LOO MA-1 REOPENS THE PALAEOZOIC PLAY IN THE SOUTH CANNING BASIN

Abstract

Looma-l was drilled as a wildcat exploration well targeting the Ordovician Nita Formation and Acacia Sandstone in EP 3S3 of the South Canning Basin. The main identified pre-drill risks and uncertainties were depth conversion/structural validity, presence of reservoir, reservoir quality and charge from an as yet unproven kitchen. The well tested interpreted structural closure in a broad, low relief anticline at three different levels, all of which were found to be hydrocarbon bearing. The primary objective Nita Formation and Acacia Sandstone both contain oil, and the secondary objective Nambeet Formation is interpreted to be gas bearing.

Both the Nita Formation and Acacia Sandstone were fully cored and good oil shows, including live oil bleeding from core were encountered in both objectives. These hydrocarbon shows were substantiated by mud gas readings and petrophysical evaluation. Core analysis confirms the presence of live oil saturation in both objectives and the presence of limited permeability in the Acacia Sandstone. Drill stem testing was not successful in establishing any significant oil flow from either objective, however, gas to surface and oil-cut-water were recovered from the Acacia Sandstone. Core analyses corroboral ed the DST results, indicating that the reservoir quality of the Nita Formation and Acacia Sandstone is relatively poor at the Looma-l location. Depositional and diagenetic models indicate that potential for better reservoir development should occur further to the east of the Looma-l location.

Looma-l has proven the presence of mature, migrated oils in both the Nita Formation and Acacia Sandstone and it is the first well in the South Canning Basin to unambiguously prove oil charge from a southern kitchen.