Messoyakhaneftegaz, the Gazprom Neft—Rosneft joint venture, has completed construction of a unique and highly complex production well — a horizontal well with two pilot (“rathole”) and two lateral wells, drilled using “fishbone” technology — at its Vostochno-Messoyakhskoye field.*
At a depth of 825 metres, the horizontal deviation from the main well equals 2,001 metres. The Drilling Complexity Index on this well (at 7.03), and the ratio between the horizontal offset and the vertical depth of the pilot borehole (at 3.06) make this well genuinely unique. This construction has made it possible to increase coverage of oil-bearing sections of productive strata, which are characterised by a complex geological structure. Initial flow rate at this high-technology well is running at 94 tonnes of oil per day.
The complex geology of the Messoyakha licence areas does not allow a uniform approach to be taken in developing hard-to-recover reserves, with non-standard enhanced oil recovery (EOR) techniques proving more effective here, together with cutting-edge drilling technology and geological prospecting. Implementation of the Messoyakha project has allowed the participating companies to enhance their skills and competencies in applying high-technology solutions to developing hard-to-recover reserves.
A total 130 wells have been built at the Vostochno-Messoyakhskoye field since the start of 2017, nine of which utilise “fishbone” technology. Construction of a further 44 high-complexity wells is planned at the northernmost onshore field under development in 2018, using multi-hole completion technology.
The Vostochno-Messoyakhskoye field is located in the Gydan Peninsula, in the Tazovsky district of the Yamalo-Nenets Autonomous Okrug, 340 kilometres north of Novy Urengoy. Recoverable oil and gas condensate reserves are estimated at more than 340 million tonnes with 106 hydrocarbon accumulations identified across 36 geological horizons. Field development is being undertaken by Messoyakhaneftegaz, jointly owned by Gazprom Neft (operator) and Rosneft. The project is being implemented on the basis of completely independent, standalone infrastructure and transportation.
* A “fishbone” well is a multilateral well with a particular trajectory, from which multiple branches lead off from a single horizontal wellbore. The well, as a result, resembles a fish skeleton, hence the name. This construction allows significantly greater coverage of oil-saturated sections of the strata in comparison with traditional horizontal wells, increasing initial oil flow rates by an average 40 percent and, moreover, requiring less extensive drilling works than would be required in creating a separate horizontal well for each individual branch. A well with a “fishbone” trajectory allows each individual branch (“lateral”) to be directed at a specific oil-bearing area, without coming into contact with adjacent strata containing water or gas.
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