System and method for carrying out well logging by utilizing transient electromagnetic simulation signal

Abstract

The invention discloses a system and a method for carrying out well logging by utilizing a transient electromagnetic simulation signal; the system comprises three parts, i.e., a ground acquisition unit, a downhole measurement unit and a cable, wherein a ground power supply module in the ground acquisition unit is used for providing direct current (DC) or alternating current (AC) to a downhole circuit power supply in the downhole measurement unit as well as a ground synchronous processing module, a ground high-precision AD conversion circuit and a ground display storage module; the downhole circuit power supply is used for providing the current to a downhole transient electromagnetic excitation power supply for supplying power (large current) and providing the current to a downhole electronic circuit for supplying power (small current); a downhole transient electromagnetic excitation main power supply is used for providing the current to a power module. According to the system and the method, the resistivity of stratum outside a casing is obtained by continuously measuring the response of a transient electromagnetic field in a cased well, and a stratum resistivity curve needed by evaluation of remaining oil is obtained; the system and the method are not affected by contact, and are easy in construction and high in working efficiency.

Description

Technical field [0001] The invention relates to a special instrument for measuring resistivity of casing well formation and evaluating remaining oil in logging construction of petroleum engineering, in particular to a system and method for logging transient electromagnetic analog signals. Background technique [0002] In the process of oil development, in order to evaluate the remaining oil saturation of the formation, it is necessary to effectively measure the formation resistivity through the casing. That is, the resistivity of the formation outside the casing is measured inside the casing. Due to the influence of the high conductivity and magnetic permeability of the bushing, it is very difficult to realize the instrument regardless of whether it is DC or AC. The current method of measuring the resistivity of the casing through the casing is the direct current method. The electrode is pierced into the casing to supply power. It can only be measured at a fixed point, which is ...

AI Technical Summary

Problems solved by technology

Due to the high electrical conductivity and magnetic permeability of the casing, it is very difficult to implement the instrument regardless of the DC or AC method

The current method of measuring formation resistivity through casing is the direct current method. The electrode is connected to the casing to supply power. It can only be measured at a fixed point, which is greatly affected by contact, has high requirements on the borehole, is difficult to construct, and has a low logging success rate.

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