| 摘要 |
A method and apparatus is disclosed for performing measurement-while-drilling operations in a borehole to interrogate the borehole and the surrounding formation utilizing electromagnetic fields. A measurement sonde is provided which includes at least one of (a) a transmitting member for generating an interrogating electromagnetic field for passage through the borehole and surrounding formation, and (b) a receiving member for receiving an interrogating electromagnetic field after passage through said borehole and surrounding formation. A measurement tubular is provided, which includes a central bore which communicates with the central bore of the drillstring. The measurement tubular couples in the drillstring in a selected location, and permits interrogation of the borehole and surrounding formation with the interrogating electromagnetic fields generated by the measurement sonde. Preferably, the measurement tubular is formed at least partially of a non-conducting or poorly-conducting material which will allow the inward and outward passage of electromagnetic fields. The measurement sonde is secured within the central bore of the measurement tubular. Preferably, it is releasably secured therein, and can be run in and out of the wellbore during drilling operations without substantial interference with drilling operations.
|
