A partnership of Quadrant Energy Ltd. and Carnarvon Petroleum Ltd. has confirmed an oil discovery in the Caley member of the Dorado-1 wildcat in permit WA-437-P in the Bedout subbasin off Western Australia as well as confirming the presence of gas and condensate in the top of the underlying Baxter member (OGJ Online, July 20, 2018).
Quadrant said additional wireline evaluation since the discovery announcement has confirmed both finds. The companies said that light oil had been recovered from a gross hydrocarbon package of 96.1 m and a net pay thickness of 79.6 m in the primary objective Caley member, which has excellent reservoir characteristics.
Light oil has now been recovered from a sand in the upper section of the Caley that is in addition to previous samples recovered. This work was undertaken to provide more information across a broader area of the Caley and enhance confidence in the results so far.
Also, gas and condensate samples have now been recovered from a good quality reservoir at the top of the Baxter, which contains an estimated gross hydrocarbon package of 21 m thickness and a net pay of 10½ m.
The combine said pressure data confirms that the Caley oil and Baxter gas-condensate discoveries are separately stacked hydrocarbon columns.
As the well has not yet completed drilling through the Baxter member, this must be taken as an interim net pay result for the Baxter reservoir. It may or may not represent a gas cap to potential further oil resources.
In addition, the well has yet to reach the Crespin and Milne members lower in the structure. The plan is to set a 7-in. liner and deepen the well to about 4,550 m during the coming week to fully evaluate the Baxter and move on down to look at the secondary targets.
Meanwhile, to the north in adjoining permit WA-435-P, the same combine is drilling ahead in its Phoenix South-3 appraisal well, which is virtually a redrill of the Phoenix South-2 gas-condensate discovery that was unable to fully evaluate the Caley member due to high pressures encountered in that well in December 2016.
The primary objective in Phoenix South-3 is to evaluate the gas and condensate potential in the Caley within the large faulted anticlinal closure that was only partially penetrated in the No. 2 well. The new well, 560 m north northeast of No. 2, has been optimally designed to overcome the pressure problems and drill carefully through the entire Caley section. It is necessarily making slower progress and is currently 5,208 m preparing to set a 7 5/8-in. liner. Results so far are consistent with those encountered in Phoenix South-2.
Dorado-1 is being drilled by the jack-up drilling rig Ensco-107, while Phoenix South-3 is being drilled by Transocean’s semi-submersible GSF Development Driller-1.
Quadrant has 80% interest and operatorship of both projects. Carnarvon has the remaining 20% interest.
