Phase Induction Logging Two Scale System And Dfil Phase Difference Detection Algorithm

After over 70 years'development, electric logging has become an independent subject. Developed from the spontaneous potential logging, induction logging and array induction logging are popular today. But how to eliminate the influence of direct coupling signal is the hardest problem when using the induction logging tool and array induction logging tool. Based on induction logging, Phase induction logging is studied to avoid the above problem, which makes the apparatus's research and manufacturing easier.The Former Soviet Union started this research early in 1960's, had obtained many important fruits and had developed the commercial logging apparatus. Current the main array phase induction logging apparatus is the Russia's High Frequency Induction Isoparametric Logging ApparatusВИКИЗ. The domestic still have no this kind of apparatus. All the related apparatus need to been imported from Russia. But this kind of apparatus is very expensive and limits the usage scope at the same time. In order to change this passive situation, the Chinese Oilfield Services Limited began to cooperate with UESTC (the University of Electronic Science and Technology of China) in 2000 researching the theory and developing the phase induction logging apparatus. To 2005 had obtained many important results in the theory and had developed Array Phase Introduction Logging (APIL) prototype apparatus. Current the Dual-Frequency Introduction Logging (DFIL) project already enters the stage of whole apparatus function adjust.Developing the phase introduction logging faces two key problems namely calibration and phase difference measurement. This paper has researched that two problems deeply and has obtained many important results. The main contents as follows:1. Studied the ideal second class calibration system, having studied kinds of parameters of the calibration system and environment's influence on the phase difference measurement and have obtained many important results. Put forward an engineering calibration system, and obtained the phase difference--electric conductivity rate curve and analyze the system's error margin etc. important...