Managed Aquifer recharge Using Treated 

Coal Seam Gas Water
2

$18.5 billion project to convert coal seam natural 

gas to liquefied LNG for export to Global Market

– Surat Basin, Queensland Australia

– A joint venture between Santos, PETRONAS, 

Total & KOGAS 

– Upstream development area in Great Artesian 

Basin. 300 mile pipeline to a liquefaction facility 

at Gladstone.

– Environmental approval granted in October 

2010 subject to a wide range of conditions

– Approximately 6,100 production wells to produce 

>100 billion gallons of water as a by-product of 

gas extraction.

– Water management is an important issue in the 

production of CSG. 

– Due to location in GAB, state government 

requests beneficial use of water.

– MAR is preferred option

CSG to LNG in Australia – An Overview
• Managed aquifer recharge (MAR) is the purposeful recharge of water to 

aquifers for subsequent recovery or environmental benefit.

• Common reasons for using MAR include:

– securing and enhancing water supplies, 

– improving groundwater quality, 

– maintaining environmental flows and GDE’s,

– reducing evaporation of stored water, or 

– preventing salt water from intruding into coastal aquifers. 

What is Managed Aquifer Recharge?
Coal Seam Gas and Water

What is CSG?
Water Management

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Groundwater Usage (ML/yr)

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Groundwater Pressure (m, AHD)

Roma Town Water Supplye

Associated Water Production

Gubberamunda Aquifer

~340 GL of water 

which could be 

used for multiple 

beneficial use 

projects 

MAR program to treat CSG water and 

replenish drinking water aquifer
Surat Basin (Sub-Basin of the GAB)
The chosen aquifer is... Gubberamunda Sandstone

Typical Characteristics

• Town water supply aquifer

• Confined ~200mbGL to top

• 40-80m thick

• T = 20 - 350 m2/d

• S = 1x10-5 to 1x10-7

• TDS = 500 to 900 mg/l

• CSG water (~3,000 mg/l) to 

be treated by RO, then 

amended to match geochem

of Gubberamunda SS
Geology

Orallo (Aquitard)

Gubberamunda (Aquifer)

Westbourne (Aquitard)
Maximal Risk Assessment

Untreated CSG Water
Core Analysis

• Core Analysis

– Gubberamunda is 86±4% quartz 

– traces of albite, orthoclase, kaolin, chlorite, mica, smectite and 

siderite

• Batch Testing

– low potential for mobilisation of metals or metalloids

– Manganese may increase if injected water is too low in TDS (< 

50 mg/l)

• Dispersion Experiments

– Aquifer clogging not expected if RO water is similar to 

receptor aquifer

– RO permeate (TDS < 150 mg/l) MAY lead to aquifer clogging 

concerns due to clay dispersion due to the presence of 

smectite
Hydraulic Calculations

• Storativity = 7.8x10-5 (from pumping test)

• Transmissivity = 42.4 m2/d (from pumping test)

• 1 Month Water Quality Impact Zone = ~35 m

• 1 Month Hydraulic Impact Zone = 13.5 km (Δ 0.2m)

• Well efficiency couldn't be determined due to impacts of a nearby 

boundary (possibly the Wallumbilla Fault)

• Injection Capacity = Up to 12 l/s (assuming 100% efficient well)

11

( )

( ) 



 



 



 



 = r S

Tt

T

Q

s 2

2.25 log 42.3

π





 





∆ = S

Q T

4π

2.3

( )

( ) 



 



 = 2

2.25

r

Tt

s

40m

10m

Obs 1 (200-221m)

Obs 2 (155-175m)

Inj 1 (204 – 225m) Q = ∏r2 . ŋe . b
Trial Approved ...
Results of Hermitage MAR Trial

Observations

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RO plant shut down

Depleted N2

CaCl2 Dosing for 

SAR Adjustment

Injection Resumed

RO EC change from 

33 to 280 uS/cm

Operational Interference

Injection/RO stopped

Forced Stop

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19/08/201220/08/201221/08/201222/08/201223/08/201224/08/201225/08/201226/08/201227/08/201228/08/201229/08/201230/08/201231/08/2012

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Lab TDS Result converted to EC (Lab TDS/0.6)

Lower Logger SWL

Upper Logger SWL
Clogging....

During commissioning we had some plant difficulties. 

Resulted in;

• highly aggressive RO permeate (TDS = 19 mg/l) being 

injected

• mildly aggressive RO Permeate (TDS = 190mg/l) being 

injected

• SAR of 60 being injected (in-situ SAR = 5)

• Casing began to rust - mild steel lay dormant for over 18 

months

The Result

• Rapid clogging 

• Aquifer contains a dispersive clay called 

“montmorillonite”.

• Low TDS and high SAR water caused immediate 

swelling of this clay

The Lesson

• Source water is key

Migration - Irriversible

Swelling - Riversible

Swelling induced migration – Party riversible

Geochemistry
Rusted Mild Steel Casing...

Clogging....

Glad this is only a trial...
Moving Forward...

New location (the Bend) (10 miles to the South) contains favorable conditions ... 

• Factor of 6 times more transmissive

• Mechanism to ensure correct water chemistry (TDS and SAR) will be provided from 

start-up.

• Current bores are 2” x greater in diameter (8” injection column).

• Bores are stainless steel vs mild steel (no galvanic reactions possible)

• Bore screen area is 100% greater than at trial location

• Bore screens will be jetted prior to injection

• Stay tuned for results next year...

Can Higher Injection Rates be Achieved
Thank You

Tom Silverman

EHS Support LLC

171 Willard Avenue

Portsmouth, NH 03801

1.802.318.6358

tom.silverman@ehs-support.com

www.ehs-support.com