Buru Energy Ltd (ASX:BRU)’s Rafael 1 gas condensate discovery in the Canning Basin in northwest Western Australia is being prepared for a production test.
Petrophysical interpretation and wireline image logs suggest that the net reservoir section is similar to the highly productive conventional dolomite reservoir at the Ungani Oilfield.
Several factors also imply that a gas column greater than that seen at the well location could be present.
“Indications are promising”
Buru Energy executive chairman Eric Streitberg said: “Subject to further analysis of data to hand, and to the results of the impending production test, the Rafael discovery has the potential to be a very material wet gas accumulation in conventional high-quality dolomite reservoir, with very low CO2 content in the gas.
“We are taking a methodical and considered approach to the evaluation of the discovery and intend to waste no time in commercialising the resource if its potential is realised.
“Buru Energy has been operating in the Canning Basin for many years and we have a deep understanding of the operating and stakeholder environment.
“Our extensive studies of the commercialisation pathways for gas in the Canning Basin have also given us a good understanding of how a resource can be monetised.
“The commercial value of a gas resource is considerably enhanced if the field is large and contains a conventional high flow rate reservoir with high pressure and significant liquids content, as we hope Rafael is confirmed to be.
“We have several more critical steps we need to take to understand what we have encountered at Rafael, but the indications are promising.”
Completion designed to maximise flow potential
Wireline logs have been acquired over the six-inch hole section below the seven-inch casing shoe and the well is currently being prepared for well testing with a 2⅜-inch (60-millimetre) tubing string as a “barefoot” completion to be set inside the seven-inch casing.
This completion configuration leaves the reservoir section below the seven-inch casing shoe uncased and is designed to maximise the flow potential of the reservoir.
Geological
Together with the dolomite section encountered at 3,785 metres before the seven-inch casing was set to control gas influxes, a total gross interval of 165 metres of interpreted gas column is present from 3,785 metres to 3,950 metres measured depth.
Several factors imply that a gas column greater than that seen at the well location could be present.
These include the estimated reservoir pressure in excess of 6,000 pounds per square inch, calculated from the mud weights required to control the gas influx from the dolomite zone at 3,785 metres.
The presence of a thick Laurel Shale top seal combined with a large structural closure is also supportive of the potential for a significantly larger gas column in the greater Rafael structure than seen at the well location, but this interpretation requires validation, including the results of the planned flow test.
Chromatographic analysis of the gas influxes to the wellbore during drilling suggests that the gas in the reservoir is likely to have very low carbon dioxide content, similar to other gas recoveries in the Canning Basin.
The percentage and composition of the liquids phase in the gas can only be fully determined from a sample from the production test, but chromatographic analysis indicates significant amounts of condensate and LPG fractions are present
Substantial accumulation of wet gas could be present
The interpreted reservoir quality and thickness, the mapped size of the structure, and the potential for a gas column in excess of that seen in the well suggest there is potential for a substantial accumulation of wet gas to be present in the Rafael structure.
A production test to gather information on reservoir deliverability, reservoir fluids, reservoir pressures and potential reservoir boundaries is required to define this potential.
This test will be conducted as soon as practicable.
Forward program
The immediate forward program includes preparing the well for the production test by running a 2⅜-inch tubing string for a “barefoot completion” of the reservoir section.
On completion, the rig will be demobilised from the Rafael site to the Ungani 8 location.
The production test equipment will be mobilised to the Rafael site as soon as the rig operations are completed, to complete the production test by late December, subject to any weather restrictions.
All equipment required for the production test is on hand.
From here, all of the data on the accumulation including the production test data will be reviewed by an independent reserves certifier to estimate the contingent resources in the accumulation.
This review is expected to be available in early 2022.