# Managed Aquifer recharge Using Treated Coal Seam Gas Water2 

### $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

0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000

1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 YearGroundwater Usage (ML/yr) 0

20

40

60

80

100

120Groundwater 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 m 2 

### /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 m 2 

### /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 

# ( **)** 

# ( **) **  ** **  ** **  ** **  ** **  ** **  ****
**=** S r Tt T Q s 2 

### 25

. 2 log 4 3

. 2 **π **  ** **  ** **  ** ∆**  **=** S Q T **π** 4 3

. 2 

# ( **)** 

# ( **) **  ** **  ** **  ****

**=** 2 

### 25

. 2 r Tt s 40m

10m Obs 1 (200

- 221m)

Obs 2 (155

- 175m) Inj 1 (204

– 225m) 

## Q = ∏r 2 

## . ŋ e 

## . b

# Trial Approved ...

# Results of Hermitage MAR Trial Observations

0 50 100 150 200 250 300 350

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00Injected Water EC (μS/cm)Injection Rate (l/s) Flow rate L/s EC us/cm

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

99 101 103 105 107 109
111 113
115
117 11919/08/201220/08/201221/08/201222/08/201223/08/201224/08/201225/08/201226/08/201227/08/201228/08/201229/08/201230/08/201231/08/20121/09/20122/09/20123/09/20124/09/20125/09/20126/09/20127/09/20128/09/20129/09/201210/09/201211/09/201212/09/201213/09/201214/09/201215/09/201216/09/201217/09/201218/09/201219/09/201220/09/201221/09/201222/09/201223/09/201224/09/201225/09/201226/09/201227/09/201228/09/2012 600 800 1000 1200 1400 1600 1800 2000Observation Well SWL (mbTOC)HOG Specific EC (μS/cm)

Upper Logger Specific Conductivity (μS/cm) Field EC 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
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