Norwegian oil company Aker BP has completed the drilling of two appraisal well and delineated the Gekko gas and oil discovery in the North Sea offshore Norway.

The Norwegian Petroleum Directorate (NPD) said on Friday that the wells 25/4-13 S and 25/4-13 A were drilled about five kilometers east of the Volund field and 200 kilometers northwest of Stavanger.

The discovery was proven in Paleocene reservoir rocks in the Heimdal formation in 1974. Prior to the drilling of wells 25/4-13 S and 25/4-13 A, the operator's resource estimate for the discovery was 4.9 million standard cubic meters (Sm3) of recoverable oil equivalents.

The NPD added that the objective of the wells was to prove a possible thicker oil column in the Heimdal formation than previously proven in wells 25/4-3 (Gekko) and 25/4-8, as well as to acquire more information about the complexity of the reservoir.

Well 25/4-13 S south on the structure encountered a 43-meter oil and gas column in the Heimdal formation, of which 6.5 meters was oil column.

Nearly the entire interval consists of reservoir sandstones with very good to excellent reservoir quality. The gas/oil contact and the oil/water contact were encountered at 2,100 meters and 2,106.5 meters total respective vertical depths below sea level.

Well 25/4-13 A north on the structure encountered an approximate 30-meter oil and gas column in the Heimdal formation, of which six meters was oil column. About 15 meters is net reservoir sandstone with very good to excellent reservoir quality. The thickness of the oil zone is somewhat uncertain due to reservoir quality variations.

The NPD said that the size of the discovery was between 0.9 and 2.3 million standard cubic meters (Sm3) of recoverable oil and 3.8-6.3 billion Sm3 of recoverable gas. The licensees are considering tie-back of the discovery to the Alvheim FPSO.

The wells, 14th and 15th exploration wells in production license 203, were not formation-tested, but extensive data acquisition and sampling have been carried out.

The appraisal wells were drilled to respective measured depths of 2,653 and 2,641 meters below the sea surface in water depth at the site is 120 meters. The wells have been permanently plugged and abandoned.

The wells were drilled by the Deepsea Stavanger drilling rig, which will now leave the Norwegian shelf, on assignment for Total.