Realization Of Dipole Array Acoustic Logging System And Research On Detection Algorithm

With the development of petroleum exploration in China, Simple oil formation has almost been over explored. Therefore it requires advanced technology and equipment to measure and explore the characteristics of formation. Meanwhile, multinational logging corporations make severe control on the exportation of high-tech equipment to restrain the development of petroleum exploration of China. With the success in developing the SL-6000 high-definition multi-task surface system, it is urgent to develop digital equipment to improve the competition in the market strengths. So we have developed the Dipole Array Acoustic Logging instrument upon consignation of China Petroleum and Chemical Corporation .See details as following:Firstly, based on the principle prototype, the effective measures are taken to make the instrument work reliably. In order to connect it with the 6000 surface system and the 5700 surface system, the communication protocol, the data format and the parameter have been integrated to satisfy the requirements of the data transmission protocol of the WTS. After having debugged on the spot, the instrument can satisfy the requirement of 5700 surface system entirely.The regular detection method of first arrival often produces the error in measuring, specially, it may lost the first arrival because of the error. The detection of the first arrival is realized through the correlation of the array signal and the processing of signal in Time-Frequency. The result of the simulating shows that the way given in this paper was more reasonable compared with utilizing noise door limit law.Because the sampling frequency of logging system is different in different logging mode, the digital signal processing method of multirate sampling is adopted in this paper. The system samples signal with the unified sampling frequency, then obtains desirable frequency through decimation, on one hand, it simplifies the designing of the instrument ,improve SNR performance and the university of system; on the other hand, it raises the transmission efficiency by compressing . the surface system recovers the primitive signal through interpolation.Lastly, We not only realizes software design and programming of the whole instrument including module communication and each module's functions on the basis of clearly understanding of the communication protocol, the formation of data and the meaning of the parameter, but also successfully realizes the co-validation of Atlas5700 surface system and its basic functions. The result showes that the system work as expected and reliably.