基于GIS的冲积扇油气管道面流侵蚀危险性评价

GIS-based risk assessment on the surface flow erosion of oil and gas pipelines crossing alluvial fans

面流侵蚀是油气管道穿越冲积扇的重要地质灾害类型之一。为了评价面流侵蚀对油气管道危险性的大小,获取灾害点抗冲性、渗透性、休止角、水量、坡度、夹角6类指标因子,基于ArcGIS提供的CASE工具建立UML模型。利用该模型,建立冲积扇油气管道数据库,通过缓冲区分析、克里金插值法、叠加分析,对最终栅格图按照自然断点法分为5级,得到缓冲区的危险强度等级。分析结果与实际管道调查结果吻合较好,表明该方法可在冲积扇油气管道面流侵蚀研究中推广应用,从而为油气管道运营过程中的危险性评价提供一种新思路。

Surface flow erosion is one of the key geological disasters for oil and gas pipelines crossing alluvial fans. In this paper, the UML model was established using the CASE tool provided by ArcGIS to assess the risks of surface flow erosion to oil and gas pipelines crossing alluvial fans in respect of six index factors at hazard points, i.e., anti-scourability, permeability, angle of repose, water flow rate, slope, and angles between pipeline and channel. The database of oil and gas pipelines crossing alluvial fans was created by using this model. By means of buffer analysis, Kriging interpolation method and overlay analysis, the ultimate grid map was divided into five classes according to natural breakpoint method, and the risk level of the buffer was defined. The study results are consistent with actual pipeline conditions obtained through investigation. Therefore, this study provides a new idea for risk assessment on the surface flow erosion of oil and gas pipelines crossing alluvial fans.