59results about How to "Improve mining efficiency" patented technology

The invention discloses a pressure-controlled drainage gas production method and system for a coal-bed gas well. The pressure-controlled drainage gas production method comprises the steps that drainage is conducted through the first daily drainage amount, wherein the first daily drainage amount meets the eliminating demand for production interference objects in a coal bed; and a pressure-supplementing medium is injected while drainage is conducted, and the downhole flow pressure daily drop amount is maintained as a first differential pressure value so as to avoid retracting and closing of pores and cracks in the coal bed. According to the pressure-controlled drainage gas production method for the coal-bed gas well, the drainage speed at the drainage state can be conveniently determined, the eliminating demands for drilling and completion fluids, pulverized coal and slack coal in the coal bed can be met, and meanwhile, retracting and closing of the pores and the cracks in the coal bed can also be avoided; and compared with the prior art, the pressure-controlled drainage gas production method is simple in process, the production efficiency of the coal-bed gas well can be greatly improved, and quite high practical value and popularization value are achieved.

The utility model discloses mechanical plugging layer-by-layer oil extraction device, including flow guide pipe, the one end of flow guide pipe is connected with the upper packer, and the other end is connected with the lower packer, and the three are all connected through upper and lower joint, the upper packer is used for plugging the upper end of the well section of plugging object, and the lower packer is used for plugging the lower end of the well section of plugging object, the upper packer, the lower packer and the flow guide pipe inside all are provided with gas flow guide passage, make the dissolved gas of lower oil layer free come out in turn through lower packer, flow guide pipe, upper packer and enter the oil jacket annular space of upper portion, finally discharge from wellhead. The utility model discloses device solved the gas lock problem of existing technology when sealing upper and extracting lower, can be used as the plugging tool of oil layer when sealing upper and extracting lower of oilfield long stop oil well, high water cut oil well, can improve oil well mining efficiency, reduce development cost, obtain greater economic benefit.

This invention relates to a method for extracting natural gas hydrates and the perfluorocarbon extractant used therein. The perfluorocarbon extractant comprises a viscosity modifier, an interface modifier, and a solvent; the viscosity modifier includes perfluorotributylamine; and the interface modifier includes perfluoropolyether and / or perfluorobutyric acid. The perfluorocarbon extractant of this invention exhibits high solubility for methane, strong hydrophobic properties, and stable physicochemical properties. During natural gas hydrate extraction, it allows methane released after hydrate decomposition to preferentially enter the extractant phase in a dissolved state and migrate within the reservoir, thereby achieving single-phase liquid extraction of methane. This technical approach can weaken or even eliminate the Jamin effect and seepage blockage caused by gas-liquid two-phase mixing, reduce reservoir flow resistance, and improve the extraction efficiency and continuous gas production capacity of natural gas hydrates in silty clay reservoirs.

The utility model relates to the technical field of oil extraction, in particular to an efficient temporary plugging anti-overflow device. Comprising an upper connector, the upper connector is fixedly and hermetically connected with a valve connector, the lower end of the valve connector is fixedly and hermetically connected with a filter pipe and an outer cylinder, the filter pipe is located on the inner side of the outer cylinder, the valve connector is provided with an air hole communicated with an annular cavity between the outer cylinder and the filter pipe, and a check valve is installed in the air hole; the lower end of the filter pipe is fixedly and hermetically connected with a lower pipe located inside the outer cylinder, the lower end of the lower pipe is blocked and fixedly connected with the lower end of the outer cylinder through a lower connector, and a temporary blocking plate is detachably, fixedly and hermetically connected into the lower connector. Through soluble temporary plugging, multi-stage filtering, gas-liquid separation and modular sealing design, the device has the core advantages of efficient overflow prevention, rapid production, airlock prevention, low maintenance cost and the like, has both environmental protection property and economical efficiency, and is suitable for oil well operation under complex working conditions.

The utility model discloses a coal mine electromechanical transmission transportation fixing device which comprises a placing table, a sliding rail is arranged on the placing table, a fixing table is connected to the sliding rail in a sliding mode, a sliding block used in cooperation with the sliding rail is arranged at the bottom of the fixing table, a first pulley is rotationally connected to the bottom of the fixing table, and fixing grooves are symmetrically formed in one side of the fixing table. The placing table is fixedly connected with a fixing plate, one side of the fixing plate is rotatably connected with a twisting block, a torsion spring is arranged between the fixing plate and the twisting block, one side, far away from the twisting block, of the fixing plate is rotatably connected with a rotating disc, and the twisting block is fixedly connected with the rotating disc. According to the coal mine motor transportation device, the situation that the coal mine motor is not firmly fixed and falls off due to bumping or complex road conditions in the transportation process is avoided, when the coal mine motor is transported to a road surface without rails, the coal mine motor can be continuously conveyed to a designated place through the pulleys, manual transportation is omitted, and meanwhile the mining efficiency is improved.

The application discloses a kind of based on flow pattern recognition's deep sea mining multiphase flow particle delivery prediction and regulation method, the method includes: by acquisition equipment periodic acquisition pressure in pipeline, flow, bubble or droplet volume fraction, solid particle volume fraction in different positions;According to pipe diameter and the gas-liquid ratio obtained by calculation, mixed flow velocity, call pre-built flow pattern division algorithm, distinguish bubble flow, slug flow, vortex, annular flow;Solve the gas-liquid discrete unit volume fraction of any diameter in different flow patterns;According to the gas-liquid discrete phase volume fraction, obtain the delivery speed of solid particles in multiphase flow;Whether the solid particle delivery speed obtained is judged to reach the best interval, according to the result control multiphase flow in pipeline flow pattern or gas-liquid ratio, to adjust the delivery speed of solid particles.The present application can improve the efficiency of seabed mineral exploitation, and avoid the dangerous flow pattern formed by unreasonable gas-liquid distribution ratio, efficiency and safety are taken into account.

The application provides a gob roof impermeable system and an impermeable method thereof, which comprises a hanging unit arranged at the back side of a working face, an impermeable layer unit for laying on the top of a filling body, and a control unit in signal connection with the impermeable layer unit, wherein the impermeable layer unit is arranged on the hanging unit; the control unit is arranged to obtain a pushing speed parameter of the working face and an injection speed parameter of the filling body, and to control the laying speed of the impermeable layer unit according to the parameters, so as to realize dynamic matching of the laying speed of the impermeable layer unit, the pushing speed of the working face and the injection speed of the filling body. The impermeable layer assembly is laid synchronously with the working face advancing, and is adjusted in real time through the control assembly to adapt to the roof deformation and the dynamic change of the filling body; the system is integrated in a hydraulic support to realize integrated operation of "mining-filling-impermeable", without additional downtime, and the mining efficiency is improved; through reliable impermeability, the sealing efficiency of carbon fixation and filling is greatly improved, and the mine realizes negative carbon mining.

This invention discloses a method for methane extraction and closed-loop carbon fixation in coal seams using hot flue gas-driven combustion-explosion fracturing. First, each horizontal branch well is divided into sections, and perforations are constructed in each section. Then, CH4 is used in each section. 4 Combustion-explosive fracturing technology utilizes in-situ synergistic combustion-explosion reactions to generate gas impact perforation fractures, allowing them to further develop and expand into a fracture network. Then, hot flue gas is sequentially injected into each horizontal branch well. Due to its high temperature, the hot flue gas promotes CH4 (chemical oxygen demand) in the coal seam. 4 Gas desorption, and CO in hot flue gas 2 SO 2 NO 2 Due to its competitive adsorption advantage, it can displace a large amount of CH4 adsorbed in extra-thick coal seams. 4 Gas, then hot flue gas and CH 4 The gas continues to be utilized in a closed loop, improving the efficiency of coal seam methane extraction while simultaneously achieving hot flue gas sequestration. Through this continuous closed-loop utilization process, the efficiency of methane combustion and fracturing, hot flue gas sequestration, and CH4 extraction in various areas of extra-thick coal seams is maximized. 4 Extraction efficiency.

The utility model relates to an oil exploitation drilling tool. The drilling tool comprises a drill body, three evenly-distributed cones, a PDC cutting structure and a plurality of auxiliary assemblies. The tooth wheel is composed of a tooth column and three layers of tooth palms, and coarse and fine layered crushing is carried out step by step, so that the drilling efficiency is improved. The PDC cutting structure is arranged at the end of the drill body and comprises a triangular prism, a column groove, a main blade, an auxiliary blade and a side blade, large-diameter PDC cutting parts are arranged on the main blade and the auxiliary blade, PDC cutting parts with the diameters gradually reduced are arranged on the side blade, the cutting effect is optimized, and the adaptability of the drilling tool in a hard rock stratum is enhanced. The adaptability of the drilling tool in soft and hard rock stratums is further improved through the small blades and the small-diameter PDC cutting pieces on the rectangular plate, and it is ensured that the drilling tool works stably and efficiently. The overall design effectively reduces the abrasion of the drilling tool, prolongs the service life, improves the drilling efficiency, and reduces the mining cost. The drilling tool is suitable for rock stratums with different hardness and has a wide application prospect in oil exploitation.

The application provides a seabed deposit mining method and relates to the technical field of ocean engineering. The seabed deposit mining method applies a multifunctional automatic deep-sea mining vehicle. The method comprises the following steps: placing the multifunctional automatic deep-sea mining vehicle in a mining area of a seabed deposit; collecting seabed deposit materials through a collecting mechanism; pushing the seabed deposit materials to a sieve plate and a transfer mechanism by a rake; removing the soil mixed in the seabed deposit materials through the sieve plate; transferring the seabed deposit materials to a crushing mechanism by the transfer mechanism; crushing, grinding and storing the seabed deposit materials in sequence by the crushing mechanism; and loading the seabed deposit materials into a bag by a loading mechanism. The multifunctional automatic deep-sea mining vehicle is used for mining operations of seabed deposits, realizes the collection, transfer, crushing and loading operations of materials (seabed deposit materials), greatly simplifies the mining operation and improves the mining efficiency.

The utility model provides a kind of light supporting device for steeply inclined thin coal seam belongs to coal mining technical field, the light supporting device for steeply inclined thin coal seam includes side support frame in both sides, light supporting assembly is set between side support frame, light supporting assembly includes supporting bottom plate and supporting net in both sides, one side of supporting net is connected with steel chain, another side is connected with steel chain, electric winch is set on side support frame, one end of steel chain is connected with supporting net, and the other end is fixedly connected with the reel of electric winch by ring buckle;Side support frame includes stand, crossbeam and inclined strut, trapezoidal bottom plate is set in the bottom of stand, crossbeam is fixedly connected with stand by bolt, one end of inclined strut is connected with stand, and the other end is connected with bottom plate;Multiple groups of sliding slots are set on crossbeam, pulley is rotatably set in sliding slot, steel chain is wound around pulley;The utility model can solve the problem that dynamic support demand cannot be met.

The present application relates to the technical field of tunnel construction, in particular to a small-angle roof coal uncovering tunnel vault small-section coal uncovering process, comprising S1, excavating a ladder-type drilling field; S2, drilling and pumping a drainage hole; S3, setting up an extraction system; S4, performing extraction operation. The ladder-type drilling field is excavated in a limited ladder form in accordance with the overall trend of the bedding, and the drainage hole is drilled in a manner perpendicular to the step drilling surface, which can realize uniform distribution of drilling holes in the target area through drilling hole channels with approximately the same length. Since the direction of the drilling hole channel is determined, the drilling angle and depth can be quickly determined, the distance to the bedding surface can be easily predicted, the drilling speed and pressure of the drilling machine can be dynamically adjusted in advance, the construction safety is improved, the construction engineering quantity is reduced, the construction efficiency is improved, the hole completion rate is improved, and at the same time, the drilling hole channel can form a small-angle intersection with the bedding surface, so that the drainage hole can effectively contact more gas-containing bedding fissures, improve the coverage of the bedding surface area, and be beneficial to improving the mining efficiency.

The invention relates to a throttling valve capable of adjusting different throttling control modes on line, and relates to the technical field of valves, the throttling valve comprises a valve body, a valve seat assembly and a flow control assembly, a mounting opening and an air outlet are formed in the two opposite sides of the valve body respectively, and an air inlet and a pressure relief hole are formed in the periphery of the valve body; a buffer cavity communicated with the mounting opening, the air inlet and the air outlet is formed in the valve body, and a plugging piece is arranged outside the valve body; the flow control assembly comprises a fixed flow control piece, a needle-shaped adjustable flow control piece and a cage sleeve type flow control piece. The valve seat assembly comprises a first valve seat, a second valve seat and a third valve seat. The air inlet is provided with a first internal thread, and the valve seat assembly is provided with a first external thread. Limiting protruding rings are fixedly arranged on the peripheries of the flow control assemblies, and a union cap is detachably installed on the outer portion of the valve body. By means of the design, the whole valve does not need to be disassembled according to working condition changes on a gas well exploitation site, and the downtime is greatly shortened.

This application provides a method, apparatus, medium, and program product for multi-round fracturing in deep coal reservoirs. It relates to the field of deep coal reservoir stimulation technology. Each round of multi-round fracturing includes hydraulic fracturing and well shut-in. A simulated fracturing scheme for the nth round corresponding to the target deep coal reservoir is obtained. If n is 2, the fracturing fluid system in the simulated fracturing scheme is a variable viscosity slickwater fracturing fluid system; if n is not 2, the fracturing fluid system in the simulated fracturing scheme is a low-concentration guar gum fracturing fluid system. Based on the real-time wellhead pressure, real-time microseismic information obtained in the (n-1)th round, and the fracture network morphology after well shut-in in the (n-1)th round, an unconventional fracture propagation model is used to predict the fracture network morphology corresponding to hydraulic fracturing in the nth round, according to the simulated fracturing scheme of the nth round. Based on the fracture network morphology, real-time wellhead pressure, and real-time microseismic information corresponding to hydraulic fracturing in the nth round, the well shut-in time for the nth round is determined. This aims to achieve balanced stimulation of deep coal reservoirs and improve EUR (Earnings Equivalent to Fluid Regulator).

The application discloses a coal mine roadway roof grouting superficial enhancement-deep anti-seepage gradient modification method and relates to the technical field of coal mine roadway reinforcement and anti-seepage, which comprises the following steps: S1, roof geological detection: geological radar is used to detect the coal mine roadway roof, and the range of the roof superficial broken zone and the development depth of the deep water-conducting fissure are determined; the application precisely divides the superficial broken zone and the deep water-conducting fissure zone by detecting the roadway roof, and the superficial high-early-strength micro-expansion composite slurry and the deep high-flow high-water-retention anti-seepage slurry are prepared in a targeted manner; the concentric double-tube gradient grouting process is adopted to realize the rapid cementation of the superficial surrounding rock to form a dense bearing shell, effectively solve the problem of the easy collapse of the superficial broken zone, and meanwhile, the deep slurry realizes long-distance penetration through the polymer crosslinking network, closes the water-conducting fissure and avoids the reinforcement failure caused by the water loss of the slurry; through the linkage design of the slurry performance parameters and the gradient construction, the dual requirements of the superficial enhancement and the deep anti-seepage are met.

The application discloses a kind of top coal crushing degree prediction methods based on image recognition, belong to image recognition field, including: real-time acquisition top coal image and analysis definition and edge sharpness, automatically adjust camera focus to obtain high-quality image, apply edge detection algorithm to extract coal block shape and size distribution characteristics, determine crushing degree parameter.If parameter matches with preset threshold value, then it is combined with geological strength and mining depth to predict crushing degree distribution by neural network, analyze change trend and judge whether to need to adjust mining process parameter.Optimized parameter is handled historical data by feedback learning mechanism, determines self-learning adjustment value and updates neural network model, to realize more accurate crushing degree prediction and mining process closed-loop control.The application is fused by image processing, feature extraction and neural network prediction, significantly improves top coal crushing degree identification precision and mining efficiency, and optimizes process parameter dynamic adjustment capability.

This invention discloses an adaptive online measurement method for basic coal seam parameters, belonging to the field of coal seam parameter acquisition technology. The method includes the following steps: Step S1, deploying a multi-parameter sensor array in the coal seam borehole to collect raw gas pressure, temperature, humidity, coal strain, and acoustic emission signals in real time; Step S2, calculating and correcting the gas pressure using a composite environmental compensation model; Step S3, constructing an unsteady diffusion-seepage equation to invert the gas concentration and pressure field; Step S4, performing time-frequency analysis on the acoustic emission signals to calculate the amount of gas released by micro-fractures; Step S5, calculating the dynamic gas content based on the amount of gas released by micro-fractures; Step S6, constructing an objective function to dynamically optimize the parameters in real time. This invention, by collecting and accurately correcting coal seam parameters, can help solve problems in coal seam mining and accelerate the production progress of the working face.

The invention relates to the technical field of coal mining, in particular to an intelligent coal mining scheduling method. The intelligent coal mining scheduling method comprises the following steps: constructing a behavior prediction model, and training the behavior prediction model to preset precision by using a historical data layer; obtaining a current actual equipment state vector and a control instruction vector; inputting the control instruction vector and the current actual equipment state vector into a behavior prediction model to obtain a predicted equipment state vector; after the control instruction vector is sent to the main execution device, an actual device state vector is obtained; performing time sequence alignment on the actual equipment state vector and the predicted equipment state vector, and calculating to obtain an instant confidence coefficient; and adjusting a scheduling strategy according to the instant confidence coefficient. According to the intelligent coal mining scheduling method provided by the invention, the problem of a control efficiency verification blind area is fundamentally solved, whether the control instruction is accurately executed or not can be directly and instantly sensed, and the comprehensive state change caused after the instruction is executed is effectively evaluated.

The utility model relates to the technical field of coal mining discloses a mine gangue pretreatment device with sliding crushing function, including support, set up on the multiaxis mobile structure of support and with the crushing head of multiaxis mobile structure connection, multiaxis mobile structure includes at least the telescopic oil cylinder of horizontal setting on the support, the utility model discloses through setting up the multiaxis mobile structure on the support to control the crushing head, has increased the crushing range, has solved the problem of poor passability of larger coal gangue, personnel waste.

This invention provides a multi-row horizontal well layered extraction device and method for natural gas hydrates. The device includes: a guide pipe; multiple evenly distributed interfaces on the lower side of the guide pipe from top to bottom, each interface being connected to a wellbore via a corrugated metal hose; multiple wellbores arranged in parallel; each wellbore being connected to an adjustment mechanism, which is mounted on the guide pipe and can adjust the vertical position of the corresponding wellbore. In this invention, the wellbore is connected to the guide pipe via a corrugated metal hose, therefore the connection between the wellbore and the guide pipe is not fixed. Furthermore, an adjustment mechanism for adjusting the wellbore position is provided. This adjustment mechanism allows for adjustment of the distance between the wellbores. When a wellbore layer fails, by reasonably adjusting the spacing between the wellbores, extraction can still be carried out on the failed layer.

The invention belongs to the technical field of natural gas exploration and development, and discloses a trajectory design method and related device for a highly-deviated well of a sand-coal superimposed gas reservoir, and the method comprises the steps: obtaining the information of a drilled well in a target area, predicting the plane distribution characteristics of a reservoir, and analyzing the geological adaptability; according to reservoir plane distribution characteristics and geological adaptability, determining an optimal trajectory of each gas-bearing layer section in the target area; and according to the determined optimal trajectory, designing a gas production process, a well drilling process and a transformation process of the highly-deviated well, and completing trajectory design of the highly-deviated well of the sand-coal superimposed gas reservoir. According to the method, multiple layers of differentiated unconventional sand coal reservoirs are utilized to the maximum extent, and the method has the advantages of being large in inclination, large in well control reserves, safe and reliable in drilling and production, environmentally friendly, sustainable and the like. The contact area of a gas storage layer can be effectively enlarged, the gas storage layer can be better penetrated, more oil and gas reserves can be obtained, unconventional oil and gas resources difficult to exploit can be better exploited, and the oil and gas exploitation efficiency is improved.

The application provides a continuous miner storage and transportation vehicle and a continuous mining system. The continuous miner storage and transportation vehicle comprises a support member, a scraper conveyor and a turnover member. The support member has a bearing part and a walking part for driving the bearing part to follow the walking of the miner. The scraper conveyor is arranged on the bearing part and is used for transferring the ore temporarily stored in the bearing part, i.e. the mined ore falls into the bearing part and is then transferred by the scraper conveyor. The whole process realizes continuous transportation of the ore and improves the mining efficiency of the continuous miner. The turnover member is arranged on the path of the ore falling from the bearing part to the scraper conveyor. The turnover member has a plurality of turnover parts arranged at intervals and a driving part for driving the turnover parts to turn. The driving part drives the turnover parts to rotate and changes the gap between adjacent turnover parts, so as to control the amount of ore falling from the bearing space to the scraper conveyor and prevent the ore gravity from directly pressing on the scraper conveyor, thereby preventing the technical problem that the scraper conveyor cannot be started.

The utility model provides a kind of broken material collecting device and mining machine, the bottom of hopper is provided with discharge port, power mechanism is set to the end of hopper, rotating shaft is rotatably set in hopper, and transmission connection with power mechanism, the outer surface of rotating shaft is equipped with the spiral structure for conveying material to discharge port, crushing assembly is set to the surface of rotating shaft. Through the above-mentioned broken material collecting device disclosed, rotating shaft is rotated by power mechanism, so that crushing assembly arranged on rotating shaft crushes material, and material is conveyed by the spiral structure of rotating shaft, so that crushed material is timely discharged through discharge port to realize continuous mining of material, compared with the existing mining equipment, the crushing system and material collecting device integrated design can not only reduce mining process, but also simplify the operation complexity and management difficulty of mining equipment, ensure the lump coal rate of coal, reduce mining cost, improve mining efficiency.

The application discloses a filling mining method of steeply inclined coal seam and relates to the technical field of coal mining. The method comprises the following steps: dividing each stage of the steeply inclined coal seam into upper layers, middle layers and lower layers; mining the upper layers, the middle layers and the lower layers; and forming a filling mining method of the steeply inclined coal seam with a sandwich type protection structure and a Z type filling structure during the mining process. The sandwich type protection structure is formed by consolidating a coal pillar, surrounding rock and concrete together, which can effectively protect the coal pillar from damage and maintain the stability of the mined-out area. The Z type filling body structure is formed by combining a reserved coal pillar, lower concrete and an inclined concrete column. The Z type filling body structure has a reserved coal pillar on the top and the bottom, and compared with other filling body structures, the Z type filling body structure formed by combining mining and filling is safer. The filling mining method of the steeply inclined coal seam can maintain the stability of the mined-out area and is beneficial to safe mining.

The application discloses a closed-loop extraction and isotope tracing method for hot flue gas displacement of coal bed methane, which comprises the following steps: first, using CH4 combustion and explosion fracturing technology to form a crack network in the in-situ coal seam by synergistic combustion and explosion reaction impact fracturing; then, injecting hot flue gas into the combustion and explosion fractured coal seam; the hot flue gas can promote the desorption of CH4 gas in the coal body due to its high temperature; the CO2, SO2 and NO2 in the hot flue gas can replace a large amount of CH4 gas adsorbed in the in-situ coal seam due to the competitive adsorption advantage; the extracted CH4 and hot flue gas can be continuously used in a closed loop; the hot flue gas storage is realized, and the coal bed methane extraction efficiency is improved; in addition, the combustion and explosion gas and the hot flue gas are marked by specific isotopes, and the migration characteristics and interaction of the combustion and explosion gas, the hot flue gas and the extracted CH4 gas in the target deep coal seam can be analyzed and reversed; therefore, the injection parameters of the combustion and explosion gas and the hot flue gas can be dynamically regulated and controlled, and the hot flue gas storage and CH4 extraction efficiency of the deep in-situ coal seam are maximized.

The application discloses a kind of filling loss mining method, which comprises: determining ground surface damage control layer;According to the related parameters of the ground surface damage control layer, the advancing distance of the coal mining face is calculated;When the coal mining face advances, according to the advancing distance of the coal mining face and the related parameters of the ground surface damage control layer, the grouting position of the separation zone below the ground surface damage control layer is grouted and filled, which can realize real-time grouting and filling of the separation zone with the advancing of the working face, and the coal pillar is not needed to be set, so as to ensure the coal seam recovery rate and improve the efficiency of coal mining.

This application discloses a backfilling mining method, apparatus, medium, and equipment for gently dipping thick ore bodies, relating to the field of underground mining technology in metal mines. The method includes: dividing the ore body into mining units along its vertical strike and determining structural parameters; selecting an adjacent mining area from one wing of the ore body as the first mining unit; and constructing a coordinated layout for drilling, ore extraction, and connecting roadways. Using the first mining unit as the basic operational unit, it is divided into a central main ore body area and upper and lower hanging wall triangular areas, and mining is carried out using a zoned coordinated mining process. Subsequent mining units are set up with the same parameters. While mining a portion of the first mining unit, the mining process is simultaneously applied to the corresponding areas of subsequent units, achieving spatial cross-construction. After mining is completed in each area of ​​the first mining unit, backfilling is carried out promptly, reserving a runway riser as a free face for subsequent mining, and reusing existing roadways as operational and ore extraction channels, achieving cyclic mining from one wing of the ore body to the other.

The invention discloses a method for determining the well opening and closing time length of an intermittent gas well, and relates to the technical field of oil and gas exploitation, and the method comprises the steps: obtaining the first pressure of a sleeve, a pressure inflection point corresponding to the first pressure and the second pressure of an oil pipe during the well closing period of the intermittent gas well in each reference production cycle, determining a plurality of reference well opening moments of the intermittent gas well according to the first pressure, the pressure inflection point and the second pressure; the gas well flow, the critical liquid-carrying flow and the second pressure of the casing pipe of the intermittent gas well in the well opening period in each reference production cycle are obtained, and multiple reference well closing moments of the intermittent gas well are determined according to the gas well flow, the critical liquid-carrying flow and the second pressure; and according to the multiple reference well opening moments and the multiple reference well closing moments of each reference production cycle, the reference well opening and closing duration of the reference production cycle is determined, according to the reference well opening and closing duration of the multiple reference production cycles, the target well opening and closing duration of the intermittent opening gas well in the target production cycle is determined, and the exploitation efficiency of the gas well can be improved.

The application provides a "7" shape shield support for mining, which comprises a top beam parallel to the roof in the ore body, a support shield beam vertical to the roof, a balance hydraulic cylinder connected between the top beam and the support shield beam, a support walking mechanism arranged on the top beam, a support sliding mechanism, and an extension shield mechanism arranged on the support shield beam, one end of the top beam and the support shield beam is hinged, the support walking mechanism is arranged on the inner side of the top beam away from the support shield beam, and has the freedom of extension relative to the top beam; the inner side of the top beam is provided with a sliding track extending along the support walking mechanism, the support sliding mechanism is arranged on the inner side of the top beam, is clamped in the sliding track, and has the freedom of sliding along the sliding track relative to the top beam; one end of the balance hydraulic cylinder is hinged with the support sliding mechanism, the other end is hinged with the inner side of the support shield beam, and the top beam has the freedom of swinging around the hinged shaft with the support shield beam under the driving of the balance hydraulic cylinder.

The invention belongs to the technical field of wellhead sealing, and particularly relates to a Christmas tree wellhead sealing device and a working method thereof. Comprising a wellhead; a Christmas tree; the two are butted through a flange plate; a sealing ring is arranged in the flange plate; a locking square column is mounted on the outer wall of the Christmas tree; the outer wall of the well mouth is connected with a positioning base; a lifting ring changing device is arranged on the positioning base; the lifting ring replacing device comprises a locking square cylinder which is connected to the top of the positioning base in a penetrating mode. The positioning base is in sliding fit with the locking square cylinder; a relative locking unit is arranged on the locking square cylinder; the relative locking unit comprises a limiting base which is installed on the side, away from the outer wall of the wellhead, of the locking square barrel. A U-shaped base is mounted on the positioning base; a rotating gear is connected in the U-shaped base; therefore, the sealing ring at the joint of the Christmas tree and the wellhead can be conveniently and quickly replaced, the Christmas tree does not need to be disassembled, the replacement efficiency of the sealing ring is improved, the oil exploitation efficiency is improved, and finally the use limitation of the wellhead sealing device is reduced.