Nitrogen electric heating method and system for in-situ pyrolysis of oil-rich coal

Abstract

The ivnention discloses a nitrogen electric heating method and system for in-situ pyrolysis of oil-rich coal. One end of a second gas pipeline is connected with a high-temperature and high-pressure nitrogen storage tank, the other end of the second gas pipeline extends into a heat injection well and sequentially penetrates through a heating cable heating structure and an electromagnetic induction heating structure, and the electromagnetic induction heating structure is connected with a variable-frequency power source device and a cooling system. The heating cable heating structure and the variable-frequency power source device and cooling system are respectively connected with a power source and a control system; high-temperature and high-pressure nitrogen enters the heat injection well through the second gas pipeline, and the second gas pipeline is heated through a heating structure; the heat injection well communicates with a mining well through a fracture, and the high-temperature and high-pressure nitrogen enters the fracture; mixed gas generated by heating of an oil-rich coal seam enters the mining well; and transmitting to an oil-gas comprehensive separation device through an oil-gas collection pipeline to obtain a series solution of the oil-rich coal seam. According to the nitrogen electric heating method and system for in-situ pyrolysis of the oil-rich coal, the efficiency of a heating system is improved, and the environmental adaptability of an underground heating device and the controllability of the heating temperature of the oil-rich coal seam are enhanced.

Description

technical field [0001] The invention belongs to the technical field of oil-rich coal oil and gas resources development, and in particular relates to a nitrogen electric heating method and system for in-situ pyrolysis of oil-rich coal. Background technique [0002] According to the grading of coal tar yield in the "Mineral Resources Industry Requirements Manual (2014 Revision)", the coal with a tar yield (Tar, d) of 7% to 12% is called oil-rich coal; the tar yield (Tar, d) is less than 7% coal is called oily coal; coal with tar yield (Tar, d) greater than 12% is called high oily coal. In a broad sense, coal with a tar yield (Tar,d) greater than 7% is called oil-rich coal. Oil-rich coal is not only a classification of coal tar yield, but also a special coal resource at present. In my country's coal reserves, oil-rich coal accounts for as high as 45%. Making full use of my country's oil-rich coal resources and increasing oil and gas supply channels is of great significance to...

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Problems solved by technology

[0007] In view of the current oil-rich coal in-situ pyrolysis utilization technology, there are relatively few heating schemes and methods for oil-rich coal seams, and some of the proposed methods do not consider the actual heating environment of oil-rich coal seams, which lack practicability

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