LONDON -- Nautical Petroleum has revised its estimate of stock tank oil initially in place (STOIIP) in the Kraken accumulation in the UK northern North Sea. Kraken is a heavy oil field in block 9/2b (Nautical 35%) and block 9/1a (Nautical 100%).
Last summer’s 9/02b-4 appraisal well and 9/02b-4z sidetrack provided wide-ranging new subsurface data. The additional reservoir penetrations have doubled the number of reference points available for correlation of the seismic with well logs.
Nautical applied techniques such as color inversion, far offset, and amplitudes. These, combined with a comprehensive study of rock physics attributes, have resulted in a new seismic interpretation.
Revised geophysical modeling of the widespread Heimdal Unit III sand, performed earlier this year, has been factored into a new geomodel. The resultant new STOIIP range, higher than previous estimates is 635-1,182-1,507 MMbbl (Low-Mid-High).
The deeper Heimdal Unit I sand, first encountered in 9/02b-2, also has been remapped using the 3D seismic taken across block 9/2b and the 2D data over block 9/1a. This reservoir is present over a large area west of the Kraken fault, extending into block 9/1a.
Here volumes have been determined statistically, with a range of 269-543-893 MMbbl (P90-P50-P10). This summer, Kraken will acquire 3D seismic across block 9/1a to better define the Unit I reservoir distribution, before drilling an appraisal well.
Nautical plans to do reservoir simulations based on the new Heimdal III sand geomodel to determine the recoverable (best estimate contingent) resources. It will use the resultant recovery factor to estimate the contingent and prospective resources for the Heimdal I sand.
Recently, Nautical signed a contract with Awilco Drilling for one firm and one optional well for the semisubmersible rigWilHunter, which would be the first of SPD’s multi-well, multi client 2011 drilling program in the North Sea.