782 results about "Coalbed methane" patented technology

The invention provides a coal-bed gas well production dynamic analysis method and system based on AI time sequence prediction, and the method comprises the steps: firstly collecting a production dynamic data sequence of a coal-bed gas well, a corresponding well position geological condition data sequence and a surrounding environment data sequence, and constructing a ternary time sequence dynamic association network comprising node dynamic time sequence segments and a connection line real-time association relationship; and then calling a pre-trained AI time sequence coupling deviation evolution mining model to process the ternary time sequence dynamic association network to obtain a ternary time sequence coupling deviation result. And a deviation conduction closed-loop path is determined according to a ternary time sequence coupling deviation result in combination with forward conduction positioning and reverse tracing verification, and a deviation conduction analysis report is generated. And finally, generating a dynamic regulation strategy based on the deviation conduction analysis report in combination with a production dynamic prediction threshold value, outputting the dynamic regulation strategy to a production control terminal, and meanwhile, feeding back regulation data to update a network node association relationship, thereby realizing accurate analysis and regulation of the production dynamic state of the coal-bed gas well.

The invention is applicable to the technical field of coal bed gas development and geological sequestration, and provides a THMC multi-field coupling simulation method and system for a process of displacing CH4 by coal bed CO2, and the method comprises the following steps: collecting multi-source parameter information of a target coal bed; according to the multi-source parameter information, constructing a coal seam structure model comprising a matrix and a crack system; constructing a control equation system based on the coal seam structure model, and introducing a multi-field coupling mechanism to obtain a fully-coupled mathematical model; performing numerical solution on the fully-coupled mathematical model to obtain a spatio-temporal evolution result of the key field variables; and according to the spatio-temporal evolution result of the key field variable, evaluating the index of the target coal seam. According to the invention, a heat-force-gas-chemical multi-physical field full-coupling simulation system is constructed, so that the CH4 recovery rate and the CO2 storage stability can be accurately predicted. The method is suitable for gas injection-storage coupling optimization of a multi-coal-rank and low-permeability coal seam, and has high precision, high adaptability and remarkable engineering guidance value.

The invention discloses a multielement multiphase fluid displacement coalbed methane 4D visual simulation experiment system and a multielement multiphase fluid displacement coalbed methane 4D visual simulation experiment method. The system comprises a gas-liquid mixed injection system, a Kr adsorption system, a visual triaxial core holder system, a CT scanning system and a tail gas analysis and treatment system. According to the experimental method, Kr similar to CH4 in dynamic diameter and other parameters is selected as a CT tracer to replace CH4, and 4D visualization of coal body internal pore and fracture structure evolution and Kr concentration field displacement migration process can be realized through three-dimensional reconstruction of CT images at different displacement moments and registration, gray correction and normalized concentration calculation of the images. The problem that the gas migration rule in the coal body in the displacement experiment is not clear is solved; the dynamic diffusion process inversion of the coal bed gas in the coal bed difficult to extract is realized by utilizing the distribution characteristic evolution of the Kr gas in the coal body, so that the in-situ coal body fissure structure in the coal sample and the dynamic migration law of methane in the displacement process are obtained, and the method has great significance for revealing the displacement development mechanism of unconventional natural gas such as the coal bed gas.

The invention discloses a biological hydrogen production method for coupling a coal seam microbial community and beet pulp waste. The biological hydrogen production method comprises the following steps: step 1, collecting coal seam microorganisms; step 2, sample pretreatment; 3, preparing a culture solution; step 4, flora enrichment culture; and 5, constructing a biological hydrogen production system to obtain hydrogen-rich gas. Microorganisms adopted in the method are original microorganisms in underground in-situ coal seam or ground coal-bed gas well drainage and mining water, sugar industry waste beet pulp is adopted as a hydrogen production substrate, and aiming at the bottlenecks of high strain cost, limited substrate applicability and the like in an existing biological hydrogen production technology, the coal seam microorganisms and sugar industry waste residues are coupled, so that the yield of hydrogen is increased. A low-cost hydrogen production system is constructed, so that the economic cost in the microbial hydrogen production process is reduced, and the beet pulp has the advantages of being safe, easy to obtain, low in cost and high in gas production rate, has the advantages of being easy and convenient to operate, economical, efficient, environmentally friendly and the like, and has a good industrial application prospect.

The invention relates to the technical field of coal bed gas development and gas extraction, in particular to an electrodialysis-liquid CO2 time sequence synergistic anti-reflection method and system. Comprising an electrodialysis pretreatment stage, a CO2 synergetic permeability increasing stage and a process regulation and energy recovery stage, a mixed solution is injected into a coal seam in a pulse injection mode, and energy recovery is conducted through pipeline fluid pressure in the injection stopping period. According to the technical scheme, through multi-stage cooperation of electrodialysis pretreatment, CO2 phase change fracturing and pulse consolidation and regulation, accurate transformation of the coal seam low-permeability area is achieved. According to the scheme, electrodialysis is utilized to drive an acidic working solution to target and migrate to a difficult-to-permeate area, mineral substances are dissolved, and pores are expanded; then, high-energy expansion stress is generated through liquid CO2 phase change, and a through fracture network is formed; and finally, a pulse injection and energy recovery mechanism is adopted, fracture closing is restrained, system energy consumption is reduced, and therefore the coal seam breathability and the gas extraction efficiency are integrally improved.

The invention discloses a method for rapidly and efficiently extracting coal mine gas in a broken and soft coal seam, and belongs to the technical field of coal seam gas development and coal mine gas prevention and control. According to the method, geological features of a coal mining planning area are determined, a ground U-shaped well and underground bottom-pumped rock drift layer-crossing drilling combined treatment system is deployed, and regional large-scale treatment is achieved in a well factory mode; the fracturing transformation range and the fracturing fluid distribution characteristics are detected by using a ground and underground combined micro-seismic monitoring and underground transient electromagnetic method, and the arrangement of layer-crossing drill holes is optimized; dividing the cross-layer drill holes into drainage holes and air exhaust holes, and formulating a collaborative extraction system in combination with different drainage and extraction stages; the method solves the problems that broken soft coal seam gas extraction is low in efficiency and long in period, and treatment blind areas exist, treatment time is remarkably shortened, cost is reduced, and safe and efficient production of a coal mine is guaranteed.

The utility model discloses a broken soft coal bed pneumatic airtight coring device which comprises a coring outer cylinder, a coring drill bit and an adapter. A pressing ball seat is arranged in the adapter, a locking mechanism core pipe is arranged in the lower end of the pressing ball seat in a sleeved mode, and the locking mechanism core pipe is further sleeved with a force storage mechanism body pipe capable of moving in the axial direction. The lower end of the power storage mechanism main body pipe is connected with the coring inner cylinder through a power storage mechanism main body pipe extension section capable of axially moving; a limiting step is arranged on the outer wall of the force storage mechanism body pipe, a locking sliding sleeve is further arranged outside the force storage mechanism body pipe in a sleeving mode, and a force storage spring is further arranged between the limiting step and the locking sliding sleeve in an abutting mode. A locking ball is embedded in the pipe wall of the lower end of the force storage mechanism body pipe and can axially limit the locking sliding sleeve. A sealing ball valve is arranged in the coring inner cylinder, and the pushing cylinder can be pushed by the locking sliding sleeve to move in the axial direction to close the sealing ball valve. The closed coring device solves the problems of hole spraying, hole collapse and the like when an existing closed coring device is used in a broken soft coal seam.

The invention provides a tight gas and deep coal bed gas collaborative exploitation simulation experiment device. The tight gas and deep coal bed gas collaborative exploitation simulation experiment device is composed of a shaft simulation device, a reservoir simulation device, a gas-liquid two-phase flow supply device and a control system. The casing pipe is provided with a plurality of transparent converging sections, and the oil pipe can be downwards inserted to different layers. And the gas-liquid two-phase flow supply device is provided with a plurality of groups of independent gas-liquid conveying manifolds which are respectively connected with each convergence section of the sleeve through the reservoir simulation device, so that the independent regulation and control of seepage parameters and production pressure difference of each layer are realized. The control system integrates pressure and flow acquisition and image recording functions, monitors and analyzes data in real time, is used for simulating an interlayer coupling relationship, a mutual interference mechanism and dynamic productivity response during multi-layer commingling production, and provides an experimental basis for collaborative production layer strategy optimization.

The invention discloses a stress demarcation-based deep coalbed methane compressible dessert evaluation method for a complex structure area. The method comprises the following steps: calculating the maximum horizontal stress, the minimum horizontal stress and the vertical stress of a single well; the single well stress type is judged based on the three-stress magnitude relation, and complex area partitioning is conducted by combining the structural boundary; geological conditions of compressibility of deep coal bed gas in different partitions are defined, and first-level and second-level index systems for compressibility evaluation of different partitions are established; a quantitative characterization method for secondary evaluation index parameters is provided; based on the type of the stress field, determining the weight of the index parameter by adopting a subjective weighting method; establishing a membership function for different evaluation index parameters; calculating the evaluation comprehensive values of the compressible desserts of the coal bed gas single well in different subareas, and carrying out the classification and classification of compressible dessert areas. According to the method, difference setting and unified comparison of compressible dessert evaluation parameter systems of coalbed methane at different depths in the same block are realized, and the existing dessert evaluation index is optimized.

The invention belongs to the technical field of drilling fluid processing, and particularly relates to a special silicate water-based drilling fluid for a coal-bed gas well as well as a processing method and a processing device of the special silicate water-based drilling fluid. The top end of the stirring tank is communicated with a first feeding hole and a second feeding hole, and the bottom end of the stirring tank is communicated with a discharging pipe; a rotating shaft is rotationally connected to the top surface of the inner wall of the stirring tank, and a sliding groove is formed in the bottom surface of the rotating shaft; a rotating shaft is driven by a first motor to rotate, and the rotating shaft drives a connecting shaft to rotate, so that fresh water and additives in a stirring tank are stirred and mixed by stirring blades, and a first screw rod can be driven by the first motor to positively and negatively rotate in a reciprocating manner in the mixing process; the first screw rod drives the connecting shaft to move up and down in the sliding groove, so that the stirring blades move up and down, the stirring blades stir and mix the water and the additive while moving, and the mixing efficiency and uniformity of the additive and the water are improved.

The invention relates to the technical field of coal bed gas development, and particularly discloses a numerical simulation method for multi-field coupling and microwave enhanced drainage and mining of a deep coal bed, which realizes accurate simulation of the whole process of drainage and mining of deep coal bed gas through six key steps: firstly, obtaining a coal bed parameter system; establishing a temperature coupling adsorption and desorption model, and quantifying the influence of the high ground temperature environment on the gas occurrence by correcting a Langmuir equation; constructing a dual-medium heat-gas-liquid-solid full-coupling control equation set which covers coal deformation, gas-water two-phase seepage, heat transfer and electromagnetic field equations; a microwave heat effect model is defined, and electromagnetic energy-heat energy conversion is calculated through a dielectric constant mixing model; deducing a porosity / permeability dynamic evolution equation, and coupling effective stress, matrix shrinkage and a thermal expansion effect; and finally, a COMSOL Multiphysics platform is adopted to realize multi-field coupling solution, and a productivity index is calculated through well circumference integration. According to the method, the inherent limitation of a static parameter model is overcome, and the precision and efficiency of numerical simulation are remarkably improved.

The invention discloses a coal bed gas biological yield increase effect dynamic monitoring and evaluation method which comprises the following steps: arranging a multi-parameter sensor in a target coal bed gas well site, and collecting background data before bacterium injection; injecting a microbial bacterial solution and a nutrient solution into the coal seam according to the experimental design, and recording parameter information in the injection process; periodically collecting a gas production sample, and analyzing gas components; analyzing microbial community structure and abundance change in the water sample; combining the gas generation rate, the isotope characteristics and the microflora analysis result to identify a gas production path and calibrate a key functional flora; and constructing a mathematical model containing microbial activity, coal quality conversion and gas production efficiency, forming an evaluation index system, and outputting field process optimization suggestions based on the model. According to the method, a scientific basis is provided for dynamic optimization of the yield increasing process, and compared with a traditional laboratory method, the method can achieve systematic analysis of the in-situ microorganism process and quantitative evaluation of the gas production effect, and has good field adaptability and popularization value.

The invention relates to the technical field of automatic control of drilling parameters, in particular to a coal bed gas underground drilling construction parameter optimization method and system.The method comprises the following steps that sound wave response signals are obtained, propagation characteristics are calculated, bit pressure data are aligned, abnormal fluctuation is recognized, pumping pressure information is extracted, and the change trend is analyzed; and comparing the consistency of the regulation and control points and organizing regulation and control actions to finally form a coal-bed gas well drilling parameter optimization control flow. According to the method, accurate calibration of an abnormal state is achieved by constructing a sound wave propagation delay sequence and synchronizing bit pressure response, key regulation and control fragments are recognized in combination with a pumping pressure change trend, a time sequence coupling relation between bit pressure and pumping pressure is established, regulation and control action combinations meeting response consistency are extracted, and sequential organization is conducted; a control instruction set with continuity and pertinence is formed, collaborative recognition and linkage regulation and control of multi-parameter change trends are achieved, and stability and response coordination in the construction process are improved.

The invention relates to a shale or coal rock gas evaluation method based on a gas-water two-phase flow isotope fractionation model. The shale or coal rock gas evaluation method comprises the following steps: 1, collecting data; 2, establishing a gas well model; 3, establishing a control equation set; 4, coupling the influence of the real gas effect and the effective stress; 5, establishing a gas transmission model and a relative permeability model; 6, establishing a relation between capillary pressure and saturation; 7, considering critical desorption pressure; 8, setting boundary conditions of initial conditions; 9, solving a control equation set; 10, calculating production dynamic parameters and isotope values; 11, performing history fitting; 12, verifying historical fitting quality; 13, predicting productivity; 14, calculating a gas dynamic output proportion; 15, identifying a fractionation inflection point and gas production mechanism conversion; by coupling gas-water two-phase flow, multiple gas transmission mechanisms, stress sensitivity and methane isotope competitive adsorption theories, yield prediction of the deep reservoir and quantitative evaluation of the dynamic proportion of produced gas are realized.

The present invention relates to a high pressure water jet automatic drilling and cutting collaborative system and method for coal seams, and belongs to the field of coal seam gas control. The system comprises a drilling and cutting collaborative control platform, an automatically regulated slotting pump unit and an automatically regulated drill; the drilling and cutting collaborative control platform comprises a coalbed gas geology management system, a decision analysis system, a drilling and cutting collaborative execution system, a monitoring and feedback system, and an information management and evaluation system; construction operation parameter instructions issued by the drilling and cutting collaborative control platform are executed by the automatically regulated slotting pump unit and the automatically regulated drill; coal seam geological information is recorded by the coalbed gas geology management system, and reasonable drilling and cutting construction parameters are analyzed and formulated by the decision analysis system based on the coal seam geological information. Drilling and cutting collaborative construction, on-site operation construction parameter monitoring, and real-time feedback and adjustment are realized by the drilling and cutting collaborative execution system and the monitoring feedback system according to the operation parameter instructions. Coal seam outburst prevention and control effects in a drilling and cutting collaborative implementation area is evaluated by the information management and evaluation system. The present invention improves safety of on-site operators, and reduces personnel input and labor intensity.

The invention relates to the technical field of oil and gas field and coal bed gas field mining equipment, in particular to a wellhead suspension centrifugal pump drive double-pipe jet flow drainage and mining device and a using method. According to the technical scheme, a lower tubing head four-way joint, a middle tubing head four-way joint and an upper tubing head four-way joint are sequentially installed on a bottom flange, a motor is installed on the upper portion of the upper tubing head four-way joint, and an inner pipe plug-in pump core catcher is installed at the lower end of a submersible water injection centrifugal pump; the lower end of the inner pipe inserted pump core catcher is movably connected with an inner layer oil pipe, and a pump core installed in the double-pipe jet pump is arranged in a pump cylinder of the jet pump. The device has the advantages that due to the fact that a packer is omitted and the device is connected with the double-pipe jet pump, sand-containing liquid in a well can be sucked, and exploitation of natural gas or coal bed gas can be achieved; the inner pipe is inserted into an elastic clamping jaw of the pump core catcher to catch the pump core; and the submersible water injection centrifugal pump and the pump core can be lifted to the ground at one time by hoisting the motor at a ground wellhead, so that the maintenance is convenient.

The application discloses a kind of gas-liquid two-phase flow numerical simulation method considering coalbed gas desorption lag, comprising the following steps: using well logging, indoor experiment means to obtain productivity calculation parameter;Desorption equation of matrix system is defined in combination with desorption lag effect, diffusion equation;Gas-water two-phase percolation equation of fracture system is defined, and desorption equation of matrix system, diffusion equation is combined, and double medium gas-water two-phase coupling flow equation set is formed;The porosity and permeability change of matrix system and fracture system in production process is calculated respectively, and the physical property change equation set of double medium is deduced;Using the numerical solver of COMSOL, the coupling equation set is solved using iterative method, and the gas production and water production are calculated.The application is simple to operate, can more scientific and reasonable assess the influence of coalbed gas desorption lag effect on gas well productivity, while greatly reducing the cost and time of gas well numerical simulation calculation, and also has important inspiration for other unconventional gas reservoir development affected by desorption lag.

The invention relates to the technical field of coal underground gasification site selection, and discloses a coal underground gasification site selection system and method based on multi-parameter collaborative evaluation.The coal underground gasification site selection method comprises the following steps that coal resource data of a target area are collected and examined, and influence factors are screened and analyzed; comparing the collected coal resource data with corresponding influence factor evaluation standards, and respectively obtaining each factor estimated value of the corresponding influence factor; calculating the suitability coefficient of each factor of the influence factors and the average suitability coefficient of the influence factors according to the estimation condition of each factor of the target area influence factors; according to the method, a complete multi-dimensional evaluation index system is constructed, the coal bed gasification suitability is comprehensively evaluated from multiple dimensions, and the one-sidedness of evaluation is avoided; meanwhile, a scientific quantitative evaluation mechanism is established, qualitative factors are converted into quantitative indexes through grade quantification, and the objectivity and scientificity of evaluation are improved by combining dimensionless processing and weight distribution.

The present application relates to a kind of fracturing perforation position selection method, belong to a kind of coalbed gas horizontal well development technical field, specifically relates to a kind of coal seam roof horizontal well fracturing perforation position selection method.The present application provides new method and train of thought for the optimal perforation position of coal seam roof horizontal well, can reduce the problem of pump pressure being too high, sanding difficulty in reservoir reconstruction process, improve the reconstruction efficiency of coal seam.

The invention discloses an intelligent prediction method for pressure channeling of a deep coal-bed gas well, and relates to the technical field of intelligent prediction. The method comprises the following steps: S1, obtaining construction well fracturing design parameters, construction well geological parameters, adjacent well geological parameters, inter-well space relation parameters and actually measured pressure channeling labels in a deep coal bed gas block, and preprocessing the parameters to obtain a data set; s2, substituting the data set into a graph neural network, constructing a heterogeneous graph comprising a node set and an edge set, and fusing parameters to obtain fusion feature representation used for representing sample characteristics; the fusion feature representation comprises fracturing section node features and adjacent well node features; and S3, based on the fusion features, predicting the pressure channeling probability in combination with an MLP model. The pressure channeling risk prediction and optimization framework based on fusion of static geologic features and construction design parameters of a'fracturing section-adjacent well pair 'sample unit is adopted, whether the deep coal-bed gas well is subjected to pressure channeling or not can be predicted in advance, and the precision is high.

The invention discloses deep coal bed gas well cementation cement paste and a preparation method thereof, and the deep coal bed gas well cementation cement paste is prepared from the following raw materials in parts by weight: 100 parts of G-grade oil well cement, 5-15 parts of water-borne epoxy resin, 1.5-3 parts of a nano silicon dioxide solution, 0.5-1.8 parts of calcium sulfate whiskers, 0.2-0.6 part of composite coating fibers, 1.2-1.8 parts of a fluid loss agent and 0.5-1.8 parts of a retarder. 0.3 to 0.5 part of a drag reducer, 0.2 to 0.5 part of a defoaming agent and 38 to 42 parts of water; wherein the composite coating fiber is hydrophilic epoxy resin modified polyethylene fiber. The cement paste can improve the well cementation cementing packing quality of a coal seam, and has good filtration property.

The invention discloses a deep coal bed gas seam network density prediction method, and relates to the technical field of reservoir development. The method comprises the following steps: extracting an average seam net distance from microseismic event point data as a seam net density representation label; establishing a multi-source data fusion framework taking a fracturing section as a sample unit, and splicing geological and engineering parameters into a feature vector; a machine learning algorithm is adopted to construct an intelligent prediction model, and a complex nonlinear mapping relation between multi-source features and labels is automatically learned. According to the method, intelligent prediction of the fracture network density is realized, and reliable support can be provided for fracturing effect evaluation and construction parameter optimization.

The invention discloses a sapphire window-based nuclear magnetic resonance device and a coal seam free gas volume correction method, the sapphire window-based nuclear magnetic resonance device comprises a computer, a gas cylinder assembly, a nuclear magnetic bearing platform, a coal sample holder, a stable displacement pump and a laser emitter, the gas cylinder assembly is connected with a left end inlet of the coal sample holder, and the coal sample holder is arranged on the nuclear magnetic bearing platform; a sapphire window is arranged on the coal sample holder, laser emitted by the laser emitter faces the sapphire window to observe a cylindrical coal sample in the coal sample holder, an outlet at the right end of the coal sample holder is connected with a test pipeline, and the coal sample holder is connected with a confining pressure control pipeline. Advanced technologies such as nuclear magnetic resonance and laser scanning are applied to the free gas content simulation experiment of the coal bed gas reservoir, and the tested data are more accurate. The device can also be used for permeability testing, methane adsorption experiments, displacement experiments and the like, test results are used for evaluating distribution characteristics of free gas in geological media such as coal seams and shale, and theoretical data support is provided for energy development in China.

The invention discloses a gas-liquid two-phase flow numerical simulation method considering coal bed gas desorption lag. The method comprises the following steps: acquiring productivity calculation parameters by using logging and indoor experiment means; defining a desorption equation and a diffusion equation of the matrix system in combination with a desorption hysteresis effect; defining a gas-water two-phase seepage equation of the fracture system, and forming a dual-medium gas-water two-phase coupling flow equation set in combination with a desorption equation and a diffusion equation of the matrix system; the porosity and permeability changes of a matrix system and a fracture system in the production process are calculated respectively, and a physical property change equation set of the double media is deduced; and solving the coupling equation set by using a numerical solver of COMSOL and adopting an iteration method, and calculating to obtain gas production and water production. The method is easy and convenient to operate, the influence of the coal bed gas desorption lag effect on the gas well productivity can be evaluated more scientifically and reasonably, meanwhile, the gas well numerical simulation calculation cost and time are greatly reduced, and important inspiration is also provided for development of other unconventional gas reservoirs influenced by desorption lag.

The invention discloses a multi-dimensional geosteering method for a middle-deep layer coal bed gas horizontal well. The method comprises the following steps that S1, three-dimensional earthquake-geologic models of a marker bed and a target coal bed are established; s2, the hole drift angle of each marker bed during drilling is determined; s3, predicting the depth, thickness, stratigraphic dip and spatial distribution characteristics of the target coal seam; s4, ensuring accurate target entering of the horizontal well by adopting a layer-by-layer approaching method; s5, comprehensively analyzing horizontal section data to ensure high drilling rate; the method is suitable for the technical field of coal bed gas development, the marker bed hole drift angle layer-by-layer approaching control target entering technology is adopted, the optimal hole drift angle of each marker bed is quantitatively determined, in the actual drilling process, geosteering personnel only need to judge whether the hole drift angle meets the design or not when drilling is carried out on each marker bed, the analysis content and steps are simplified, and the efficiency is improved. And the analysis time when the depth deviation with the designed marker bed is large is saved, and the drilling time efficiency is improved.

The invention relates to the technical field of oil and gas field and coal bed gas field drainage and mining, in particular to a buoyancy lift pump core ring jet flow pump and a using method. According to the technical scheme, a low-density buoyancy lift pump core is installed in an inner cavity of a pump cylinder, an annular gap is formed between the low-density buoyancy lift pump core and the inner wall of the pump cylinder, a formation liquid suction inlet is formed in the lower side of the annular gap, an annular throat pipe is arranged below the formation liquid suction inlet, a diffusion cavity is formed below the annular throat pipe, and a pump core supporting seat is arranged at the bottom of the diffusion cavity; a mixed liquid outlet is formed in the lower side of the diffusion cavity, and the diffusion cavity is communicated with the mixed liquid discharge cavity. The low-density buoyancy lift pump core has the advantages that due to the fact that the overall density of the low-density buoyancy lift pump core is adjusted and reduced, the power hydraulic pressure and the using amount for pulling out the low-density buoyancy lift pump core can be reduced, and operation cost is reduced; in addition, the low-density buoyancy lift pump core is simple in structure, an annular jet flow structure is formed between the low-density buoyancy lift pump core and the pump cylinder, the liquid drainage and production amount is increased, the working condition of the low-density buoyancy lift pump core suitable for pumping media is wider, and the manufacturing cost is lower.

The invention belongs to the technical field of strip mine residual coal resource recovery, and particularly relates to a strip mine end slope residual coal underground gasification re-mining process and system.The strip mine end slope residual coal underground gasification re-mining process comprises the following construction steps that S1, a directional drilling system is constructed at a strip mine end slope coal seam outcrop and comprises a gas injection drilling hole, an exhaust drilling hole and a drainage drilling hole, forming a gasifier type I suitable for a thick coal seam or a gasifier type II suitable for a thin-medium thick coal seam; s2, injecting a gasification agent into the gasification furnace to perform coal bed gasification to generate coal gas and capture CO2 in gasified tail gas; s3, pressurizing and liquefying the captured CO2, injecting the liquefied CO2 into a combustion space area, and performing mineralization and storage in combination with alkaline ash; wherein the gas injection drill hole and the exhaust drill hole are arranged at the bottom or the top of a coal seam according to the thickness difference of the coal seam, and part of accumulated water is reserved in the whole drainage drill hole to prevent gas leakage. Therefore, efficient recovery of residual coal and full-process low-carbon emission are realized through differential gasification furnace structural design, dynamic sealing of the drainage drill hole and collaborative filling technology of the combustion space area.

The invention provides a method for characterizing coal pore wettability based on coal macerals, and relates to the field of coal wettability analys.The method comprises the steps that centrifugal treatment experiments at different rotating speeds are conducted on a saturated coal rock sample, and coal rock sample parameters of each centrifugal treatment experiment are measured and recorded; calculating pore water content, free water content and centrifugal force; fitting the centrifugal force and the free water content to determine the movable water content; deriving a liquid state equation, and simplifying the liquid state equation according to assumed conditions; and substituting the pore specific surface area, the movable water content and the adsorbed water content into the simplified liquid state equation to calculate the thickness of a sample adsorption layer, performing robust normalization processing on the thickness of the adsorption layer and the coal macerals, and fitting the normalized coal macerals and the coal pore wettability index to establish a coal pore wettability prediction model. According to the method, the coal pore wettability is accurately and losslessly represented, and then the relationship between the coal maceral and the coal pore wettability is accurately established, so that efficient development and production of coal bed gas are assisted.

The invention discloses a coal bed gas typical reservoir gas content evaluation method based on well logging information, and relates to the technical field of coal bed gas evaluation. According to the coal bed gas typical reservoir gas content evaluation method based on the logging information, logging data and core data of a set area are obtained and preprocessed; performing screening processing based on the logging data to obtain a screening set of the set area; based on the core data, constructing a lithology indication matrix and physical property constraint characteristics of the set area; constructing a constrained multiple linear regression model of the set area based on the screening set of the set area, the lithology indication matrix and the physical property constraint characteristics; according to the method, the target logging data of the to-be-evaluated target layer section are obtained, analysis is carried out in combination with the logging coefficient set, and the coal seam gas content value of the to-be-evaluated target layer section is obtained, so that the gas content of coal seam gas is evaluated more accurately; and the accuracy and reliability of the evaluation result are improved.

The invention relates to the technical field of oil and gas field and coal bed gas field mining and drainage engineering, in particular to a multi-stage high-speed centrifugal pump driven underground sand blockage prevention jet flow drainage and drainage system and a using method. According to the technical scheme, the output end of a horizontal centrifugal pump is connected to a well mouth through a pipeline, the sand blocking prevention tubular jet pump is installed on an underground oil production layer through an oil pipe, a plurality of sand setting bearing umbrellas are installed on the small-diameter oil pipe in a segmented mode, and a plurality of sand setting bearing covers are installed on the oil pipe in a segmented mode. The problems that a pump shaft of a multi-stage high-speed centrifugal pump is large in length and high in rotating speed and is in axial fluctuation in the starting and working process of the pump, consequently, a common coupling force transmission and dynamic sealing structure is difficult to adapt to the high-rotating-speed working condition, and the fault rate is high are solved. In addition, the sand blockage prevention tubular jet pump is improved, the sand blockage prevention performance of the sand blockage prevention tubular jet pump is enhanced, the sand blockage prevention tubular jet pump is novel and simple in structure, safe and reliable, a plurality of sand setting bearing umbrellas are installed on a small-diameter oil pipe in a segmented mode, and sand blockage of an underground pump and a tubular column caused by the fact that setting sand sinks into a pump cylinder is avoided.