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公开(公告)号：EP1470437A4
公开(公告)日：2007-01-24
申请号：EP02794324
申请日：2002-12-20
摘要： An acoustic tool that provides a programmable source waveform is disclosed. Numerous advantages may be achieved from the configurability of the source waveform. Notably, acoustic logs at multiple frequencies may be acquired with a single pass. The waveform may be frequency-adapted to maximize formation response and amplitude adapted for gain control. In one embodiment, the acoustic tool comprises: a controller, a digital-to-analog controller (DAC), an acoustic transducer, and a linear driver. The DAC converts a digital waveform from the controller into an analog waveform. The acoustic transducer converts an electrical signal into an acoustic signal. The linear driver receives the analog waveform from the DAC and responsively provides the electrical signal to the acoustic transducer. The electrical signal is proportional to the analog waveform. The tool may further include a memory for storing the digital waveform and/or software for generating the digital waveform.
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公开(公告)号：EP1177463A4
公开(公告)日：2006-08-02
申请号：EP00922079
申请日：2000-04-12
IPC分类号： G01V1/48
CPC分类号： G01V1/48
摘要： A method (Fig. 1) for creating a frequency or time domain semblance for use in conjunction with acoustic logging tools (100, 130, 140, 145). The frequency domain semblance (Fig. 2F) may be obtained by transforming an acoustic signal (150) received at multiple depths into the frequency domain, combining the received waveforms corresponding to the different depths, and expressing the result in a graph with slowness and frequency axes. Another aspect of the invention is the treatment of two or more time domain semblances (Fig. 2B) as probability density functions of the slowness for an acoustic signal. This enables the combination of time domain semblances from the same depth in the wellbore. Once combined the time domain semblances more accurately depict the slowness of an acoustic wave through the formation at the selected depth. In addition, a related self-adaptation method to compress the waveform data downhole for storage or transmission is also disclosed.
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公开(公告)号：EP1090269A4
公开(公告)日：2006-02-08
申请号：EP99931938
申请日：1999-06-25
CPC分类号： G01V1/52 , E21B44/00 , E21B47/02208 , E21B47/082 , G01B15/04 , G01B21/20
摘要： A method and apparatus are provided for estimating the cross-sectional shape and orientation of an earth borehole and the motion of a tool therein. The method and apparatus involve measuring the distance from the tool to the borehole wall at a plurality of locations around the periphery of the tool and fitting those measured distances to a predetermined shape function using a nonlinear parameter estimation technique to minimize the error between the estimated shape of the borehole and the measured distances. The method and apparatus may be used to estimate elliptical and higher order borehole shapes. Additionally, the method and apparatus may be used while drilling the borehole.
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