Innovations and risks in the technology of opening isolated layers from the main horizontal wellbore (on the example of the Messoyakha group of fields)

UDK: 622.24.085

DOI: 10.24887/0028-2448-2020-8-38-41

Key words: hard-to-recover reserves, lithologically shielded geological object, innovations in drilling, fishbone technology, well profile, horizontal wellbore, side branch, problems and risks during drilling

Authors: E.G. Kurbasov (Tyumen Industrial University, RF, Tyumen; Messoyakhaneftegas JSC, RF, Tyumen), S.N. Bastrikov (Tyumen Industrial University, RF, Tyumen), S.N. Lavrinov (Messoyakhaneftegas JSC, RF, Tyumen)

The article deals with the experience of developing the Vostochno-Messoyakhskoye field with lithologically shielded hydrocarbon deposits using innovative technical and technological solutions for opening them with multilateral segments from the main horizontal one using the fishbone technology. Both the standard design of wells with a horizontal wellbore of 800 m and with 8 branches in the zones of isolated layers in order to cover reserves in dissected geological objects with low filtration and reservoir properties are presented. The attention is focused on the presence of intervals of permafrost. These intervals must be passed using special technological modes of drilling, and during casing well they should be isolated by special casing – thermocases. Termocases allow eliminating the influence fluid temperature on permafrost: to prevent thawing during well operation, and to reverse freezing and breaking the columns during well shutoff. Technical and technological solutions for implementing the designed profile in the productive part of the formation, the layout of the bottom of the drill string, and the parameters of the drilling fluid are presented. Special attention is paid to the problems and risks when drilling both the main and side holes in difficult geological conditions (drilling mud loss, cavings, collapses of well walls, showing oil and gas, keyseating, difficult descent of the liner into the main hole). In 2019 Messoyakhaneftegas JSC drilled 33 wells using regarded technology with an average number of branches of 7 pieces up to 400 m long. This made it possible to increase the efficiency of the development of hard-to-recover reserves of the Messoyakha group of fields, to determine new directions for their development and the development of well construction technology. References 1. Kutuzova M., Northern points of growth. Production at fields in the arctic climate zone (In Russ.), Neftegaz.Ru, 2017, no. 3, pp. 14–18. 2. FISHBONE: Technologies of the future at Messoyakha (In Russ.), Neftegaz.Ru, 2017, no. 3, pp. 37–38. 3. Kulakov K.V., Wells in the form (In Russ.), Sibirskaya neft', 2016, no. 8(135), pp. 48–49.