Santos encounters traces of oil at second Dorado appraisal well. Drilling continues

Australian oil firm Santos has encountered traces of oil during drilling at the Dorado-3 appraisal well offshore W. Australia.

The Noble Tom Prosser jack-up rig; Source: Noble Corp.

The well, spudded late in July using the Noble Tom Prosser jack-up rig, and designed to appraise the original Dorado oil discovery, has a final target depth of 4575 meters.

According to the latest update from Wednesday, as at 6:00 am (local time) Wednesday morning, the well was drilling ahead in 8-1/2” hole size at a depth of approximately 4,357 meters MD.

Carnarvon, Santos’ partner in the field, said Wednesday that increased resistivity observed from Logging While Drilling tools indicated porous and permeable zones with indications of hydrocarbons as anticipated in the Caley and Baxter Members.

Carnarvon said: “Wireline logging is required to obtain definitive results and this will commence once the final core section is extracted and the well has drilled to the total depth of approximately 4,575 meters Measured Depth (“MD”).”

To remind, the original discovery well last year found hydrocarbon-bearing reservoirs in the Caley, Baxter, Crespin and Milne Members of the Lower Keraudren Formation, in what was described as one of largest oil discoveries ever on Australian NWS.

Also, the recent Dorado-2 appraisal well, located around 2.2km northeast of the Dorado-1 well, confirmed hydrocarbon-bearing reservoirs in the Caley, Baxter, and Milne and importantly demonstrated connectivity within each reservoir between the two wells.

Following the second well completion, 2C liquids estimates increased from 102 to 158 mmbbl (gross), and 2C gas estimate increased from 328 to 628 Bscf (gross).

As for the Dorado-3 well currently being drilled, it is the second appraisal well at the Dorado project. It is located approximately 900 meters northwest of the Dorado-1 discovery location.

The Dorado-3 well has been designed to enhance the Santos’ and Carnarvon’s confidence in the subsurface characteristics and confirm reservoir productivity.

The well is planned to conduct 2, and potentially up to 3, flow tests targeting the Caley, Baxter, and Milne reservoirs, as well as acquire approximately 380 meters of full-bore core in the Caley, Baxter, Crespin and Milne Members.

Santos, which acquired the Dorado rights by buying the former operator Quadrant Energy, has said that the Dorado was a world-class liquids-rich petroleum system with high quality reservoirs and offered excellent economics for shallow water tiebacks to a future Dorado Hub.

According to Santos, the Dorado-3 well provide critical dynamic & fluid data (from well tests) to underpin field development planning and final investment decision. Santos has previously said that the final investment decision for the Dorado field would be made in late 2020.

Offshore Energy Today Staff

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