NCS: Presto well is dryillustration: Pixabay

NCS: Presto well is dry

The Agat formation proved not to be an easy target.

Equinor did not find any gas in the Lower Cretaceous sandstones in 36/1-3 in the northern North Sea. 

The primary and secondary exploration targets for the well were to examine reservoir rocks from the Early Cretaceous Age (upper and lower part of the Agat formation), according to 

Well 36/13 encountered the Agat formation with a thickness of about 180 m, of which 55 m of reservoir rocks with good to very good reservoir quality.  

The Agat discovery (35/3-2), made in 1980, located to the NW of well 36/1-3, contains an estimated 43 billion m3 of gas and condensate, which are stratigraphically trapped within a westerly-thickening classic wedge of Aptian-Albian deep-water sandstone.  

In 2001, the German energy company RWE-DEA (51%) and Aker Maritime (49%) received a license to develop the field. In the spring of 2002, the two companies drilled an exploration well a few kilometres from the main field, Agat, to clarify the reserve base, but it turned out to be dry. 

A bit to the south, in PL 636, the Cara discovery (36/7-4) proven in 2016, demonstrated that the Early Cretaceous Agat Fm can contain commercial hydrocarbons. The field will be developed with a subsea development tied-back to the Gjøa facility. The plan for development and operation (PDO) was submitted in February 2019, and production is planned to start around the turn of the year 2020/2021. 

The Agat fm is not an easy target, mainly due to its areal deposition on the Måløy Terraces, strongly influenced by the topography created by the Late Jurassic rifting.  During the late Early Cretaceous the Måløy Terrace had a low-gradient slope towards the deeper Sogn Graben in the west (Shanmugham, 1995; Bugge et al. 2001). Accommodation on the terrace was controlled by differential subsidence of underlying mud-rich sediments along a N–S trend controlled by the Jurassic faults, and/or by slope accommodation created by large-scale slides or slumps (Bugge et al. 2001). 

Geographical distribution and schematic transect setting of the Agat Formation (Source: Norlex)

PL885 is shared by Capricorn Norge AS (30%), Wellesley Petroleum AS (30%), Equinor Energy AS (operator 20%) and Petoro AS (20%). 

NCS Exploration 2019, May 21-22, Fornebu: Recent Advances in Petroleum Exploration