Трубопроводы на севере России: обзор проблем при взаимодействии с вечной мерзлотой

МИНОБРНАУКИ РОССИИ

Федеральное государственное бюджетное образовательное учреждение

высшего профессионального образования

«Ухтинский государственный технический университет»

(УГТУ)

Кафедра документоведения, истории и философии

ПИСЬМЕННЫЙ ПЕРЕВОД НАУЧНОГО ТЕКСТА

 Pipelines on Russian North: review of problems of interaction with permafrost. Трубопроводы на севере России: обзор проблем при взаимодействии с вечной

мерзлотой.

Выполнил                                                                        

Проверил                                                                        

Ухта, 2023

CONTENT

Abstract        3                    

1. Introduction        3

2. Experience of pipelines construction on the Russian North        4

3. Failures on the northern pipelines        5

4. Basics of the interaction of pipelines with permafrost        6

    4.1 Thermal interaction        6

    4.2 Mechanical interaction: an example from Medvezh’ye gas field,
Western Siberia        8

5. Review of cryogenic processes affecting pipelines        11

6. Geotechnical problems at compressor stations        15

7. Conclusion        16

References        18

ABSTRACT

Construction and operation of pipelines in cryolithozone leads to forming or activation of geocryological processes developing in a zone of direct interaction of soil with the pipeline and surrounding land. As a result of an increase of up to 2 times the depth of the active layer, development of thermokarst depression of up 2.0 м and thawing of frozen soil there is formation of taliks along gas pipelines operating a temperature above 0ºC. There are significant horizontal and vertical deformations of the gas pipelines resulting in occurrence of intense stress - corrosion of pipes, and swamping of the surrounding land occurs. For pipelines operating below 0C there are new problems associated with the freezing of taliks crossed by the gas pipeline, and the subsequent freezing. Recent statistics show a large number of failures on the northern pipelines; some of them are induced by the permafrost processes.

1. INTRODUCTION

The world consumption of oil and natural gas is still increasing; however, recourses are limited. North is one of most promising reserves, and Russian northern resources are located both on land and on the continental shelves. Exploration sites and pipelines disturb the earth surface: change water flows, relief, and animal migration. The major feature of the Northern environment is permafrost. Permafrost is widely distributed, especially in Asia, and permafrost landscapes are extremely sensitive to disturbance. Gas and oil pipelines were maintained in cryolithozone of Russia from middle of sixties of the last century. It is the only country operating long-distance pipelines in permafrost conditions. There are one hundred and fifty thousand kilometers of pipelines in Russia. Generally, two types of pipelines are in use: feeder pipes delivering gas from the wells to plants (mostly above ground) and gathering pipelines (typically buried at depths of 1.5-2 m); both types are affected by cryogenic processes. An artificial warming is considered to be one of the most important factors affecting pipeline interaction with permafrost. Average age of the major Russian pipelines is about 22 years. More than 30% of the compressor stations need to be refurnished, 15% of them work more than 25 years. Total number of failures of oil and gas pipelines is about fifty thousand a year, according official data of Gosgortechnadzor of Russian Federation, third part of them leads to massive leaks.

Underground pipelines are considered economically reasonable, protected and safe. However, failures of the underground pipelines are forty times more than above ground ones in Norilsk area. It was considered that the thawing of soil under the influence of a thermal flow from the gas pipeline would result in loss of bearing capacity. Surrounding areas are also disturbed, thus interaction between pipeline and permafrost may be a reason for damage of pipes. However, it is still poorly known, which part of the failures is connected to cryogenic processes. Unfortunately, in spite of widely distributed opinion of danger of pipeline-permafrost interaction, failures caused by frost heave or thawing of soil, as well as other processes need to be proven: Detailed analyses of the occurrences of failures including stress-strain calculations are not published yet. A number of publications both Russian (Chigir et al., 1997; Remizov, 2000;) and Western (Rowley et al., 1975; Nixon et al., 1983; Carlson & Butterwick. 1983; Burgess et al.,1993; Razaqpur and Wang, 1996; Seligman, 2000) consider many aspects of the problem; however, the present conditions of the pipelines and failures connected to permafrost in the Russian North still needs to be examined.

1. EXPERIENCE OF PIPELINES CONSTRUCTION ON THE RUSSIAN NORTH

The first in the world gas pipeline in the area of permafrost (Promushlenny - Yakutsk) was constructed in 1965 - 1967 in Yakutia - Saha Republic (Luglaev etc., 2001). The first gas pipeline located above the polar circle in the area of permafrost distribution (Messoyaha - of Norilsk) was above ground (partly underground) and entered into operation in 1969. In 1972 in Medvezh’ye (Western Siberia) gas field the pipeline Medvezh’ye-Nadum-Punga was constructed with diameter 1220 and 1420 mm. The pipeline from Urengoy field was entered into operation in April, 1978; the pipeline from Yamsovei gas field was put into operation in 1997. Zapoliarny pipeline was constructed in 2001. The first gas pipeline Hariaga-Usinsk in the European North of Russia was constructed in 1980.