高分遥感影像在页岩气开发水土流失监测中的应用

Application of high-resolution remote sensing image to monitoring soil erosion in shale gas development

以人工观测为主的监测水土流失的传统方法,具有空间局限性高、时效性差、成本高、缺乏直观性、区域限制等缺点。为了克服上述缺点,基于高分遥感影像和区域水土流失强度监测模型,提出了一种可广泛应用于天然气开发过程水土流失动态监测的方法,并以四川省页岩气开发C项目区、Z项目区为研究对象,根据其土地利用、植被盖度、地形地貌和高分遥感影像等数据信息,采用土壤侵蚀综合因子法开展了较大尺度、多时序的水土流失分析和变化监测。研究结果表明:①2017年C、Z项目区的土壤侵蚀情况与2012年相比,侵蚀面积均整体减少,但占总土地面积的比例较小,侵蚀强度以轻度和中度为主;②油气田开采区域局部土地扰动增多,土壤侵蚀强度增大,水土流失严重;③水土流失的主要原因在于社会经济发展建设,次要原因是油气田生产建设相关活动。结论认为:①C、Z项目区的油气开发尚处于初期阶段,随着开发工作的推进,水土流失风险将增加,需高度重视水土流失防治工作;②高分遥感影像评估方法的准确度受土地利用、坡度、植被盖度、高分遥感影像分辨率等相关因子精度的影响和制约。

The traditional methods on monitoring water and soil conservancy are mainly based on manual observation, which have such disadvantages as high space limitation, poor timeliness, high cost, regional restriction, and a lack of intuition. In view of this, based on the high-resolution remote sensing image and the monitoring model for regional water and soil conservancy, a monitoring method, which can be widely applied to the oil & gas exploration and development process, was proposed to dynamically monitor the conditions of water–soil conservancy and ecological environment within the surrounding areas. Taking two shale-gas development project areas of C & Z in Sichuan Province as the research objects, we adopted a comprehensive factor method of soil erosion, according to the data of land use, vegetation coverage, topography and high-resolution remote sensing image in the research area, to carry out large-scale and multiple time series soil erosion analysis and change monitoring there. The monitoring results from the two project areas show that compared with 2012, the soil erosion area in 2017 both decreased and the erosion intensity was mainly mild and moderate;but in the exploitation areas, the regional land use disturbance and soil erosion intensity increased, and soil erosion was getting serious mainly due to social and economic development and construction, and activities related to production and construction of oil and gas fields. On this basis, we suggest that in the initial development stage of two project areas, great importance should be attached to the prevention and control of soil erosion. The accuracy of the high-resolution remote sensing image is restricted by such factors as land use area, slope, vegetation coverage, image resolution, etc. The monitoring results of the two project areas show that the technical method has good practicability, which can provide an effective monitoring technical means for the water and soil loss caused by the oil and gas exploration and development process.