Gazprom Neft completes drilling and well testing at Dolginskoye field

Dolginskoye field operator Gazpromneft-Sakhalin (a subsidiary of Gazprom Neft) completed testing of a well drilled at the Dolginskoye field, Pechora Sea, in summer 2014. The completion of geophysical and hydrodynamic testing will allow clarification of the underlying structure of the field and the development of a programme for its further investigation. This is the first time that such a major volume of work has been completed at a well during this region’s short ice-free season.

Dolginskoye field, Pechora Sea

Drilling of an exploratory well (to a depth of 3,500 metres) in the northern part of the Dolginskoye field was completed in late August 2014. A range of geophysical investigations (geophysical well logging) were undertaken in the process of constructing the well, including core sampling and sampling of drill cuttings, as well as vertical seismic profiling (a type of seismic survey, with detection equipment placed directly in the well), and testing of four different field strata, and other activities.

The completed programme allowed the collection of new information on the geological structuring of the Dolginskoye field, and the clarification of porosity, permeability and other geological features of the field, as well as other key criteria. Preparation of final reports on the results of drilling and well testing is coming to a close, with specialists from the Gazprom Neft Joint Scientific and Research Centre undertaking thoroughgoing analytical research on the samples and data obtained. The data collated will be used to develop a programme of works for the 2015 ice-free season.

Self-elevating drilling (‘jack-up’) rig GSP Saturn, Pechora Sea

At the beginning of November, following completion of all planned works, the well was abandoned, all equipment dismantled, and the empty wellhead hermetically sealed to ensure complete isolation from the external environment. Drillin g and well testing were undertaken by means of the GSP Saturn jack-up rig, delivered to the Dolginskoye field in mid-June. The GSP Saturn rig will be towed to the port of Murmansk in November.

REFERENCE

The Dolginskoye oil field is located in the centre of the Pechora Sea, 120 kilometres south of the Novaya Zemlya archipelago and 110 kilometres north of the mainland coast. The field, discovered in 1999, lies under seawater extending to some 35–55 metres in depth. 2D seismic surveys extending to more than 11,000 linear kilometres have been undertaken at the field, as well as 3D seismic surveys covering an area of 1,600 kilometres. Four exploration wells have been drilled — three in the north and one in the south of the Dolginskoye field. Recoverable reserves at the Dolginskoye field are currently estimated to be in excess of 200 million tons of oil equivalent (mtoe).

Gazpromneft-Sakhalin holds the license to the Dolginskoye field in the Pechora Sea, and to the Severo-Vrangelevskoye field (covering the East Siberian and Chukchi seas).

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