Messoyakhaneftegaz, a Gazprom Neft—Rosneft joint venture, has completed the construction of several “fishbone wells” (an industry name given to a system involving lateral wells (“laterals”) drilled in sequence from a main horizontal well) at its Vostochno-Messoyakhskoye field — the northernmost wells of this type in Russia. Applying this new technology has resulted in greater drilling efficiency (given the complex underlying geology of the field) as well as eliminating several technological limitations in its development.
The key design feature of the wells drilled at the Vostochno-Messoyakhskoye field lie in multilateral wells branching off from a single horizontal wellbore — giving the well a shape like a fish skeleton, precisely the reason for it being called a “fishbone” well. This construction allows significantly greater coverage of oil-saturated sections of the strata in comparison with traditional horizontal wells while, at the same time, involving less extensive drilling works than are required in creating a multistage well. The fishbone construction allows each of the branches (“laterals”) to be directed at separate reservoirs, without having to encroach on adjacent strata with either water or gas. The laterals can extend in any direction from the horizontal wellbore, at significantly lower cost than drilling individual wells — although the process of drilling fishbone wells is, itself, significantly more complex.
Prior to starting drilling specialists from the Gazprom Neft Scientific Research Centre developed geo-mechanical models of the new-generation wells, subsequently controlling the process of well construction round-the-clock from the Gazprom Neft Drilling Support Centre. This technology has already been tested at four wells at the Vostochno-Messoyakhskoye field, thus far. The total length of all wells drilled stands are more than 10 kilometres, of which more than six kilometres comprises the length of the lateral wells. This technology has resulted in a 40-percent increase in the initial oil flow rate in comparison with traditional horizontal wells.
The implementation of new drilling technologies is part of Gazprom Neft’s Technology Strategy, with the company not only building new high-technology wells but also using more effective drilling fluids in its operations, participating in the development of domestic drilling equipment, and implementing new hydraulic fracturing (fracking) technologies.
The Messoyakha fields include the Vostochno (Eastern) and Zapadno (Western) Messoyakhsky acreages, the northernmost onshore fields in Russia at which production is currently ongoing. Licenses for both blocks are held by Messoyakhaneftegaz, jointly owned by Gazprom Neft and Rosneft, in which both have an equal controlling interest. Gazprom Neft is operator on the project.
The fields, originally discovered in the 1980s, are the northernmost (of the known to date) onshore oil fields in Russia. The Messoyakha fields are located in the Gydan Peninsula, in the Tazovsky district of the Yamalo-Nenets Autonomous Okrug, 340 kilometres north of Novy Urengoy, in Russia’s Arctic zone. Oil and gas condensate reserves at the Messoyakha group fields are estimated at more than 470 million tonnes of oil and 188 billion cubic metres of gas.
