| 摘要 |
FIELD: survey of boreholes or wells, particularly for geophysical and well-operation investigations, including that to be performed during well drilling. ^ SUBSTANCE: device is located in sub joined with self-contained downhole instrument and formed of diamagnetic material. Sub is divided into two zones by throttle. Device comprises body of diamagnetic material passing through central valve opening, measuring membrane arranged inside the body and provided with channels and with elastic compensators isolated from borehole liquid and taking up borehole liquid pressure in separate zones. Channels are filled with liquid not subjected to thermal expansion, for instance with organosilicone one. The membrane has resistive-strain sensors connected with intelligent electronic switch through sealed lead-in. Electronic switch is inserted in the device to switch-on power source of electronic downhole instrument circuit. Body of downhole instrument may be made of diamagnetic material. Compensators may be formed of oil-resistant rubber. Electronic switch may have measuring half-bridge with instrument amplifier, the first comparator, magnetoresistor with instrument amplifier, the second comparator, single-chip microprocessor and electronic switch. Method involves applying magnetic field of remote constant magnet to electronic switch having magnetic field sensor through instrument body before downhole instrument lowering into well; linking power source with electronic circuit; performing time delay necessary for overland downhole instrument testing; transferring electronic switch into standby state characterized by with minimum power inputs and disconnecting electronic circuit from power source by taking out remote constant magnet field. During downhole instrument operation power source is connected to electronic circuit by applying impulse of borehole liquid pressure change to electronic switch. ^ EFFECT: increased autonomy level of downbore instrument due to reduction of power inputs. ^ 5 cl, 1 dwg
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