Carnarvon Petroleum Limited (ASX:CVN) has started Dorado-2 appraisal well near the site of the significant Dorado-1 oil and gas discovery on the North West Shelf offshore Western Australia.
The new well will appraise the oil and gas discovered in the Dorado-1 well in 2018, which intersected several independent hydrocarbon columns.
Columns in the Caley, Baxter and Milne reservoirs were interpreted to extend beyond the reservoir intersected in Dorado-1 and Dorado-2 will target these in a down-dip location.
Since arriving at the Dorado-2 location, around 2.2 kilometres from the Dorado-1 well location, the ready to operate process has been completed on the Noble Tom Prosser jack-up drilling rig.
The Dorado project joint venture team has also drilled the surface hole and installed the surface casing.
Majority JV partner and project operator is Santos Ltd (ASX:STO) with Carnarvon holding 20% and the project is around 160 kilometres north-northeast of Port Hedland in the Bedout Sub-basin.
Dorado and Roc South reside in WA-437-P in which Carnarvon holds a 20% interest.
The rig will drill the 17-1/2 inch hole to the planned section depth of about 1,200 metres measured depth (MD) followed by setting the 13-3/8 inch casing.
Drilling is in water depth of around 95 metres.
Dorado-2 is the first appraisal well of the Dorado oil and gas field, which is one of the largest oil resources ever found on the North West Shelf.
The Dorado-1 well discovered hydrocarbon-bearing reservoirs in the Caley, Baxter, Crespin and Milne Members of the Lower Keraudren Formation.
Dorado-2 has several objectives designed to increase the certainty regarding the hydrocarbon contacts and further understand the characteristics of the key reservoirs.
Location of Dorado-2 down-dip of Dorado-1.
Dorado-1 well intersected net 130 metres of hydrocarbons of which almost 80 metres was within the Caley reservoir, thus making this the main target for the appraisal well.
The new well has been planned to intersect hydrocarbons within this reservoir and extending the oil column.
It is expected to encounter similar high-quality reservoir to that discovered in Dorado-1 in the Caley.
To confirm this, a full well-bore core is planned to be extracted over the Caley section.
While Dorado-2 has been designed to intersect potential hydrocarbon-water contacts in the Caley reservoir, the location has also been chosen to intersect hydrocarbons in the Baxter and Milne reservoirs.
It will take about one month to drill and set the surface and intermediate casings to a point just above the main Caley reservoir.
An approximate 200-metre full well-bore core will then be cut and extracted over the Caley and Baxter reservoirs.
The well will then be drilled to final depth of around 4,550 metres before wireline logging will commence.
At the completion of the wireline logging program the JV will be able to ascertain the quality of the reservoirs encountered and the presence and composition of hydrocarbon fluids.
Following the Dorado-2 well, the rig is scheduled to drill the near-field exploration well Roc South-1 followed by the Dorado-3 appraisal well.