23 results about "Coal matrix" patented technology

The invention relates to the field of coal seam anti-reflection, and particularly discloses a coal seam carbon dioxide and static expanding agent synergistic anti-reflection system and method. Slurry prepared by mixing a static expanding agent and water is injected into the expansion fracturing drill hole, in the process that the static expanding agent is subjected to hydration reaction and generates expansion stress, carbon dioxide gas is injected into the expansion fracturing drill hole through the carbon dioxide gas injection pipe, carbon dioxide and the hydration product of the static expanding agent are subjected to carbonization reaction to generate larger expansion stress, and the expansion fracturing drill hole is formed. Expanding the coal body fractures to form expansion fractures; the carbon dioxide is driven by differential pressure to seep into a coal matrix along expansion fractures, and adsorbed gas is driven to be desorbed into a free state through a competitive adsorption effect; and under the combined action of extraction negative pressure and carbon dioxide displacement, the free-state gas moves from the fracture channel to the extraction drill hole, and extraction is conducted through the gas extraction system. Carbon dioxide and the static expanding agent cooperate to improve permeability of the coal body, the displacement effect of carbon dioxide on gas is promoted, and the gas extraction effect is improved.

The invention discloses a method for enhancing coalbed methane recovery efficiency by an external magnetic field, which comprises the following steps of: arranging a plurality of electrified coils or magnetic field generators connected with a power supply in a coalbed to generate an alternating magnetic field in the coalbed; cH4 molecules show diamagnetism under the action of a magnetic field, a repulsive effect is generated in a coal seam, and the adsorption effect of CH4 and a coal body is weakened; and on the other hand, as the coal body contains ferromagnetic or paramagnetic minerals, the alternating magnetic field excites the annular eddy current in the coal body through electromagnetic induction so as to generate Joule heat. Therefore, coal matrix expansion and microfracture expansion can be induced by temperature rise of the coal body, the permeability of the coal body is further improved, and more channels are provided for CH4 desorption and flowing; the clean, efficient and environment-friendly coal bed gas exploitation method is provided on the basis of superposition of multiple production increasing mechanisms, and a new technical approach is provided for exploration and development of unconventional oil and gas resources.

The invention provides a gas occurrence dynamic response modeling method based on coal matrix surface multi-parameter coupling, which mainly comprises the following steps: (1) collecting a coal sample, and then processing and preprocessing the coal sample; (2) carrying out micro-scale surface parameter detection on the processed and pretreated coal sample; (3) performing coupling model construction and parameter calibration on the detected coal sample; and (4) carrying out model verification and comparative analysis on the constructed coupling model. Quantitative correlation of microscopic surface property evolution and macroscopic adsorption behaviors in the gas occurrence process is achieved for the first time, the prediction error is improved by 2-3 times compared with the prediction precision of a traditional single-parameter model, and theoretical support can be provided for efficient development of coal bed gas.

The invention discloses a soft coal seam nanofluid fracturing propping material and a preparation method thereof.The soft coal seam nanofluid fracturing propping material is prepared from, by weight, 80-90% of a base material, 1-5% of a super-hydrophobic coating, 5-10% of a catalytic active component and 5-15% of a rheological enhancer, the base material is a compound of high-purity silicon dioxide nanoparticles and graphene nanosheets GNP, the particle size of the high-purity silicon dioxide nanoparticles is 50-200 nm, the super-hydrophobic coating is a fluorosilane modified layer, the thickness of the super-hydrophobic coating is 5-20 nm, and the invention relates to the technical field of coal bed gas exploitation. According to the soft coal seam nanofluid fracturing propping material and the preparation method thereof, the surface of the material is provided with a super-hydrophobic coating, friction force with a coal matrix is reduced, high embedding resistance is achieved, the flow conductivity is specifically enhanced, an extra flow channel is provided through a porous nanostructure, the fracturing fluid permeability is improved, and meanwhile gas desorption can be cooperated; catalytic active sites are introduced to the surface of the material to promote adsorption and diffusion of methane molecules.

The invention discloses a low-cost and green phosphorus coal composite negative electrode material and a preparation method thereof. The preparation method specifically comprises the following steps: pretreating phosphate ore and raw coal; mixing the phosphate ore powder with the raw coal powder to obtain a phosphorus-coal mixed precursor; feeding the phosphorus-coal mixed precursor into a fluidized bed reactor for reaction to generate mixed gas; introducing the mixed gas into a cyclone separator, and separating solid particle impurities; the phosphorus steam is converted into liquid phosphorus, residual phosphorus steam and other impurities are adsorbed, and primary separation of the phosphorus steam from CO and H2 is achieved; and mixing phosphorus steam and H2, introducing the mixture into a CVD reactor, adding the high-specific-surface coal matrix, carrying out a reaction, and carrying out washing and drying. According to the phosphorus-carbon composite material disclosed by the invention, phosphorus steam is uniformly deposited on the surface and pores of a high-specific-surface coal matrix; the porous structure of the high-specific-surface coal matrix provides an expansion buffer space for phosphorus, and meanwhile, part of phosphorus and oxygen-containing functional groups on the carbon surface form chemical bonds, so that the interface bonding strength is enhanced.

The application discloses an interface activity buffer additive and a pulverized coal deliming method, and a gradient proportioning composite acid system of nitric acid-hydrochloric acid-hydrofluoric acid is used in cooperation with an interface activity buffer additive (containing a specific zwitterionic betaine derivative and a citric acid buffer pair) to construct a H+ concentration gradient microenvironment on the surface of coal particles, target dissolution of ash minerals in a high concentration area, and protection of coal matrix in a low concentration area. The deliming rate is greater than 98%, acid consumption is reduced by 35%, and waste liquid is easy to handle up to the standard. The application solves the industry problems of poor selectivity, great coal damage and heavy secondary pollution of traditional pickling, and provides key technical support for efficient and clean utilization of high-ash coal.

The present application provides a kind of quantitative evaluation shale, coal matrix free gas conduction ability test method, for the limitation of existing coal matrix diffusion coefficient test method, this method uses raw coal as experimental object, by monitoring the dynamic deformation evolution characteristics of coal matrix system in gas injection process, combined with the coal matrix effective diffusion coefficient model based on dynamic strain constructed, the diffusion coefficient of different characteristic directions of coal matrix system is back calculated, so as to achieve the goal of quickly and accurately testing the anisotropy of coal matrix system free gas diffusion coefficient.This method can simultaneously achieve the goal of testing the anisotropy of raw coal sample free gas diffusion coefficient, so as to provide more accurate reservoir physical parameter for the free gas migration characteristics in coalbed methane, shale gas exploitation, and provide reference basis for later reservoir reconstruction and development.

The present invention discloses a gas injection permeability enhancement and low-permeability coal seam gas extraction system, comprising a gas injection and sealing assembly, a drainage and sealing assembly, a pressurizing assembly, a gas injection assembly, and a drainage assembly. The low-permeability coal seam is provided with a gas injection hole and a drainage hole, a gas injection screen is provided in the gas injection hole, one end of the gas injection screen is connected to the gas injection pipe, the other end of the gas injection pipe is provided with a gas injection pipeline and a drainage assembly in parallel, the other end of the gas injection pipeline is provided with a pressurizing assembly, the other end of the pressurizing assembly is connected to the gas injection assembly via a first pipeline, and the gas injection and sealing assembly is used to achieve sealing of the gas injection hole after the gas injection screen is placed. A gas injection and permeability enhancement and gas extraction method for low-permeability coal seam gas extraction is also disclosed. The system can effectively increase the internal gas pressure of the coal body, increase the spacing between cracks, and accelerate gas desorption within the matrix by utilizing the adsorption differences of different gases by the coal matrix, providing sufficient power and a reliable channel for gas migration within the coal seam, thereby ensuring efficient gas extraction.

The invention discloses a VTI medium-based coalbed methane reservoir rock physical modeling method and system, and belongs to the technical field of unconventional oil and gas resource exploration, and the method comprises the following steps: determining mineral components and content of a coal matrix, and calculating an equivalent stiffness coefficient of the coal matrix by using an anisotropic self-consistent model; adding the adsorbed gas into the coal matrix, and calculating an equivalent stiffness coefficient of the coal matrix containing the adsorbed gas; determining components and contents of brittle minerals, adding the brittle minerals into the adsorption gas-containing coal matrix, and calculating an equivalent stiffness coefficient of a coal matrix dry skeleton; adding pores and fractures into the coal matrix dry skeleton, and calculating an equivalent stiffness coefficient of the pore and fracture-containing coal matrix dry skeleton; free gas is added into the pore-fissure-containing coal matrix dry skeleton, and the equivalent stiffness coefficient of the coal bed gas reservoir is calculated; and calculating the longitudinal wave velocity, the transverse wave velocity, the density and the Thomsen anisotropy parameter of the coalbed methane reservoir rock based on the modeling result. The method can improve the prediction precision, and provides theoretical guidance for seismic inversion.

The invention discloses a method and a device for fixed-point modification of a coal adsorption position based on infrared detection-pulsed nanoparticles, and relates to the technical field of coal mine safety engineering. According to the method, infrared is used for detecting the surface of a coal sample, an adsorption potential distribution diagram is drawn through emissivity data, and a high / low-density area is identified. The nanoparticles-containing foams are directionally delivered to a target area according to a modification target (enhancing or weakening adsorbability), and enrichment is guided by means of a magnetic field. Then, laser irradiation is adopted to enable the coal matrix to be heated in a transient state, and fixed-point transformation of the adsorption site is achieved. Finally, the effect change is verified through infrared scanning and methane adsorption testing. According to the method, fixed-point weakening and enhancement of the adsorption position can be achieved, and a new technical approach is provided for improving the coal bed gas exploitation efficiency and reducing the coal and gas outburst risk.

The invention discloses a porous coal surface in-situ growth amine modified copper oxide composite material as well as preparation and application thereof. The composite material takes coal as a raw material and comprises the following steps: firstly, converting pulverized coal into a porous coal matrix through a high-temperature activation process; then jointly adding the porous coal and copper salt into a mixed solvent of water and ethanol, and stirring to realize full dispersion; sequentially adding sodium hydroxide and an amine compound into the system, and continuously stirring to complete precursor regulation and control; then raising the temperature of the reaction system to 60-90 DEG C, keeping the temperature and stirring for 2-4 hours to promote complete reaction, and finally performing centrifugal separation, washing purification and drying treatment to obtain the target amine modified copper oxide / coal-based composite material. According to the prepared coal-based composite material, the surface of the coal matrix is uniformly covered with a large number of amine modified copper oxide active components, and the structure can provide rich active sites for a carbon dioxide reduction reaction. Based on the characteristics, the composite material shows excellent performance in a reaction for preparing ethylene through electrocatalytic reduction of carbon dioxide, the maximum Faraday efficiency of ethylene can reach 70.4%, the maximum current density can reach 342.3 mA / cm < 2 >, and the overall electrochemical performance is remarkably superior to that of a traditional material.

The invention discloses a broken soft coal seam roof pressure-injection synergetic permeability-increasing extraction and carbon sequestration method, which is characterized in that horizontal long drill holes are arranged in a broken soft coal seam roof, comb-shaped drill hole branches for hydraulic fracturing are arranged at intervals, and the branches face the direction of a coal-rock interface. A 1 # pressure-injection pipe extends into the first drill hole branch, and hydraulic fracturing and gas extraction are conducted in sequence; after the gas extraction concentration in the first drill hole branch is reduced and gradually tends to be stable, the second pressure-injection pipe extends into the second drill hole branch to conduct hydraulic fracturing and gas extraction as well; cO2 is injected into the first drill hole branch through a 1 # pressure-injection pipe to displace coal seam gas, then plugging liquid is used for conducting interface modification on a coal matrix, and the carbon sequestration target that gas is sealed through liquid is achieved; and by parity of reasoning, fracturing, extraction, gas injection and plugging operations are carried out by adopting an alternate method. Based on the method, the gas extraction effect is remarkably improved, and the stability and reliability of carbon sequestration are improved.

The invention provides a test method for quantitatively evaluating the conductivity of free gas in shale and coal matrix, aiming at the limitation of the existing coal matrix diffusion coefficient test method, the method adopts raw coal as an experimental object, and the conductivity of the free gas in the shale and coal matrix is evaluated by monitoring the dynamic deformation evolution characteristics of a coal matrix system in the gas injection process. And reversely deducing the diffusion coefficients of the coal matrix system in different characteristic directions in combination with a constructed coal matrix effective diffusion coefficient model based on dynamic strain, thereby achieving the target of rapidly and accurately testing the anisotropy of the free gas diffusion coefficient of the coal matrix system. According to the method, the target of testing the anisotropy of the free gas diffusion coefficient of the raw coal sample can be achieved at the same time, more accurate reservoir physical property parameters are provided for free gas migration characteristics in coal bed gas and shale gas exploitation, and a reference basis is provided for later reservoir transformation and development.

The invention relates to the field of gas layer resource evaluation, and provides a deep coal bed gas adsorption state proportion calculation method and system.The method comprises the steps that a coal matrix wall surface molecular model and a coal bed gas molecular model are established, molecular dynamics simulation is conducted on coal bed gas molecules and the coal matrix wall surface molecular model on the basis of the adsorption molecular model, and the coal bed gas adsorption state proportion is calculated. The method comprises the following steps: carrying out statistical analysis on a coalbed methane adsorption equilibrium track through density distribution calculation, fitting coalbed methane adsorption quantities under different pressures, fitting free coalbed methane physical property parameters through NIST database query, and calculating the free-state density of the coalbed methane according to a coalbed methane isothermal adsorption curve and a coalbed methane free-state density equation. And calculating the mass of the adsorption-state coal bed gas and the mass of the free-state coal bed gas to obtain the adsorption-state proportion of the coal bed gas. The precision and efficiency of the absolute adsorption quantity of the deep coal bed gas on the surface of the coal rock are improved.

The invention belongs to the field of clean utilization of coal, and particularly discloses an electric field enhanced hydrothermal treatment method and system for high-alkali coal, and the method specifically comprises the following steps: mixing high-alkali coal to be treated with water to form coal slurry; performing hydro-thermal treatment on the coal slurry and applying a directional electric field at the same time, so that a water-soluble alkali metal compound of the high-alkali coal to be treated is dissolved and ionized to generate alkaline cations, and the alkaline cations are directionally migrated to a cathode under the action of a direct-current electric field and further separated from a coal matrix; and carrying out solid-liquid separation on the coal slurry subjected to hydrothermal treatment, and drying to obtain the low-alkali coal. According to the method, water-soluble alkali metal compounds in coal can be ionized, alkaline cations are directionally migrated to a cathode under the action of a direct-current electric field so as to be separated from a coal matrix, meanwhile, water molecules and organic matters in the coal are polarized through an alternating electric field, the porosity of the coal matrix is increased, alkali metal is promoted to be separated out, and the coal yield is increased. Therefore, the alkali metal in the high-alkali coal is efficiently removed under the condition that no chemical agent needs to be added.

Strictly controlling methane concentration is a crucial measure in coal mining projects. Due to the low efficiency of direct extraction, complete recovery of methane resources is difficult. Triaxial compression tests are performed on samples taken from target coal seams to determine the compressive strength and determine the injection pressure for high-temperature steam and liquid carbon dioxide. The coal seams are then perforated with an insertion-type perforating gun, allowing the injected high-temperature steam and liquid carbon dioxide to penetrate deeply into the coal seams. The injection rate of high-temperature steam is controlled by a methane concentration monitor, while the injection rate of liquid carbon dioxide is determined based on the Langmuir adsorption isotherm. High-temperature steam, liquid carbon dioxide, and the resulting thermal expansion and contraction reactions of these two factors increase the number of fractures in the coal seam. Furthermore, these factors promote the desorption of methane adsorbed in the coal matrix and its release into fractures and pores, making it easier for methane to be displaced, maximizing methane displacement and collection, and preventing gas explosions in coal mining projects.

The invention relates to the technical field of coal bed gas development, in particular to a mercury injection experiment data correction method based on apparent density and true density of coal. The invention relates to a coal apparent density and true density-based mercury injection experimental data correction method, which comprises the following steps of: identifying and correcting a pressure interval by adopting a consistent volume and intrusive volume identification method, and determining actual initial mercury injection pressure and closing pressure; the consistency effect stage is that the mercury injection pressure is smaller than or equal to the actual initial mercury injection pressure, the compression effect stage is that the mercury injection pressure is larger than or equal to the closing pressure, and only mercury injection experiment data of the consistency effect stage and the compression effect stage are corrected, and in the consistency effect stage, the corrected mercury injection experiment pore volume is equal to 0; and in the compression effect stage, the corrected stage pore volume is equal to the apparent mercury feeding amount-the coal matrix volume compression amount-the mercury volume compression amount. The method is simple in parameter value taking and operation, accurate and reliable in correction result and capable of providing reference for accurate characterization of the coal pore structure.

The invention discloses a coal seam gas control method based on hydrothermal activation type adsorption capsules, and belongs to the technical field of coal mine gas control and coal seam gas extraction. Comprising the following steps: preparing a hydrothermal activation type adsorption capsule from a double-layer capsule outer membrane and an adsorbent complex, and designing the shell wall thickness of a capsule inner membrane according to target activation time and the dissolution rate of a shell material; the adsorption capsule is delivered to the target coal seam hole section in a delivery mode; underground water in a target coal seam permeates and dissolves the capsule outer membrane and the capsule inner membrane, so that a large number of water molecules and CaO particles are subjected to a violent exothermic reaction to release heat, and a large number of methane molecules in an adsorption state are driven to be desorbed from a coal matrix; desorbed high-concentration methane molecules are rapidly captured and fixed through active carbon particles. According to the method, accurate targeted treatment of the gas is achieved by accurately feeding the adsorption capsules, the desorption rate and the total amount of the gas are remarkably increased through a CaO particle exothermic reaction, and passive adsorption is changed into active displacement-adsorption.

The invention relates to a method for removing sulfur in lignite by adopting DMF (Dimethyl Formamide) swelling. The problems that an existing coal desulfurization technology is high in cost and energy consumption and complex in process or the desulfurization rate needs to be improved can be solved. According to the method, DMF is used as an efficient swelling solvent, molecules of DMF permeate into a three-dimensional macromolecular network structure of lignite, interaction force (such as hydrogen bonds) among the molecules is weakened, the coal body is expanded, and a pore structure is opened, so that sulfur-containing minerals (especially inorganic sulfur) wrapped in a coal matrix are exposed; then, under the conditions of heating and stirring, sulfur removal is promoted. The method comprises the following steps: mixing a pretreated lignite sample with DMF (Dimethyl Formamide) according to a specific mass ratio, carrying out swelling desulfurization treatment under heating and condensation reflux conditions, and finally carrying out solid-liquid separation to obtain desulfurized coal. The method is easy to operate, mild in condition and low in cost and energy consumption, the highest removal rate of sulfur in the lignite can reach 83.05%, and remarkable economic and environmental benefits are achieved.

The invention relates to the technical field of coal sample bound water determination, in particular to a coal sample bound water sample preparation device and a nuclear magnetic detection method thereof.The coal sample bound water sample preparation device comprises a sample cup used for containing a coal sample needing sample preparation, and valves are arranged at the upper end and the lower end of the sample cup; the sample cup lower end valve is connected with an air source and a water injection pump through a three-way valve, and pressure detectors are arranged on the air source and the water injection pump; the sample cup upper end valve is connected with a vacuum pump and a back-pressure valve through a three-way valve, and the back-pressure valve is connected with a back-pressure pump through a pipeline. By arranging the sample preparation device, related treatment and processing are carried out on a rock sample, a related calculation mode is established by utilizing bound water of the rock sample, and by virtue of detection of the sample preparation device and the nuclear magnetic detector, the rock sample can be accurately detected; therefore, the bound water content of the coal matrix pore fracture can be comprehensively tested without damage.

The invention belongs to the technical field of oil-gas field development and unconventional natural gas extraction, and discloses a deep coal seam in-situ pore wettability characterization method based on molecular simulation. The method comprises the following steps: screening a coal macromolecular structure model, and constructing a deep coal seam coal matrix model by adopting a coal molecular structure unit; constructing a layered interface model for calculating different interfacial tensions, performing molecular dynamics simulation on the layered model, and recording a pressure tensor track; pressure tensor data in the dynamic simulation process is extracted, layered statistics is conducted in the Z direction, the interfacial tension is calculated based on a pressure tensor method, and then the contact angle is calculated to represent the wettability of the reservoir. The convergence condition of the pressure difference along with the displacement can be automatically monitored, and the real boundary of the volume phase and the interface phase is judged, so that the calculation error generated by the simulation box boundary effect is eliminated, and the interface tension calculation reliability is improved; the micromechanism of low efficiency at the initial stage of deep coal bed gas drainage and production is explained through the layered interface model, and the method has extremely high industrial application value.

The invention discloses a deep coal reservoir true triaxial hydraulic fracturing physical simulation method, and relates to the technical field of coal bed gas exploitation. Comprising the following steps: S1, filling a soluble stress buffer medium, a coal matrix modified embedded steel bar adhesive and a micro-convex threaded steel pipe into a low-crack coal briquette to obtain a coal sample; s2, loading the coal sample through a true triaxial pressure chamber, and performing temperature control compensation at the same time; and S3, simulating the displacement requirement of the underground fracturing operation through the prepared fracturing fluid and the constant flow pump, determining the fracture in the coal sample through the sensor and the CT scanner, and obtaining the three-dimensional expansion path of the fracture. According to the invention, the reinforcing material is matched with the mechanical property of the coal body, the stress concentration is reduced, the breakage rate of the coal sample in the experiment is reduced, meanwhile, the micro-convex threaded steel pipe is combined with the raw material belt for sealing implantation, and the compactness of the embedded steel bar is verified through CT scanning, so that the integrity of the shaft structure and the unblocked channel of the fracturing fluid are further ensured.

The invention discloses a gas-containing coal moisture invasion and microscopic damage visual measurement system and method, and belongs to the technical field of gas-containing coal body tests. Comprising a visual triaxial coal sample holder, an environment control system, a fluid injection system, a desorption system and a coal sample microscopic damage evolution collaborative characterization unit, loading shaft confining pressure on the coal sample and then simulating a gas pressurization adsorption process on the coal sample; methane desorption is simulated through a desorption system, and the permeability of the coal sample is measured by adopting a transient method; coal matrix strain is analyzed by using a DIC technology, and micro-fracture evolution is monitored by using an acoustic emission technology; according to the invention, the response mechanism and the moisture penetration process of the coal seam after moisture intrusion in a real stratum environment can be truly simulated, and full-scale visual analysis from microscopic damage to macroscopic response is completed, so that theoretical support is better provided for a coal seam anti-reflection technology and gas outburst.