Azra N. Tutuncu, Colorado School of Mines

Harry D. Campbell Chair, Petroleum Engineering Director, Unconventional Natural Gas and Oil Institute (UNGI)

EPA SAB Advisory Panel Member on Hydraulic Fracturing Research

December 5, 2013 Rio de Janeiro, Brazil

Technical and Environmental Challenges for

Unconventional Gas and Oil Developments

UNGI

Energy Supply Contribution from Unconventional Resources in the U.S.

EIA’s Annual Energy Outlook (AEO) 2013 early release

U.S

. dry

nat

ural

gas

pro

duct

ion

1

990-

2040

(tril

lion

cubi

c fe

et)

U.S

. dom

estic

crud

e oi

l pro

duct

ion

199

0-20

40 (m

illio

n ba

rrel

s/da

y)

UNGI

Footprint Reduction

Vertical Well Contact Area

~ 160 ft2

2000 ft Horizontal Well

100 ft

20 times Vertical Well

Contact Area ~ 3,207 ft2 Horizontal Well

No fractures

UNGI

~ 957 Vertical 48 Horizontal Well

2000 ft Horizontal with 10 multistage fractures

150 ft length each

Contact Area ~ 153,207 ft2

Shale Reservoir Development Challenges

• Effectiveness of the fracturing operations strongly depend on – Production rates, drainage area and recovery efficiency – Knowledge of in situ stress state, formation characteristics and

anisotropy influence the design and execution of the operations • Main challenges include

– Reservoir and fracture characterization/ sweet spot identification – Upscaling/downscaling for capturing heterogeneity and anisotropy – HF/ NF coupled geomechanics/flow modeling for permeability – Zonal production contribution enhancement – Environmental issues – Adequate infrastructure

UNGI

Surface and Ground Water Protection and Air Quality

• Public and media attention concerning potential ground water contamination

from hydraulic fracturing • A Hz well ~5000 ft with 20-25 stages use 2-6 million gallons water

• Recycled water contains particulates, suspended solids, dissolved organics

(organic acids), silica and bacteria • Waste water disposal is also a concern for induced seismicity • NOx, CO, particulate matter, benzene, toluene, other volatile organic

compounds (BTEX) and ozone are among pollutants of concern for air quality • Radionuclides like radium, thorium and radon from the wastewater treatment

of fluids, malodors and methane are additional sources of air pollution

UNGI

• Acids • Sodium Chloride • Potassium Chloride • Sodium/Potassium Carbonate

• Petroleum Distillates • Citric Acid • Polyacrylamide • Ammonium Bisulfite • Ethylene Gylcol

• Guar Gum • N, n-Dimethyl Formamide • Borate Salts • Proppant • Isopropanol

Shale Reservoir Characterization

• Reservoir mechanical properties and strength are lithology dependent • Clay type and fraction determines rock-fluid interaction and associated alterations in formation strength • Presence of natural fractures and

heterogeneities add complexity • Stress orientation, natural fracture density and difference in the horizontal stress magnitudes play significant role in fracture propagation

UNGI

+ TOC

Integrated Geomechanics Program in Optimizing Reservoir Management

Stress Shadowing

Geomechanics Program for

Optimum Reservoir

Management

3D Geomechanical model

Experimental characterization

Synthetic Microseismic Modeling

Seismic Azimuthal Anisotropy

Re-fracturing Assessment

Stress-sensitive productivity

Fully Coupled Reservoir Simulation

Mineralogy-Brittleness Characteristics

Production-Induced Stresses

Discontinuity Characterization

Effective networking

UNGI

UNGI 3rd Generation Coupled-Geomechanics-Flow Characteristics Laboratories

UNGI

Mechanical Properties of Shales Direction Dependent

02000400060008000

1000012000140001600018000

0 0.02 0.04 0.06

Devi

ator

ic S

tres

s (ps

i)

Axial Strain

EF-1-1VEF-1-2V

Pc=2260 psi, EF-1-1V --> E=1.30 Mpsi

Pc=3390 psi, E=2.01 Mpsi

Pc=1130 psi, EF-1-1V --> E=0.7 Mpsi

EF-1-1V

EF-1-2V

Dr. Azra N. Tutuncu, Director-UNGI Harry D. Campbell Chair in Petroleum Engineering

UNGI

UNGI Direction Dependent Shale Mechanical Properties

and Interaction with Natural Fractures

Sxx: -30 -20 -10 0 10 20 30 40

Hydraulic Fracture

Hydraulic Fracture

Anisotropy Effect Stress Change Velocity Change

X-direction

Hydraulic Fracture

Hydraulic Fracture

Anisotropic

Hydraulic Fracture

Hydraulic Fracture

Syy: -200 -120 -40 40 120 200

Hydraulic Fracture

Hydraulic Fracture

Szz: -60 -40 -20 0 20 40

Hydraulic Fracture

Hydraulic Fracture

Hydraulic Fracture

Hydraulic Fracture

Y-direction

Z-direction

Isotropic Vpx: 4100 4150 4200 4250 4300

Vpy: 4000 4300 4600 4900

Vpz: 3700 3860 4020

psi m/s Anisotropic Isotropic

X-direction

Y-direction

Z-direction

Tutuncu (2012)

SRV Determination

Observation Well

Warpinski, 2011

Observation Well

SPE 125079

Tight Gas Sand Shale

Lithology Effect Fluid Effect

Shale-Fluid Interaction Impact on Velocity

Mese (2000)

2500

2550

2600

2650

2700

2750

2800

2850

2900

0 3000 6000 9000 12000 15000Time (min)

Vp

(m/s

)

0

500

1000

1500

2000

2500

3000

3500

PO

RE

PR

ES

SU

RE

(psi

)

Compressional Acoustic WavePore Pressure

Circulation of Sodium Silicate solution with

20% w/w NaCl Circulation of 8% w/w

NaCl solution

Saturation with

8%w/wNaCl

solution

2900

2850

2800

2750

2700

2650

2600

2550

2500 0 3000 6000 9000 12000 15000

Pore

Pre

ssur

e (p

si)

3500

3000

2500

2000

1500

1000

500

0

Vp (m

/s)

Time (minutes)

Compressional Velocity Pore Pressure

dPp = 1604 psi

Pp= 1536 psi

Circulating Pressure Pp= 3140 psi

Dr. Azra N. Tutuncu, Director-UNGI Harry D. Campbell Chair in Petroleum Engineering

Mese (2000)

Upscaling Stress and Rock Property Anisotropy Evaluation from Logs and Cores

UNGI

Padin and Tutuncu (2013)

Willis and Tutuncu (2013)

Injected 5,000 bbl of 1,000 ppm salinity water as fracturing fluid Water saturation in fractures, fraction Water salinity in fractures, ppm

Properties Fractures Inorganic matrix Organic matrix

Porosity (-) 0.002 0.054 0.03

Permeability (mD) 0.01 0.0001 0.0001

Wettability - Mixed-wet Oil-wet

Osmotic efficiency (-) - 0.1 0.1

Salinity (ppm) 150,000 150,000 150,000

Maximum adsorption (scf/ton) Langmuir coefficient (1/psi)

- - 2000 0.00044

Coupled Geomechanics and Fluid Flow with Fluid Effect on Production

(Osmotic Pressure)

Gas flow rate

Cumulative Gas

0-day shut-in

7-day shut-in

15-day shut-in

30-day shut-in

Water saturation in fractures, fraction

Well Shut-in Increases Gas Flow Rate Fakcharoenphol, Kazemi and Tutuncu (2013)

Wettability with Osmotic Pressure

Water-wet rock 15-day shut-in

Oil-wet rock 15-day shut-in

Osmotic Pressure Helps Increase Gas Flow Rate

Fakcharoenphol, Kazemi and Tutuncu (2013)

UNGI Speeding Up the Learning Curve

GONZALES COUNTY WELLS

OIL

CONDENSATE

GAS

Vaca Muerta Shale Play, Neuquén Basin,West Argentina

GAS

CONDENSATE

OIL

LA SALLE COUNTY WELLS

VACA MUERTA WELLS

UNGI Observations from Microseismic data

Unconventional R&D Industry, Academia and Government for Global Collaboration

• Coupled measurements and modeling of fluid flow and geomechanical characteristics of the reservoir for realistic life cycle representation

• Research and development for novel geoscience and engineering methodologies to enhance low permeability formation productivity and contribute best practice development for field development and optimization

• Investigation for environmental challenges and contributing toward solutions A) Research Consortia – UNGI CIMMM (Eagle Ford)

– UNGI Vaca Muerta – NREL Geothermal – UNGI Brazil in development – UNGI CFMG in development – Other consortia are in development

B) Proprietary Research Projects C) Training Classes – TOPCORP Regulator Training (Domestic) – UGTEP Collaborative Program (International)

Dr. Azra N. Tutuncu, Director-UNGI Harry D. Campbell Chair in Petroleum Engineering

UNGI Faculty & Staff (55+ Faculty)

Joe Chen, Al Sami, Denise Winn-Bower, Lori Eger

• Brian Asbury

• Jennifer Aschoff

• Linda Battalora

• Michael Batzle

• Jerry Boak

• Tom Bratton

• Mary Carr

• Tzahi Cath

• John Curtis

• Kadri Dagdelen

• Tom Davis

• Rod Eggert

• Alfred W. Eustes

• William Fleckenstein

• Ramona Graves

• Marte Gutierrez

• Todd Hoffman

• John Humphrey

• Tissa Illangasekare

• Daisuke Katsuki

• Hossein Kazemi

• Carolyn Koh

• Ning Lu

• John McCray

• Carrie McClelland

• Mark Miller

• Jennifer Miskimins

• Mike Mooney

• Dag Nummedal

• Erdal Ozkan

• Ronny Pini

• Piret Plink-Bjorklund

• John Poate

• David Pyles

• Andre Revil

• Rick Sarg

• Paul Sava

• Dendy Sloan

• Kathleen Smits

• Steve Sonnenberg

• Amadeu Sum

• Azra Nur Tutuncu

• Ilya Tsvankin

• Craig van Kirk

• Wendy Wempe

• Yu-Shu Wu

• David Wu

• Yuan Yang

• Xiaolong Yin

• Terry Young

• Luis Zerpa

http://ungi.mines.edu

UNGI

Dr. Azra N. Tutuncu, Director-UNGI Harry D. Campbell Chair in Petroleum Engineering

UNGI Affiliations UNGI

NETL Morgantown NETL Golden NREL Idaho National Laboratories Lawrence Berkeley Lawrence Livermore Los Alamos National Laboratories Sandia National Laboratories COGCC Texas Rail Road Commission (TRC) Pennsylvania DEP EPA IOGCC Department of Energy Department of State

Petroleum Engineering Civil Engineering Environmental Engineering Geology and Geological Engineering Geophysical Engineering Chemical Engineering Chemistry and Geochemistry Material Science Mechanical Engineering Mining Engineering Economics

ENI ExxonMobil Chevron GE Oil and Gas Halliburton Hess Oil Company PEMEX PlusPetrol Schlumberger Statoil Shell Oil Company Talisman Energy Weatherford

Dr. Azra N. Tutuncu, Director-UNGI Harry D. Campbell Chair in Petroleum Engineering

University of Texas at Austin Penn State University Northwestern University

UNGI http://ungi.mines.edu

THANK YOU