Near-bit electromagnetic wave electrical resistivity and gamma logging instrument

Abstract

The invention discloses a near-bit electromagnetic wave electrical resistivity and gamma logging instrument. The near-bit electromagnetic wave electrical resistivity and gamma logging instrument comprises a transmitting section and a receiving section. The transmitting section comprises a gamma detector, a gravity sensor, a transmitting circuit unit, an electromagnetic wave transmitting device, and a transmitting antenna; and the receiving section comprises receiving antennas, a receiving circuit unit, logging-while-frilling electrical resistivity (EPR), and logging-while-frilling electromagnetic wave electrical resistivity (AER). An electromagnetic wave signal is subjected to power amplification and is transmitted and output by the transmitting antenna, the electromagnetic wave signal, output by the transmitting antenna and passing through underground well floors, is received by the two receiving antennas, andthe signal is subjected to differential amplification and pass filter, and is sent to a digital signal processing unit for processing after being converted into a digital signal; a gamma signal adopts wireless electromagnetic transmission and a drill collar is used as a medium to transmit an electric signal to complete short distance wireless transmission of information; near-bit gamma measurement can be provided, the distance to a drill bit is short, accurate measurementis achieved, and a reservoir boundary can be measured earlier.

Description

technical field [0001] The near-drill bit electromagnetic wave resistivity plus gamma logging instrument related to the present invention is a logging-while-drilling instrument and equipment applied to petroleum geological exploration, especially related to geographic space geosteering analysis, and specifically emits electromagnetic waves near the drill bit, so that The receiving antenna behind the screw can receive the signal, so as to perform long-distance phase difference and attenuation resistivity measurement. The distance between this product and the drill bit is close, so it can timely and accurately grasp formation information and optimize wellbore trajectory. At the same time, the near-drill gamma and resistivity measurements share the same transmitting antenna, which optimizes the structural design, improves the utilization rate of the instrument, and saves costs. Background technique [0002] At present, in drilling projects such as petroleum geological explorat...

AI Technical Summary

Problems solved by technology

[0005] 1. The detection radius is small, the farthest is only 2 to 3 meters, geosteering can only explain and analyze the formation information near the wellbore;

[0006] 2. Does not have azimuth characteristics

Unable to orient near formation boundaries in real time, unable to avoid entry into shale or other hard formations

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