124 results about "Low permeability" patented technology

The invention discloses a soil-pile foundation collaborative response seismic liquefaction discrimination device and method based on seismic oscillation time-frequency characteristics, and the method comprises the steps: building a multi-field coupling evolution model comprising a soil body domain, a fluid domain and a structural body, constructing a variable-scale grid architecture through a finite element method, balancing the high sensitivity and calculating the load, and carrying out the calculation of the load. Meanwhile, the fluid domain is directly coupled with the soil body unit through the shared node, and the Poisson's ratio is dynamically calibrated according to the void ratio. The multi-field coupling modeling mode can accurately simulate a soil-water-structure collaborative response mechanism, the problem of time-frequency characteristic mismatch caused by a scale effect in the prior art is avoided, and the strength degradation law and the aging characteristic of the in-situ soil body are accurately reflected. Compared with a traditional physical model which cannot reproduce nonlinear dynamic response under complex geological conditions, the method has the advantages that accurate description of high void ratio and low permeability of the soft sand is realized through numerical modeling, and the reliability of seismic liquefaction judgment results is further improved.

The invention discloses a shallow shale gas self-sealing reservoir formation identification method, which comprises the following steps: firstly, carrying out dual-energy CT scanning on a shale full-diameter core sample to obtain DEI values, and the difference of the DEI values embodies different lithologic (physical property) longitudinal change rules, i.e., different shale lithologic grain interlayer interlayers, different shale lithologic grain interlayer interlayers, different shale lithologic grain interlayer interlayers, different shale lithologic grain interlayer interlayers, different shale lithologic grain interlayer interlayers, and different shale lithologic grain interlayer interlayers; the development of the top and bottom plates of the high-quality shale reservoir enables the shale gas to have a self-sealing reservoir forming characteristic; then simulating the adsorbability of the shale gas through laboratory thermal cracking to obtain a shale gas adsorbability rule, and identifying whether the shale gas has a self-sealing reservoir forming characteristic or not. And finally, measuring the distribution rule of the microscopic porosity and the pore diameter through a scanning electron microscope, judging whether the shale layer is a non-or ultra-low permeability layer under the formation temperature and pressure condition or not, and identifying whether the shale gas has the self-sealing reservoir forming characteristic or not. According to the method, the self-sealing reservoir forming of the shale gas is identified in multiple aspects, and the method provides effective technical support for evaluating the favorable layer section of the shale and is of great significance in improving the exploration and development effect of the shale gas.

The invention provides a coastal area foundation pit dewatering system and method, and belongs to the technical field of foundation pit dewatering, the coastal area foundation pit dewatering system comprises a foundation pit, a plurality of light well points, a deep tube well and an electroosmosis auxiliary module, and the light well points are annularly arranged in a shallow layer area on the periphery of the foundation pit; the deep tube well extends to a deep area from the ground; and a plurality of electro-osmosis auxiliary modules are arranged in the peripheral clay layer area of the foundation pit. The annularly-arranged light well points evenly intercept shallow underground water around the foundation pit, the deep pipe wells can rapidly reduce the deep underground water level, and the drainage problem of a low-permeability clay layer area is effectively solved through the synergistic effect of the arranged electro-osmosis auxiliary modules and the well points / pipe wells; the synchronous precipitation uniformity of the complex soil layer is improved, layered targeted precipitation design is adopted in a shallow area, a deep area and a clay layer area, and the overall precipitation efficiency is improved. According to the foundation pit dewatering system in the coastal area, the problem that in the prior art, in the environment with complex hydrogeological conditions, the dewatering efficiency of a single dewatering measure is low is solved.

The invention discloses a high-capping-index and low-permeability single coal seam construction, pressing and explosion alternate permeability increasing method, which comprises the following steps of: performing pressure relief and permeability increasing on a coal seam through large-drill-diameter extraction, hole formation through a seam penetrating machine, and changing rock stratum structures of a coal seam top and a bottom plate through hydraulic fracturing so as to increase a gas diffusion channel, during large-drill-diameter extraction, drill holes are controlled to incline upwards by 20 m and incline downwards by 15 m respectively, the trend of the left contour line and the trend of the right contour line are controlled to be 15 m respectively, one group of drill holes are constructed at the interval of 5 m, and the drill hole construction diameter is phi 133 mm; hydraulic fracturing is carried out through the large-drill-diameter layer-penetrating drill holes to respectively fracture a top plate and a bottom plate of the coal seam, damage the rock stratum structure of the top plate and the bottom plate of the coal seam, change stress distribution of the coal seam and increase gas diffusion channels; after the outburst prevention measure layer-crossing construction in the large-drill-diameter area is carried out, fixed-point hole forming is carried out on a coal seeing section according to the actual coal seeing condition of the layer-crossing drilling holes at intervals of one group of construction layer-crossing hole forming drilling holes, and hole forming phi is 500 mm. According to the method, the gas extraction effect of the low-permeability coal seam can be greatly improved, and the probability of coal and gas outburst during tunneling is reduced.

The embodiment of the invention provides a method and device for determining the petroleum migration state of tight sandstone oil accumulation, and relates to the technical field of petroleum and natural gas. The method comprises the following steps: acquiring permeability and a plurality of flow velocity and pressure gradient curves of a plurality of sandstone samples; according to the flow velocity and pressure gradient curve, the Reynolds number and friction coefficient calculation formula related to the permeability and the apparent permeability calculation formula, a Reynolds number and friction coefficient curve related to the permeability and an apparent permeability pressure gradient curve are obtained through calculation; and according to the permeability, the permeability-related Reynolds number friction coefficient curve and the apparent permeability pressure gradient curve, constructing a migration flow state change chart. According to the method, the migration flow state change plate is constructed, and the plate displays three areas where petroleum cannot be migrated, nonlinearly migrated and linearly migrated in the sandstone sample; and determining the migration state of the petroleum in the sandstone sample and the minimum permeability of the petroleum in the sandstone sample through the migration flow state change chart.

The invention provides a method for determining a nanofluid oil displacement effect of a low-permeability reservoir, and relates to the technical field of oil exploitation. The method comprises the following steps: providing a core of a low-permeability reservoir, and measuring the particle size of nanoparticles in a target nanofluid; performing high-pressure mercury injection test and nuclear magnetic resonance measurement on the rock core to respectively obtain a rock core pore throat radius-distribution frequency relation curve and a first T2 image, and performing benchmarking on the two images to obtain a pore throat radius-relaxation time relation curve; carrying out displacement experiments (oil displacement, first water displacement, nanofluid displacement and second water displacement) on the rock core, and carrying out nuclear magnetic resonance measurement to obtain T2 images; and observing or calculating the area enclosed by the curve and the relaxation time in each image, and combining with a pore throat radius-relaxation time relation curve to obtain the oil displacement effect of the nanofluid on different pores of the oil reservoir. The oil displacement effect of the nanometer system is determined according to the characteristic parameters of the reservoir core before and after the nanometer fluid is injected, and the method has important guiding significance for formulating a scheme for improving the recovery effect of the low-permeability oil reservoir.

The present application relates to the technical field of geological data processing, and more particularly to a low-permeability reservoir geological dessert prediction method and system and a medium. The method comprises the following steps: obtaining low-permeability reservoir geological data; preprocessing the low-permeability reservoir geological data to obtain standard low-permeability reservoir geological data; performing multi-dimensional feature recognition on the standard low-permeability reservoir geological data to obtain multi-dimensional geological feature data; extracting key low-permeability reservoir information from the multi-dimensional geological feature data to obtain key low-permeability reservoir information; and extracting low-permeability reservoir cores from the key low-permeability reservoir information to generate low-permeability reservoir core data. Through data processing technology, pattern recognition technology and machine learning technology, the present application realizes multi-dimensional analysis of low-permeability reservoir geological features and correlation analysis in combination with the seismic characteristics of low-permeability reservoirs, thereby improving the accuracy of low-permeability reservoir geological dessert prediction.

A conformance control method includes identifying a target location of a wellbore formed from a terranean surface to two subterranean formations that include a high permeability formation having a first permeability and a low permeability formation having a second permeability that is equal or less than one-third of the first permeability. The method includes forming a first plurality of tunnels in the high permeability formation from the wellbore; injecting, into the high permeability formation and the low permeability formation, a chemical fluid from the wellbore through the first plurality of tunnels; expanding a sweep area of the injected chemical fluid by injecting the chemical fluid into the high permeability formation through the first plurality of tunnels; forming a second plurality of tunnels in the low permeability formation from the wellbore; and increasing a contact area of an injection fluid in the low permeability formation with the second plurality of tunnels.

The invention discloses a coal seam tunnel permeability increasing system based on supercritical CO2-pulsed water composite injection and a permeability increasing method of the coal seam tunnel permeability increasing system, and belongs to the technical field of high-ground-stress low-permeability coal seam tunnel gas extraction permeability increasing. The system comprises a supercritical CO2 injection unit, a pulse water injection unit, an intelligent monitoring regulation and control system and a rotary spray head assembly. According to the method, a multi-fracture network is formed through high permeability of supercritical CO2, then high-frequency impact of pulse water is used for expanding fracture opening and enhancing connectivity, meanwhile, water consumption is reduced so as to reduce the water blocking effect, and the permeability increasing requirement of the high-ground-stress low-permeability coal seam can be met. According to the method, supercritical CO2 and pulse water are used for synergic permeability increasing, the permeability increasing radius is effectively enlarged, compared with traditional hydraulic fracturing, the effect is obviously improved, and the connectivity of a fracture network is high. The rotary injection of the pulse water enables the energy to be uniformly distributed, and hole wall collapse caused by excessive fracturing is avoided.

The invention discloses a bionic fracture network fracturing device for a low-permeability coal seam, and relates to the technical field of efficient exploitation of oil fields. A bionic fracture network fracturing device for a low-permeability coal seam comprises a recycling mechanism 1 and a hole sealing mechanism 2. The recycling mechanism comprises a recycling body, a signal transmission module is fixedly embedded in one side of the recycling body, a liquid injection module is fixedly embedded in the other side of the recycling body, and fixing pieces are clamped to the two ends of the recycling body respectively. A first connecting assembly used for being in butt joint with the hole sealing mechanism is arranged on the lower side of the middle of the recycling body. A rod cracking hole located between the signal transmission module and the fixing piece on the same side is formed in one side of the recycling body in a penetrating mode, and a gas hole located between the liquid injection module and the fixing piece on the same side is formed in the other side of the recycling body in a penetrating mode. A rod cracking mechanism is arranged at the rod cracking hole, and a gas mechanism is arranged at the gas hole; the filling liquid flows through the crack pipes and the branch crack holes to form the bionic cracks of the main channel and the pre-branch, so that the connectivity and the coverage range of the crack network are remarkably improved.

A method for collecting a heated fluid from a fractured subterranean formation can include removing a fluid having a liquid phase from the fractured subterranean formation through a wellbore that is in fluidic communication with the fractured subterranean formation. The method can also include collecting from the wellbore the heated fluid having a vapor phase that is expelled from a low permeability rock matrix of the fractured subterranean formation. The method can also optionally include injecting an injection fluid having the liquid phase into the low permeability rock matrix of the fractured subterranean formation through the wellbore when a parameter falls outside a range of acceptable values.

The utility model relates to the technical field of gas extraction, in particular to a soft low-permeability coal seam gas extraction drilling wall protection supporting device which comprises a supporting pipe, a threaded pipe is arranged on the inner wall of the top end of the supporting pipe, a threaded groove is formed in the inner wall of the bottom end of the supporting pipe, an anti-loosening mechanism is arranged on the threaded pipe, an annular cavity is formed in the supporting pipe, and the annular cavity is communicated with the threaded groove. A connector is formed in one side of the threaded pipe and communicates with the annular cavity, a through groove is formed between the annular cavity and the threaded groove, a sealing ring is arranged on the threaded groove, and an inflation mechanism is arranged between the annular cavity and the supporting pipe; according to the structure, the whole supporting structure can be inflated only through one connector of the threaded pipe on the uppermost supporting pipe, the inflation bag is expanded and protrudes outwards in the inflation groove to be tightly attached to the wall face of a drilled hole, strong lateral supporting force is provided, and the supporting structure is particularly suitable for being used in a soft and low-permeability coal seam and can effectively prevent the wall face of the drilled hole from collapsing.

The application provides a low-permeability stratum contaminated groundwater remediation device and method, which comprises an industrial computer, the industrial computer is used for controlling the working state of an extraction mechanism according to the information inside a pumping well, a first monitoring mechanism and a second monitoring mechanism monitor the concentration change of groundwater pollutants, and feed back the groundwater pollution condition to the industrial computer, the extraction mechanism extracts groundwater into the inside of a groundwater purifier for treatment, and a transmission mechanism changes the position of the extraction mechanism according to the distribution of the groundwater pollutants; the low-permeability stratum contaminated groundwater remediation device and method have the advantages of improving the groundwater extraction efficiency, effectively improving the extraction effect of the groundwater pollutants, and reducing the operation cost of the groundwater extraction.

The invention discloses an ultra-low / ultra-low permeability reservoir blockage determination method based on a sidetrack coring technology. The method comprises the following steps that 1, a rock core sample at a preset position is obtained; 2, recording and numbering the positions of the rock core samples; 3, the permeability and porosity of the obtained rock core samples are measured respectively, the permeability and porosity damage degree of each rock core is calculated according to the original permeability and porosity of a reservoir, and the permeability damage and the horizontal distance from the rock core to a shaft and the porosity damage and the horizontal distance from the rock core to the shaft are calculated; and 4, determining the damage space distribution condition of the rock core sample according to the data of the permeability damage degree and the porosity damage degree obtained in the step 3, and completing the determination of the blockage position of the permeability reservoir. The invention belongs to the technical field of oilfield development and detection, and solves the problems that a reservoir damage analysis method in the prior art is relatively large in limitation, cannot accurately reflect the pore damage phenomenon of an ultra-low / ultra-low permeability reservoir, cannot directly carry out experimental analysis from the microscopic level of the reservoir, and is difficult to measure the damage degree of the pore level of the reservoir.

This disclosure relates to a chemical flooding development method for highly heterogeneous, low-to-medium permeability reservoirs. The method involves preferentially injecting a first substance into the thin, poor-permeability layer of the reservoir, followed by the simultaneous injection of a second, third, and fourth substance into both the thin, poor-permeability layer and the good-permeability layer. The second substance blocks the dominant flow channels in the target layer; the third substance adjusts the liquid absorption profile of the target layer, expands the swept volume, and improves the oil displacement efficiency; and the fourth substance prevents the third substance from advancing along the dominant flow channels. Ultimately, the remaining oil in the thin, poor-permeability layer is effectively displaced, and the dominant flow channels in the good-permeability layer are blocked, forming a balanced, continuous, and effective displacement method suitable for highly heterogeneous, low-to-medium permeability reservoirs. Therefore, the chemical flooding development method provided by this invention can effectively improve the recovery rate of low-to-medium permeability reservoirs.

The application relates to an intermittent pumping sampling method for a low-permeability reservoir, which comprises the following steps: calculating the lower limit of the formation mobility of continuous pumping sampling of an ultra-low-permeability reservoir; when the mobility is less than the lower limit of the formation mobility of continuous pumping sampling, intermittent pumping is carried out; the breakthrough volume of the formation fluid is obtained, and the original invasion depth of drilling fluid is obtained through simulation inversion; according to experimental data, the initial invasion speed of mud filtrate under different original invasion depths is obtained, and the upper limit of the continuous invasion speed of mud filtrate in the pumping sampling process is determined; the numerical simulation of the key factors of intermittent pumping is carried out, intermittent pumping operation schemes under different conditions and the total operation time of the corresponding operation schemes are obtained; the optimal pressure recovery ratio is determined; the intermittent pumping operation scheme under the continuous invasion speed of mud filtrate and the optimal pressure recovery ratio and the total operation time of the operation scheme are obtained. The scheme can solve the sampling problem of the ultra-low-permeability reservoir and improve the success rate of sampling.

The invention discloses an ultra-low permeability reservoir development well type optimization method based on oil layer stacking modes. The method is specifically implemented according to the following steps that 1, the oil layer stacking modes are divided into a thick oil layer, a thin oil layer and a thin interbed according to ultra-low permeability reservoir sand body structure characteristics and reservoir physical property characteristics; 2, according to actual block reservoir parameters, oil reservoir mechanism models corresponding to three oil reservoir stacking modes of a thick oil reservoir, a thin interbed and a thin oil reservoir are established respectively; 3, a directional well, a highly-deviated well and a horizontal well are arranged in the thick oil layer oil reservoir mechanism model, the thin interbed oil reservoir mechanism model and the thin oil layer oil reservoir mechanism model respectively, and numerical simulation calculation is conducted through numerical simulation software; 4, well type optimization is conducted on the thick oil layer, the thin oil layer and the thin interbed according to calculation results of numerical simulation. The problems that in the prior art, the well type adaptability is poor, and the single well yield is low are solved.

The invention discloses a method for evaluating compressibility of a deep ultra-low permeability rock reservoir, which comprises the following steps of: analyzing a relationship between a main control factor of the compressibility of the reservoir and the fracturing difficulty of the reservoir, and determining a relational expression for representing the influence degree of the main control factor on the compressibility of the reservoir; quantitatively representing the influence degree of the main control factors on the reservoir compressibility based on the relational expression of the influence degree of each main control factor on the reservoir compressibility; and based on the influence degrees of different main control factors, evaluating the reservoir compressibility by adopting an analytic hierarchy process. According to the method disclosed by the invention, more accurate reservoir compressibility evaluation is realized by quantitatively representing the influence degree of the elastic modulus, the Poisson's ratio, the fracture toughness, the crustal stress and the natural fracture on the reservoir compressibility.

The application discloses a kind of low permeability pore-fracture multiscale structure in non-aqueous phase pollutants space-time transmission tracking method, comprising: integrated C-ERT technique simulates the long-term migration process of NAPLs in low permeability pore-fracture multiscale structure formation, real-time continuous acquisition of the resistivity space-time distribution of contaminated soil;Study the influence of NAPLs concentration on the resistivity of contaminated soil, establish the mathematical correlation model of the resistivity of contaminated soil and NAPLs concentration;Obtain the theoretical value of the space-time distribution of NAPLs concentration;Obtain the measured value of NAPLs concentration, correct mathematical correlation model, and as the quantitative evaluation basis of space-time transmission tracking process.The application can simulate the long duration, large scale migration and transformation process of NAPLs in low permeability pore-fracture multiscale structure formation, and real-time continuous tracking of pollutant trace, realize the visualization analysis of the space-time distribution of pollutant concentration, and it is of great significance to the targeted repair and management of pollutants.

The present invention belongs to the technical field of petroleum development, and specifically relates to a method for making a microscopic glass model of heterogeneous rock pores. The method includes, during the process of making an image negative film, obtaining a pore map with different permeability gradients based on a thin film image of a cast body of a core with different permeabilities to make a negative film; converting the width of the pores in the high permeability zone according to the depth requirements of the design, obtaining a contracted size, and performing photoetching on a chrome plate; etching glass to form three-dimensional channels of different depths, first etching several shallow depth zones, one part as a low permeability zone and one part as a high permeability zone; sealing the channels etched as the low permeability zone portion; and etching the channels etched as the high permeability zone portion a second time to form high permeability zone channels. The model made by the method of the present invention has three-dimensional channels of varying depths, which can simulate the actual situation of fluid migration in the channels, reflecting the difference in permeability not only in the plane but also in the vertical direction.

A conformance control method includes identifying a target location of a wellbore formed from a terranean surface to two subterranean formations that include a high permeability formation having a first permeability and a low permeability formation having a second permeability that is equal or less than one-third of the first permeability. The method includes forming a first plurality of tunnels in the high permeability formation from the wellbore; injecting, into the high permeability formation and the low permeability formation, a chemical fluid from the wellbore through the first plurality of tunnels; expanding a sweep area of the injected chemical fluid by injecting the chemical fluid into the high permeability formation through the first plurality of tunnels; forming a second plurality of tunnels in the low permeability formation from the wellbore; and increasing a contact area of an injection fluid in the low permeability formation with the second plurality of tunnels.

The invention discloses a coal seam accurate fracturing and permeability increasing method based on a low-field nuclear magnetic resonance test combined parameter well, samples of different depths of a coal seam are obtained by constructing the parameter well, and parameters such as porosity of the samples of different depths of the coal seam are obtained by testing based on a low-field nuclear magnetic resonance test technology. Then the production casing extends into the well bottom, well cementation is conducted through a well cementation truck special for an oil field, a parameter well is transformed into a fractured well, an accurate fracturing scheme is formulated according to a low-field nuclear magnetic resonance test result, the number of perforations is increased for the position with the low permeability in a reservoir, hydraulic fracturing parameters are adjusted, and therefore a complex fracture network is constructed; fracturing difficulty is reduced, coal seam permeability is effectively improved, and finally accurate permeability increasing of the regional coal seam is achieved. In addition, the low-field nuclear magnetic resonance test method provided by the invention has no requirement on the appearance of a test sample, and can effectively solve the problem that a complete sample cannot be obtained from a soft coal seam.

The invention discloses a low-permeability oil and gas reservoir identification method and device, a medium and electronic equipment. The method comprises the following steps: acquiring reservoir parameters, wherein the reservoir parameters comprise reservoir abundance, permeability, porosity, effective sand body thickness, oil saturation and starting pressure gradient; determining the comprehensive weight of the reservoir parameters according to the identification degree of the reservoir parameters on the low-permeability oil and gas reservoir; determining a reservoir level identification interval according to the reservoir parameter comprehensive weight; and based on the reservoir level identification interval, identifying the low-permeability oil and gas reservoir. The accuracy of identifying the type of the low-permeability oil and gas reservoir can be improved.

The present application relates to low permeability oil and gas reservoir oil testing layer selection method technical field, it is a kind of low permeability reservoir oil testing layer selection evaluation method, including fresh rock sample every 1 hour is carried out once nuclear magnetic resonance experiment, according to the total porosity of core just when out of cylinder and the total porosity of last nuclear magnetic resonance experiment, the content of light hydrocarbon component in total pore is calculated, light hydrocarbon component dispersion coefficient X is calculated again, with the oil testing result of oil well that has been tested and light hydrocarbon component dispersion coefficient X establish low permeability reservoir oil testing layer selection chart.The present application is advantageous in that using nuclear magnetic resonance full diameter core experiment, light hydrocarbon component dispersion coefficient is calculated, the permeability and oil-gas-bearing property of core are dynamically reflected, avoid the problem of big difference in artificial rock sample test result.Light hydrocarbon component dispersion coefficient is compared and analyzed with the oil testing result that has been tested, and low permeability reservoir oil testing layer selection chart is established, low permeability reservoir oil testing layer is guided, and oil and gas rate of oil testing is improved.

The invention discloses a CO2 mineralization sequestration and geological hydrogen synergistic enhanced mining method and a simulation experiment method, which are applied to a geological hydrogen reservoir containing ultra-basic rock, and the method comprises the following steps: screening the ultra-basic rock reservoir rich in magnesium iron minerals, and arranging a bottom injection well and a top recovery well; supercritical CO2 is injected into the bottom injection well, and fracturing is carried out to form a fracture net; a migration channel for CO2 sinking and H2 floating is established; geological hydrogen is extracted, the recovery pressure difference is regulated and controlled to limit upward flowing of CO2, and components and yield of extracted gas are monitored; carrying out CO2 mineralization storage and artificial geological hydrogen supply; and in multiple cycles, the geological hydrogen recovery rate is increased, and CO2 mineralization and storage are completed step by step. According to the method, aiming at the characteristics of low porosity and low permeability and fracture control seepage of the ultra-basic rock reservoir, a supercritical CO2 fracturing technology and CO2 displacement are adopted to improve the permeability and reaction contact area of the reservoir, the geological hydrogen recovery efficiency and the CO2 storage efficiency and economy can be synchronously improved, and cyclic synergistic enhancement of hydrogen energy development and CO2 mineralization storage is realized.

The application discloses a kind of special low permeability sandy conglomerate reservoir well bottom flow pressure level keeping prediction method, including the statistical special low permeability sandy conglomerate body oil reservoir core sample's permeability and pressure sensitivity relationship data;Calculate the ratio of the permeability of rock sample under each level net confining pressure condition and the permeability tested under initial net confining pressure condition;Draw the relationship curve of net confining pressure value and permeability change rate;Predict the permeability loss ratio of reservoir near the bottom of production well with the increase of production pressure difference;Calculate production pressure difference, compare permeability classification data, calculate the permeability reduction ratio in the range of salt well bottom and the influence on fluid production rate.The application is mainly aimed at the production characteristics of the production well of special low permeability sandy conglomerate reservoir, explains the internal cause of its change, and provides development theoretical basis;It has guiding significance for the initial development mode, method and production pressure control of special low permeability sandy conglomerate reservoir.

The application discloses a kind of low permeability reservoir underground gas storage multi-cycle injection-production condition under the prediction method of effective reservoir capacity boundary dynamic evolution, and the application is based on injection-production intensity driving seepage parameter self-adaptive evolution under the condition of low permeability reservoir underground gas storage multi-cycle strong injection and strong production, and the effective reservoir capacity boundary is dynamically predicted, to solve the systematic overestimation problem caused by parameter static, threshold effect neglect and connectivity loss in the effective reservoir capacity boundary prediction of low permeability reservoir underground gas storage under the condition of multi-cycle strong injection and strong production. Realize: the effective reservoir capacity boundary of injection stage and production stage is predicted respectively;Seepage parameter self-adaptive evolution with cycle and injection-production system intensity, not dependent on field testing / monitoring data;Through threshold-conductivity-connectivity accessibility triple criterion, the effective reservoir capacity boundary meeting engineering definition is obtained.

The invention relates to a CO2 injection and production collaborative optimization method, device and system for a low-permeability reservoir. The method comprises the steps that geological parameters of a target area and a current injection-production well pattern strategy are obtained; inputting the injection-production well network strategy into a preset pressure-deformation coupling model to obtain a pressure distribution matrix of each reservoir, a surface deformation vector diagram and a pressure value of each wellhead of the target area output by the pressure-deformation coupling model; inputting the geological parameters, the current injection-production well pattern strategy, the pressure distribution matrix of each reservoir, the surface deformation vector diagram and the pressure value of each wellhead into a BP neural network which completes training, and obtaining a prediction result output by the BP neural network; determining an optimization direction of a preset multi-target optimization model based on the prediction result; and on the basis of the optimization direction, an NSGA-II algorithm is adopted to carry out optimization solution on the multi-objective optimization model, and an optimized injection-production well pattern strategy is obtained. According to the scheme, the reasonability of the CO2 injection-production collaborative optimization scheme of the low-permeability reservoir is improved.

The invention discloses a low-permeability reservoir carbon dioxide flooding numerical simulation method based on Maxwell-Stefan cross diffusion, and belongs to the technical field of reservoir numerical simulation and recovery efficiency improvement. Comprising the following steps: establishing a mass conservation equation of each component based on an oil reservoir thermodynamic field, a rock physical property field, an effective diffusion coefficient matrix and reaction kinetic parameters; a diffusion flux item is expressed by a generalized Fick law based on a Maxwell-Stefan theory so as to describe a multi-component cross diffusion effect; a reaction source convergence item is determined by a COand crude oil reversible miscible phase kinetic model so as to describe a miscible phase and split phase dynamic process; sequentially executing a diffusion transmission step and a chemical reaction step for solving by adopting an operator splitting method to obtain an updated concentration field, and synchronously updating the thermodynamic field, the rock physical property field, the reaction kinetic parameters and the effective diffusion coefficient matrix; repeatedly iterating until each field and parameter change meet a convergence condition, and completing simulation of each chemical component concentration field; according to the method, the physical simplification defect in low-permeability simulation is overcome, and high-precision prediction of the displacement process is achieved.