Research On Identification And Evaluation Methods Of Geological Disasters Along Oil And Gas Pipelines

China is a geological disaster-prone country,especially in the southwest region with large topographic relief,high vegetation coverage and complicated geological environment,a large number of landslide,collapse,debris flow,ground cracks,ground collapse and ground subsidence and other geological disasters occurred.With the development of China's economic construction,Oil and Gas Pipeline network has become an important national infrastructure and livelihood project,an important part of modern energy system and modern comprehensive transportation system,and occupies a very important strategic position in the national economy.Built and planned pipeline networks inevitably cross mountains,hills and plains,and various types of geological hazards may develop in the areas through which pipeline networks passes.Once the Oil and Gas Pipeline network is damaged by landslide,debris flow and other geological disasters on both sides of the line,it will cause huge economic losses and casualties.The traditional geological hazard survey is mainly based on manual line inspection,which has a long cycle and high cost,and the quality of survey results is difficult to guarantee.In recent years,the new remote sensing technology based on INSAR has been widely used in the research and application of geological disasters in the early stage of large-scale identification and later stage of high-precisionmonitoringby virtue of its ability to obtain the surface micro-deformation at all-weather,all-time and long-distance.This paper takes QingLong county,GuiZhou province as the research area and QingLong section of China-Myanmar Oil and Gas Pipeline as the main research object,and the Oil and Gas Pipeline network geological hazard identification technology is adopted,which mainly uses InSAR time series analysis technology to comprehensively identify the early hidden trouble points of geological hazards,and at the same time uses GIS technology to establish the index system of the research area by using the information method to carry out the risk assessment of regional geological hazards,Thenthe geological hazard risk zoning map is obtained.Finally,the preliminary geohazard hazard points and regional geological hazard risks identified by InSAR The zoning map is superimposed and comprehensively evaluated to obtain a small number of high-precision regional "census" results,providing data support for the later space-based "detailed inspection" and manual ground "verification".The specific researchcontents and results are as follows:(1)The Sentinel-1 data covering the new and old route of Qinglong section of the China-Myanmar Oil and Gas Pipeline is used,with a time span of about three years,including 33 scenes of ascending and descending data.The deformation rate results of the study area were obtained by using PS-InSAR and SBA-InSAR methods.Within the range of the old routing buffer zone,50 target areas were manually and interactively interpreted.Among them,through loading multi-period Google Earth images,it was found that there were 30 obvious surface change map spots and another 1 obvious natural landslide.Within the scope of the new routing buffer zone,26 target areas were manually and interactively interpreted,among which 11 obvious surface change map spots were found by loading multi-period Google Earth images.In general,the hidden dangers along the old road are significantly more than those along the new road,indicating that the geological environment along the old road is complex and the risk probability of geological disasters is high.Judging from the recognition results ofascending and descending data,the ascending data is slightly higher.InSAR surface deformation monitoring results from different orbits have good consistency.(2)Based on GF-1 image,DEM data and geological map data in the study area,the extraction of the slope,slope direction,formation lithology,geological structure,vegetation coverage,land use type,rivers,disaster influence factors such as the traffic network,the information method is adopted in the study area was carried out regional geological hazard risk assessment,reveal some regional spatial distribution of different risk level.Specific conclusions are as follows: from the comprehensive evaluation results of the new and old roads,the high and higher risk areas are mostly concentrated in the area with slope >45° and fault influence degree,and the distribution is obvious on both sides of the river.In terms of the statistical area,the areas with medium and above risk levels of new and old roads account for 55.27% and 62.67%,respectively,that is,the potential geological hazard risk of old roads on both sides is higher than that of new roads.From the risk segment of the pipeline itself,the proportion of higher-risk segments and high-risk segments in the old route is also higher than that of the new route.The geological hazard development in the study area is closely related to the geological environment.In general,the geological hazards in the study area show the characteristics of wide area,medium and above risk areas showing the zonal distribution.(3)In the early stage of the InSAR time-series analysis technology to identify hidden trouble,on the basis of geological disaster sites zoning map superposition of regional geological disaster evaluation,comparative analysis shows that the number of medium-risk areas decreases after comprehensive evaluation,andthe number of highrisk areas and higherrisk areas increased.After comprehensive evaluation,the number of medium and above risk areas of the old route was significantly greater than that of the new route;In the new routing buffer range,InSAR identified26 hidden troublepoints and the number of intermediate and above-risk areas after the comprehensive evaluation of InSAR survey results was 22,which was reduced by about 15%.The number of spots identified by InSARas potential hidden trouble points was 50,and the number of spots at medium or higher risk areas after comprehensive evaluation of InSAR census results was 32,witha decrease of about 36%.After the comprehensive evaluation of InSAR census results,the number of map spots used for field manual verification decreased significantly,and the average efficiency was estimated to be increased by about 15%~20%.To sum up,this paper further improves the accuracy of early-stage identification results through comprehensive evaluation,providing data support for later space-based detailed inspection and manual ground verification.This method is more scientific,improves efficiency,has practical operability,and has certain use value.