Apache Northwest Pty Ltd (Apache) is the operator of the Stag Field Production and Export Facility (Stag Facility). The facility is located 53 km northwest of Dampier in approximately 49 m water depth in the Commonwealth waters of the North West Shelf (NWS). Oil is currently produced from the Stag Reservoir  via  production  wells,  and  seawater  is  injected  via  injection  wells.  Ongoing  drilling  and completions  activities  will  be  necessary  to  maintain  oil  production,  and  eventually  decommission the facility. The Operational Area (Permit WA-15-L) is located in Commonwealth waters in the Carnarvon Basin, north Western Australia. The boundary of the permit WA-15-L has been used as the ‘Operational Area’ within which petroleum activities covered under this environment plan will occur.
Petroleum activities at the Stag field are proposed to be ongoing for five years, from January 2015 to December 2019. Precise timing of each drilling operation is dependent on the analysis of field production and  reservoir  data,  MODU  availability  and  is  subject  to  approvals.  Due  to  their  responsive  nature, petroleum activities will depend on the maintenance requirements of existing wells, production rates of existing wells and analysis of data for the likely presence and location of undrained hydrocarbons. It is expected that approximately thirty petroleum activities would occur over the five year program.
The basis for listing the maximum anticipated number of petroleum activities at 30 is based on the anticipated yearly activity as follows:
•   Approximately four (4) new producer wells from slot reclamations;
•   Approximately two (2) producer wells from side-tracking existing wells;
•   Approximately two (2) injector wells;
•   Approximately four (4) work overs per year; and
•   Contingency activity 10% – to account for any unforseen issues.
These activity estimates have been based on historical activity in the Stag field. Since 2010, there have been 35 petroleum activities: 5 appraisal wells, 7 producers from reclaimed slots, 1 producer from side-tracking an existing producer, 1 open water injector, and 22 work overs (40% of all activities).
Assuming that each well drilling activity takes 10 to 50 days, the number of drilling days could be up to approximately 400 days, weather dependant.
The Stag Drilling and Completions EP covers drilling activities in all seasons.
Note: This information has been extracted from the EP Summary. Please refer to the attached EP Summary for more information.