic chemicals in frac fluid Flow back fluid Surface spills Water consumption Fracturing triggered seismicity Land use 15

16 RISK MITIGATION: FISSURES TO SURFACE DEPTH (m MDGL) 500 FORMATION & MUD WEIGHT 50 m Quaternary Tertiary 151 m Transgression Upper Cretaceous 675 m FORMATI ON 282 m 376 m Campanian Santonian + Coniacian Turonian 598 m Cenomanian (faulted) Albian LITHOLOGY LI Marl The subsurfacemust be characterized The caprock must contain sufficiently thick flow barriers Lower Cretaceous 1128m Wealden (Bueckeberg Fm) 1355m Obermalm m Obermalm m Obermalm m Obermalm m Upper Jurassic (Malm) 1802 m 1204m 1734 m 1851 m Aptian Valanginian Kimmeridgian Oxfordian zeta Clay Fissured deepseating fault zones must be avoided Middle Jurassic (Dogger) 2307 m Lias 2032 m Dogger Delta sst. delta 2106 m gamma 2182 m beta 2265 m alpha 2321 m zeta epsilon (Posidonia) 2361 m delta 2493 m TD = ~ 2044 m MDGL below Dogger Delta Sandstone Weak to medium oil shows Strong oil shows Strong gas shows epsilon Claystone Sandstone Marlstone Claystone/Sha Sand/Sandsto Marlstone Shale Lithostratigraphy: Typical North German Situation Source: ITE,

17 RISK MITIGATION: FISSURES TO SURFACE Fracture growth must be modeled Micro-Seismicity Fracture growth can be monitored Source: Fischer in AOGR, 2010 Vertical FrackGrowth and Groundwater for Barnett Play From Burri, 2012: Apache Fracture Results in Horn River Basin 17

18 RISK MITIGATION: LEAKS ALONG WELLS Wells must be proven tight Pressure testing Acoustic well logging = Cement Bond Log (CBL) Geomechanical modeling Pressure monitoring Source: ConocoPhillips Adapted Well Bore Schematic 18

19 RISK MITIGATION: TOXIC FRAC FLUID ADDITIVES Fracfluid environmental Typical frac-fluid composition for proppant frac compatibility must be improved Water =90,6% Others =0,44% Proppants =8,96% 0,120% 0,100% 0,080% 0,060% 0,040% 0,020% 0,000% Replacement of toxicadditives Change of fracking process to allow decrease of additives Additives for Slick Water Fracs <0,2% Source: Miskimins, SPE,

20 RISK MITIGATION: FLOW BACK AND SPILLS To mitigate fluid-related risks surfaces must be sealed equipment must be (pressure) tested fluids must be collected and recycled or properly disposed Source: RWE Dea,

21 RISK MITIGATION: LAND USE Source: EIA, 2011

22 Bochum Dortmund North Rhine-Westphalia wells wellsdeeper than 100m 600 wells deeper than 1.000m Carboniferous wells approx wellsnrw total wells deeper than 100m wells deeper than 1.000m

23 RISK MITIGATION: LAND USE Source: EIA, 2011 Until 2008: ca wells (ca. 1 well/km 2 ) therefrom until 2000: ca vertical wells until 2005: ca. 500 directional wells after 2005: ca fraced horizontal wells Today: increasingly multifraced, multilateral-/horizontal wells

24 RISK MITIGATION: LAND USE Drill Site Classical Vertical Well- Technology Multilateral Well-and Multifrac- Technology Canadian Association of Petroleum Producers, 2010

25 SHALE GAS SOME FACTS ABOUT THE USA US Gas Reserves growth since 2000: 54% US #1 in discoveries since 2000 US #1 gas producer in 2009 Source: T. Ahlbrandt 2012 Development of US Natural Gas Production N-America self sufficient in gas, will become LNG exporter (2015?) 25

26 SHALE GAS SOME FACTS ABOUT THE USA Collapse of gas price in US Benefits to US economy: B$/y* 1 Mio new jobs created by 2010 Reduction of 450 Mio t of CO 2 as a result of gas substituting coal Gas attractive for hydrogen production (now source for 90%) * Bloomberg 26 Jan 2012 Natural Gas Price $/MSCF Gas Price (TTF) Europe Mai 2012: 2,4 c/kwh 0,5 c/kwh Jan 05 Jul 05 Jan 06 Jul 06 Jan 07 Jul 07 Jan 08 Jul 08 Jan 09 Jul 09 Jan 10 Jul 10 Jan 11 Jul 11 Jan 12 Jul 12 Development of US Natural Gas Price 26

27 CONCLUSION Shale gas resources of Western Europe are significant Risks associated with its utilization are manageable Standards should be reviewed, new technology developed More dialogue is needed to increase acceptance Thank you for your attention

28 CONCLUSION and don t forget to switch off the light every now and then Source: Burri, 2012