The Meda No. 1 Well was drilled with WAPET's National 100 rig to the total depth of 8,809 feet. The well was spudded in alluvium, which overlies the Blina Shale to 60 feet. Below the Blina Shale, the Permian sequence was penetrated, consisting of the Liveringa Formation, Noonkanbah Formation, Poole Sandstone with its Nura Nura Member, and Grant Formation. A disconformity is present between the Poole Sandstone and the Grant Formation.
The Grant Formation unconformably overlies the Anderson Formation (Upper Carboniferous) at 4,201 feet. The Laurel Formation (Lower Carboniferous) was penetrated from 4,935 to 5,483 feet. The boundary between the Lower Carboniferous and Upper Devonian (5,483 feet) is tentatively picked at the change from interbedded limestone and siltstone to oolitic limestone. The main objective ofthe test, the Upper Devonian reef complex, was penetrated at 6,620 feet and drilled to the basal conglomerate at 8,360 feet. Precambrian basement was encountered at 8,663 feet. The Permian and Carboniferous sequences could be correlated with the equivalent sequences in The Sisters No. 1 Well. Because of different facies, no formation correlations could be made in the Devonian sequence.
The test resulted in the recovery of several gallons of paraffin-base crude oil. The oil-bearing zone is in the upper part of the Laurel Formation and is confined to a bed of fine-grained slightly porous, calcareous and dolomitic sandstone between 5,125 and 5,133 feet. However because of slight permeability and high water saturation this zone is of no commercial value in this well.
Numerous gas zones were penetrated in the Upper Devonian reef complex but they yielded only weak gas flows, predominantly of methane.
The discovery of hydrocarbons in the Laurel Formation and Devonian reef complex makes Meda No. 1 of great importance in oil exploration of the Kimberley district.
The drilling results show that future oil exploration on the Lennard Shelf should have two main objectives:
(a) structural closures in the Lower Carboniferous
(b) Devonian reef facies.
