公开(公告)号：AU630867B2

公开(公告)日：1992-11-12

申请号：AU2920089

申请日：1989-11-04

Applicant: THE STANDARD OIL COMPANY

Inventor： WESLEY N. COBB

IPC: E21B41/00 ,  E21B47/08 ,  G01N29/07 ,  G01N29/11 ,  G01N29/34 ,  G01N29/42 ,  G01N29/44 ,  G01N29/46 ,  G01S7/00 ,  G01S7/526 ,  G01S15/06 ,  G01S15/88

Abstract: An acoustic transducer (102) having a curved surface (102) to match the inner (108) or outer surfaces of a target surface (100) such as a cylindrical borehole tubular is disclosed. A sequence of excitation pulses causes the transducer to launch a series of high-frequency pulses (308) toward the tubular. The characteristics of the tubular surfaces, including the location, area and depth of any corrosion pits on the tubular surfaces, are determined from a full echo waveform. A rule-based Expert System analyzes the full waveform of the echo pulses returned from the tubular to determine the most likely characteristics of the surfaces which produce the full echo waveform. More specifically, the Expert System uses expertise about the acoustic properties of the target medium, as well as constraints chosen by an expert, to determine which signal structures are informational and which signal structures are confounding. The present invention also involves preprocessing and transmitting information. The present invention reduces the absolute amount of information that is transmitted without reducing the amount of meaningful information that is conveyed. The present invention transmits more meaningful information than conventional transmission systems. It also reduces the amount of information processing at the destination.