Polar plate of micro-disc type focused logging device

Abstract

The invention discloses a polar plate of a micro-disc type focused logging device. The polar plate comprises the polar plate and polar plate electrodes arranged on the plate surface of the polar plate, wherein the polar plate is in the shape of a rectangle, the two ends of the polar plate are in circular arc-shaped structures, and the polar plate electrodes comprise a main electrode A0 at the center of the plate surface of the polar plate, as well as an annular electrode M0 and an annular electrode A1 which are sequentially distributed on the periphery of the main electrode A0 from inside to outside; and two groups of semi-circular electrodes, namely a monitor electrode M1 and a monitor electrode M1', as well as monitor electrode M2 and a monitor electrode M2', are symmetrically distributed on the two sides of the annular electrode A1, the electrode distances from the monitor electrode M1, the monitor electrode M2', the monitor electrode M2 and the monitor electrode M1' to the main electrode A0 are equal, and after signals acquired by the two groups of the monitor electrodes are synthesized by a transformer, the two groups of the monitor electrodes controls the main current measurement. Since the electrodes of the novel polar plate are the two groups of the semi-circular type electrode structures and the overall dimension and the shape of the polar plate are further changed, the novel polar plate has the advantages of stable electric field, a large measurement dynamic range, high measurement precision, good layering capability and the like.

Description

technical field [0001] The invention relates to a novel micro-focus series logging instrument polar plate, in particular to a sensor-micro-disk focusing polar plate (MPFL) of a novel micro-disk focused logging tool. Background technique [0002] In the field of petroleum geological logging, it is currently the most effective logging interpretation method to judge the properties of oil, gas, and water in the formation by measuring the change of resistivity at different depths in the lateral direction (perpendicular to the well axis). The microsphere focusing series logging tool is the best method to measure the resistivity Rxo of the formation flushing zone at home and abroad. [0003] The original Microsphere Focused Logging tool plate was designed in 1983 with reference to the Microsphere Focused Logging (MSFL) tool of Schlumberger Company. After more than 20 years of use, the plate has the following problems: [0004] 1. The measurement curve of the plate electric field ...

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Problems solved by technology

Among them, the most important problem is: the plate size design is unreasonable, and the measurement main current phase changes greatly with the formation resistivity.

[0006] 2. The plate width is too large to be used in slim hole oil wells

In this way, although the width of the plate is reduced to 9cm, the detection depth of the small plate is also reduced by 40%. Since the method of microsphere focused logging requires a detection depth of 10-15cm, the newly developed microsphere focused small Due to the insufficient detection depth of the polar plate, it has not been widely used

[0009] 3. The old plate is not easy to combine with other logging tools

Practice has proved that reducing the width of the plate proportionally will greatly reduce the measurement performance of the instrument

Although the microcolumn focusing logging tool (MZFL) invented by Schlumberger Logging Company in the United States has narrowed the size of the plate, it has not been widely used because of the low resistivity (Rmc) of the mud cake.

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