A multilateral “fishbone” well — unique to the industry and comprising eight sidetracks — has been built at Gazprom Neft’s Vostochno-Messoyakhskoye field.* The productive shaft runs to a total 5.1 kilometres in length, with the total length of the well reaching 9.1 kilometres. Composite oil-net thickness in the drilling zone did not exceed 12 metres.
“Fishbone” wells have become Messoyakhaneftegaz’ trademark. Multilateral wells of this construction can increase well productivity by 40 percent over traditional horizontal wells, as well as allowing each branch to be directed at specific oil zones, without breaching gas- or water-bearing intervals. Using this technology is particularly appropriate for the geology of the Vostochno-Messoyakhskoye field, where reserves are located in segmented sandy deposits with shale breaks at depths of less than one kilometre.
131 high-technology wells were built at Russia’s northernmost onshore field last year, one in four involving “fishbone” technology. A further 25 or so similar wells, involving multiple sidetracks are expected to be built at the Vostochno-Messoyakhskoye field in 2019.
Victor Sorokin, CEO, Messoyakhaneftegaz, commented: “Fishbone well construction technology increases oil inflows, improving viability in field development. The business is now starting to develop marginal oil-bearing deposits, with highly complex reserve structures. We will continue using high-tech methodologies to increase drilling volumes and maintain our high production growth.”Victor Sorokin CEO, Messoyakhaneftegaz
The Messoyakha group of fields includes the Vostochno (Eastern) and Zapadno (Western) Messoyakhskoye blocks located in the Gydan Peninsula, in the Tazovsky district of the Yamalo-Nenets Autonomous Okrug. The Vostochno-Messoyakhskoye field is the northernmost onshore oilfield in Russia currently under production. Licenses for both blocks are held by Messoyakhaneftegaz, jointly owned by Gazprom Neft and Rosneft, in which both have an equal controlling interest. On 21 September 2016 Vladimir Putin, President of the Russian Federation, gave the instruction to commence commercial production at the Vostochno-Messoyakhskoye field, via video link. Total production at the field reached 4.5 million tonnes of oil in 2018.
* “Fishbone” well construction refers to a multilateral well running at a specific trajectory, with multiple offshoots running form the horizontal shaft — giving the well a “fishbone” shape, hence the name. The well’s trajectory significantly increases coverage of oil-saturated reservoirs in comparison with traditional horizontal wells, while requiring less extensive drilling works.