Hydraulic fracturing, or fraccing, is a highly regulated and controlled process.
We use a small number of additives in fraccing fluid, all of which you will find in a typical household in items you may use, such as food and cleaning products.
Hydraulic fracture stimulation, hydraulic fracturing or fraccing is a proven and accepted well completion methodology which has been used for over 60 years internationally and for over 40 years in Australia. The fraccing process is a controlled and closely monitored activity. Fraccing enables a more effective release of gas and water from underground reservoirs.
Fraccing increases well productivity and means that fewer wells are required. Over the life of our project we expect to frac approximately 30% to 40% of our wells.
In some areas, such as where the coals have low permeability (i.e. gas does not flow freely through natural fractures or pathways in the coals towards the well), fraccing is necessary to enable a more effective flow of gas.
Fraccing can convert a non productive well into a productive one and can increase the drainage area of each well. This means that fewer wells need to be drilled in order to produce the same amount of gas.
Most of our current CSG production is in high permeability (or high flow areas) where fraccing is not generally required. However, over time we will produce in lower permeability areas where fraccing will be necessary. Over the life of our project we expect to fracc approximately 30% to 40% of our wells.
Fraccing fluids are 99% water and sand
Fraccing fluid, comprising about 99% water and sand, is pumped down the well under pressure. The water in fraccing fluid forces the coal seams to open and the sand keeps the fractures open, providing a pathway for gas to flow more easily to the well. The resulting fractures are approximately 1 to 20 millimetres thick.
A small amount, typically about 1%, of salts and other chemicals are added to the fraccing fluid, which otherwise consists of water and sand. The additives have important roles in enabling the fluid to form a gel, later breaking down the gel, stabilizing clay and controlling acidity levels and bacteria.
The additives are not harmful
We currently use up to 16 chemical additives in our fraccing fluid. Not all 16 chemicals are used in any one fluid, the make up of the fluid is matched to the requirements of each well. The fluids are mixed on the surface as part of the process for stimulating each well – the fraccing fluid is not supplied pre-made from a generic supplier.
All the added chemicals we use in fraccing fluids are found in a typical house in food and cleaning products and are not harmful in their diluted form. Chemicals typically used by Australia Pacific LNG in fraccing fluids are shown in the following chart. Additives include acetic acid (vinegar), caustic soda (found in hair remover), calcium chloride (found in sports drinks) and guar (found in ice cream).
For a full list of the additives which may be used in our fraccing fluid please refer to the list below (click to enlarge).
Fraccing fluids are contained from the environment
Fracturing takes place hundreds of meters below any water supply aquifers. The cemented steel casing in the well protects shallow aquifers from contamination.
The majority of the fluids which are pumped underground during the hydraulic fracturing process are recovered from the well after the fraccing is completed. While underground the fluid is further diluted by the water already present in the coal seams, so that when it is brought back up to the surface the chemicals are barely detectable.
These fluids are then disposed of in accordance with strict regulatory guidelines. The small amounts of fluids that remain in the coal seams degrade over time into water that is similar in composition to the existing salty water that is contained in the coal seams.
Australia Pacific LNG does not use BTEX (benzene, toluene, ethylbenzene and xylene) in our fraccing fluids. Nor is BTEX present in any of the chemical additives that we use.
BTEX is naturally occurring in many substances including diesel and, surprisingly, in some olive and other vegetable oils.