Method of calculating stratum true conductivity by using well axis electric field distribution

Abstract

The invention provides a method of calculating stratum true conductivity by using well axis electric field distribution, which is simple and effective. The electric field distribution is generated by a transmitting coil after gradual moving of devices, and apparent conductivity distribution is acquired by a plurality of receiving coils, and requirements under conventional technical conditions are satisfied. The method comprises steps that step 1, electric field intensity distribution is measured along a well axis in a wellbore; every time a well logging device moves to a field point, the corresponding electric field distribution is measured; step 2, the measured electric field intensity distribution is converted into an apparent conductivity function; step 3, the apparent conductivity function is used for wellbore correction; step 4, a correct function value is selected from apparent conductivity function values after the wellbore correction, and the stratum true conductivity is acquired. By adopting the brand new induced electric field well logging method principle, the stratum true conductivity is calculated, and therefore the method is simple, calculation efficiency is high, and accuracy is good.

Description

technical field [0001] The invention relates to the technical field of well logging, in particular to a method for calculating the true conductivity of formations by using the electric field distribution of the well axis. Background technique [0002] In the field of petroleum engineering, the true conductivity of the formation is an important physical parameter for identifying oil and gas layers. The actual formation is a heterogeneous medium, and the potential (true conductivity) cannot be obtained by directly solving Maxwell's equations. Therefore, an engineering quantity—the apparent conductivity—is introduced to describe its electrical characteristics. The apparent conductivity is considered to be the weighted average of the formation conductivity, and the weighting coefficient is considered to be a geometric factor that has nothing to do with the formation. For decades, a great deal of work has been done on the relationship between apparent and true conductivity. One...

AI Technical Summary

Problems solved by technology

However, it is no longer able to meet the needs of the current technical conditions. It is necessary to discuss the relationship between the induced electromotive force and the apparent conductivity from a deeper level, so as to establish the relationship between the apparent conductivity and the true conductivity.

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