Inversion method for determining coal-rock interface section distribution position

A section and interface technology, which is applied in the direction of electric/magnetic detection, measuring device, earthwork drilling and mining for well logging records, can solve the problem of inability to meet the requirements of resistivity measurement accuracy and inability to realize coal-rock interface detection and inversion imaging and other problems, to achieve the effect of saving drilling operation cost, improving drilling efficiency and ensuring safe production

Active Publication Date: 2021-08-03
XIAN RES INST OF CHINA COAL TECH& ENG GROUP CORP
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Problems solved by technology

[0003] Aiming at the defects and deficiencies in the prior art, the present invention provides an inversion method for determining the distribution position of the coal-rock interface section, so as to solve the problem that the azimuth electromagnetic wave instrument while drilling cannot Meet the requirements of resistivity measurement accuracy and cannot realize the detection and inversion imaging of coal-rock interface

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  • Inversion method for determining coal-rock interface section distribution position
  • Inversion method for determining coal-rock interface section distribution position
  • Inversion method for determining coal-rock interface section distribution position

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Embodiment 1

[0057] In this embodiment, a two-layer stratum model is first established for simulation experiments. The upper layer of the two-layer stratum model is a coal seam with a resistivity of 1000Ω·m, and the lower layer is a floor mudstone stratum with a resistivity of 1Ω·m. Then, set the azimuth electromagnetic logging tool while drilling on the drill collar of the drilling rig to perform measurement while drilling. After the azimuth electromagnetic logging tool travels down through the coal seam until it is close to the bottom plate, it adjusts its trajectory and drills upwards, away from the bottom plate. In this embodiment, the drilling trajectory of the azimuth electromagnetic wave logging tool in the formation model while drilling is as follows: figure 2 As shown, the azimuth electromagnetic wave logging tool can measure data of different azimuths at different depths during the process of measurement while drilling.

[0058] This embodiment discloses an inversion method for...

Embodiment 2

[0114] In this embodiment, the distribution position of the coal-rock interface section of Huaibei Coal Mine is inverted, and the specific steps are the same as those in Embodiment 1.

[0115] The Huaibei Coal Mine in this example is a typical high gas outburst mining area in my country. The geological structure is complex and the gas disasters are serious. There have been many gas outburst and explosion accidents. Therefore, it is extremely necessary to carry out gas pre-extraction before coal mining. Underground rock tunnels are usually drilled through layers or horizontally drilled in coal tunnels for pre-extraction of gas. Due to the soft and low permeability of coal seams, the gas extraction volume of a single hole is low, and it takes a long time for the drainage to reach the standard, and the contradiction between mining and replacement is very prominent. At the initial stage, vertical fracturing vertical wells were used for surface coalbed methane extraction, which achi...

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Abstract

The invention discloses an inversion method for determining the coal-rock interface section distribution position, wherein the method comprises the steps: obtaining an induced electromotive force and a phase difference signal at any detection depth position of a target coal seam and the top / bottom plate of the target coal seam through a while-drilling azimuth electromagnetic wave logging instrument, and through the conversion of the induced electromotive force and the phase difference signal, carrying out two-dimensional imaging processing by utilizing an improved Newton algorithm based on Broyden to obtain a section resistivity distribution diagram of the target coal seam and the top / bottom plate of the target coal seam; and finally, carrying out resistivity boundary distribution difference processing on the obtained section resistivity distribution diagram of the target coal seam and the top / bottom plate of the target coal seam to obtain the coal-rock interface section distribution position. According to the method, advanced detection along the target coal seam is achieved in the early stage of coal seam mining and digging work, so that the ideal drilling track is determined, the drilling efficiency can be effectively improved, the drilling operation cost of enterprises is saved, and safe production is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of coal and coal bed gas mining detection, and in particular relates to an inversion method for determining the distribution position of a coal-rock interface profile. Background technique [0002] With the continuous advancement of science and technology, numerical simulation methods have been widely used in geophysics. On this basis, geophysicists have obtained many electromagnetic field simulation methods of classic geophysical models. Based on the electromagnetic field distribution data obtained by these methods, combined with the geoelectric model structure, the corresponding relationship between the electromagnetic field data and the stratum model can be established. In coal mining operations, the traditional method of calculating apparent resistivity using amplitude ratio and phase difference signals, As the resistivity of the target layer increases, the effectiveness of judging the interface distance...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V3/30G01V3/38E21B49/00
CPCG01V3/30G01V3/38E21B49/00Y02A90/30
Inventor 陈刚郝世俊李泉新陈龙张冀冠连杰
Owner XIAN RES INST OF CHINA COAL TECH& ENG GROUP CORP
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