Term Definition 
Acid gas venting The process of venting acid gases such as CO2 from the process gas stream (reservoir CO2) prior to liquefaction of gas into LNG.
Adverse exposure zone The area for which an oil spill response plan is prepared. 
Airshed The affected atmosphere immediately surrounding the facility which may be impacted by atmospheric emissions.
Anthropogenic emissions Emissions of gases to the atmosphere as a result of human activity.
Antifouling The treatment of a ship's hull with a paint designed to prevent growth of marine organisms (biofouling).
Area of Influence  The maximum geographic area that may be affected in the event of an unplanned hydrocarbon spill. The area of influence reflects the outer boundary of repeated stochastic modelling outputs of the combined worst-case credible scenarios that may occur during the Crux project. It illustrates the maximum extent to which hydrocarbons may travel from any worst-case credible spill scenario and includes the extent to which stakeholders may see oil on the water's surface.
As Low As Reasonably Practicable - ALARP A risk management principle which is the point at which the cost (not just in monetary terms) is grossly disporportionate to the benefit gained.
Australian Marine Parks Australian Marine Parks (AMPs) have been established by the Australian Government, to provide for the protection and sustainable management of representative marine networks around Australia.
Backfill gas supply A supply of natural gas from a new source that will support the continued operation of an existing facility or operation. In the Crux project context, gas from the Crux field and surrounding reservoirs is proposed to provide backfill gas for the operational Prelude FLNG facility. 
Ballast water  The water taken on by a ship to manage stability and balance. The water can contain aquatic microbes and organisms.
Benthic  The lowest region of the sea including the interface between the sediments and the lowest part of the water column. Organisms in the benthic environment commonly live on, or in, the seafloor.
Bilge effluent The contaminants from within a ship's hull.
Biofouling The growth of marine organisms on hard surfaces, such as vessels, platforms and pipelines.
Biologically Important Area A defined area where individuals from a regionally significant species come together for reasons including: breeding, foraging, resting or migration.
Blowout preventer Large mechanical valves / equipment installed on a drilling rig or platform, designed to seal and control oil or gas wells to prevent a blowout (an uncontrolled release of oil or gas from a well).
Boiler blowdown Water used in the boiler to generate steam which ocassionally needs to be discharged.
Cetaceans Whales, dolphins and porpoises.
Christmas Tree A piece of equipment consisting of an assembly of valves and other fittings that provide flow control for the producing well.
Commonwealth Heritage Places Areas of indigenous, historic and natural heritage value afforded protection under Australian Commonwealth legislation.
Commonwealth marine area  The area of ocean within Australia's exclusive economic zone and/or over the continental shelf of Australia that is not State or Northern Territory waters. The area stretches from 3 to 200 nautical miles from the coast. The environment within the area is referred to as the Commonwealth marine environment.
Condensate A very light oil, which is contained within gas reservoirs.
Conservation Values Atlas (Commonwealth of Australia 2015) To learn more about the values atlas visist: https://www.environment.gov.au/topics/marine/marine-bioregional-plans/conservation-values-atlas
Continental slope demersal fish communities Bottom-dwelling fish assemblages, identified as being of regional importance in the Commonwealth marine environment.
Cooling water The water that is used to remove heat from a system or process.
Desalination brine A concentration of salt in water higher than that of seawater.
Drilling cuttings The fragments of solid material removed from the well bore.
Drilling fluids "The liquids pumped down the well bore during drilling to cool and lubricate the drill bit, recover cuttings from the well bore, and maintain sufficient pressure for safe drilling operations."
Electrochlorination Technology which generates hypochlorite from seawater and electricity which is used to manage marine fouling in the cooling water system.
Environment Plan A plan required by NOPSEMA for approvals, prior to commencing an offshore activity (e.g. drilling, seismic, commissioning or operations, decommissioning) under the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations.
Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) The Commonwealth legislation for the protection of the environment, focused on protecting Matters of National Environmental Significance (MNES). http://www.environment.gov.au/epbc
Environmental Performance Outcomes An environmental performance outcome is a measurable level of performance required for the management of environmental aspects of an activity to ensure that the environmental impacts and risks will be of an acceptable level.
Environmental receptor A feature of the environment that may be impacted, or is at risk of being impacted, by the activities undertaken during the project. Environmental receptors include the physical, biological and socio-economic features of the environment.
Filter feeders Ocean floor species which include organisms such as sponges.
Flexible riser A flexible pipe that transfers gas or other materials from the seafloor up to the platform / surface facility.
Fuel oil A heavy fuel used by various ships.
Fugitive emissions Emissions of gases or vapours from pressurised equipment due to leaks and other unintended or irregular releases of gases
Gazetted petroleum exclusion zones Petroleum exclusion zones, are areas defined around offshore structures, within which vessels are prohibited from entering, for safety, operational or security reasons. In many cases, this is the same as a petroleum safety zone (see below <link/ anchor point>).
Hook-up The activities between construction and commissioning a facility.
Hydrocarbons A compound of hydrogen and carbon, which are the main components of petroleum and natural gas.
Hydrotest water The water that is used to test the pressure integrity of infrastructure, such as pipelines, pipeworks and process equipment.
In-field development area The geographic area incorporating the proposed development of the Crux field and associated reservoirs. This includes an area within a radius of 30 km from the Crux platform, excluding a 1 km buffer around shoals.
International Maritime Organization The international maritime peak body.
Key Ecological Features (KEFs) Elements of the Commonwealth marine environment considered to be of regional importance for biodiversity or which maintain the function and integrity of the ecosystem. 
Loss of containment (LOC) Commonly known as a spill. Loss of containment is the unplanned release of liquids. 
Loss of well control Loss of control to the subsea wells, which may lead to a spill. (View an image of Prelude's subseainfrastucture)
Macroalgae  A broad range of organisms similar to sea grass. They include kelp and other plant like organisms.
Marine Protected Areas Marine protected areas are protected areas of seas, oceans or esturies. MPAs restrict human activity for a conservation purpose. 
Maritime Arrivals Reporting System A biosecurity reporting system.
MARPOL  The international convention for the prevention of pollution from ships.
Matters of National Environmental Significance 

Matters of National Environmental Significance (MNES) include:

  • world heritage properties
  • national heritage places
  • wetlands of international importance
  • threatened species and ecological communities
  • migratory species
  • Commonwealth marine area
  • nuclear actions
  • a water resource, in relation to coal seam gas development and large coal mining development.

MNES are protected under the EPBC Act.

Matters of National Environmental Significance fauna  Fauna (animals) that are listed as threatened or migratory under the EPBC Act
Mixed bed polisher effluent Water residual from generating de-mineralized water.
National Heritage Places Places described on the National Heritage List, Australia’s list of natural, historic and Indigenous places that contribute to Australia's national identity.
National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) The Commonwealth authority responsible for the safety and environmental regulation of petroleum activities in Commonwealth waters. https://www.nopsema.gov.au/
Naturally occurring radioactive materials (NORM)  Naturally occurring radioactive material (NORM) is the term used to describe materials containing radioactive materials that exist in the natural environment. 
National Pollutant Inventory The National Pollutant Inventory is a database of Australian pollution emissions managed by the Australian Commonwealth, State and Territory Governments.
Not normally manned A platform or facility designed to be typically unmanned during normal operations. NNM facilities do not accommodate personnel for extended stays, and are supported by periodic maintenance visits.
Offshore Petroleum and Greenhouse Gas Storage Act 2006 The Commonwealth legislation providing the regulatory framework for offshore petroleum exploration, production, and greenhouse gas activities in the Commonwealth marine area. The Act, and subsidiary regulations, outline the requirements for the environmental management of petroleum activities in the Commonwealth marine environment. NOPSEMA is the regulator responsible for assessing if the Crux OPP meets the requirements of the Act and subsidiary regulations. https://www.legislation.gov.au/Details/C2017C00051
Offshore Project Proposal An Offshore Project Proposal (OPP) is a document that describes a petroleum or greenhouse gas activity in Commonwealth waters. An OPP outlines how the activity will be carried out in a manner consistent with the principles of ecologically sustainable development set out in Section 3A of the EPBC Act. An OPP also outlines how the environmental impacts and risks of an activity will be of an acceptable level. An OPP is assessed by NOPSEMA against the requirements of the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009.
Oil Pollution Emergency Plan Oil Pollution Emergency Plans (OPEPs) are plans required under the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations. OPEPs detail the planning and arrangements in place to response to hydrocarbon spills from petroleum activities. OPEPs are assessed against the requirements of the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009 by NOPSEMA.
Operational area The area of planned petroleum activities.
Petroleum safety zones Petroleum safety zones are specified areas surrounding petroleum wells, structures or equipment, within which vessels are prohibited from entering or being present in, for operational safety reasons.
Piling The act of driving a pile into the ground or seabed to support the installation of infrastructure. Piles are typically driven or hammered into the ground, using a heavy weight.
In the context of Crux, steel piles are required to support the Crux platform legs.
Planktonic communities The a variety of organisms living in seawater, ranging from tiny bacteria, algae, and protists to microscopic and macroscopic animals (such as fish larvae).
Prelude Floating Liquefied Natural Gas (Prelude FLNG)  Prelude is a floating liquefied natural gas facility (producing LNG, LPG and condensate) located 475km north-north east of Broome in Western Australia. For more information on Prelude visit www.shell.com.au/prelude
Produced Formation Water The water that occurs naturally within the same rock formation as a hydrocarbon reservoir and flows to the surface with hydrocarbon from production wells. The nature of PFW is dependent on the reservoir, and typically increases in volume over time as the reservoir approaches end of life.
Protected matters database  The database records matters of national environmental significance or other matters protected by the Environment Protection and Biodiversity Conservation Act 1999. A search tool exists for individuals interested in the database. https://www.environment.gov.au/epbc/protected-matters-search-tool
Ramsar wetlands The sites that are recognised under the Convention on Wetlands of International Importance (Ramsar Convention) and protected from significant impacts under the EPBC Act.
Safety zone 
An exclusion zone around the facility.
Shell's Biosecurity Management Plan  A plan that outlines all Shell's biosecurity risks and mitigations.
Shoal A shoal is a submerged feature that rises from the seabed towards the surface. Shoals typically support fish, coral and other marine organisms of environmental value. Biodiversity at shoals in the Timor Sea is typically higher than the surrounding continental shelf environment.
Subtidal corals Coral reef systems which are below the tidal line and therefore never exposed to air.
TEG regeneration off gas  The waste gas from the dehydration process undertaken to remove water from natural gas prior to processing.
Total Petroleum Hydrocarbon  - TPH A total of different types of petroleum hydrocarbons.
Triethylene glycol Triethylene glycol (TEG) is the compound used in the dehydration process.
Turbidity   A measure of water quality that describes suspended particles or sediments that makes the water cloudy or hazy.
Vertical seismic profiling  A standard technique to collect geophysical information within a well bore. Using a seismic energy source (typically a small airgun array) to generate impulses. A reflection of the impulses is measured by receivers lowered down the well bore. The data collected provides information on the geology of the formations intersected by the well bore.
Wastewater Any liquid produced from a system or process requiring management or disposal. This may include domestic sewage water, greywater, cooling water or other streams.
Well blowout A well blowout is the uncontrolled release of natural gas from a well after pressure control systems have failed. Modern wells have blowout preventers intended to prevent such an occurrence.
Well intervention A method of controlled access to the cased subsea well at the well head.
Well Operations Management Plan A Well Operations Management Plan (WOMP) is required to be submitted and approved by NOPSEMA. A WOMP provides for the management of well activities, demonstrating that risks to the integrity of the well will be reduced to as low as reasonably practicable (ALARP).
Wet storage The temporary subsea storage of equipment for future use.
World Heritage Properties Sites of internationally important cultural, historical, scientific or ecological significance. Sites are selected by the United Nations Educational, Scientific and Cultural Organization (UNESCO). In Australia, the sites are protected from significant impacts under the EPBC Act.
Zone of potential influence The furthest extent at which oil could potentially be detected in a worst credible oil spill scenario.

Learn more about Shell’s projects and assets

The Crux Project

The Crux natural gas field remains an important longer term backfill opportunity for the existing Prelude FLNG facility. Learn more about this development.

Prelude FLNG

Floating liquefied natural gas (FLNG) is a revolutionary technology that will allow Shell to access offshore gas fields that would otherwise be too costly or difficult to develop.

Shell’s QGC business

Shell’s QGC business is located in Queensland in Eastern Australia. We are one of Australia’s leading natural gas producers, focused on developing Queensland’s world-class onshore gas reserves.

Joint Ventures

Shell is a joint venture partner in a number of major gas projects, mainly off the north-west coast of Western Australia, and in south and central Queensland.