As well as the Codes of Practice that apply to all resources industry exploration, there are two Codes of Practice that apply specifically to the coal seam gas (CSG) industry for both exploration and production:

It is a requirement of a company's exploration licence that any well must be drilled in accordance with the Code of Practice for Coal Seam Gas Well Integrity which stipulates:

  • Mandatory practices for well design and construction to ensure activities are environmentally safe and groundwater resources are protected;
  • Guidelines for well monitoring and maintenance; and
  • Methods for the management of water from the extraction process.

Under the Code, the design of all CSG wells must guarantee the safe production of gas by:

  • Preventing any interconnection between coal seams and aquifers;
  • Ensuring gas is contained within the well and associated pipe work and equipment without leakage;
  • Ensuring isolation between different aquifers and water bearing zones;
  • Not introducing substances that may cause environmental harm; and
  • Requiring all chemicals used to be disclosed during the approvals process.

This Code of Practice is supported by the Guideline for mineral exploration drilling: drilling and integrity of petroleum exploration and production wells, which gives guidance on developing, maintaining and decommissioning boreholes and wells associated with all resources, including CSG.

Drilling and testing

A CSG well is created by drilling through layers of earth and rock as deeply as 1000 metres below the surface. Multiple layers of steel casing and cement are pressure injected so the well adheres to the surrounding rock.

A strong seal prevents gas or fluid leakage into permeable layers, including aquifers.

The process of drilling and installing the well can take more than a month. Before activation, the well is subjected to a high pressure test. A geophysical logging tool is lowered into the well hole to inspect the casing and ensure it meets Government standards.

These measures limit the potential for drilling activities to interfere with water resources and the environment.

Regulation of wells

The independent Environment Protection Authority (EPA) is the lead regulator of gas activities in NSW, with responsibility for compliance with and enforcement of all conditions of gas activities, excluding work health and safety conditions, for which the Division of Resources and Energy is responsible. The EPA has the power to inspect and prosecute companies for environmental and health breaches.

End of well

Once a well has exhausted gas reserves from the coal seam, it is cemented and plugged in accordance with regulatory requirements.

The title holder must rehabilitate all well sites and the surrounding land to their previous state, or per their agreement with the landholder. Rehabilitation of the well may include restoring the natural surface contour of the land and planting seeds to ensure adequate plant coverage of the area.

Location of CSG wells in NSW

The Division maintains an online map that shows the status of CSG wells in NSW. The most up-to-date data on CSG drill holes and wells is available in the Geoscientific Data Warehouse external link.

You can also visit the web application Common Ground external link for a comprehensive overview of mining and exploration activities (including CSG) in NSW.