Questions raised over Perth Basin resources 

TWO days after Warrego Energy released its statement to market on a third party assessment of gas resources in its Perth Basin West Erregulla acreage prepared by RISC, operator and joint venture partner Strike Energy has queried the results and complained it has not been provided a copy of the report. 
Questions raised over Perth Basin resources  Questions raised over Perth Basin resources  Questions raised over Perth Basin resources  Questions raised over Perth Basin resources  Questions raised over Perth Basin resources 

Division over West Erregulla resource estimates

Helen Clark

Editor

 
Strike (50%) drilled West Erregulla-2 last year reaching a total vertical depth of over 5000m and hitting gas across all three targets. 
 
Even pre-spud Strike managing director Stuart Nicholls had been suggesting one trillion cubic feet of gas  potential but Warrego's estimate released to market Monday suggested a 2C resource of half that, at 513 billion cubic feet. 
 
"Strike has requested a copy of the report and the assumptions behind it but is yet to receive any information on how the data was interpreted and relied upon,"  Strike said today. 
 
"It is important to note, as detailed in Warrego's release, ‘seismic attributes were not used to assess the extent of the field', which indicates that the full dataset of available information was not taken into consideration.
 
"Strike's rigorous geological and geophysical work in the Basin broke open this deep gas play, proving the existence of major conventional gas fields deeper and further eastward than any previous subsurface interpretation has led to."
 
The main issue is the view on whether seismic anomalies, especially at the great depths Strike was drilling at, can be relied upon to deliver most accurate estimates, with Strike long believing the anomalies detected point to huge gas resources thousands of metres below ground. 
 
RISC did not add this to its interpretation, relying on flow rates from the well and other seismic data, leading to two separate 2C continent resource estimates of 513 billion billion cubic feet of gas, versus Strike's third party assessment from last November of 1.2 trillion cubic feet of gas. 
 
Strike's statement  was compiled by Igesi Consulting. 
 
"It's not uncommon that JVs carry different volumetrics for volume estimates and we know that Waitsia was initially subject to materially different views between AWE and Origin," Nicholls told Energy News this morning. 
 
"The operator's (AWE) numbers were more accurate." 
 
RISC was AWE's certifier, as it happens. 
 
Waitsia was the Perth Basin's big shot in the arm and after the Waitsia-4 well flowed at unheradled rates in late 2017, RISC upgraded it assessment by 78%, setting off a bidding war for AWE, whose former managing director David Biggs now sits on the Warrego board. 
 
 
"As we undertake further drilling and analysis we expect the resource to grow even further, and will convert contingent resources to reserves," Nicholls continued. 
 
The JV plans to spud two wells in the second half of the year and a third, West Erregulla-5, to be decided on by November.  
 
"We're in the very late stages of rig procurement," Nicholls said, adding that the company is still discussing sharing a rig with other operators who plan to press ahead with drilling plans despite the pandemic slowing work. 
 
"Mobilisation and demobilisation with ongoing lack of activity it can be quite costly. We may be able to support their ability to get their wells up, a rising tide raises all boats." 

 

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