Searching for a complex of technical solutions to ensuring the reliability of support for gas wells in conditions of the distribution of permafrost soils

Introduction. Gas production from fields in the northern region faces with some of challenges related with climatic and geocryological restrictions during of drilling, building and operating of wells. One of the most crucial factors complicating process of gas manning is the process of thawing of permafrost soils, it is possible in the result of thermal impact from fluid produced from the bottom of well to wellhead through the well casing. This process occurs at the depths of up to several hundred meters. As the temperature of the rock around of the well casing, the icy soils lose their strength properties and this may lead to a reduction in the strength of the wellbore support and casing deformation. In the result of permafrost thawing is formation of wellhead subsidence, appearing of non-project excessive loads on well supports. Movement of soils can lead to accidents caused by wellhead equipment and li` pipes depressurisation with outflow of hydrocarbon fractions from the wellhead releases of hydrocarbon fractions into the atmosphere. During construction of gas wells in areas of ice spreading, special thermal stabilization technologies are used to provide the required thermal protection while at the same time imposing additional costs on the total well construction cost. Goal. The purpose of this work is to search, test and implement a set of technical solutions and heat-insulating materials that provide thermal stabilization of wells in permafrost conditions and have maximum technical and economic indicators, which will increase the technical security of wells and reduce the total costs of their construction.
Materials and methods. The Gazprom ne` company group has carried out research to select technologically effective and technically feasible ways of conserving permafrost soils and preventing damage to the integrity of gas well structures, provided the technology implementation costs are reasonable. In the paper presents the results of modeling of thawing permafrost soils with regard to the application of the considered thermal insulating materials and well casing designs laboratory tests of various thermal insulating materials as well as the possibilities for optimization of the existing technologies by using alternative thermal insulating solutions which have not been considered before in perimeter of vertically integrated oil companies.
Results. Based on laboratory tests, confirmation of the presence of more effective heat-insulating materials (relative to basic solutions) was obtained, which can be used to ensure thermal stabilization of permafrost soils during well construction and allow increasing the technical and economic indicators of well construction.
Conclusion. Based on the presented data, it is recommended to carry out bench and pilot tests of new thermal insulating materials as part of a thermally insulated casing pipe and the use of thermal cement with microspheres during well construction.

1. Vasilchuk Yu.K., Krylov G.V., Podborny E.E. Cryosphere of oil and gas condensate fields of the Yamal Peninsula. Vol. 1. / Ed. St. Petersburg: “Nedra”, 2006. — 346 p.

2. Poskonina E.A., Kurchatova A.N. Determination of the minimum length of a thermal case at a selected distance between wells // PRONEFT. Professionally about oil, 2019. — No. 2. — P. 66–70.

3. Melnikov I.V., Nersesov S.V., Osokin A.B., Nikolaychuk E.V., Vasilyeva A.O., Mikhalchenko D.I. Geotechnical solutions for the construction of gas wells in particularly difficult geocryological conditions of the Yamal Peninsula // Gas Industry, 2019. — No. 12. — Pp. 64–71.

4. “VET” systems for temperature stabilization of soils in the wellhead zones of oil and gas wells // Sphere. Oil and gas, 2019. — No. 2. — P. 36–40.

5. Merzlyakov M.Yu., Yakovlev A.A. Application of grouting solutions with the inclusion of hollow microspheres when casing wells in the permafrost zone // Mining Information and Analytical Bulletin (scientific and technical journal), 2015. — No. 5. — Pp. 370–376.

6. Anisimov M.V., Rekunov V.S. Experimental determination of the thermal conductivity coefficient of ultra-thin liquid composite heat-insulating coatings // News of Tomsk Polytechnic University. Resource Engineering, 2015. — Vol. 326. — No. 9. — Pp. 25–30.

7. Georgiyadi V.G., Agapov A.A., Attorney Yu.S., Zenkov E.V., Gilev N.G. Application of ultra-thin thermal insulation in the development of fields in areas of permafrost // CJSC “Publishing House “Oil Industry”, 2023. — No. 1. — Pp. 52–57.

8. Patent No. 156025. Russian Federation, IPC E21B 36/00 (2006.01). Device for eliminating heat flows from a production well into permafrost: No. 2015100388/03: application. 01/14/2015: publ. 10.27.2015/ Khrustalev L.N., Chuvilin E.M., Gunar A.Yu. — 2 p.

9. Bukhmirov V.V., Sozinova T.E., Solnyshkova Yu.S. Calculation of heat transfer through impermeable walls. / Ivanovo: Ivanovo State Energy University named a` er V.I. Lenin, 2015. — 32 p.

10. Petrov A.N., Sartori A.V., Filimonov A.V. Comprehensive assessment of the state of scientific and technical projects through the level of readiness of technologies // Scientific examination, 2016. — Vol. 2. — No. 4. — Pp. 244–260.