UK North Sea focused oil and gas company Ithaca Energy has said that a sidetrack well (30/6a-8Z) in the Stella field has confirmed a fully hydrocarbon-saturated reservoir interval in the Andrew sandstone.
The company said that sampling and pressure tests have also provided essential fluid composition information to help scope development of the Stella field.
Well 30/6a-8Z was drilled to find out the nature of the hydrocarbons at an intermediate depth in the reservoir up-structure from the initial vertical well (30/6a-8).
Data acquired during the operation now permit accurate interpolations to be undertaken that define the compositional changes from gas and condensate to oil with increasing depth.
The well intersected an 18ft (true vertical thickness) section of Paleocene Andrew sandstone reservoir, a similar thickness to that seen in other wells on and near the Stella structure. A full suite of wireline logs have been acquired and indicate porosities up to 27% providing further confirmation of the lateral extent and quality of the reservoir interval.
A full set of pressure data has been acquired to allow the company to commence detailed analysis to determine the depth of the gas/oil contact in the Andrew reservoir, above the light oil encountered in the vertical well (30/6a-8). Data was also gathered over the Ekofisk chalk interval penetrated by the well.
Ithaca has commissioned Sproule Associates to provide an updated reserves report that will reflect the results of this drilling program. The report is expected before the end of second quarter of 2010.
The Stella appraisal program is complete and it is predicted that the rig will be demobilized after 89 days on location (compared to a pre-drill estimate of 79 days). The final cost of the program is anticipated to be within budget, the company said.
Current JV Partners in block 30/6a (Stella and Harrier) are Ithaca (68.33%), Dyas UK (31.67%). Post completion of the farm out to Challenger Minerals (North Sea) (CMI) interests will be Ithaca (50.33%), Dyas UK (31.67%), CMI (18%).