30 results about "Enhanced recovery" patented technology

The embodiment of the invention provides a method for simulating full-life-cycle gas-water occurrence and utilization of a low-permeability tight gas reservoir, and belongs to the technical field of gas reservoir development. The method comprises the following steps: constructing an online nuclear magnetic core displacement experimental device; debugging test parameters of the online nuclear magnetic core displacement experiment device; according to the online nuclear magnetic core displacement experimental device, gas-water occurrence and dynamic changes of a reservoir forming stage, a depletion exploitation stage and a gas injection recovery efficiency improving stage are continuously simulated for a core. According to the method, the gas-water occurrence and dynamic change characteristics in the full life cycle process of low-permeability tight gas reservoir filling reservoir forming-depletion exploitation-gas injection recovery efficiency improvement can be accurately described from the microscopic angle, and technical support is provided for deployment and adjustment of a gas reservoir development scheme and optimization of technical measures for gas injection recovery efficiency improvement in the later development period.

The application provides a method for improving the recovery of natural gas hydrates in permafrost regions. The method comprises the following steps: (1) discharging free gas from the target permafrost region natural gas hydrate reservoir by depressurization, so that the reservoir temperature of the target permafrost region natural gas hydrate reservoir is less than 0 DEG C and greater than or equal to -6 DEG C, and the reservoir pressure reaches 0.8-1.2 times the phase equilibrium pressure of the natural gas hydrate; (2) injecting a mixed gas of CO2 and H2 into the target permafrost region natural gas hydrate reservoir for multiple rounds of throughput sweeping; wherein, between each round of throughput sweeping, huff and puff is carried out, and the temperature of the target permafrost region natural gas hydrate reservoir is maintained at less than 0 DEG C and greater than or equal to -6 DEG C; (3) after the throughput sweeping is completed, injecting CO2 into the target permafrost region natural gas hydrate reservoir for sweeping to recover free H2 and for geological storage of CO2. The method can significantly improve the recovery of natural gas in permafrost regions, effectively ensure the stability of the reservoir, and achieve geological storage of carbon dioxide.

There is provided herein a liquid solution for the recovery of oil from carbonate reservoirs comprising a solid chemical composition comprising Polyhalite in a % weight range of 70 to 99.5; NaCl in a % weight range of 5 to 30; SiO2 in a % weight range of 0.1 to 5; and injected water selected from the group including sea water, diluted sea water, desalinated seawater, produced water, aquifer water, river water, surface water, fresh water, distilled water or a combination of thereof;wherein said solid chemical composition is dissolved in said injected water in an amount of 1-10 grams of said solid chemical composition per 1 liter of said injected water.

This invention provides a method for preparing a high-salinity zinc oxide-resistant nanofluid mediated by Halomonas sp. and its application in enhancing oil recovery. Specifically, it includes: a Halomonas sp. strain CDH-2, with accession number CCTCC NO: M 2025786, which can rapidly grow in high-concentration salt solutions and produce salt-resistant extracellular metabolites. Fermenting and culturing CDH-2 under high-salt conditions yields a fermentation broth with a surface tension below 30 mN / m. Mixing and culturing the obtained fermentation broth with a metal precursor solution yields a high-salinity-resistant metal nanofluid. The resulting metal nanofluid maintains good stable dispersibility in high-salinity water and effectively reduces oil-water interfacial tension. It alters the wettability of oil-wetting surfaces, emulsifies and disperses crude oil, and reduces crude oil viscosity. Therefore, it can be used as an enhanced oil recovery agent in high-salt reservoirs and is widely applied in oilfield flooding, well huff and puff, and heavy oil viscosity reduction.

The invention relates to a combined development method and system for improving the recovery ratio of a deepwater gas field, and the method is characterized in that the method comprises the steps: calculating the acid gas content of each newly developed gas field based on the acid gas content of each newly developed gas field and the distance between a newly built production platform and each newly developed gas field; the position of a newly-built production platform and the arrangement and connection relation of underwater facilities of all newly-developed gas fields are determined; determining the optimal relying direction of each newly developed gas field in different development stages of the whole cycle according to the relying facility process treatment facility capacity, the conveying flow and the pressure relation; according to the method, idle pipelines are utilized, based on a relational graph of pipeline conveying flow and conveying pressure, natural gas is reversely driven through a newly-built production platform, the pipeline conveying flow of a newly-developed gas field is increased, and the wellhead pressure of the gas field is reduced, so that the cumulative yield of the gas field can be increased, and a technical support is provided for development of the deepwater marginal gas field; the device can be widely applied to the field of deepwater oil-gas field development.

The present application relates to the technical field of enhanced recovery in water flooding extra-high water cut stage, and particularly relates to a method for improving recovery by using the advantage of plugging in bypass well, comprising: performing flushing capacity test experiment according to permeability and gel system injection scheme, if the experimental result does not meet the first requirement, adjusting the gel system injection scheme to determine the optimal injection scheme; performing recovery and residual oil saturation test experiment according to the plugging position and the optimal injection scheme, if the experimental result does not meet the second requirement, adjusting the plugging position and / or the gel system injection amount in the optimal injection scheme to determine the final plugging position and / or injection scheme. The present application can realize effective plugging in deep high permeability reservoir, make the injected water divert to displace the remaining oil in low permeability reservoir, and finally realize the improvement of water flooding recovery.

The invention discloses a method for determining a chemical flooding block popularization benefit oil price limit, and solves the problems that a chemical flooding scheme is long in economic evaluation time consumption and cannot meet medium and long term planning in tertiary oil recovery. The method comprises the following steps: acquiring a chemical flooding potential block well pattern adjustment mode and investment allocation; chemical flooding economic evaluation and development parameters are obtained; establishing a chemical flooding enhanced recovery efficiency economic limit model, and calculating enhanced recovery efficiency economic limits under different development modes, different oil prices and different single well controlled reserves to obtain an economic limit chart; based on the development parameters of the chemical flooding potential block, when the recovery efficiency improving technical level of the chemical flooding potential block is equal to the recovery efficiency improving economic limit, according to the economic limit chart, interpolation is carried out to obtain the popularization benefit oil price of the chemical flooding potential block; the benefit oil prices are sorted from small to large, and the development and popularization sequence is optimized. According to the method, the popularization economic benefits and the popularization sequence of different blocks can be determined, so that a scientific and reasonable decision basis is provided for medium-and-long-term planning of tertiary oil recovery.

The invention belongs to the technical field of energy exploitation, and particularly relates to a multi-objective optimization method and system for gas reservoir injection, extraction and storage, and the method comprises the steps: firstly obtaining regulation and control parameter variables of extraction and storage, and calling an improved sampling algorithm for sampling combination to generate sample data; calling CMG data files for batch modification, extracting well names and DATE commands from the original dat file, simulating by combining sample parameters, generating a new scheduling block, inserting the new scheduling block into the last DATE command of the original file, generating a new CMG file, and exporting and merging CSV after processing; constructing a multi-output regression prediction model, and training the model by using a CSV file; then all regulation and control parameter variable combinations are extracted, data are exported, the trained model is called for prediction, and a parameter full combination is obtained; and finally, constructing a multi-objective optimization model, and exporting a Pareto optimal solution as a result by taking maximization of cumulative yield and storage efficiency as an objective. According to the invention, the problems of low efficiency and inaccurate precision of collaborative operation of sealing and natural gas exploitation in the prior art can be solved.

The invention discloses a coal-series gas carbon dioxide production increasing simulation method based on a low-field nuclear magnetic resonance technology, and belongs to the technical field of coal-series gas development. The method specifically comprises the following steps: (1) simulating gas bearing conditions of different lithologic reservoirs under a waste condition; (2) identifying the occurrence state of polymorphic CH4 in each lithologic reservoir based on a low-field nuclear magnetic resonance technology; (3) CO2 is injected into all the lithologic reservoirs, and the CO2 air inflow in all the lithologic reservoirs is recorded in real time; (4) quantitatively representing the phase change of the multiphase fluid along with the CO2 injection time after the CO2 enters each lithologic reservoir based on the dynamic quantification of the multiphase fluid; and (5) constructing a response surface model, and determining the optimal injection condition of CO2. According to the method, the CO2 injection amount, the multi-state CH4 occurrence state change and the multi-phase fluid phase evolution in different lithologic reservoirs under the waste condition are monitored in real time, data support is provided for optimizing parameters such as CO2 injection pressure, temperature and duration, and the double targets of efficient utilization of coal series gas residual resources and CO2 geological sequestration are achieved.

The invention discloses a recovery efficiency improving method and device for horizontal well volume fracturing development and a medium. The method comprises the steps that S10, basic parameters of a target oil reservoir are obtained; s20, determining a volume fracturing and seam spacing driving and mining development mode; s30, parameter optimization of the inter-seam driving and mining system is carried out; s40, selecting an inter-seam drive-production injection-production process, and establishing an implementation parameter optimization method; s50, construction parameters are determined; and S60, fracturing design and on-site construction are carried out. According to the method, through volume fracturing and an inter-seam driving and mining development mode, an inter-seam driving and mining full-life-cycle process parameter optimization method is formed, and the problem that the depletion type development recovery rate of the tight oil reservoir is low is solved; by selecting an inter-seam drive-production injection-production process, an implementation parameter optimization method is established, and energy supplementation of the horizontal well in the whole life cycle is achieved; the method has universality for tight oil reservoirs, the method is used for constructing driving and production fracturing design suitable for different reservoirs, the method can be popularized to different tight oil blocks, and the crude oil yield and recovery efficiency are effectively improved.

The invention discloses a method for intensively recovering sulphide ore by regulating and controlling the surface tension of ore pulp, which comprises the following steps: with sulphide ore as a research object, grinding raw sulphide ore and preparing into ore pulp with fixed concentration, and regulating and controlling the surface tension of the ore pulp of the sulphide ore to be within a range suitable for floating by adding a flotation collecting agent, a pH regulator and a foaming agent. And efficient flotation recovery of sulfide ore is achieved. The method is technically characterized in that under the action of the combined reagent, gangue minerals are effectively inhibited by regulating the surface tension of ore pulp to be within the range suitable for floating, meanwhile, sulfide ores are activated, and through the direct flotation technological process, strengthened recovery of the sulfide ores is successfully achieved. The technology has the advantages of high recovery rate, good selectivity, strong adaptability and the like, and is suitable for industrial production. In a gold-bearing sulfide ore flotation experiment, the ore pulp surface tension is regulated and controlled to be 48-50 mN / m, the concentrate grade and the recovery rate are successfully improved, the gold concentrate grade is improved to 39.42 g / t from 34.02 g / t before application, and the recovery rate is improved by 10.37%.

The present application relates to the technical field of carbon dioxide capture, utilization and geological storage, and particularly to a method, system, device and storage medium for CO2 enhanced gas reservoir recovery and storage, the method comprising: S100, acquiring dynamic parameters of a developed target gas reservoir in a current state, and analyzing key factors; S200, constructing a potential prediction model for CO2 enhanced recovery of the target gas reservoir, and generating a CO2 displacement recovery enhancement range of the target gas reservoir; S300, analyzing whether the CO2 displacement recovery enhancement range of the target gas reservoir is greater than an economic production range; S400, constructing a basic numerical simulation model of an actual development well group of the target gas reservoir, and generating an economic net present value and a CO2 geological storage amount; S500, generating a conversion timing and corresponding simulation engineering parameters by using a Bayesian adaptive direct search algorithm, and calculating a target function; and S600, generating optimal engineering parameters. By using the present application, the CO2 recovery rate can be improved, the effective storage amount can be maximized, the optimization cost can be reduced, and the optimization efficiency can be improved.

The application discloses a carbonate rock oil reservoir recovery improvement method and system, and performs thermal gravity analysis on crude oil extracted from a light oil reservoir, divides the whole process of crude oil oxidation according to a DSC curve peak value and an inflection point; different oxygen concentration reduction oxygen air is configured for the divided whole process of crude oil oxidation; oxygen concentration, gas injection amount and oxidation time of the different oxygen concentration reduction oxygen air are changed based on reservoir temperature and pressure, the different oxygen concentration reduction oxygen air is injected into a stratum, and influence on crude oil oxidation characteristics is analyzed; the best reduction oxygen air injection parameter suitable for the light oil reservoir is determined according to the influence of the different oxygen concentration reduction oxygen air on the crude oil oxidation characteristics, and the recovery of the carbonate rock oil reservoir is improved. The crude oil production is greatly improved, and the application prospect is wide.

The application provides a low-permeability sand-shale oil reservoir partitioned gas-water injection enhanced recovery method, which comprises the following steps: step 1, carrying out sand-shale different facies belt reservoir characteristic research; step 2, determining gas-water injection partitioned boundary; step 3, dividing partitioned range of different development modes; step 4, determining development technical policy in different partitioned ranges; step 5, preparing development scheme of full-area differential development mode and implementing; and step 6, tracking and adjusting partitioned range and implementing scheme. The low-permeability sand-shale oil reservoir partitioned gas-water injection enhanced recovery method is based on low-permeability sand-shale oil reservoir different facies belt reservoir connectivity characteristics, adopts differential partitioned gas-water injection mode to supplement formation energy, improves effectiveness of formation energy supplement, and greatly improves low-permeability sand-shale oil reservoir recovery.

The application provides a balanced steam injection method for improving the recovery of extra-heavy oil reservoirs, comprising the following steps: step 1, injecting wet saturated steam under the condition that the pressure is not higher than the fracture pressure of the extra-heavy oil reservoir; step 2, comprehensively considering the variable mass flow and variable dryness of the injected steam in the oil layer section and the reservoir properties of the oil layer section, determining the required division of the steam injection section in the oil layer section; step 3, establishing a process calculation method for balanced steam injection, and determining the shunt injection amount of each injection distributor; step 4, forming a balanced steam injection process string of the injection distributor + heat insulation tubing for balanced steam injection; and step 5, forming a high-temperature steam cavity and a drainage cavity which are balanced and expanded along the oil layer section. The balanced steam injection method for improving the recovery of extra-heavy oil reservoirs forms a high-temperature steam cavity and a drainage cavity which are balanced and expanded along the oil layer section in the reservoir, thereby avoiding the problem that the heated crude oil cannot effectively flow back due to the steam path during the steam injection process of the extra-heavy oil, and reducing the water recovery rate, the oil production and the recovery rate.

The present application relates to a kind of shale matrix two-phase flow simulation and phase permeability curve determination method and device, belong to shale gas multiphase flow simulation technical field.The present application discloses a kind of shale matrix two-phase flow simulation and phase permeability curve determination method and device, comprising: the single-phase permeability of the target reservoir core under different effective stress is determined;PNM model is extracted based on connected pore;The radius of pore and throat after deformation in PNM model under different effective stress and the permeability after deformation are simulated and calculated, and the single-phase permeability after deformation is fitted;PNM model under different effective stress is updated;Capillary inlet pressure is calculated;Relative permeability in PNM model under different effective stress is calculated.The present application is used for the gas-water two-phase flow simulation of shale gas reservoir under variable stress, and also can be used for stress-sensitive simulation and analysis of dense sandstone and carbonate rock and other various lithology reservoirs, has wide application value in the aspect of shale gas development practice and enhanced recovery.

The application discloses a tackifier, a preparation method of the tackifier, a composite plug oil displacement agent and an enhanced oil recovery method. The tackifier contains structural unit A, structural unit B, structural unit C and structural unit D, and the mass ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D is (2000-20000):(2000-40000):(4000-60000):(6000-100000), n is 1-15, m is 1-20, and the viscosity average molecular weight of the tackifier is 45-50 million. The tackifier has the following advantages: under the condition of a temperature of 60-70 DEG C and a salinity of 10000 mg / L, the viscosity of a polymer solution is greater than 100 mPa s; when the concentration of the polymer solution is 1000 mg / L, the surface tension is less than 40 mN / m, the tackifier has the function of emulsifying and dispersing crude oil, and the oil displacement efficiency of a physical model is increased by more than 12%.

The present application belongs to the technical field of energy exploitation, and particularly relates to a multi-target optimization method and system for gas reservoir injection, extraction, production and storage. First, the control parameter variables for extraction and storage are obtained, and an improved sampling algorithm is called to sample and combine to generate sample data. Then, a CMG data file is called to modify in batches, and the well name and DATE command are extracted from the original dat file. The sample parameters are simulated, a new scheduling block is generated and inserted into the original file at the last DATE command, a new CMG file is generated, and the processed CSV is exported and merged. Next, a multi-output regression prediction model is constructed, and the model is trained with the CSV file. Then, all the control parameter variables are combined and exported, the trained model is called to predict, and the parameter full combination is obtained. Finally, a multi-target optimization model is constructed, the cumulative production and storage efficiency are maximized, and the Pareto optimal solution is exported as the result. The present application can solve the problem of low efficiency and inaccurate precision in the existing technology of storage and natural gas exploitation collaborative operation.

The invention discloses an experimental device and method for simulating multi-element medium injection huff and puff of a fractured horizontal well, and relates to the technical field of oil and gas exploitation multi-element medium injection for improving the recovery ratio and geological storage. The invention provides a multi-element medium injection huff and puff model and experimental method for a horizontal well, the type of the horizontal well can be a multilateral well, a fishbone well and the like, the simulated injection medium comprises water injection, gas injection and chemical flooding injection, and the corresponding model and experimental method can meet the requirement that under the action of edge and bottom water, the water injection efficiency can be greatly improved. Multiple injection medium huff and puff exploitation modes of multiple types of horizontal wells are adopted, so that actual production conditions in an oil reservoir are closer; according to the designed physical model and the experimental method, the range that the model is suitable for injection-production development of multiple fluids of the horizontal well is widened, then the development effect evaluation requirement of the horizontal well under the condition of multiple injection media is met, the indoor simulation method is closer to the actual oil reservoir condition and development mode, the evaluation time is shortened, the development cost is reduced, and the development efficiency is improved. And an indoor evaluation technology for improving the recovery efficiency is perfected.

The invention relates to the field of viscosity reduction and recovery efficiency improvement of thick oil, and discloses a compound with functions of reducing viscosity and improving the recovery efficiency of thick oil as well as a preparation method and application of the compound. The compound has a chemical structure as shown in a formula 1 and has relatively high temperature resistance, salt resistance and calcium and magnesium resistance, and a solution of the compound can form a stable oil-in-water emulsion with thickened oil, so that the flow resistance is reduced, and the viscosity of crude oil is greatly reduced.

The invention belongs to the technical field of oil and gas field recovery efficiency improvement, and discloses a CO2 gas driving soluble foaming agent and a preparation method thereof.The preparation method comprises the steps that diisocyanate is added into a solvent to be completely dissolved, disaccharide is added, and an intermediate A is obtained after the reaction is finished; under a nitrogen atmosphere, adding fluoroalcohol into the intermediate A, uniformly stirring, dropwise adding a catalyst, and reacting to obtain an intermediate B; and adding a sulfonating reagent into the intermediate B, and stirring for reaction to obtain the CO2 gas-driving soluble foaming agent. The CO2 gas displacement soluble foaming agent prepared by the method has remarkable advantages in the aspects of solubility, oil resistance, temperature resistance, salt resistance, environmental friendliness and the like, and the foaming agent has wide application prospects and important economic values in the fields of oil exploitation, gas displacement and the like due to the advantages.

The present application provides a kind of multi-round throughput horizontal well multi-element thermal fluid pressure control oil discharge enhanced recovery method, the multi-round throughput horizontal well multi-element thermal fluid pressure control oil discharge enhanced recovery method includes: step 1, inject viscosity reducer into reservoir;Step 2, inject foam or gas into reservoir;Step 3, inject high-temperature oil displacement agent into reservoir;Step 4, inject high dry steam into reservoir;Step 5, after soaking well, open well production.The multi-round throughput horizontal well multi-element thermal fluid pressure control oil discharge enhanced recovery method strengthens viscosity reduction and oil washing efficiency, improves development effect, can effectively improve the recovery of heavy oil reservoir after multi-round throughput, horizontal well pressure control oil discharge throughput technology, form a kind of multi-round throughput horizontal well multi-element thermal fluid pressure control oil discharge enhanced recovery method.

The invention relates to the technical field of low-permeability reservoir pressure-drive water injection development, and provides a method for optimizing the injection rate of a carbon dioxide slug before pressure-drive water injection. The method comprises the following steps: establishing a three-dimensional geologic model according to pre-acquired oil reservoir data of a target block; carrying out numerical simulation by utilizing the model, obtaining the accumulated oil production of each pressure-driving water injection parameter in a preset time period, and calculating the difference value between the accumulated oil production of different preposed carbon dioxide slug pressure-driving water injection parameters and the accumulated oil production of conventional pressure-driving water injection parameters to obtain the relative accumulated oil increase of different pressure-driving water injection parameters; and on the basis of the oil reservoir geological reserves and the total carbon dioxide injection amount of the target block, the recovery efficiency improvement range, the oil change rate and the final corresponding pressure flooding water injection preposed carbon dioxide slug injection amount are obtained. By means of the method, the relation between the injection amount of the carbon dioxide slug before pressure flooding water injection and the improved recovery efficiency range and oil change rate can be predicted, and the influence on the low-permeability oil reservoir development effect is reflected.

The application discloses a kind of gas-water alternating injection device and method based on carbon dioxide extraction, to solve the technical problem of long response time of existing gas channeling control technology depends on manual analysis, the gas-water alternating injection device includes production well monitoring device, injection well monitoring device and control device, by integrated monitoring and control technology, overall monitoring and accurate control to oil and gas exploitation process are realized.The gas-water alternating injection method is based on the optimization of gas-water alternating injection strategy by gas-water alternating injection device, the maximum injection capacity is obtained by dynamic seepage capacity, and the control effect of gas channeling is ensured by accurate water slug injection.The above-mentioned device and method reduce the system fluctuation caused by manual operation, improve the response speed and the accuracy of operation, and the reliability and stability of the system.

The invention relates to the technical field of unconventional shale oil and gas reservoir exploration, in particular to a method, a device, equipment and a medium for predicting the imbibition utilization efficiency of stratified shale oil. According to the method, the imbibition utilization efficiency of the stratified shale oil can be quickly predicted, and an effective means is provided for revealing an interaction reaction mechanism of shale reservoir rock and an injected medium, a shale reservoir rock imbibition oil extraction mechanism, a shale reservoir recovery efficiency improving mechanism and the like. According to the present invention, the imbibition oil discharge indoor test under the oil reservoir temperature and pressure condition is combined with the two-dimensional nuclear magnetic analysis, and the use conditions of the crude oil in different aperture spaces are distinguished according to the two-dimensional nuclear magnetic T1 and T2 spectrograms of the nuclear magnetic diagnosis, such that the respective imbibition oil discharge efficiency functions and the overall critical use lower limit of different aperture intervals are established so as to be adopted as the data volume model; the method for rapidly predicting the imbibition utilization efficiency of the stratified shale oil by using the two-dimensional nuclear magnetic technology under the conditions of rapidness, accuracy and no damage to the rock core is provided.

The invention provides an electric field enhanced dry hot rock mining system and mining method which can be used for geothermal mining and comprises a ground power supply device and a ground circulating system. A high-pressure pump of the ground circulating system injects liquid in a liquid storage tank into an injection well, and liquid extracted from a production well enters a heat exchanger; positive and negative electrodes of the direct-current power supply are connected with the production well and the injection well; when cold front propulsion needs to be delayed and thermal breakthrough needs to be inhibited, the production well is connected with the positive electrode, the injection well is connected with the negative electrode, the electric field direction points to the injection well from the production well, the electroosmotic flow direction is opposite to the pressure-driven Darcy flow direction, the overall flow velocity can be weakened, and thermal front propulsion can be delayed; when heat exchange needs to be enhanced or short-term heat production capacity needs to be improved, polarity is switched to enable electroosmotic flow and Darcy flow to be in the same direction, and therefore fluid circulation is accelerated. The external direct-current electric field is applied to the reservoir, transmission of fluid and heat is actively adjusted through the electroosmotic flow effect, and therefore thermal breakthrough is effectively delayed, the geothermal recovery efficiency is improved, and the service life of the system is remarkably prolonged.

The application discloses a kind of waste condensate gas reservoir condensate oil gas enhanced recovery method, comprising the following steps: collecting microbial sample from waste condensate gas reservoir related sample, and culture;Nutrients are pretreated to ensure that it is suitable for injection formation;Microorganism and nutrient substance are mixed and injected into waste condensate gas reservoir through injection well;During stewing well, relevant parameters of formation are closed and monitored, relevant conditions of microorganism are evaluated and corresponding measures are taken according to the evaluation result;After stewing well, the yield and quality parameters of mining are monitored, and the mining parameters are optimized according to the relevant data in the mining process;After mining, the formation environment is evaluated and repair measures are taken when there is adverse effect.The microbial enhanced oil recovery of the application mainly uses microorganism and its metabolites to improve recovery efficiency, and the microorganism can naturally breed and grow in the formation, and the cost of required nutrients is relatively low, compared with expensive chemicals in chemical flooding method, which greatly reduces the mining cost.

The application discloses a kind of for low permeability reservoir water drive effect driving unit division and evaluation method, it is related to oil and gas field development technical field, and the present scheme is based on streamline model to the injection-production unit is spatially segmented, and face flow ratio (flow-area comprehensive index) and water cut (streamline dynamic water saturation) are defined as two-dimensional evaluation parameters innovatively, and two kinds of indexes are adaptively classified by clustering algorithm;Face flow ratio represents unit area production efficiency, and water cut reflects the dynamic characteristics of water drive front, and the classification threshold of both can be dynamically adjusted according to actual reservoir development needs;Finally, through the arrangement combination of two kinds of indexes, generate multi-scale driving unit type (such as "high speed-high water cut", "medium speed-low water cut" and the like), accurately depict the water drive difference characteristics caused by low permeability reservoir heterogeneity.This method is especially suitable for the low permeability reservoir with high water cut and serious water channeling in the middle and late stages of development, and provides quantitative decision basis for dynamic optimization of injection-production strategy and enhanced recovery.

The present application belongs to the technical field of oil shale enhanced recovery, and discloses a production cycle calculation method for in-situ conversion of oil shale by using high salinity brine combined with electric heating, in which two horizontal wells opposite to each other are selected as positive and negative electrodes of electric heating; fracturing is performed on the two horizontal wells, and the fracturing fluid is retained in the fracture network; the two horizontal wells are subjected to energization operation to heat the shale reservoir; during the heating process, the time of temperature rise of the electrically heated formation, the time of organic matter thermal cracking conversion in the oil shale reservoir, the time of upward migration of the oil and gas generated by organic matter thermal cracking conversion under the action of buoyancy, and the production time of the upper horizontal well are calculated; and the production cycle of in-situ conversion of oil shale by using high salinity brine combined with electric heating is calculated according to the foregoing results. The present application calculates the time required for each stage, and finally obtains the total time of one cycle of in-situ conversion production of oil shale when using the heating electric heating method.

The present application relates to the technical field of enhanced oil recovery, and is a method for improving the recovery ratio of low-grade oil reservoirs by thermal internal drive, which utilizes an existing circular well pattern, optimally selects a well at a high position of a structure, side-drills and transforms the central well, establishes a communication passage with a neighboring one-line gas injection well, then side-drills a branch central well for high-temperature ignition and gas injection, after the bottom hole temperature of the gas injection well reaches a certain temperature, the gas injection well is used for gas injection, when the fire line is pushed outward from the first circle of well groups to the second circle of well groups, the second row of gas injection wells are ignited by using the method of wind transfer and fire connection, one well group is pushed outward each time, and the remaining gas injection wells are synchronously injected with gas. The present application firstly utilizes thermal internal drive to generate heat in situ, heats the reservoir skeleton and fluid through heat conduction and heat convection, promotes the fluid in the pores which is difficult to be displaced, and after being heated, the fluid is self-displaced and flows to the production well by expansion or vaporization, which can further tap the remaining oil in low-permeability oil reservoirs and improve the recovery ratio of low-permeability reservoirs.