The Pluto gas field, located 190 km northwest of Karratha, Australia, in 400 to 1000m water depth was discovered in April, 2005. A more recently discovered nearby satellite gas field, Xena, is located 10 km east of Pluto. The combined estimated dry gas recoverable volume of the Pluto and Xena fields is approximately 5 Tcf. The early implementation of a well integrated data acquisition strategy has been central to achieving development milestones. Integration of detailed core analysis with high quality wireline logs enabled reservoir understanding in a complex geological setting.
The Pluto field was penetrated by one exploration and five appraisal wells and the Xena field by one exploration and two appraisal wells. The wells targeted the Triassic Mungaroo and Brigadier reservoirs which are fluvio-estuarine in nature with multi Darcy flow properties. The reservoirs are expected to behave as a well connected gas depletion system.
The occasionally radioactive (high gamma ray), heterogeneous inter bedded nature of the Triassic reservoirs necessitated a multi faceted core-log interpretation. Good quality core data and photography coupled with high resolution density-neutron, resistivity image and nuclear magnetic resonance data allowed confident net to gross estimation. Data acquisition and interpretation was designed to address petrophysical, geological, reservoir engineering, quantitative interpretation (QI) geophysical and geomechanical uncertainties in the fields. This knowledge has been used in the construction of geomechanical analyses, static models and dynamic simulations.
This paper demonstrates the benefits of an extensive integrated data acquisition interpretation strategy to aid effective reservoir characterisation early in field life. This strategy assisted optimised development drilling targets, detailed well and completion designs and accelerated field development planning.