Chemical drilling wastes and disposal
What are the Industrial Chemicals used for drilling
While gas mining companies argue that drilling and fracking fluids contain only a small percentage of chemicals, the overall volume of fluids used creates a considerable chemical load.
The scale of chemical use in a developed gas mining operation was illustrated by a US House of Representatives Committee finding that over a four year period, 14 companies used more than 2,500 hydraulic fracturing products containing 750 chemicals and other components, to make up (excluding water added at the well site) 780 million gallons of hydraulic fracturing products.
In Australia, in some cases, large quantities of chemical additives are used both at the drilling stage and during hydraulic fracturing. A risk assessment provided to the Queensland Department of Environment and Resource Management (DERM) listed approximately 18,500 kilograms of chemical additive used per well with up to 40% (7,500kg) not recovered.
The following information was compiled from research by the National Toxics Network and shows the drilling fluids that can be used in Australia:
- Viscosifiers (e.g., bentonite, polyacrylamide)
- Weighting agents (e.g., barium sulphate)
- Bactericides/biocides (e.g., glutaraldehyde)
- Corrosion inhibitors (e.g., zinc carbonate, sodium polyacrylate)
- Defoamers (e.g., glycol blends, light aromatic and aliphatic oil, naptha)
- Emulsifiers and deemulsifiers
- Lubricants (e.g., chlorinated paraffins)
- Scale inhibitors (e.g., anionic polyacrylamide, acrylamide copolymer)
- Polymer stabilisers (e.g., Sodium sulfite)
- Breakers (e.g., diammonium peroxydisulphate, hemicellulase enzyme)
- Salts (e.g., potassium chloride, sodium chloride, calcium chloride)
Hydraulic fracturing fluids usually include:
- Gelling agents (e.g., guar gum, diesel, alkanes/alkenes)
- Gel stabilisers (e.g., sodium thiosulphate)
- Gel breakers (e.g., Ammonium persulfate, sodium persulfate)
- Friction reducers (e.g., polyacrylamide, mixtures of methanol, ethylene glycol)
- Surfactants (e.g., isopropanol, 2-Butoxyethanol /2-BE)
- Biocides (e.g., glutaraldehyde, Tetrakis hydoxymethyl phosphonium sulfate/THPS,
- 2-Bromo-2-nitro-1,3-propanediol (Bronopol), 2,2-Dibromo-3-nitrilopropionamide
- Clay stabilisers (e.g., tetramethyl ammonium chloride)
- Buffer fluids and cross-linking agents.
Fracturing fluids may also include:
- Corrosion inhibitors (e.g., formamide, methanol, naphthalene, naptha, nonyl phenols, acetaldhyde)
- Scale inhibitors (e.g., ethylene glycols)
- Iron control agents (e.g., citric acid, thioglycolic acid)
- pH adjusting agents (sodium or potassium carbonate)
- Diluted acid to dissolve minerals (e.g., hydrochloric acid, muriatic acid)
Mining waste disposal onto farmland
Drilling mud and fluids disposal as well as dewatered coal seams can be disposed of onto farmland in the exploration stage and is termed agricultural quality water and land farming.
Due to few examples of this occurring in Victoria and lack of historical records, this issue of wastewater/mud disposal onto farmland needs to be further clarified.
- …After drilling activities are complete, the waste fluid becomes contaminated with formation material and the final result is a large volume of liquid and solid waste that must be managed. The exact amount of waste drilling fluid produced is dependent upon numerous factors, including the depth of the well being drilled. For example, one company estimates that for a single coal seam gas well, there will be 45–55 cubic metres of cuttings and 200 cubic metres of fluids (Australia Pacific LNG Pty Limited & Worley Parsons, 2010). https://www.ehp.qld.gov.au/management/non-mining/documents/drilling-muds-fact-sheet.pdf
If an unknown amount of chemicals will be used in the development of onshore gas and an unknown amounts of deep sedimentary chemical elements and compounds will be brought to the surface what will be the regulatory provisions to monitor, test, treat and dispose of those chemicals. But also of equal importance is what will be the ongoing data collection to analyse and maintain this information to ensure transparency.
When disposed on the land or used for irrigation, these chemically enriched waters can interfere with crop uptake for clean water availability to crops which will affect crop yield. Additionally, any co-produced water with high sodium, low calcium and low magnesium concentrations increase the potential to disperse soils and significantly reduce the water infiltration rate.
The potential environmental effects need to be factored into management options from basic treatment systems but also to the interaction between soils, plants, livestock and ecosystems from disposing co-produced waters onto land and, thus, entering the food chain.
Currently these controls do not exist and with existing and past mining activities in Gippsland already disposing industrialised waste in our water ways, the added and increased chemical interaction needs to be factored into any onshore gas development.
Therefore, chemically enriched co-produced waters need to be properly characterised, treated, and disposed to safeguard the environment without compromising other natural resources.
How much and how long can the waterways of Gippsland be the sewered aqueducts of Gippsland receiving and transporting industrial water feeding into the Lakes System.
What studies have been carried out for the whole of the Gippsland river system specific to quantify the effects arising from our existing mining and industry wastewater disposal prior to any further exploration and to the added stress an onshore gas industry would have on a farmer’s ability to irrigate livestock and crops safely.
So the question needs to be asked to ensure farmers have a greater understanding of what the waste water discharge to land permit conditions mean rather than the attraction of a new free source of water - how will the farmer be made aware of:
- permit conditions allowing for the treated wastewater to be discharge onto his land
- water quality and to its cumulative effects on its toxicity
- suitability to plant type
- soil permeability and ongoing drainage issues
- criteria for water testing, analysing and data retention
National Vendor Declaration Statements
CSG and NVDs: SAFEMEAT perspective by Beef Central, 24 March 2014:
•CSG and NVDs: Are producers liable for contaminants caused by mining? By James Nason, 24 March 2014
“If you’re a cattle producer or feedlot operator working in close proximity to a Coal Seam Gas field, consider the following scenario.”
ONG mining will introduce pollutants via drilling and create pollutant waste via extraction that will enter our waterways, farmlands and air so how will these impacts be managed throughout the life-cycle of the planned gasfield(s) - and beyond rather than just production plus three years.
How can a livestock farmer sign a national vendor declaration for known chemical interaction if chemicals used and extracted are not declared to the farmer?
How can they be assessed by toxins authority, NICNAS and the like, for dilution strengths, etc. if it is not covered by any mandatory regulative legislation?
If the government is confident that there is no risk from potential contamination then landowners should be guaranteed complete indemnity for all adverse impacts, both immediate and consequential, upon their business, land, water and assets. Landowners need the assurance that redress is not just available for the life of the resource project.