This Triangle Energy Operations (TEO) Environment Plan (EP) is the 5-year update to the Cliff Head Operations EP. The Cliff Head oil field is located off the Western Australian coast within Production Licence WA-31-L.
Production from the Cliff Head Oil Field Development involves transferring oil and produced formation water (PFW) from the Cliff Head Alpha (CHA) offshore wellhead platform to the Arrowsmith Stabilisation Plant (ASP) via a production pipeline. At the ASP, the PFW is removed from the product stream, the crude oil is stabilised and then transferred to road tankers and transported for refining.

This 5-year update to the Cliff Head Operations EP considers only the offshore components of the Cliff Head development, namely those that occur beyond the Commonwealth-State boundaries at 3nm from the coastline, these are:

• The CHA: an unmanned well head platform to accommodate the well heads and support equipment;
• Eight well heads with the current arrangement of five production wells with electrical submersible pumps (ESPs) to enable artificial lifting of the produced fluid (i.e. crude oil and water), and three water injection wells;
• An insulated subsea production pipeline, which transports the produced fluids from CHA to the onshore ASP;
• An insulated subsea water injection pipeline from ASP to the three injection wells at CHA; and
• A subsea power and communication cable, and chemical supply umbilical running from ASP to CHA.

The production pipeline transports the produced fluids from the CHA to the ASP where oil is separated from the produced formation water (PFW). The PFW is then transported via the water injection pipeline to the injection wells, where it is then injected into the geological formation that hosts the hydrocarbon reservoir.

In addition to activities associated with the ongoing operations of the facility, the EP also covers pipeline inspection, maintenance and repair activities.

The offshore components of the pipelines that lie within Commonwealth waters are approximately 4.9 km in length and are operated under pipeline licence WA-12-PL, which is administered by the National Offshore Petroleum Titles Administrator (NOPTA). The offshore components of the pipelines that lie within state waters (i.e. between the state waters limit and the mean low water mark) are approximately 6.9 km in length and are operated under Access Authority (AA3T) which is administered by the Department of Mines, Industry Regulation and Safety (DMIRS).

TEO anticipates that the Cliff Head field offshore operations will transition to the Non-Production Phase within the five year period covered by the EP. Cessation of production is currently targeted for mid 2025 (based on best estimate 2P Reserves position). Activities within the NPP are therefore covered within the scope of this EP. TEO’s progress and planning for decommissioning is outlined in the EP; however, future decommissioning activities, including plug and abandonment of wells, will be conducted under separate EPs.