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Methods & Advancements in Hydraulic Fracturing Technologies as Applied to In-Situ Biological and Chemical Remediation

Vincent E. Barlock P.G . &

John Fontana P.G.

Hydraulic Fracturing

(hydrofracturing/fractuirng/fracing)

– A Down-Hole Process by which the

Existing Subsurface Lithologies, Porosity,

or Fracture Network is Artificially

Enhanced (Fractured) by the Injection of

Fluids, Air, or Steam Under Very High

Pressure

– Was Originally Developed for the Oil and

Gas Industry. Initial concept as far back as

1929.

O&G Well Heads Equipped for Hydraulic Fracturing.Technology undertaken at depths between 2,000 and 20,000 feet bgs.

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O&G Depths: typically >2,000 ft

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Massive Infrastructure Needs

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The Up-Side of Hydraulic Fracturing to Environmental Remediation

• Enhanced Injection of Remedial Fluids/Solids

• Enhanced Recovery of Impacted Fluids

• Enhanced Porosity and Storage to improve

remediation success

• Enhanced Radius-Of-Influence

• Decreased Capital Cost & Long-Term O&M

Costs

Temporal Changes in Hydraulic Fracturing• The Technology has been taken to shallow depths

(i.e. 150 to 4 feet bgs) and effectively implemented

for remediation since the mid-1980s.

• 1980-1990: Simple single fractures; horizontal;

limited volumes, limited R.O.I monitoring.

• 1990-2000: D.O.E & D.O.D- funded grants for

Multiple fractures per boring; larger volumes;

horizontal and vertical; enhanced R.O.I monitoring.

• 2000- 2010: Diversity of Proppants; Fracturing in of

Pure remedial compounds; 3D modeling of

fractures; Emplaced in more difficult geology

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UST Sites Refineries

So - What Sites are Being Hydraulic Fractured ?

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D.O.D & NASAFacilities

(D.F.C, P.C.D, R.A)

Solid Waste FacilitiesMilitary and Private

Industrial /CommercialFacilities

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Pueblo Chemical DepotPueblo, CO.

•2.4 Million

Gallons of EVO

injected

•~ 600Points

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• THE REAL QUESTIONS ARE:

• WHAT is the Ultimate Purpose(s) of the Fractures? Both Short- and Long-term.

• WHAT Method of Fracture Emplacement is Best Suited to Meet This Purpose? And

• WHAT Are the Key Factors Affecting the Method Selected?

• Effective Implementation And Successful

Remediation Is Directly Related To Strategic

Targeting Of Fractures Under Ideal Site Conditions

• Host Rock, Depth of Impact, Vertical &

Horizontal Extent of Impact, and Contaminant

Mass must be known.

So How Does One Proceed ?

HOWEVER THIS IS RARELY THE CASE

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(1) HYDRO GEOLOGY

•Tightness (i.e., low “K” of the lithologic units);

• Lithologic heterogeneity:

• Shale, siltstone/claystone, limestone, etc.

• Cohesiveness of unconsolidated soils; plasticity;

• Degree of cementation/induration;

• Flow direction & Magnitude

(2) PROXIMITY TO STRUCTURE•Anthropomorphic (bldgs., pools, utilities)

•Geologic (faults, antiforms/synforms, joints/fractures)

(3) CAN YOU MAINTAIN YOUR SEAL DURING

FRACTURING?

Key Factors Affecting Hydraulic Fracturing Method Selection

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Key Factors That Adversely Affect Fracturing Method Selection

• Where and how are the impacts distributed in the

subsurface (i.e., COCs in discrete intervals or large

smear zones) ??

• Very shallow 2-10 feet vs: 10 -100 ft

• COC Distribution (Spotty or massive)

• Conflicting reports and questionable data;

• Poor logging/sampling techniques; incorrect soil/rock

classifications;

• Difficult geology: fractured bedrock; massive or

heterogeneous soils

SO Which Method Is It ??

Direct Push or Packers, or a Combination ?

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•DPT Method Best for Emplacement of

Fractures in Unconsolidated Materials

Courtesy of Foremost

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Conceptualized DPT Emplaced Bionets ™/Fractures at a UST Site

•Courtesy V. Barlock / Paul Willet

DPT - Dual WallDPT Points with Ground Monitoring

Courteous of Foremost

EPA & Foremost 1995 Introduced Fracturing at the Denver Federal Center

•EPA & Others emplaced

multiple hydraulic fractures at

the Center to remediate

groundwater impacts.

• The DFC was the Site of the

first enhanced in-situ

bioremediation system utilizing

hydraulic fracturing with Isolite

as both the proppant and pre-

inoculated carrier of indigenous

microbes and nutrients.

• In 2009 Sites at the DFC

were again hydraulically

fractured using DPT methods.

18Courtesy USGS

DFC – 2009

Fracturing and KMnO4

Injections Via DPT methods:

(Mactec/Vista GeoScience)

• 217 Fractures

completed in Denver

Formation

•Approximately 300K

Gallons of Potassium

Permanganate Injected

•

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Packers w H.S.A Drilling Typically Best for Bedrock, & Semi-Consoldated Soil

20•Typical Bedrock Sandstone in Denver Formation

•Courtesy TAM International

Packer Method - Equipment• Drills

– Hollow-Stem- Auger

– Rotary

• Mud

• Air

– Dual DPT/H.S.A

• Pumps

• Progressive Cavity

• Double Diaphragm

• Piston

• Mixers

• Hoppers

• Augers

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Various In-Situ Injection/Fracture Rigs

90% of Fracture Rigs in U.S. Today Emplace Fractures Using Guar-gum as Breaking Fluid and Carrier

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•Courtesy Foremost

Hydraulic Kerfing. Is it Required?

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Straddle-Packer Technology for Fracture and Proppant Emplacement

•Video & Animation Courtesy: Mr. Paul Willett

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Advances in Hydraulic Fracture Remediation

• Bionets ™ and Fractures for Enhanced Injection /

Extraction

• PROPPANTS:

– Permanent: Proppant stays in the fracture and is not

degraded over time

• (i.e., porous ceramics; silica sands; synthetics)

– Temporary: Proppant degrades over time

• (i.e., chitin, solid oxidants [i.e., K MnO4])

• FRACTURE MONITORING

– Survey and Rods for Radius of Influence (R.O.I)

– Enhanced Real-time 3D modeling for R.O.I

Direct Advances

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• BIOREMEDIATION

• (Bio-stimulation & Bio-augmentation via fractures)

• Pre-inoculated support matrices using commercially available

inoculums

• Emplacement of Bio-augmented Reactive Lenses/Fractures or

Reactive Columns

• Enhance and “Sustain” bioactivity with primary organic

nutrient formulation injections via either DPT of hydraulic

fractures

Direct Advances in Hydraulic Fracture Remediation (cont.)

Proppants (Permanent)

• Silica Sand

• (Most Widely use

Proppant)No. 10/20 mesh

– (Ne ~25-32%)

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Example of an Emplaced Sand Fracture/BioNet ™

•EPA Site: (Foremost Solutions)

Proppants (Permanent)• Isolite – Porous Ceramic

– 1 gram = 55 ft 2 surface

area

– Can house up to 100M

microbes

– 0.5-2 mm (Ne ~ 54-62%)

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Emplaced Isolite Fracture/Bionet ™EPA Site: (Foremost Solutions)

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Proppants (Permanent)

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• Various Resin-coated

Silica Beads

– (Ne ~32%)

– Reduced Friction &

Enhanced flow

Proppants (Temporary)

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•Courtesy EPA

• IRON

• Zero Valent Iron

Proppants (Temporary)

• Chitin (Polysaccharide)

• A class of carbohydrates, such as starch and cellulose

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•Courtesy EPA

Proppants (Temporary)

• Solid Oxidants (Potassium

Permanganate- KMnO4)

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•Courtesy EPA

•Courtesy Carus Chemicals

Fracture Monitoring Advances

Past:Visual Inspection of Tilt-

Rods to measure ground

displacement

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Current:

Survey & Rod

To measure ground

displacement (Pre & Post)

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Advances in R.O.I Monitoring

Real-Time:Sensitive Tilt Meters for

Monitoring Ground

Deformation in Real Time

(Mid 1990’s to Current)

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Advances in R.O.I Injection Monitoring Technology

•Conventional Bi-axial •Future Wireless

• Very Sensitive • Quickly Deployed•Courtesy Slope Indicator Inc.,

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Characteristic Temporal Injection / Hydraulic Fracture Tilt Meter Responses

Monitoring Advances In Fracture / Bionet ™ Imaging

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•Accurate GIS Mapping

of Monitoring Array

• 3D Plots of Inferred

Fracture Morphology

and ROI.

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Indirect Advances

•Enhanced Vertical Profiling to Target Fracture:

– MEMBRANE INTERFACE PROBE (MIP)

– (Example Presented)

– Fiber optic & Laser detection

– PDBs / Permeable membrane technology

– Heat-pulse or electromagnetic boreholeflow meters

•Fracture/ Bionet ™ Mapping/Delineation

•Tilt meters

•Conventional and new wireless tech.

•Electrical Resistance Mapping

Membrane Interface Probe

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• Real-time In the field modifications to

proposed fracture locations and

depths.

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Initial MIP investigation 2008

• Initial Location of Source

(PCE)

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• Clays (CL) and Silts (ML)

• Bedrock surface w/

DNAPL

• Aquifer (SP/SW)

Enhanced MIP investigation 2009. Can Now Strategically Target Fractures/Injections

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•The Smoking Gun!!

(PCE neutralization

tanks )

• Located the

Vertical Conduit to

Bedrock surface

w/ DNAPL

• Initial Location of

Source (PCE)

•Courtesy Columbia Technologies

Resistivity Monitoring

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1980’s 2010

Typical No. of Fractures per Boring 1 1 to 5

Casings per Boring 1 1 to 4

Sand Injected (lbs) 500-2000 500-40,000

Delta Storage Created / Fracture (ft3) 5 to 20 5 to 400

Average range in R.O.I (ft) 5 to 45 5 to 175

Porosity / Yield Increase

(Order-of Magnitude) 1 to 1.5 1 to 3

Time to Emplace Fracture (days) 1 to 4 0.5 to 1

Temporal Changes in 3 Decades of Hydraulic Emplacement

Performance

Conclusions:

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• Hydraulic Fracturing Via DPT and Conventional Packer Methods

is becoming the most-widely accepted means of in-situ remediation

for Sites constrained by low permeability soils and elaborate

infrastructure.

• Hydraulic Fracturing and Enhanced Pressure Injections

significantly improves the distribution of remedial solutions and

contact time with contaminants, and accelerates the clean-up

period, dramatically reducing costs $$$.

• Advances in monitoring the distribution of hydraulic fractures and

viscous fluids has refined characterization of R.O.I and reduced the

need for physical confirmation.

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Figure, Animation, and Photo Acknowledgements

Vincent E. Barlock P.G . &

John Fontana P.G.

Seth Hunt

Paul Willett

WebSite

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Thank YouFor More Information Contact us at:

Vincent E. Barlock P.G . &

John V. Fontana P.G.

www.vistageoscience.com

Seth Hunt

www.foremostsolutions.com

Ron Bell, Geophysicists

www.IGSdenver.com

International Geophysical

Services LLC (HGI)