Nuclear magnetic resonance imaging observing device and method in coal rock crack development process

Abstract

The invention discloses a nuclear magnetic resonance imaging observing device and method in a coal rock crack development process. The device comprises a nuclear magnetic resonance imaging analyzer and a rock core vacuum saturation instrument; the method provides a low-field magnetic resonance technology, namely a special nuclear magnetic resonance imaging analyzer with the magnetic field strength of lower than 1.0 Tesla is used for carrying out imaging analysis on a distribution condition of inner cracks of a rock coal sample; the sample is subjected to vacuum saturation water treatment and an image for reflecting a distribution condition of a rock core porosity is formed by signals generated by water in sample pores; an image resolution is higher and a recovery degree to an inner structure of the sample is better; and the method not only can accurately recover a pore environment inside the sample, but also can analyze and research a development process of sample cracks by means of repeatedly testing.

Description

technical field [0001] The invention relates to a nuclear magnetic resonance imaging technology, in particular to a method for observing the development process of coal-rock gaps using the low-field magnetic resonance imaging technology. Background technique [0002] In the field of coalbed methane development, the permeability of coal reservoirs is the key to determining the productivity and development effect of gas wells. Compared with rock types such as sandstone and carbonate rock, coal rocks are denser, have lower porosity, and have strong internal heterogeneity. The size of the coal permeability is mainly related to the degree of fracture development. Therefore, in the reservoir evaluation of coalbed methane exploration and development, the description and evaluation of fractures are very important. [0003] The traditional visual description methods of coal fractures mainly include: macroscopic description of mine coal wall, microscope and scanning electron microsc...

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Problems solved by technology

Optical methods such as microscopy and scanning electron microscopy have strict requirements on samples (generally, the sample size is about 1cm, and special sample preparation is required). These methods can only observe cracks below the microcentimeter level, and can only obtain plane information of cracks in the sample. The three-dimensional spatial distribution information of fractures cannot be obtained

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