Ultimate Recovery Factor Analysis on the Dullingari Field, Cooper Basin
David Kulikowski, 2013
Honours Degree of Bachelor of Science (Petroleum Geology and Geophysics)
The Australian School of Petroleum
The University of Adelaide
The Dullingari Field is located in the southeast portion of the Cooper Basin, South Australia. A recovery factor analysis focused primarily on the Patchawarra Formation examined regional recovery factor trends and provided insight into potential future development strategies. Petrophysical data was collated on a well by well basis for individual sand reservoirs to determine the lateral continuity of sand thickness and the variation of other reservoir properties across the field.
To adequately model recovery factor trends, the Dullingari Field was compartmentalised into 5 sectors bounded bystructural saddles with limited pressure communication across them. A recovery factor for individual reservoir sands was determined from estimated ultimate recovery and original gas in place.
The actual recovery factor was compared with the theoretical Barley recovery factor, which was based on permeability, well bore skin factor (Wellbore damage), drainage area per well and well life. The results indicate significant unaccessed gas, particularly within lower Patchawarra Formation reservoir sands. An overall ultimate actual recovery factor of 36% was calculated for the Dullingari Field. This compared poorly with the calculated theoretical Barley recovery factor of 62%. This latter figure is highly suspect however, as evidence suggests that gas production is largely controlled by water saturation and its direct effect on relative permeability. Furthermore, halite and calcite scale precipitation is also a significant obstacle to production flow.
This analysis identifies opportunities to improve gas production within the Dullingari Field and offers generalised concepts that can be applied to similar hydrocarbon fields with low permeability reservoirs.