Gazprom Neft has acquired development rights to two new assets — the Tazovskoye and Severo-Samburgskoye fields — in the Yamalo-Nenets Autonomous Okrug. Subsoil usage rights to the Tazovskoye block run to 2025, and rights to the Severo-Samburgskoye block to 2027.
The Tazovskoye field is located 500 kilometres north—east of Salekhard. As at 1 January 2016, recoverable oil reserves at the field as recorded in the State Register of Mineral Reserves stand at 72 million tonnes, condensate at 4.6 million tonnes, and non-associated (free) gas at 183.3 billion cubic metres. In Q1 2017 Gazprom Neft, in its capacity as operator on development of the field, re-tested two wells and began preparations for cluster drilling.
The Severo-Samburgksoye license block is located in the Purovsky District, 100 kilometres north of Novy Urengoy. Recoverable reserves at the Severo-Samburgskoye field, as recorded in the State Register of Mineral Reserves as at 1 January 2016, stand at 90.5 million tonnes. Gazprom Neft is currently undertaking pre-commissioning works at the Severo-Samburgskoye field, with two wells having been de-mothballed (reactivated) and re-tested, and 3D seismic works undertaken in order to clarify data on the geological structure of the field. Pilot drilling at the Severo-Samburgskoye license block is scheduled for the
Vadim Yakovlev, First Deputy CEO, Gazprom Neft, commented: “Gazprom Neft is continuing its ongoing development of what is a key region for the company — the Yamalo-Nenets Autonomous Okrug. It was here that we commissioned two of the most significant fields — the Novoportovskoye and Vostochno-Messoyakhskoye — in 2016. Concurrently with this Gazprom Neft is, thanks to the implementation of cutting-edge technologies, continuing to increase production at traditional fields in the Noyabrsk region. The development of gas-cap-drive fields at the Tazovskoye field, and the Achimov deposits at the Severo-Samburgskoye field, are giving the company further experience in hard-to-recover reserves, allowing us to scale-up solutions successfully implemented previously.”
A gas cap drive (or an “oil rim”) reservoir is one that forms part of an oil or gas condensate deposit in which gas constitutes a considerably greater volume than oil. It is, in fact, a thin seam between a significantly larger gas cap and a water-bearing stratum. The main issue in developing oil rim reservoir relates to the ingress of gas and water into oil-producing wells. The effective development of such resources demands the implementation of new technological solutions in the drilling of complex wells, the identification of ways of lifting liquid with a high gas content, and the extreme precision required in integrated design engineering.
The Achimov formation consists, both horizontally and vertically, of poorly continuous lenticular sandy-aleuritic strata, located in the lower part of Cretaceous (chalk) deposits almost directly above the oil-bearing Bazhenov formation. The Achimov strata occur throughout the central zone of the West Siberian basin, with the thickest strata found in the Urengoy District of the Yamal-Nenets Autonomous Okrug. The Achimov strata are characterised by a complex geological structure, with low permeability and porosity, together with poor reservoir connectivity, necessitating the use of technologically complex inflow-stimulation techniques in developing these reserves.