Measurement Of Samples' Acoustic Velocity And Physical Simulation Of Acoustic Full Waveforms In A Scale Model Well

Acoustic well logging is one of the important well logging methods in oil well logging. It can be used to explore the site and the character of oil and gas by continuing record and instant acoustic source pulse which is excitated in the well and affected by formation . It is an important basis to make sure the attribute and parameter of the formation. The scale model well's full wavefoems measurement in the laboratory may to practice the the role of guidance. The physical model is small than the actual exploration well in size.Both of them need to meet a certain proportion of relations in order to achieve practical results and scale model well waveforms measurement result.According to physical modeling similarity theory,we manufacture scale model well for the purpose of simulating the actual logging.scale model well not only can be used to model the actual logging instrument calibration and can also be used to Forward Simulation Analysis. This has the vital significance to the actual oil well logging.Main work what I did is in experiment aspect, first step is surveied wave velocity of the samples by the instrument in the laboratory; further surveied and analysised full wave of semi-infinite media and horizontal layered medium;finally surveied the full waveforms in the scale well model. I did some numerical simulation also.According to the actual conditions of the laboratory, I selected parameter to simulates the well full waveforms.Compared the experimental measurement with the simulate full waveforms and got the conclusion. This paper work summarized as follows:When test on the samples,five samples were tested.We got the speed of compression wave and shear wave. The speed and the speed of known standard samples are in good agreement.Using different frequencies probing measure the velocity of the same samples, get a numerical differences. For aluminum and iron samples there is little different between the different frequencies probing;but for nylon and rock-33,there have significant differences. This difference may be due to sample dispersion,may also be caused by probes'differences in the structure.When using different frequency probing measure the sample,for the structure of the difference probing, the measuring results of the main frequency of 1MHz probing is always smaller than others'.We surveyed full waveforms of semi-infinite media and horizontal layered medium. Observing in the infinite hard medium,there are compression wave packet and shear wave packet,the compression wave packet is smaller. For an infinite soft medium, it's great Compression wave packets, and the share wave is immersed in the full waveforms. In the experiments of measure the full-wave in the scale model well wegot the following conclusion:in the hard formation circumstances, the Shear wave, Compression wave and the border reflection wave of the two wave can be seen clearly.Stoneley wave and the Pseudo-Rayleigh wave components also can be seen in the full waveforms. The obtained Compression wave velocity and the Shear wave speed in good agreement with the sample's velocity.In the soft formation circumstances, observing less than obvious shear wave components and there also have the border reflection wave.In the borehole experiment,we blocks the bore-hole with the cotton. In the soft formation circumstances the cotton. can effectively prevent Stoneley wave. but in hard formations there are still very strong Stoneley wave.According to both hard and soft formation scale model well parameter,I simulated full waveforms.The simulate full waveforms is in good agreement with the experimental measurement. In this paper,I have measured the laboratory sample sonic speed ,and have analysised the frequency dispersion of the sample;have surveyed full wave of the horizontal layered medium and have carried on the simple analysis; have measured the full-waveforms of scale model well,and done some numerical simulation by using Matlab software. Acoustic Laboratory building of jilin University still in the initial stage. May the building in the laboratory to grow and develop.