A transient electromagnetic logging tool

Abstract

The invention relates to a transient electromagnetic well logging instrument, which comprises a casing, a circuit module arranged in the casing and an electromagnetic probe system connected with the circuit module. The circuit module is a DC power supply circuit composed of a DC power supply connected in turn to a power supply voltage stabilization module, a PWM modulation module, a high-power isolation transformer group and a power conversion module. The core is a digital signal processor, and the periphery is equipped with a communication bus, a power bus, and a control bus. And the main control circuit of the data bus. The electromagnetic probe system consists of a transmitting coil with a magnetic core and multiple receiving coils. The instrument realizes casing damage detection and effective measurement of formation resistivity of open hole and cased hole in a non-contact manner. The high-power transient excitation is realized through the built-in iron core of the coil, which improves the excitation intensity of the transient electromagnetic field; through the necessary calibration and processing of the measured original signal, the resistivity of the formation is finally obtained.

Description

technical field [0001] The invention relates to a transient electromagnetic well logging instrument, which belongs to the technical field of casing quality detection for open-hole and cased wells and special instruments for measuring the formation resistivity of open-hole and cased wells in petroleum well logging construction, in particular to a pair of casing It can effectively detect pipe damage, and can effectively measure the formation resistivity parameters of open hole and cased hole. Background technique [0002] In the process of petroleum exploration and development, the measurement of formation resistivity is an important parameter for evaluating oil saturation. Especially in cased wells, measuring formation resistivity is of great significance to understanding the distribution of remaining oil. In the prior art, the casing damage detection adopts the magnetic flux measurement method, the open hole resistivity logging has double induction, array induction and doub...

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Problems solved by technology

[0006] The purpose of the present invention is to propose a transient electromagnetic system that adapts to complex well conditions and improves logging resolution and detection depth in view of the harsh logging conditions in the prior art and the measurement results are greatly affected by the measurement conditions. Logging instrument

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