Lnapl Tn For Tceq Tf 2010 100504 Sec 1to3

http://www.h2altd.comSlide 1

LNAPL Transmissivity (Tn)

Remed ia t i on Des ign , P rog ress and Endpo in t s

H2A Environmental, Ltd.

J. Michael Hawthorne, P.G.

[email protected]

May 2010


Acknowledgements• Andrew Kirkman - AECOM• Mark Adamski - BP• Tim Smith - Chevron• Charles Stone - TCEQ• Roger Rinas - Valero• Dr. Charbeneau - UT• Dr. Huntley - SDSU• Dr. Sale - CSU

©2010 by H2A Environmental, Ltd., All Rights Reserved

Intr

oduc

tion


Questions Tn Can Answer• Understanding

– What is the best way to quantify mobile LNAPL impacts?– How can I do this cost-effectively?

• Comparison– I have 10 ft of diesel and 2 ft of neat toluene – How can I compare them?– Which one is more likely to migrate? How much more likely?– Which one will I be able to pump the most LNAPL from?– Which one will operate longer?

• Prediction– How many bbls/gals will each well produce?– How long will my recovery last?– What remediation technology will be most effective/efficient?

• Management– I manage 300 sites with LNAPL – How do I rank and prioritize potential

migration risk and recovery potential?– I’ve been pumping water and LNAPL for years; Can I quit? When can I quit?


Intr

oduc

tion


Analogs• Hydrogeology

– Aquifer Testing yields K and T for water movement / production• Pumping Tests and Slug Tests

– Normalizes all sites to one measurement standard to:• Analyze – Compare – Predict – Design

• Multiphase Fluid Mechanics– Multiphase Saturation Distributions add Complexity– Different Fluid Properties Result in Different Flow Characteristics– Relative Permeabilities - Fluids Compete for Pore Space– Result: Generally Inhibited LNAPL Flow

• Petroleum Engineering– Production Decline Curve Analysis

• Rate Transient Analysis (RTA)• Expected Ultimate Recovery (EUR) Analysis


Intr

oduc

tion


Outline• LNAPL Metrics for Hydraulic Recovery

• LNAPL Transmissivity (Tn)

– Definition

– Determination

– Applicability

– Limitations

• Tn and TRRP NAPL Mgmt Responses

– TRRP-32 Endpoints

– Remediation Design

– Operational Performance

• Examples (Not in Handout)


Intr

oduc

tion


LNAPL Metrics in TRRP-32

• End Point - a Decision Point at which an activity ceases (e.g., risk-based cleanup levels attained so remediation stops).

• Metrics, Decision Points and End Points are captured in tables and flow charts in the TRRP-32 NAPL Management guide.


Met

rics

for

Hyd

raul

ic R

ecov

ery

• Metric - a numeric or semi-numeric standard against which remediation need or progress is measured (e.g., Tn).

• Decision Point - a Metric at which a change is made (e.g., de minimis liquid recovery so convert from MPE to SVE).


Ideal LNAPL Metric• Collective Property

– incorporates physical & chemical properties of the aquifer & LNAPL (e.g., permeability, viscosity)

– Incorporates LNAPL Type (benzene vs. bunker oil)

– Incorporates aquifer type (sand vs. clay)

• Fundamental or Characteristic Property

– Repeatable for given conditions

• Saturation / Mass Driven

– Multiphase saturation distribution

– Varies directly with LNAPL mass

• Easily Measured

– Supported with multiple lines of evidence

– Obtained prior to or during remediation

Met

rics

for

Hyd

raul

ic R

ecov

ery



Non-Ideal Metrics - ThicknessM

etric

s fo

r H

ydra

ulic

Rec

over

y


• Inconsistent under varying hydrostatic conditions

• Same mass exhibits different thicknesses in different soil types

Modified after Kirkman (2009)


Non-Ideal Metrics - ThicknessM

etric

s fo

r H

ydra

ulic

Rec

over

y


• Tn increases with increasing recovery, thickness exhibits no clear trend but decreases with increasing recovery

Mod

ified

afte

r K

irkm

an (

2009

)


Non-Ideal Metrics - RecoveryM

etric

s fo

r H

ydra

ulic

Rec

over

y


Benefits

• Direct measure of remediation performance

• Provides predictive data for decline curve analysis – EUR and Rate Transient analysis

Problems

• Strongly affected by system operational settings

• Varies by technology – not directly comparable

• Can’t be used to predict performance prior to startup


Tn – An Improved Metric

• Can be easily determined prior to, during and after remediation

• Comparable across soil types

• Comparable across LNAPL types

• Comparable across Technologies

• Comparable across unconfined, confined and perched conditions

– Must understand LCSM

– Must calculate drawdown correctly

• Comparable between sites

• Varies directly with LNAPL saturation / mass

• Measures hydraulic recoveryMet

rics

for

Hyd

raul

ic R

ecov

ery



Section 2

• LNAPL Transmissivity (Tn)

– Definition

– Determination

– Applicability

– Limitations


Sec

tion

Bre

ak


Tn Definition• Transmissivity (T) for water is the

volume of water flowing through a cross-sectional area of an aquifer that is 1 foot wide X the thickness of the aquifer (b), under a hydraulic gradient of 1 ft/ft, in a given amount of time (e.g., 1 day)

• LNAPL Transmissivity (Tn) is the volume of LNAPL flowing through a cross-sectional area of an aquifer that is 1 foot wide X the thickness of the mobile LNAPL interval in the aquifer (bn), under a hydraulic gradient of 1 ft/ft in a given amount of time (e.g., 1 day)

Tra

nsm

issi

vity

(T

n)


ww

wrwww l

hgkkK

nn

nrnnn l

hgkkK

bKT ww

nnn bKT


Five Measurement Methods

1. Baildown Testing

2. Manual Skimming Testing

3. Recovery Data Analysis

4. Physical Properties Analysis

5. Tracer Testing

Tra

nsm

issi

vity

(T

n)


• Critical References:

– Huntley (2000) Groundwater

– Charbeneau (2007) API

– Sale et al (2007) Groundwater

– ASTM (2010) Under Development


Baildown Testing

• Drawdown Calc (>0.5 feet)

– Confined / Unconfined

– Perched

• Field Methods

– Remove Borehole Volume

– Minimize CGWS Disturbance

• Boundary Conditions

• Analytical Options

– Bouwer & Rice

– Discharge-based Methods

• 1/Q, s/Q, SSR

Tra

nsm

issi

vity

(T

n)



Manual Skimming Testing• Basis – Skimming Recovery

Equation

• Field Methods

– Remove Borehole Volume Repeatedly

– Establish Sustainable NAPL Discharge

– Minimize CGWS Disturbance

• Applicability

– <0.5 Feet or Rapid Recharge

– Minimizes Gauging Errors

• Equation:Tra

nsm

issi

vity

(T

n)


)1(

)ln()ln(

rn

w

oin

n

w

oin

n b

rRQ

s

rRQ

T


Recovery Data Analysis

• NAPL only Removal

– Skimming

• Vacuum-Enhanced NAPL Removal

– Vacuum-Enhanced Skimming

• Water-Enhanced NAPL Removal

– Total Fluids Pumping (Single or Dual Pump)

• Water & Vacuum-Enhanced NAPL Removal

– MPE

Tra

nsm

issi

vity

(T

n)



Skimming (NAPL Only Removal)

• Considerations

– Adjust for bn changes

– ln(Roi / rw) estimated at 4.6

– bn(1-ρr) is max drawdown

– If operating at less than max drawdown, use Qn and operating drawdown

• Equation (Charbeneau 2007)

Tra

nsm

issi

vity

(T

n)


n

woinn s

rRQT

ln

rn

woinn b

rRQT

1

ln IDEALPUMPDEPTH

NON-IDEALPUMPDEPTH


Vacuum-Enhanced Skimming• Considerations

– If RaI not known, estimate RaI via Charbeneau (2007) equation – be careful in layered stratigraphy

– 1st equation uses air flow and open screen to calculate vac influence

– 2nd equation uses vacuum and ln(RaI / rw) to calculate vac influence

• Equations (Charbeneau 2007)

Tra

nsm

issi

vity

(T

n)


Tn QnkraKwbar

arQa

Tn Qn2

r lnRaIrw

sa


Water-Enhanced NAPL Removal• Total Fluids Pumping

– Single or dual pump

• Considerations

– Simple Form (1st Equation) assumes swater is much greater than sn

– If any doubt, use 2nd Equation

• Equations

– Charbeneau (2007)

Tra

nsm

issi

vity

(T

n)


Tn

rQnTw

Qw

Tn QnTwQw

r snswater


Water & Vac-Enh NAPL Removal• MPE – DPE or TPE

• Considerations

– If RaI not known from pilot testing/operation, estimate RaI as in VES

– Air flow or Vacuum/RaI options similar to VES

• Equations (derived from Charbeneau 2007)

Tra

nsm

issi

vity

(T

n)


Tn rQn

raQakraKwba

QwTw

Kirkman (2009)

w

w

wai

a

nrn

T

Q

rR

sQ

T

ln2

Hawthorne (2010)


Physical Properties / Modeling• Laboratory Analyses

– NAPL Saturation

– Grain-Size Analysis

– Capillary Pressure Curves

– Core Photography

– and others

• Modeling– LDRM

– Input/Calibration Points• Kw / Tw / Tn / vG parameters

• Saturation

• Recovery Data

– Outputs• Daily and Cumulative Recovery

• Saturation Profiles

• Specific / Recoverable Volumes

• Tn thru Time

Tra

nsm

issi

vity

(T

n)


Capillary Pressure Curve


Tracer Testing

• Developmental Stage

• Concerns

– Localized Qf but large scale NAPL gradient

– Uncertain Well Convergence Factor

– Initially Capital Intensive

Tra

nsm

issi

vity

(T

n)


(Sale et al 2007)


Tracer Testing

• Field Test

– Tracer Concentrations (UV/VIS spectrometer )

– Gradient

– LNAPL Thickness

– Well Construction

• Analytical Options

– Calculate LNAPL flux through well

– Calculate LNAPL flux through formation

– Calculate Tn

Tra

nsm

issi

vity

(T

n)


L

LfLL

wLfL

wLwL

o

t

i

bqT

qq

Dtq

aDtq

a

C

C

cos2sincos2

Where: Ct = Tracer concentration at time Dt (M/L3)Co = Initial Tracer concentration (M/L3)qwL = LNAPL flux through well (L/T)Dt = change in time between measurements (T)D = diameter of well (L)bL = continuous thickness of LNAPL in the formation (L)iL = LNAPL gradient (L/L)a = flow convergence factor (L/L)qfL = LNAPL flux in the formation (L/T)TL = LNAPL Transmissivity (L2/T)

(Tim Smith, Chevron, 2010)


Applicability – Uses for Tn

• Inexpensive, numeric alternative to laboratory NAPL saturations• Calibration Parameter for multiphase model

– API / Dr. Charbeneau – LNAPL Distribution and Recovery Model (LDRM)

– Calibrate to initial pre-remediation Tn values (and other site data)

– Calibrated Model Provides Predicted Values for:

• Tn and specific/recoverable volumes over recovery time

• Technology-specific recovery curves for LNAPL – rate and total volume estimates

• LNAPL/water saturations through time versus residual/irreducible saturations

• LNAPL thickness profile over time

• Drawdown profile

• Remediation Design Parameter• Operational Progress Metric• End or Decision Point for Hydraulic Recoverability – 0.3 to 0.8 ft2/day• Technical Impracticability Threshold for Hydraulic Recovery

Tra

nsm

issi

vity

(T

n) -

Des

ign



Applicability - Scale• Individual Wells

– Increased Precision

– Reduced Area of Relevance

• Collective Recovery Data

– Decreased Precision

– Travel Time Considerations

• Interlocked Network

• Interception / Capture Barrier

– Increased Area of Relevance

• Scale of Measurement

– Match to Scale of Recovery

Tra

nsm

issi

vity

(T

n)


t3t2t1


Limitations / ConsiderationsT

rans

mis

sivi

ty (

Tn)


• LCSM Critical

• Regulatory Acceptance

• Threshold Values Evolving

• Tn applies only to hydraulic removal of LNAPL to the extent practical

• Tn does NOT address dissolved or vapor phase risk-based drivers

• Tn measures recoverable, not residual or total LNAPL, and therefore measures progress towards soilres


Section 3

• Tn and TRRP NAPL Mgmt Responses

– TRRP-32 Applicability

– Decision Points

– Remediation Design

– Operational Performance


Sec

tion

Bre

ak


TRRP-32 NAPL Management

• Five (5) Step Process

– TRRP-12A

– Trigger Identification

– Response Objectives / Endpoints

– Design Phase (SIN / RAP)

– Implementation / Evaluation


Tn

and

TR

RP

1

•NAPL Assessment

2

•ID NAPL Triggers

3

•NAPL Response Endpoints

4

•NAPL Mgmt Strategy (SIN/RAP)

5

•Implement / Evaluate SIN/RAP


TRRP-32 NAPL ManagementTn Application


Tn

and

TR

RP

Endpoints (TRRP-32)

Migrating NAPL Zone Trigger

Recovery Only

• Tn time-series analysis

Control (via TI)

• Model Calibration Parameter• Hydraulic Recoverability Metric

Recovery • Tn time-series analysis

NAPL Contact w/ GW Zone Trigger

Recovery Only

• Design Parameter

Design

• Technology Selection Based on Hydraulic Recoverability of LNAPL• Model Calibration Parameter to Generate LNAPL Production Curves• Equipment Sizing, Volumetric Waste Mgmt. Plans• Fixed Base / Mobile Infrastructure Cost-Benefit Analysis

Performance Evaluation

• Operational Performance Metric• Model Calibration Parameter• Hydraulic Recoverability Metric


NAPL Response Endpoint Types


Tn

and

TR

RP

– S

TE

P 3

Recovery Control

Recovery Only Control via TI

Recovery Control

Recovery ControlRecovery

Only

Control via TI

NAPL Response Endpoint Types


NAPL Response Endpoint Matrix(Migrating NAPL Zone Trigger)


Tn

and

TR

RP

– S

TE

P 3

Site Condition(from STEP 2)

NAPL Response Objective

NAPL Response Endpoint

Recovery Endpoint Control Endpoint

NAPL in vadose zone ≤ 15 ft below ground surface

NAPL in saturated zone, not in PMZ

NAPL zone migration in the vadose zone or saturated zone

Abate NAPL zone migration

(Sec 3.3.1)

RECOVERY ONLY NAPL recovered to

residual saturation and/or to arrest NAPL migration

CONTROL (via TI) NAPL zone

migration arrested with physical control

NAPL discharge to ground surface, surface water or sediment

NAPL recovered sufficient to eliminate NAPL discharge(Sec 3.3.1.1) (Sec 3.3.1.2)

(L)NAPL in saturated zone in a PMZ

RECOVERY NAPL recovery

sufficient to arrest NAPL migration

CONTROL NAPL zone

migration arrested with physical control or natural methods

(Sec 3.3.1.3) (Sec 3.3.1.4)

Nat

. C

ont

rol -

NS

ZD


NAPL Response Endpoint Matrix(NAPL Contact with GW Trigger)


Tn

and

TR

RP

– S

TE

P 3

Site Condition(from STEP 2)

NAPL Response Objective

NAPL Response Endpoint

Recovery Endpoint Control Endpoint

NAPL contact w/ Class 1 groundwater

NAPL contact w/ Class 2 / Class 3 groundwater not in PMZ

Groundwater restoration

RECOVERY ONLY Recover soluble

NAPL fraction sufficient to eliminate source contributions to GW PCLE zone

CONTROL (via TI) Control soluble

NAPL fraction sufficient to create stable (or shrinking) PCLE zone

(Sec 3.6.1) (Sec 3.6.1.1) (Sec 3.6.1.2)

NAPL contact w/ Class 2 / Class 3 groundwater, in PMZ

Compliance with PMZ performance criteria at

NAPL zone

RECOVERY Recover readily

recoverable NAPL fraction

(only address recovery endpoint, if

applicable)

(Sec 3.6.2) (Sec 3.6.2.1) (Sec 3.6.2.2)

Alt.

Te

ch –

NS

ZD

?


TI Demonstration


Tn

and

TR

RP

– S

TE

P 4

• RECOVERY ONLY

– If Conventional & Alternative Technologies Cannot Achieve Endpoint.

• RECOVERY

– If Inability to File an Institutional Control Forces Site into Recovery and Conventional and Alternative Technologies Cannot Achieve Endpoint.

• Requirements

– Tool B - Qualitative Screen for TI of Individual Conventional Technologies Based on Site Characteristics Such as K – Should Not Take the Place of Site-Specific Pilot Testing, Analysis, Engineering and/or Design.

– TI Requires Technically Rigorous Analysis of Time-Series Data from Operation of Alternative Technology Recovery System OR of Data from an Appropriate On-Site Pilot Test and Modeling Study.

– Tn May be Incorporated into Site-Specific Pilot Testing, Analysis, Engineering and/or Design as a Direct Recoverability Threshold Metric and/or as a Calibration Parameter for a TI Modeling Study.


Conventional vs. Alt. Technologies


Tn

and

TR

RP

– S

TE

P 4

Potential for NAPL Recovery byConventional Technologies

1. by SOIL TYPE

Clay - Silt Silt - Sand Sand - Gravel

0-1 +1

4. by NAPL OCCURRENCE

(in saturated zone withdouble porosity)

(in other saturatedzone)

(in coarse-grained capillaryfringe)

HIGHMEDIUMLOW

0-1 +1

3. by NAPL VISCOSITY

(mixed-phase DNAPLPCBs, coal tar)

(heavy refinedpetroleum (e.g., no.

6 fuel oil)

(light refined petroleum(e.g., gasoline)

HIGH MEDIUM LOW

0-1 +1

2. by MAX TRUE NAPL THICKNESS

< 2 in 2 in - 12 in > 12 in

0-1 +1

SCORE

TOTAL SCORE

TOTAL SCORE

+2 to +4

-1 to +1

-4 to -2

Potential for NAPL Recoveryby Conventional Technology

HIGH: recovery likely

MODERATE: recovery possible

LOW: consider alternative tech


Conventional vs. Alt. Technologies


Tn

and

TR

RP

– S

TE

P 4

from STEP 3: DetermineNAPL Response

Objectives and Endpoints

Using TOOL A(Table A.1)

Evaluate qualitativepotential for effective NAPLrecovery by conventional

recovery technologies

Ispotential for

NAPL recovery byCONVENTIONALTECHNOLOGIES

LOW?

YES

Use of ALTERNATIVETECHNOLOGIES

should be consideredfor NAPL recovery

endpoint

CONVENTIONALTECHNOLOGIES may be

reasonable choice forachieving NAPL recovery

endpoint

NO

to STEP 4: DevelopIntegrated NAPL

Management Strategyusing appropriate level of

recovery technology

Decision Pt. for Change from Hydraulic Recovery Technology Based on Tn


Design Uses for Tn

• Estimate upper boundary for specific discharge and seepage velocity – ignores entry pressure head. Valid for plume interior, not margins.

• Calculate Average NAPL Conductivity from Tn and bn

• Specific Discharge (Darcy Velocity or Flux) Equation Yields Volumetric Flow

• Divide Specific Discharge by NAPL Filled Porosity to Get Seepage Velocity for NAPL - Yields Movement (distance per unit time)

Tn

and

TR

RP

– S

TE

P 4


nnn

sn S

iKv

n

nn

nnn

b

TK

bKT

vKiA

Q

KiAQ


Remediation Design and Tn

• Direct Measure of Hydraulic Recoverability

– Hydraulic vs. Pneumatic vs. Alternative Technology Selection

• Modeled LNAPL Recovery Technologies

– Calibrated to Readily Obtained Site Wide Tn Values

– Technology-Specific Production Curves

– Sustainability

– Predicted Decline Curve Analysis for Rate and Total Volume Data

– Relative Technology Performance Data – Technology Selection

• Design Cost-Benefit Analysis

– Projected Operational Lifetime

– Capital vs. Mobile Infrastructure

• Design Considerations

– Equipment Sizing

– Waste Mgmt / Recycling Volumes


Tn

and

TR

RP

– S

TE

P 4


Implement & Evaluate

• Implement NAPL Management Strategy– Use Appropriate Monitoring Methods

– Collect NAPL Response Action Performance Data

– Conduct Evaluations after each Monitoring Event

• Evaluations (all supported by Tn)

– Ability of Response Action to Achieve Endpoints

– NAPL Endpoints Achieved?

– Should the Technology Change?

– Is TI Supported by the Data?


Tn

and

TR

RP

– S

TE

P 5

Evaluation

Endpoints Achievable and/or Achieved?

• Operational Performance Metric• Model Calibration Parameter• Hydraulic Recoverability Metric

Technology Change Needed? • Hydraulic Recoverability Metric

TI Warranted?• Model Calibration Parameter• Hydraulic Recoverability Metric


Operational Performance Metric

• Single Well Recovery Data Analysis During System Operation to Monitor Tn Progress

• Combine with EUR and Rate-Transient Decline Curve Analysis to Evaluate Progress Towards Hydraulic Recovery Endpoint

Tn

and

TR

RP

– S

TE

P 5



Summary

• Tn is an improved metric for hydraulic recoverability

• Five calculation methods:– Baildown Testing– Manual Skimming Testing– Recovery Data Analysis– Physical Properties

Analysis– Tracer Testing

• Tn use as a metric

– Indirect – model calibration parameter

– Direct – recoverability (0.3-0.8 ft^2/day)

• TRRP-32 and Tn

– Design Parameter • Technology Selection

• Production Rate

• Production Lifetime

• Model Calibration

– Response Endpoints• Migrating NAPL Zone

• Contact with GW

– Decision Point• Conventional vs. Alt.

Technologies

• Augment Tool B for Technical Impracticability


Tn

and

TR

RP


Section 4

• Tn Examples

– Not in Handout


Sec

tion

Bre

ak

Lnapl Tn For Tceq Tf 2010 100504 Sec 1to3

Technology

Transcript of Lnapl Tn For Tceq Tf 2010 100504 Sec 1to3