Strike Energy has observed that the primary objective at its multi-target West Erregulla-2 well in the Perth Basin, Western Australia, may hold the same excellent reservoirs seen at the neighbouring Waitsia gas field. Cuttings from the Kingia sandstones drilled to date include clean sands with some evidence of grains being coated in chlorite, a mineral that is a key element required for the preservation of porosity at depth.
Strike Energy has received a hint that the primary objective Kingia sandstones at its multi-target West Erregulla-2 well in the Perth Basin, Western Australia, may hold the same excellent reservoirs seen at the neighbouring Waitsia gas field.
Multiple drilling breaks with associated elevated mud gas readings were observed while drilling through the upper section of the Kingia.
Additionally, cuttings from these sections include clean sands with some evidence of grains coated in what is inferred to be the mineral chlorite.
Management said that chlorite and illite from the sediments buried and worked in with the sand at the time of deposition are understood to be the key play elements required for the preservation of porosity at depth.
This mechanism for porosity preservation is the main ingredient to the excellent reservoirs seen at neighbouring Waitsia gas field, according to the company.
Waitsia, which is held by fellow Australian company Beach Energy and Japan’s Mitsui E&P, is one of the largest onshore conventional gas discoveries in Australia.
West Erregulla-2 is currently at a depth of 4,800 metres with Strike interpreting that it has drilled about halfway through the formation.
Given that the best reservoir zones at the Waitsia gas field occur within the bottom 25% of the Kingia sandstones, the company likewise expects to encounter the equivalent section at West Erregulla-2 when drilling ahead into the lower Kingia sands.
The well is located within EP469, which is held equally by Strike and Warrego Energy, and has already intersected 10.2m of net gas pay with porosities of up to 14% in the secondary objective Wagina sandstone.
Additionally, the reservoir pressure in the Wagina was recorded at more than 6,800 pounds per square inch.
This result compares well with the nearby Beharra Springs gas field, which flowed gas at rates of up to 38 million cubic feet per day during flow testing from a 10.4m net gas column in the Wagina sandstone with porosities of about 9.5% and reservoir pressure of about 5,780 pounds per square inch.
There is still more drilling to go for Strike at West Erregulla before the company can tell for sure if it has found an analogue to Waitsia at the West Erregulla-2 well location, however, the positive sand cuttings look to be a step in the right direction.