Method for extracting shale oil and high-calorific-value fuel gas by self-heating type underground dry distillation of oil shale

Abstract

The invention discloses a method for extracting shale oil and high-calorific-value fuel gas by self-heating type underground dry distillation of oil shale. The method has the advantages that the dry distillation is completed by the synergistic reaction of oxygen-enriched gas and water vapor and the oil shale, so that the pyrolysis reaction is promoted, the reaction of the oil shale is thorough, and the self-cracking dry distillation process is formed by the coupled heat release / heat absorption pyrolysis reaction; after the dry distillation is started, the required heat is mainly provided by the heat released by low-temperature oxidizing of fixed carbon produced by cracking of the oil shale, the remained fixed carbon is gasified into the fuel gas of H2, CO and the like, and the high-temperature sensible heat produced after the dry distillation reaction is also recycled; the problems of complicated oil and gas extraction systems by dry distillation of the oil shale, large management difficulty, low oil yield and the like are solved; and the operation is simple, the extraction cost is lower, the extraction efficiency and resource utilization rate are higher, the emission of three wastes is little, the environment benefit is obvious, and the like.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploitation, in particular to a method for extracting shale oil and high calorific value fuel gas from self-heating underground dry distillation oil shale. Background technique [0002] Oil shale is a kind of sedimentary rock containing combustible organic matter and high ash content (high inorganic matter content). The organic matter contained in it can be obtained by dry distillation to obtain shale oil similar to crude oil. As an unconventional fossil fuel resource, oil shale has huge global reserves. If converted into available shale oil, it is equivalent to 5.4 times the proven oil reserves. Therefore, oil shale is listed as one of the most important alternative energy sources in the 21st century. [0003] Because the organic matter of oil shale (mainly kerogen with macromolecular structure) is insoluble and infusible, it is difficult to extract with common solvents. Currently, thermoc...

AI Technical Summary

Problems solved by technology

[0004] However, the current underground technology is still difficult to obtain practical application

One of the main technical bottlenecks is that the organic matter in oil shale has a solid cross-linked macromolecular network structure, and it needs to be heated above 500°C to crack the organic matter into oil and gas products. However, heating and heating oil shale deposits underground extremely difficult to operate

At present, the in-situ heating technology is relatively mature with electric heating technology, which consumes a lot of energy.

At the same time, in the underground carbonization process, the carbon produced after the cracking of oil shale remains in the ground without application, which is a waste of resources because the carbon has a high calorific value

In addition, if the oil shale is directly heated to above 500°C with heat carrier gas, a large amount of heat carrier gas needs to be heated to above 650°C first. The high temperature heat carrier gas will cause secondary cracking and coking of oil and gas and reduce oil recovery. At the same time, a large amount of heat carrier gas is used to cause a large amount of gas at the outlet of carbonization, and the oil recovery system is huge. Because a small amount of oil gas is mixed in a large amount of heat carrier gas, the oil content ratio in the gas at the outlet of carbonization is diluted, which not only makes it difficult to condense and recover oil. Moreover, the low-content oil in a large amount of hot carrier gas cannot be recovered, which reduces the oil recovery rate. After the oil is condensed and collected, the non-condensable gas is mixed with a large amount of N 2 Waiting for non-combustible gases makes the calorific value of the gas products very low, and sometimes it cannot be ignited. It is necessary to build a gas generator to supplement the heat source for carbonization, which not only increases the initial investment, but also increases the operating cost. They are mixed together, so when condensing and collecting oil, the hot carrier gas must be condensed at the same time, which is equivalent to the operation of repeatedly heating up and condensing a large amount of hot carrier gas

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