The development well that became an exploration well

The development well that became an exploration well

In a press release issued by Equinor yesterday, the company states that it has found additional volumes worth 19 – 26 million barrels of oil equivalent in the Tyrihans field in the Norwegian Sea.

However, the NPD carries 6407/1-A-3 BH as a development well.

In most cases where companies explore a new segment of a field on the Norwegian Continental Shelf, the well is classified as a wildcat or an appraisal well. So, there is a slight discrepancy between how the authorities perceive the well versus how the operator does.

What is going on?

The cross-section below gives a clue how to interpret the situation. The 6407/1-A-3 BH well, as the press release stated, was drilled to test the Ile and Tilje Formations for the presence of hydrocarbons. This is below the Garn Formation where most if not all production from Tyrihans must been from to date. In that sense, the well could be classified as an exploration well.

N-S section through the Tyrihans field, showing the Ile gas prospect that was likely drilled by 6407/1-A-3-BH. Source cross-section.

At the same time, the well could also be seen as a producer or development well for the overlying Garn reservoir, as it probably drilled through the Garn sands to reach the underlying target. This is turn may be the explanation for the well being classified as a development well by the NPD.