Geological and geophysical factors influenceon oil-and-gas pipelines selection in Siberia and Far East

The choice of oil-and-gas pipelines laying tracks at the design stage envisages theadvanced geological and geophysical studies, including the electric survey. Corrosion environment has the greatest influence on theoperating conditions and the service life of underground metallic structures; it depends on the electrical properties of the earth surface(soil resistivity) being extremely high at the low electrical resistivity. It is primarily necessary for the selection of oil-and-gas tracks inthe poorly studied and unexplored regions of Siberia and the Far East characterized by difficult natural conditions including the presenceof permafrost. Currently, the electrical exploration works on the slopes of projected oil-and-gas pipelines are run by methods of the"heavy" geophysics - method of vertical electrical sounding, etc. The complexity of such works causes the weak study of the Siberiaand Far East territories. According to the data of the Institute of Geophysics, only 10% of the territory is studied by electricalphotographed methods (VES, VES-IP, MT, SD, ICC, PCHZ, WFP, etc.), but at the same time the main area (90%) is "the white spot"geophysically. It is important that according to the geophysical survey map of the USSR, the northern part of Western Siberia, almost allEastern Siberia and the Far East are located to the north of the southern limit of permafrost. Almost all the routes of planned and existingoil-and-gas pipelines are concentrated in these areas. The authors propose to use the method of radio-electromagnetic sensing (REMS)for the electrical exploration of planned routes of oil-and-gas pipelines. The use of this method increases significantly the efficiency andthe reliability, and reduces the time and cost of measurements by several times. The measurement results of the electrical properties ofthe underlying surface in the range of 10 kHz - 1000 kHz on the territory of Siberia the staff of Tomsk State University received byREMS method can serve as the starting material. According to the results of experimental studies by REMS method, a map of theelectrical properties of the underlying surface of Tomsk region was built. This map reflects the corrosion aggressiveness of soils in theoil-and-gas routes. The analysis of the map shows that the pipeline routes in Tomsk region pass through the joints (boundaries) of siteswith soils of different corrosion degree. It allows to identify dangerous areas in terms of corrosion, to take additional protectivemeasures and to further adjust the selection of planned routes. REMS method is proposed for the implementation in innovative programsof oil-and-gas companies for mapping the corrosiveness of soils, including the design of the pipeline "Altai" in order to increase thereliability and to reduce oil-and-gas pipeline accidents.

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