Research On Some Methodological Issues Of Geophone Calibration

In this dissertation, some researches on several methodological issues of geophone calibration were made, which was associating with the project from China National Petroleum Corporation named as "Development of high-precision vibration calibration system".In chapter1, the purpose and significance of the dissertation were presented. First, the classification of geophones, their performance indicators and calibration methods were introduced. Second, the present research status of a geophone calibration system at home and abroad was given and its development trend was also pointed out. At last, the main research content and aim of the dissertation were emphasized.In chapter2, an automatic method for the geophone calibration system was proposed. The principle of calibration system’s automation and the hardware of the system were introduced, and the computer control methods of the instruments in the system were analyzed and designed, and the original vibration-level-adjustment algorithm was improved, and the development of an automatic calibration software was completed.In chapter3, a calibration method for the geophone’s magnitude-frequency and phase-frequency characteristics were studied. First, the dynamics model of a geophone was established. Then, the calibration methods of geophone’s magnitude-frequency and phase-frequency characteristic were introduced. Specially aimed at the phase-frequency characteristics, two methods were designed:the first one was the secondary method based on a standard sensor, and the other was the primary method based on the sine-approximation method.In chapter4, a detecting method for the geophone’s spurious frequency was studied. First, the generation mechanism of the geophone’s spurious frequency was analyzed. Then, a new detecting method named as transverse vibration compensation method was proposed based on the analysis of the shortage of existing detecting methods, and the details of the detecting principle and the software implementation were given.In chapter5, the multi-sine calibration method for a geophone was studied. First, the principle of the multi-sine calibration method was expounded. Secondly, the vibration-level-adjustment algorithm of the multi-sine calibration method was researched. Finally, the software for the multi-sine vibration calibration method was designed according to the proposed vibration-level-adjustment algorithm.In chapter6, experimental research of a calibration system for geophones was done. The adjustment efficiency and accuracy of the vibration-level for the automatic calibration system, the calibration and measuring methods mentioned in the dissertation, and other functional modules were mainly tested. The overall evaluation was given based on the analysis of the above experimental results.In chapter7, the achievements and future research work were put forwards.