Vertical shaft and horizontal shaft joint ignition method in underground coal gasification mining

An underground gasification and horizontal well technology, applied in coal gasification, underground mining, special mining, etc., can solve the problems of small underground space, difficult ignition, long ignition time, etc., to save time, increase ignition success rate, and expand storage. volume effect

Active Publication Date: 2016-12-07
中嵘能源科技集团有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the small underground space in the initial stage of the common ignition method, it is difficult to ignite and the ignition time is long.

Method used

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  • Vertical shaft and horizontal shaft joint ignition method in underground coal gasification mining

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Effect test

Embodiment 1

[0018] A method for combined ignition of vertical wells and horizontal wells in underground coal gasification mining, comprising the following steps: Step 1. Carrying out coal field exploration, drilling vertical wells (2) and horizontal wells (1), and the horizontal well (1) is at the bottom of the coal seam (8) 65cm; step 2. Drill out a hole with a diameter of 85cm and a length of 2m at the expected ignition position with the drill bit. After reaming, the large hole is 25cm away from the underlying stratum; the connection between the wellbore and the coal seam (8) uses a perforating gun method of perforating; step 3. carry out high-pressure hydraulic fracturing to the coal seam (8), and the fracturing range is 12m; step 4. inject a weight ratio of 1:2 ammonium nitrate and chlorine 1 ton of mixture composed of potassium chloride is injected into 17000 square meters of air, and then 0.5 ton of oxalic acid is injected; step 5. after step 4 is completed, inject oxygen-enriched pi...

Embodiment 2

[0020] A method for combined ignition of vertical wells and horizontal wells in underground coal gasification mining, comprising the following steps: Step 1. Carrying out coal field exploration, drilling vertical wells (2) and horizontal wells (1), and the horizontal well (1) is at the bottom of the coal seam (8) 55cm place; Step 2. drill out a hole with a diameter of 80cm and a length of 2.5m at the expected ignition place with the drill bit. After the hole is expanded, the large hole is 22cm away from the lower overburden; the connection between the wellbore and the coal seam (8) adopts perforation Gun mode perforation; Step 3. Carry out high-pressure hydraulic fracturing to the coal seam (8), and the fracturing range is 11m; Step 4. Inject the ammonium nitrate and A mixture of 1.5 tons of potassium chloride is injected into 18,000 square meters of air, and then 0.6 tons of oxalic acid is injected; step 5. After step 4 is completed, inject oxygen-enriched pilot gas (4) into t...

Embodiment 3

[0022] A method for combined ignition of vertical wells and horizontal wells in underground coal gasification mining, comprising the following steps: Step 1. Carrying out coal field exploration, drilling vertical wells (2) and horizontal wells (1), and the horizontal well (1) is at the bottom of the coal seam (8) 70cm; step 2. Drill out a hole with a diameter of 85cm and a length of 3m at the expected ignition position with the drill bit. After reaming, the large hole is 30cm away from the underlying stratum; the connection between the wellbore and the coal seam (8) uses a perforating gun method perforation; step 3. carry out high-pressure hydraulic fracturing to the coal seam (8), and the fracturing range is 13m; step 4. inject the ammonium nitrate and chlorine 2 tons of the mixture of potassium chloride, then inject 20,000 square meters of air, and then inject 0.8 tons of oxalic acid; Step 5. After step 4 is completed, inject oxygen-rich pilot gas (4) into the coal seam (8) t...

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Abstract

The invention relates to a vertical shaft and horizontal shaft joint ignition method in underground coal gasification mining. In order to solve the problems that according to an existing ordinary ignition method, due to the fact that the initial underground space is small, ignition is difficult, and the ignition time is long, perforation and fracturing are conducted on a coal bed, and a mixed combustion improver and oxygen-rich ignition gas are added, so that the fracturing success rate is increased, ignition can be conducted effectively, the time is shortened, and the human cost is reduced.

Description

technical field [0001] The invention relates to a method for combined ignition of vertical wells and horizontal wells in underground coal gasification exploitation, belonging to the field of underground coal gasification. Background technique [0002] Underground Coal Gasification (UCG) is the combustion and gasification of underground coal in the coal seam to generate synthetic gas and transport it to the ground. As an energy or chemical raw material, it is especially suitable for coal seams that are unrecoverable or uneconomical by conventional methods, as well as secondary coal mines. or multiple retakes. The produced gas can be processed, transported through pipelines, or directly used for power generation or chemical synthesis. Underground coal gasification is a comprehensive energy production technology integrating multiple disciplines, involving a series of technologies such as geology, hydrology, drilling technology, ignition and combustion control technology, produ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/295
CPCE21B43/295
Inventor 邓惠荣
Owner 中嵘能源科技集团有限公司
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