direct push high-pressure jet injection method for …...direct push high-pressure jet injection...
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Direct Push High-pressure Jet Injection Method for Delivery of in Situ Remediation
Agents in Clay Till
Chapman Ross – Geosyntec Consultants
Co-Authors and Partners
Mads TerkelsenLone Tolstrup KarlbyCamilla Christiansen
FRx
Neal DurantChapman RossOwen Cadwalader
Bill Slack
Capital Region of Denmark
Hydraulic Fracturing Experts
Torben JørgensenLars Nissen
Problem Statement: Develop Method to Treat DNAPL Residual and Solvents Diffused into Clay Till
~40% of Denmark covered in highly fractured clay till
~1,500 chlorinated solvent sites in clay till in Capital Region alone
Result: many long term difficult to treat sources
High Pressure Jet Injection Mechanisms
How it worksUp to 690 bar (10,000 psi) water jetting erodes conduits in
clay in a chosen orientation.10.3 to 27.6 bar (150 to 400+ psi)
slurry introduced which creates hydraulic fractures extending from the ends and between the conduits.Slurry contains proppant/reactant
(sand, ZVI, etc) which holds fracture open and either enhances permeability or reacts with contaminants directly.
HorizontalFracture
Conduits
Cavity
High Pressure Jet Injection –Pilot Testing Chronology
Initial DK Pilot Test
DPT Proof of Concept Testing
DPT Jet Injection Testing – Phase I
Year 2011 2012 2013
Location Denmark US (SC) US (OH)
Geology Clay Till Saprolite Clay Till
Delivery Method Blank PVC Well DPT (single line) DPT (dual line)
Jetting Fluid Water Water w/ Green Dye Water
Injection Slurry
Amendment Slurry w/ Rhodamine WT Dye
noneCross-linked Guar
Gel Slurry w/ Rhodamine WT Dye
Initial Jet Injection Pilot TestTaastrup, Denmark, November 2011
Initial Denmark Pilot Test - Objectives - Taastrup, Denmark, November 2011
Deliver aqueous slurry ZVI via jet injection into PVC wells in fractured basal clay till formation at 3-7 meters below ground surface. Determine whether sub-horizontal, homogeneous distribution of remediation material is possible.Determine whether injection conduits can cut-across natural fractures. Determine how closely conduits can be induced at various depths.
Initial DK Pilot Test – Methods
Jetting through PVC casing and well grout caused many problems including injection short-circuiting
Initial DK Pilot Test - Primary Fractures
IW-1 IW-2
~2 m ~2 m
Initial DK Pilot Test– 3D Visualization of Primary Vertical Fractures
Initial DK Pilot Test – Summary of Results- Taastrup, Denmark, November 2011
Aqueous slurry containing zero valent iron (ZVI) was distributed into fractured basal clay till.Vertical fractures were observed 6-7 m across.Sub-horizontal, homogeneous distribution of ZVI was not achieved.
ZVI was distributed through primary and secondary sub-vertical and sub-horizontal fractures.Natural vertical fractures were not bypassed.
Failure ModeTOO MUCH KINETIC ENERGY LOSS
DPT Proof of Concept TestingTravelers Rest, South Carolina, July 2012
SC DPT Proof of Concept Testing - Objectives - Travelers Rest, South Carolina, July 2012
Determine whether DPT Jet Injection:Achieves a more controlled fracturing distribution, relative
to injection into PVC wellsIs less susceptible to short-circuiting than injection into
PVC wellsCan emplace conduits/fractures across natural fractures.
Determine whether injection into multiple nozzles simultaneously increases conduit length.
SC DPT Testing – Methods
Multi-port DPT Injection Tip
Dye mixing tank
Water blaster
Probe tip with nozzle inserts
SC DPT Testing– Excavation
Path of jet cutting across weathered rock
SC DPT Testing – Excavation
1.8 m
1.4 m
View from either side of the jet (parallel to jet-rod plane)
SC DPT Testing – 3D Visualization of Sub-Horizontal Fracture Form
(Dimensions in meters, Hach Colorimeter results in Pt-Co color units)
Conclusions – SC DPT Testing
Cavity size ranged from 0.3-0.9 m (conduits observed).Horizontal fracture widths ranged from 1.0 to 2.1 m across, often shifted off-center from injection point.Formed fractures that were perpendicular to geologic features.
DPT jet injection achieved more controlled fracture/conduit emplacement than jet injection into PVC wells.
DPT Jet Injection Development – Phase I August to December 2013
DPT Jet Injection – Phase I Tooling Design
Two new tooling designs were developed for field testing, improving on tooling used in the 2012 SC pilot test. Design modifications included:Separate water jetting and slurry injection linesModification for use with Geoprobe® expendable drive tipsDesign of 4-nozzle and 6-nozzle tips with differing slurry
line flow paths.
DPT Jet Injection – Phase I Tooling Design
DPT Jet Injection Tooling –Working Prototypes
4 Nozzle Design
6 Nozzle Design
Test SiteSchillig Farm - Alliance, Ohio
Clean test site identified in glacial clay till.Hand auger borings used to confirm presence of clay till. During pilot testing, advancement of geologic borings guided the selection of injection locations and depths.Soil borings identified the redox boundary and facilitated injection testing below this boundary.
http://www.dnr.state.oh.us/tabid/7143/Default.aspx (Canton Quadrangle)
Site MapSchillig Farm - Alliance, Ohio
Core 410 m
Core 3
Core 1
Core 2
JI-C
JI-B
JI-AExtent of
excavation
N
• 4 Geoprobe® borings for site characterization• 4 injection locations
• JI-A and JI-F in shallow soil – jetting only• JI-B and JI-C below redox boundary – jetting and slurry
injection
JI-F
Core 4
Site GeologySchillig Farm - Alliance, Ohio
0 to 0.4 m Topsoil and brown silty clay
Core 4
0.4 to 2.2 m Light brown to grey silty clay, some layers silt and fine sand
2.2 to 4.5 m Dense grey silty clay, trace sand and gravel
Target depth for injections: 2.2 – 3.8 mRedox Boundary
Depth Interval Soil Description
Detailed Operating Parameters
Test Location JI-F: 6-Jet Nozzle
Star-shaped cavity with six individual conduits eroded by each jet
0.9 m
0.3 m
Test demonstrated effectiveness of conduit formation:No venting or daylighting of fluids during prolonged
jetting (> 2 minutes) at a depth of only 1.1 m bgsNo evidence of fracturing activated by jetting alone.
Test Location JI-B: 4-Jet Nozzle
3.3 m
Redox Boundary
Injection in dense, grey clay till below redox boundary
Gravel Layer
Observed Dye
Test Location JI-B: 4-Jet Nozzle
HorizontalFracture
1.0 m
Cavity0.4 m
1.4 m
1.4 m
0.7 m
3.2 m
NObservations during excavation:Largest dimension of cavity
measured 1.8 mLargest dimension of horizontal
fracture measured 2.0 mDye observed in naturally
permeable features (sand & gravel layer) 3.2 m from injection
Test Location JI-B: 4-Jet Nozzle
Collapsed Cavity
Conduit eroded to 1.4 m away from jets
Test Location JI-B: 4-Jet Nozzle
Horizontal fracture formed in grey clay till between sub-horizontal sand and gravel layers.Fracture achieved despite proximity to highly permeable features.
Gravel Layer
Fine Sand/Silt Layer
Test Location JI-C: 6-Jet Nozzle
1.0 m
ObservedDye
HorizontalFracture
Cavity
0.9 m0.9 m
2.5 m
2.1 m
0.3 m
0.4 m
N
Collapsed Cavity
Observations during excavation:Largest dimension of cavity measured 0.7 mLargest dimension of horizontal fracture measured
1.8 mDye observed in naturally permeable features (silty
sand and gravel layers) 2.5 m from injection
Test Location JI-C: 6-Jet Nozzle
Created sub-horizontal fracture in dense glacial clay till.Fractures propagated from edges of cavity.
Successfully demonstrated controlled cutting of conduits with no surface venting with both tooling designs.4-jet design achieved an X-shaped cavity with four clearly defined conduits; horizontal fractures were formed both between the conduits and extending outward from the conduit tips.
Summary of Findings
6-Jet Design
Maximum fracture widths in Phase I testing likely limited by moderate slurry injection volumes (95 liters/injection).
6-jet design performed better at preventing slurry line clogs during tooling advancement. Developed procedure for preventing nozzle clogging during advancement.
Controlled Conduit Cutting
Observed Dye
HorizontalFracture
Cavity
Next Steps
Phase II testing of DPT Jet Injection method at a contaminated test site in Capital Region later this year.Refinement of injection procedures to:
Increase conduit lengths and uniformityIncrease horizontal fracture widths
Injection of zero-valent iron slurry into a clay till source zone and performance monitoring to evaluate treatment effectiveness.Evaluation of method performance in fractured clay till.
Questions?
Pressure Logs
Slurry pressure monitored at well head during injection.Head loss in 3-inch rod minimal
pslurry = pfracturing
Datalogged at ½ HertzTrend of pressure consistent with propagation of horizontal hydraulic fracture.
Breakdown
Net inj start
Declining trend
Shut-in