Gazprom Neft improves efficiency in oil-rim-deposit development at the Chayandinskoye field

Yakutsk, May 18 - Neftegaz.RU. Gazpromneft-Zapolyarye has commissioned its 1st “fishbone” well at an oil-rim deposit at the Chayandinskoye field in Yakutia. The initial flow rate from this multi-branched well has exceeded that of previously used horizontal structures, at about 400 tonnes per day.

This initial multi-branched “fishbone” well, at an oil-rim deposit at the Chayandinskoye oil and gas condensate field (COGCF), has a main shaft running to a length of 1.5 km, with 6 lateral branches, each up to 830 m long. Total borehole drilling exceeded 8.1 km, of which 5.2 km was along productive strata (the “pay zone”).

This construction has made it possible to increase coverage of the deposit, increasing the oil recovery factor (ORF). The initial flow rate through this fishbone well is more than 380 tonnes per day — double the level achieved through the standard horizontal wells previously used at Chayanda.

The Chayandinskoye field is marked by a complex geological structure and exceptionally low formation pressure. A 3D hydrodynamic model of the COGCF’s oil-rim deposit was used in creating the development programme for this asset. Specialists at Gazprom Neft’s Science & Technology Centre and Gazpromneft-Zapolyarye made approximately 500 multivariate calculations in comparing the advantages of various well types for producing Chayandinskoye oil before finally coming down in favour of a “fishbone” well.

A total 44 high-tech fishbone wells are to be drilled at the COGCF oil-rim deposit by end-2024, with 5 such multi-hole wells being commissioned this year. The company is currently operating seven oil-producing wells at the COGCF, and drilling several more.

Full-scale development of the COGCF oil-rim deposit will start in 2020. The CPF (which has a planned capacity of one million tonnes per year) is expected to be expanded and modernised by 2022. Gazpromneft-Zapolyarye is now building a 70-km pressure pipeline to connect the COGCF to the East-Siberia Pacific Ocean (ESPO) trunk pipeline. The field’s production plateau is expected to be reached by 2023, at about 3 million tonnes of oil equivalent (mtoe) per year.

“Developing this oil-rim deposit - the reserves at which are classified as ‘hard-to-recover’ - is further complicated by the geological features present at Chayanda. The key to these deposits has proved to be cutting-edge drilling technologies and high-tech, intricately designed wells. These have already proved their effectiveness and, I am sure, will help us unlock the full potential of oil reserves at the COGCF - one of the largest fields in Eastern Siberia”, said Vladimir Krupenikov, Director General of Gazpromneft-Zapolyarye.