Modeling Technology Research Of Subsurface By GPR

In some areas, subsurface structure is complex, and the environment is harsh, which has brought a lot of difficulties to the seismic exploration and static correction. So the methods of surveying and modeling subsurface structure have become an increasingly hot topic in recent years, causing more and more people’s attention. The GPR is a new electromagnetic wave detection technology developed in recent years to determine the distribution of underground medium. Compared with the traditional geophysical methods, the GPR has many advantages, for example, its quick, convenient and simple operation, strong anti-interference and ground adaptability, and high detection resolution.Based on the micro-logging and small refraction method, methods of establishing near-surface model by GPR are developed. The specific processes are:(1) processing the GPR data;(2) layered formations on the basis of understanding the background of the work area;(3) using the micro-logging and small refraction method to conduct the calibration of the layered formations;(4) conducting time-depth conversion and getting the depth of each section;(5) conducting interpolation to finally get the depth model of the whole work area.Have reaserched on the relationship between the elastic wave’s velocity and the electromagnetic wave’s velocity. Based on the previous studies statistical regularity between resistivity and speed, the statistical formula was improved. We have obtained the relationship between elastic wave velocity and resistivity from the statistics of a certain area of xinjiang rock samples. Electromagnetic wave method is obtained by the basic theory of electromagnetic wave, Linking the elastic wave velocity and electromagnetic wave velocity.We have summarized the step of level calibration of micro logging, small refraction, and other existing data. The existing data such as micro logging, small refraction has advantages and disadvantages respectively, and the best way is combination of a variety of information, so that we can improve the accuracy of level calibration.By establishing the model, the time-depth conversion rule and method of GPR are summarized up, and programming.We have developed the software of GPR data processing and interpretation. The software mainly includes three modules: file processing, data processing and data interpretation. File processing module mainly includes the geological radar data reading and preservation; the data processing module mainly includes: removal of direct wave, filtering and gain; data interpretation module mainly includes: stratigraphic division, level calibration, and the time-depth conversion.Finally we use the written software to process and interpret the GPR data in Xinjiang Awa region, and then we map the depth model of the 1st and 2nd subsurface layer by surfer.