CN114876460B - Method for realizing fluidization exploitation by in-situ oxidative degradation of deep coal - Google Patents
Method for realizing fluidization exploitation by in-situ oxidative degradation of deep coal Download PDFInfo
- Publication number
- CN114876460B CN114876460B CN202210515325.8A CN202210515325A CN114876460B CN 114876460 B CN114876460 B CN 114876460B CN 202210515325 A CN202210515325 A CN 202210515325A CN 114876460 B CN114876460 B CN 114876460B
- Authority
- CN
- China
- Prior art keywords
- coal
- well
- fluidized
- liquid injection
- oxidant solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C41/00—Methods of underground or surface mining; Layouts therefor
- E21C41/16—Methods of underground mining; Layouts therefor
- E21C41/18—Methods of underground mining; Layouts therefor for brown or hard coal
Abstract
The invention belongs to the technical field of fluidized mining by in-situ oxidative degradation of coal, and provides a method for realizing fluidized mining by in-situ oxidative degradation of deep coal, which comprises the following steps: step 1, drilling two horizontal wells in a coal bed to be fluidicly exploited, wherein a liquid injection well is drilled above, and a exploiting well is drilled below; step 2, carrying out hydraulic fracturing on the coal bed between the liquid injection well and the exploitation well until the coal bed forms a fracture seepage channel; step 3, injecting an oxidant solution into the coal seam through the liquid injection well to enable the oxidant solution to generate an oxidation effect with the coal seam and generate a fluidization product; and 4, producing fluidized products from the production well. The invention provides a new thought of coal seam oxidation fluidization, which provides a reference for coal seam oxidation fluidization exploitation. The method has the advantages of mild applicable conditions, low equipment requirement, simple operation process and low economic cost.
Description
Technical Field
The invention belongs to the technical field of fluidized mining by in-situ oxidative degradation of coal, and particularly relates to a method for realizing fluidized mining by in-situ oxidative degradation of deep coal.
Background
Coal will still be the main energy and basic energy of our country in a quite long period in the future, but nearly 70% of coal resources of our country are distributed below 2000m, so deep coal resource exploitation is imperative. However, the mining depth of solid minerals cannot extend to deep infinitely according to the existing mining mode and the mining technology, and the conventional mining mode and the current technology are insufficient to support deep solid resource mining.
In order to solve the problem of extreme depth in the traditional coal exploitation mode and solve the problems of safety and environment in the deep coal resource exploitation process, a group of scholars propose the concept of deep coal resource in-situ fluidization exploitation. The fluidized exploitation refers to an exploitation technical system for converting deep solid mineral resources into fluidized resources such as gas, liquid or gas-solid-liquid mixed state in situ and realizing unmanned intelligent exploitation, selection, charging, thermoelectric conversion and the like under the well.
Common fluidization mining techniques such as: deep in-situ energy-induced physical crushing fluidization exploitation technology: deep high stress is utilized to induce deep coal to protrude to form mixed fluid substances such as particle flow, gas, liquid and the like by drilling and water jet rock breaking, so as to form particle size conforming to pipeline transmission, but harmful disturbance can be generated in the process of induced cracking; such as: the in-situ gasification technology for deep coal fluidization exploitation is an important way for deep coal in-situ fluidization exploitation, and the underground coal gasification can convert the coal into fuel gas to be output to the ground. However, the technology needs to establish a gasification bin in the goaf, and has higher gasification condition requirements, so that the exploitation cost can be increased.
In the above, the technical content of oxidizing coal in situ by injecting an oxidant into a coal bed and directly mining fluidized products is not related, and a fluidized mining method for in-situ oxidative degradation of deep coal is provided.
Disclosure of Invention
The invention aims to solve the problems recorded in the background technology and provides a method for realizing fluidized mining by in-situ oxidative degradation of deep coal.
In order to achieve the above purpose, the invention adopts the following technical scheme: a fluidized mining method for deep coal in-situ oxidative degradation comprises the following steps:
step 1, drilling two horizontal wells in a coal bed to be fluidicly exploited, wherein a liquid injection well is drilled above, and a exploiting well is drilled below;
step 2, carrying out hydraulic fracturing on the coal bed between the liquid injection well and the exploitation well until the coal bed forms a fracture seepage channel;
step 3, injecting an oxidant solution into the coal seam through the liquid injection well to enable the oxidant solution to generate an oxidation effect with the coal seam and generate a fluidization product;
and 4, producing fluidized products from the production well.
In a preferred embodiment of the present invention, in step 1, the coal seam is a low rank coal seam having a depth of burial of 500 to 800 m.
In a preferred embodiment of the present invention, in step 1, after the injection well is drilled, a first high pressure pump is installed at the wellhead of the injection well, a heating device and a second high pressure pump are installed in the well of the injection well, the first high pressure pump is communicated with the heating device, and the heating device is communicated with the second high pressure pump.
In a preferred embodiment of the present invention, in step 3, the first high pressure pump provides initial power to inject the oxidant solution into the heating device, the oxidant solution is heated to 40-200 ℃ by the electric heating device, and then the heated oxidant solution is injected into the coal seam by the second high pressure pump.
In a preferred embodiment of the present invention, in step 3, the oxidizing agent solution is formulated by dissolving a solid or liquid oxidizing agent having strong oxidizing property in water.
In a preferred embodiment of the invention, in step 3, the oxidizing agent solution comprises sodium hypochlorite in a mass concentration of 1 to 6% or 15 to 30% hydrogen peroxide and 6% acetic acid.
In a preferred embodiment of the present invention, in step 3, 6% acetic acid is injected into the coal seam, followed by 15-30% hydrogen peroxide, or 1-6% sodium hypochlorite is directly injected into the coal seam.
In a preferred embodiment of the invention, the oxidation time is from 1d to 7d.
In a preferred embodiment of the invention, in step 1, the pressure used for hydraulic fracturing is below 20MPa.
In a preferred embodiment of the invention, in step 4, the fluidized product is extracted and then further separated and refined to obtain the non-energy chemical product.
The principle and the beneficial effects of the invention are as follows: 1. the oxidant selected by the method can react with the aromatic structure in the coal to degrade the coal into water-soluble compounds (carboxylic acid and the like), so that the method is widely applicable to low-order coal seams with vitrinite reflectivity less than or equal to 0.65%.
2. Through the oxidation reaction of the oxidant and the coal body, at least 20% of solid carbon can be converted in situ, and the efficiency is high.
3. The method is combined with hydraulic fracturing, and partial oxidant solution in the injection well can be diffused to the periphery of the coal seam through the original fracture of the coal seam, the fracture generated by hydraulic fracturing and a spontaneous imbibition mode. The seepage velocity of the injected oxidant solution and the seepage velocity of the fluidized product can be improved, thereby improving the reaction rate.
4. The new thought of coal seam oxidation fluidization is provided, and a reference is provided for coal seam oxidation fluidization exploitation.
5. The method has the advantages of mild applicable conditions, low equipment requirement, simple operation process and low economic cost.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic diagram of a coal seam for realizing a fluidized mining method by in-situ oxidative degradation of deep coal.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
In the description of the present invention, it should be understood that the terms "longitudinal," "transverse," "vertical," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the invention and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and thus should not be construed as limiting the invention.
In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, mechanical or electrical, or may be in communication with each other between two elements, directly or indirectly through intermediaries, as would be understood by those skilled in the art, in view of the specific meaning of the terms described above.
The application provides a fluidized mining method for realizing in-situ oxidative degradation of deep coal, which comprises the following steps:
step 1, as shown in figure 1, according to geological features and the prior construction technology, two horizontal wells are drilled in a coal seam to be fluidicly exploited (the coal seam is a low-rank coal seam with the burial depth of 500-800 m), one of the horizontal wells is a liquid injection well positioned above the coal seam to be exploited, the other horizontal well is a fluidized product exploiting well positioned below the coal seam to be exploited, after the liquid injection well is drilled out, a first high-pressure pump is arranged at the wellhead of the liquid injection well, a heating device and a second high-pressure pump are arranged underground the liquid injection well, the first high-pressure pump is communicated with the heating device, and the heating device is communicated with the second high-pressure pump.
And 2, carrying out hydraulic fracturing on the coal bed between the liquid injection well and the exploitation well, wherein the pressure used for hydraulic fracturing is lower than 20MPa until a fracture seepage channel is formed in the coal bed.
And 3, injecting the oxidant solution into the heating device by providing initial power by the first high-pressure pump, heating to 40-200 ℃ by the heating device, and injecting the heated oxidant solution into the coal seam by the second high-pressure pump, so that the oxidant solution and the coal seam generate oxidation and generate fluidized products, wherein the oxidation time is 1-7 d in the embodiment. In this embodiment, the oxidizing agent solution is prepared by dissolving a solid or liquid oxidizing agent with strong oxidizing property in water, and in this embodiment, the oxidizing agent solution includes sodium hypochlorite with a mass concentration of 1-6% or hydrogen peroxide with a mass concentration of 15-30% and acetic acid with a mass concentration of 6%. When the method is specifically used for injection, 6% of acetic acid is injected into the coal seam, then 15-30% of hydrogen peroxide is injected into the coal seam, and the two solutions can generate peroxyacetic acid in the stratum, so that the peroxyacetic acid has higher oxidizing property than that of the hydrogen peroxide of 30% alone; the sodium hypochlorite with the concentration of 1-6% can be directly injected (the injection process is the working flow of the first high-pressure pump, the heating device and the second high-pressure pump). Part of the oxidizer solution in the injection well may diffuse around the coal seam by way of the original fractures of the coal seam, fractures created by hydraulic fracturing, and spontaneous imbibition.
In this example, the oxidative degradation process of coal is as follows:
sodium hypochlorite: heteroaromatics, some aromatics with electron withdrawing groups (such as carboxyl, nitro, carboxyl, etc.), can form resonance structures that stabilize carbanions and are susceptible to oxidation by sodium hypochlorite. Sodium hypochlorite is prone to attack carbon atoms containing acidic hydrogen, and these compounds form stable carbanions upon loss of hydrogen. Therefore, the phenol structure in the coal can generate chloro-compounds through a series of reactions such as chloro-substitution, hydrolysis, ring opening and the like; various aromatic ring-containing structures can be oxidized and opened to generate aromatic acid.
Hydrogen peroxide + acetic acid:
acetic acid is an organic reagent, can better dissolve organic matters in coal, contacts more oxidation active sites, and enables oxidative degradation to be more sufficient, so that hydrogen peroxide and acetic acid can be used together to decompose an aromatic ring structure. Therefore, in this embodiment, the oxidant solution adopts sodium hypochlorite or acetic acid and hydrogen peroxide, which is environment-friendly and does not damage the coal seam. The oxidant solution can react with aromatic structures in coal, so that the method is suitable for the oxidation fluidization of low-rank coal beds. The small-scale low-pressure hydraulic fracturing modification of the fluidized mining coal bed is performed before the injection of the oxidant solution, so that the seepage speed of the injected oxidant solution and the seepage speed of fluidized products are improved, and the reaction rate of the oxidant solution and the coal is improved (the contact area between the oxidant solution and the coal bed is enlarged by the fracturing of the coal bed, and the reaction rate is further improved).
And 4, exploiting the fluidized product through a exploitation well, and further separating and refining the fluidized product after exploitation, namely separating the oxidant solution, the fracturing fluid and the like remained in the fluidized product, and finally obtaining the non-energy chemical products with high added value such as carboxylic acid and the like.
In summary, the method comprises the steps of carrying out small-scale low-pressure fracturing transformation on the coal seam, forming a crack seepage channel between the liquid injection well and the exploitation well, then injecting an oxidant solution into the underground coal seam to act with coal, outputting the produced fluidized products, fine particles and an unreacted solution together from a shaft of the exploitation well to the ground, and further separating and refining to obtain non-energy chemical products with high added value such as carboxylic acid, thereby realizing non-energy utilization of deep coal.
According to the method, the oxidant solution injected into the coal seam is heated to the specified temperature through the underground heating device, the high temperature can improve the oxidation rate, and meanwhile, the oxidant can be suitable for coal seams with different buries.
Compared with the physical crushing fluidization exploitation technology and the deep coal fluidization exploitation in-situ gasification technology, the method has the advantages of mild field application conditions, low technical difficulty and the like, and is not limited by the geological structure conditions of the coal bed, the damage of the top and bottom plates or the surrounding rock of the roadway, the hardness of the coal body and the like.
Compared with a fluidization loop mining structure and method applicable to deep coal resources in the prior art 202010156902.X, the method has the advantages that how to fluidize coal is clarified, meanwhile, the setting of a transfer station is reduced, and the mining cost is reduced.
In the description of the present specification, reference to the terms "preferred implementation," "one embodiment," "some embodiments," "example," "a particular example" or "some examples" and the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.
Claims (5)
1. The method for realizing fluidized mining by in-situ oxidative degradation of deep coal is characterized by comprising the following steps of:
step 1, drilling two horizontal wells in a coal bed to be fluidicly exploited, wherein a liquid injection well is drilled above, and a exploiting well is drilled below; after a liquid injection well is drilled, a first high-pressure pump is arranged at a wellhead of the liquid injection well, a heating device and a second high-pressure pump are arranged in the well of the liquid injection well, the first high-pressure pump is communicated with the heating device, and the heating device is communicated with the second high-pressure pump;
step 2, carrying out hydraulic fracturing on the coal bed between the liquid injection well and the exploitation well until the coal bed forms a fracture seepage channel;
step 3, injecting an oxidant solution into the coal seam through the liquid injection well to enable the oxidant solution to generate an oxidation effect with the coal seam and generate a fluidization product; the first high-pressure pump provides initial power to inject the oxidant solution into the heating device, the oxidant solution is heated to 40-200 ℃ through the electric heating device, and the heated oxidant solution is injected into the coal seam through the second high-pressure pump; the oxidant solution is prepared by dissolving solid or liquid oxidant with strong oxidizing property in water; in the step 3, the oxidant solution comprises sodium hypochlorite with the mass concentration of 1-6% or hydrogen peroxide with the mass concentration of 15-30% and acetic acid with the mass concentration of 6%; or firstly injecting 6% acetic acid into the coal bed, then injecting 15-30% hydrogen peroxide into the coal bed, or directly injecting 1-6% sodium hypochlorite into the coal bed; the oxidizing agent is capable of reacting with aromatic structures in the coal to degrade the coal into carboxylic acids;
and 4, extracting fluidized products from the extraction well to finally obtain the carboxylic acid.
2. The method for realizing fluidized mining by in-situ oxidative degradation of deep coal as claimed in claim 1, wherein in the step 1, the coal seam is a low-rank coal seam with a burial depth of 500-800 m.
3. The method for achieving fluidized mining through in-situ oxidative degradation of deep coal as claimed in claim 2, wherein the oxidation time is 1d to 7d.
4. The method for realizing fluidized mining by in-situ oxidative degradation of deep coal as claimed in claim 1, wherein in the step 1, the pressure used for hydraulic fracturing is lower than 20MPa.
5. The method for realizing fluidized mining by in-situ oxidative degradation of deep coal according to claim 1, wherein in step 4, fluidized products are further separated and refined after mining, and non-energy chemical products are obtained.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210515325.8A CN114876460B (en) | 2022-05-12 | 2022-05-12 | Method for realizing fluidization exploitation by in-situ oxidative degradation of deep coal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210515325.8A CN114876460B (en) | 2022-05-12 | 2022-05-12 | Method for realizing fluidization exploitation by in-situ oxidative degradation of deep coal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114876460A CN114876460A (en) | 2022-08-09 |
| CN114876460B true CN114876460B (en) | 2023-06-23 |
Family
ID=82675754
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210515325.8A Active CN114876460B (en) | 2022-05-12 | 2022-05-12 | Method for realizing fluidization exploitation by in-situ oxidative degradation of deep coal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114876460B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0327060D0 (en) * | 2000-04-24 | 2003-12-24 | Shell Int Research | In situ recovery from a hydrocarbon containing formation |
| CN106753503A (en) * | 2016-12-03 | 2017-05-31 | 吉林大学 | A kind of method that oil shale in-situ catalytic oxidation extracts shale oil gas |
| CN110924919A (en) * | 2019-12-11 | 2020-03-27 | 中国矿业大学 | Method for increasing production of coal bed gas by waste heat in underground coal gasification process |
| CN113803048A (en) * | 2021-08-11 | 2021-12-17 | 太原理工大学 | Coal in-situ separation mining method based on pyrolysis |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5967233A (en) * | 1996-01-31 | 1999-10-19 | Vastar Resources, Inc. | Chemically induced stimulation of subterranean carbonaceous formations with aqueous oxidizing solutions |
| US8469099B2 (en) * | 2008-10-29 | 2013-06-25 | ACT Operating Company | Hydraulic fracturing of subterranean formations |
| US7770647B2 (en) * | 2008-10-29 | 2010-08-10 | ACT Operating Company | Hydraulic fracturing of subterranean formations |
| WO2011133218A1 (en) * | 2010-04-21 | 2011-10-27 | Ciris Energy, Inc. | Solubilization of carbonaceous materials and conversion to hydrocarbons and other useful products |
| US10081759B2 (en) * | 2012-10-09 | 2018-09-25 | Eric John Wernimont | Method, apparatus, and composition for increased recovery of hydrocarbons by paraffin and asphaltene control from reaction of fuels and selective oxidizers in the subterranean environment |
| US20140096958A1 (en) * | 2012-10-09 | 2014-04-10 | Eric John Wernimont | Method, apparatus and composition to increase recovery of hydrocarbons by reaction of selective oxidizers and fuels in the subterranean environment |
| CN107387052B (en) * | 2017-09-13 | 2019-05-28 | 吉林大学 | A kind of oil shale in-situ recovery method |
| US11125069B1 (en) * | 2021-01-19 | 2021-09-21 | Ergo Exergy Technologies Inc. | Underground coal gasification and associated systems and methods |
-
2022
- 2022-05-12 CN CN202210515325.8A patent/CN114876460B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0327060D0 (en) * | 2000-04-24 | 2003-12-24 | Shell Int Research | In situ recovery from a hydrocarbon containing formation |
| CN106753503A (en) * | 2016-12-03 | 2017-05-31 | 吉林大学 | A kind of method that oil shale in-situ catalytic oxidation extracts shale oil gas |
| CN110924919A (en) * | 2019-12-11 | 2020-03-27 | 中国矿业大学 | Method for increasing production of coal bed gas by waste heat in underground coal gasification process |
| CN113803048A (en) * | 2021-08-11 | 2021-12-17 | 太原理工大学 | Coal in-situ separation mining method based on pyrolysis |
Non-Patent Citations (1)
| Title |
|---|
| 褐煤非能源化利用研究进展;贾建波;杜贺贺;黄光许;刘全润;邢宝林;张传祥;郭红玉;潘结南;;现代化工(第06期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114876460A (en) | 2022-08-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103696747B (en) | A kind of oil shale in-situ extracts the method for shale oil gas | |
| CN110541695A (en) | Efficient oil extraction method for in-situ pyrolysis of oil-rich coal by superheated steam | |
| CN106753503A (en) | A kind of method that oil shale in-situ catalytic oxidation extracts shale oil gas | |
| CN101871339A (en) | Method for underground in-situ extraction of hydrocarbon compound in oil shale | |
| CN112392445B (en) | Combined exploitation system and method for hydrate reservoir and conventional oil and gas reservoir | |
| CN103232852A (en) | Method and process for extracting shale oil and gas by in-situ shaft fracturing chemical distillation of oil shale | |
| CN108756839B (en) | Oil shale heat insulation synergistic in-situ conversion method and system | |
| CN101333922A (en) | Fracturing process for removing breakdown fluid contamination | |
| CN113236212B (en) | Method for collaborative in-situ mining of oil shale and coal interbed | |
| CN113775376B (en) | In-situ pyrolysis and CO (carbon monoxide) of oil-rich coal 2 Geological storage integrated method | |
| CN112878978A (en) | Supercritical water fracturing synergistic hydrogen production method for underground coal gasification | |
| CN113605892B (en) | Associated abandoned mine multifunctional complementary system and application method | |
| CN114412434B (en) | Underground in-situ fluidized mining method for deep coal resources | |
| CN109424345A (en) | A kind of method of in-situ retorting oil shale | |
| CN203499663U (en) | Device for extracting shale oil and gas by virtue of fracturing and chemical dry distillation of oil shale in-situ horizontal wells | |
| CN114876460B (en) | Method for realizing fluidization exploitation by in-situ oxidative degradation of deep coal | |
| CN114876437A (en) | Coal bed in-situ hydrogen production method utilizing supercritical water | |
| CN114017032B (en) | Self-heating in-situ conversion development method for medium-low-maturity organic-rich shale | |
| CN113803048A (en) | Coal in-situ separation mining method based on pyrolysis | |
| CN113464103A (en) | In-situ cracking and modifying method for preparing nano catalyst under well | |
| CN114165281A (en) | Method for filling biomass solid/liquid energy-producing source gas in underground space of mine | |
| CN112727419B (en) | Method for exploiting oil and gas products by underground pyrolysis of thin and medium-thickness oil shale deposits | |
| CN113250666B (en) | Shallow heavy oil reservoir burning auxiliary steam huff and puff exploitation method | |
| CN114183115A (en) | Efficient natural gas hydrate exploitation system and method | |
| CN110259424B (en) | Method and device for extracting oil shale in situ |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |