70 results about "Material balance equation" patented technology

The invention relates to a dynamic reserve calculation method and system for a fracture and cave type carbonatite oil reservoir fracture and cave unit. The method comprises a fracture and cave unit type division step, a material balance equation simplification step and a dynamic reserve calculation step. According to the method, firstly, the driving types of the fracture and cave unit are divided according to the communication relationship between the fracture and cave unit and a water body; then, a simplified material balance equation is obtained according to different driving types; then, the dynamic reserve calculation parameters in the material balance equation are optimized by combining production dynamic data through the combined relationship of the ground crude oil density, the natural gas relative density and the gas-oil ratio and the relationship between the elasticity modulus and the porosity; and the dynamic reserve in the dynamic reserve calculation parameters is calculated. The method and the system have the advantages that the precision and the accuracy of the dynamic reserve calculation result are improved; and the basis is provided for the oil reservoir development and exploration and the engineering layout.

The invention discloses a method and a system for partitioning total output of a single shaft gas-steam combined cycle generating set. The method comprises the following steps: (a) establishing a mathematical model of a gas compressor, a combustion chamber and a gas turbine; (b) acquiring a real-time production parameter of the generating set; (c) calculating the power of the gas turbine and the consumed power of the gas compressor according to the results of the steps (a) and (b); (d) deducting the consumed power of the gas compressor from the generated power of the gas turbine to obtain the output of the gas turbine; (e) listing a material balance equation and an energy balance equation for a waste heat boiler; and (f) establishing a mathematical model of a steam turbine, listing a heat balance equation for the waste heat boiler, and calculating the output of the steam turbine through the mathematical model of the steam turbine. The method and the system can master the contributions of the gas turbine and the steam turbine to the total output of the set and the performance of each key part in real time so as to perform effective adjustment and control according to the actual conditions of the set.

The invention belongs to the technical field of mineral resources, and particularly relates to a method for computing unsteady state output of a shale gas reservoir complex fracture network. The method comprises the following steps that S1, basic parameters of shale gas reservoir strata and shale gas are collected, and a shale substrate porous media capillary tube permeability model is established; S2, shale gas reservoir microseism fracture imaging data is collected, a box method is applied to acquire fractal dimensions, a two-dimensional discrete fracture network model is established, and animproved cubic law is adopted to calculate the complex fracture network permeability; S3, it is considered that a shale gas reservoir fracturing horizontal well outer region is a substrate area infiltration area and a shale gas reservoir fracturing horizontal well inner region is a complex fracture network area flow area, and a shale gas reservoir fracturing horizontal well steady-state productivity model is established; according to a shale gas pressure propagation radius equation and a shale gas reservoir material balance equation, a continuous quasi-steady method is applied to establish ashale gas reservoir fracturing horizontal well unsteady state model. The method for the computing unsteady state output of the shale gas reservoir complex fracture network has the advantages that theconsideration factors are close to the actual conditions of strata, and computed results are more accurate.

The invention relates to a leaching rate prediction and optimization operation method in the wet metallurgical leaching process. The method comprises the following steps: predicting a leaching rate by an established mixing model and giving optimization operation instructions, wherein an integrative dynamic mechanism model of the leaching process is established, and a material balance equation and an energy balance equation are gradually established in the leaching process on the basis of the ore-leaching dynamic principle of the integrative dynamic mechanism model. The device comprises a leaching rate prediction and optimization operation system in the leaching process, a host computer, a PLC and a field sensing transmitting part which comprises a pH value detecting instrument, a temperature detecting instrument, a flow detecting instrument, and the like. With the technical scheme, the leaching process can be greatly improved, the production can be constantly kept in an optimal state, the consumption of raw materials and energy sources is reduced, the operation period of equipment is prolonged and the relation change between supply and demand on markets can be reflected in time.

The invention discloses a calculation method for dynamic reserves of gas reservoir. The calculation method aiming at solving the problems that an existing gas reservoir dynamic reserve calculation method is lack of information, harsh in use conditions or complicated in analysis process, the calculation method is based on the advantages of a material balance method and is combined with the gas seepage process, a vertical pipe flow model, a gas well productivity equation and a material balance equation. The calculation method comprises the following steps that S1, production dynamic data are prepared; S2, the bottom hole flowing pressure is calculated, specifically, the bottom hole flowing pressure of a gas well is calculated according to the processed production dynamic data of the gas well; S3, the formation static pressure is calculated, specifically, a binomial deliverability equation of the gas well is adopted to calculate the average formation pressure of the gas well; S4, flow stages are divided, specifically, a boundary control flow stage, an unstable flow stage and a transition stage are determined; and S5, the dynamic reserves are calculated, specifically, the dynamic reserves after the unstable flow stage of the gas well is finished is calculated, and the dynamic reserves is added to the cumulative gas production in the unstable flow stage to get the true dynamic reserves of the gas well.

The invention discloses a shale gas reservoir total reserve calculation method considering multiple factors, comprising the following steps: testing and collecting basic parameters and production dataof the shale gas reservoir; considering fractured free gas, porosity of adsorbed phase, volume change of adsorbed phase, critical desorption pressure of adsorbed gas and shrinkage effect of adsorbedgas desorption on matrix, and considering multi-component adsorption and dissolved gas simultaneously, establishing the material balance equation of shale gas reservoir, and finally obtaining the total reserves equation of shale gas reservoir; the basic parameters and production data of shale gas reservoir are processed according to the established material balance equation, and the relevant curves are drawn; finally, calculating the total reserves of shale gas reservoir Gt. A material balance equation of a new shale gas reservoir is established by comprehensively considering that shrinkage effect of multi-component adsorption and dissolving gas, fracture free gas, adsorption phase porosity, adsorption phase volume change, adsorption gas critical desorption pressure and adsorption gas desorption on a substrate, and the equation has important guiding significance for reasonably calculating the dynamic reserve of the shale gas reservoir.

The invention relates to modeling and optimization methods for the wax-oil hydrogen cracking process. The modeling method includes the steps that according to an industrial hydrogen cracking device, design parameters and operating data which are required by modeling are determined, and a hydrogen cracking lumped partition method is determined, wherein the design parameters comprise lengths and diameters of all beds, and the operating data comprises the feeding flow, inlet-and-outlet temperatures of all the beds, the relative density and distillation range data of feeding and a product and theproduct yield; a hydrogen cracking reaction network, a reaction kinetic equation, a material balance equation and an energy balance equation are determined; a hydrogen cracking mechanism model is solved; based on actual industrial operating data, the hydrogen cracking lumped kinetic parameters are corrected. The modeling and optimization methods for the wax-oil hydrogen cracking process are wide in adaptation and can be used for simulating and optimizing hydrogen cracking industrial reactors with different reaction-bed number times and different product yield requirements.

The invention discloses a method for predicting recoverable reserves and evaluating a development effect of a gas drive reservoir. The method comprises: starting from an oil-gas two-phase seepage law,based on an exponential function relationship of gas-oil relative permeability, through a material balance equation and a Darcy law, deducing and establishing a novel gas-drive characteristic curve relation between the gas-oil ratio and accumulated oil under the condition of stable seepage of a gas-drive development oil field, reducing use of uncertain parameters, and providing a reliable oil reservoir engineering method for calculation of recoverable reserves in the middle and later periods of gas-drive oil field development; furthermore, drawing a gas-drive oil reservoir development effectevaluation chart through gas-drive characteristic curve derivation, the chart visually describing the internal relation among the gas-oil ratio, the recovery degree and the recovery ratio, and providing a basis for evaluation of the effects of oil field measures, comprehensive adjustment and the like.

The invention discloses a shale gas reservoir reserve solution method considering multiple factors. The method comprises the following steps: testing and collecting basic parameters and historical production data of a shale gas reservoir; establishing a substance balance equation by considering factors such as free gas of the matrix and cracks, adsorption phase apparent porosity, adsorption phasedensity, dissolved gas in kerogen, corrected rock compression coefficient, adsorption gas critical desorption pressure and shrinkage effect of adsorption gas desorption on the matrix, and obtaining ashale gas reservoir total reserve expression; according to the established material balance equation, processing basic parameters and production data of the material balance equation, and drawing related curves; and finally calculating the total reserve V of the shale gas reservoir. According to the method, the matrix, crack free gas, adsorption phase porosity, dissolved gas diffusion, adsorptiongas critical desorption pressure and the shrinkage effect of adsorption gas desorption on the matrix are comprehensively considered, a new shale gas reservoir substance balance equation is established, and the equation has important guiding significance for reasonably calculating shale gas reservoir dynamic reserves.

The invention provides a quantitative identification method and system for the water invasion amount of a fractured edge water gas reservoir, and the method comprises the steps: obtaining geological and production data, and obtaining geological parameters and production data according to the geological and production data and a water invasion amount quantitative identification algorithm; accordingto the geological parameters, the production data and a preset gas reservoir and water body radius value, calculating a water invasion amount value through a fractured edge water gas reservoir waterinvasion amount calculation formula; according to a water drive gas reservoir material balance equation and the water invasion amount value, obtaining a dynamic curve through a linear regression method, and obtaining a linear regression coefficient corresponding to the dynamic curve through calculation according to the dynamic curve; and when the linear regression coefficient is greater than a predetermined threshold, obtaining a water invasion amount identification result according to the dynamic curve, the geological parameters and the production data.

The invention relates to a catalytic cracking reaction system process simulation optimization model and a solution method thereof. A novel model is a model based on Gupta and the like; in order to contribute to solving the model in process simulation software such as AspenPlusTM, a new form is provided for part of expressions in a material balance equation, an energy balance equation and a fluidized state computation model; and components or stream physical property calculation subprograms provided by the process simulation software are called in the model solution process, so that the simulation optimization work of the model is finished by the process simulation software, the model is convenient to apply to engineering and the calculation result is accurate.

The invention relates to a dynamic modeling method for syngas one-step dimethyl ether preparation. The method is a novel method for dynamical modeling for the syngas one-step dimethyl ether preparation and firstly shows that including heat loss into the energy conservation equation for performing iterative computation to judge whether the temperature in a reactor is reasonable so as to calculate the ingredients in the reaction according to atomic material conservation, reaction kinetics equation and energy conservation equation; when calculating, the temperature and the content of each ingredient in the syngas one-step dimethyl ether preparation reactor are assumed; the contents of the ingredients in the reactor are calculated through the material conservation equation and reaction kinetics equation, and then whether the assumed temperature is reasonable is determined through the energy conservation equation. According to the reactor-based dynamic modeling method for syngas one-step dimethyl ether preparation, a novel path is provided for the calculation of dynamic modeling for the dynamic modeling method for syngas one-step dimethyl ether preparation.

The invention relates to a shale gas well production fitting and prediction method, which belongs to the field of shale gas well productivity evaluation, and solves the problems that shale gas well production prediction errors are large, the process is tedious and the like at present. The shale gas well production fitting and prediction method is characterized by comprising the following steps of:dividing a shale gas reservoir into a fracture system and a matrix system; simultaneously establishing a productivity equation and a material balance equation of the fracture system and the matrix system; carrying out production history fitting on flowing bottomhole pressure and water yield for two production modes of fixed yield and fixed pressure of a shale gas well; and respectively predictingthe gas yield and the water yield of the shale gas well under the two production modes of the fixed yield and the fixed pressure after the fitting is successful. The shale gas well production fittingand prediction method is good in fitting effect, high in prediction precision and high in generalizability.

The invention relates to a dynamic modeling method of a flash evaporator. On the basis of modeling and calculation of a traditional flash evaporator, dynamic flash evaporation modeling is put forward for the first time according to the principle that the physical volume of the inside of the flash evaporator is unchanged, namely a novel method for dynamic modeling of the flash evaporator is put forward by the combination of an energy balance equation, a normalization equation, a phase balance equation and a material balance equation. In the calculation process, firstly, temperature and pressure in the flash evaporator are assumed, content and composition of gas and liquid in the flash evaporator are calculated by means of the material balance equation, the normalization equation and the phase balance equation, and then according to the energy balance equation and the principle that the volume of the flash evaporator is unchanged, whether the assumed temperature and pressure are reasonable or not is judged. The dynamic modeling method reduces the difficulty of flash evaporation calculation, and meanwhile, develops a novel road for calculation of modeling of the flash evaporator.

The invention provides a method for calculating in-water solubility of methane based on a PRSV state equation. A phase simulation gradual iteration number calculating method is established based on aPRSV state equation, an HV mixing rule, a material balancing equation and a thermodynamic balance equation set. A parameter expression which is correlated with temperature is adopted. In a condition of 273.15K-603.15K and 0.1-140MPa, the in-water solubility of the methane can be accurately calculated. The method according to the invention has advantages of high calculating speed, high precision and wide range. The method can effectively supply reference data to actual engineering.

The invention discloses a method for calculating real pressure and reserves of a low-permeability gas reservoir by using production data. The method comprises the following steps: S1, exporting the production data of a certain well in a gas field development information network; S2, reading the casing pressure, the daily gas production rate, the accumulated gas production rate and the accumulatedwater production rate in the production data, and calculating the flowing bottomhole pressure Pwf through the casing pressure; S3, assuming an original pressure Pi of a gas reservoir, and solving a yield equation; S4, trying to cut the original pressure Pi, and observing the linear shape until the linear correlation is satisfactory; and S5, calculating single-well control reserves G. According tothe method, the controlled reserves of the low-permeability gas reservoir are solved by using a material balance method, and a material balance equation can form linear formation pressure, namely thesolved pressure, by continuously trying to cut off the pressure, and meanwhile, the controlled reserves of a single well are also solved.

The invention relates to the technical field of oil and gas field development, and particularly discloses a shale oil and gas reservoir fracture parameter inversion method based on fracturing fluid flowback data, which comprises the following steps: constructing a shale oil and gas reservoir fracture parameter inversion mathematical model and a matrix seepage mathematical model; pseudo-pressure and pseudo-time are introduced, a variable separation method and the Duhamel principle are used for solving the crack parameter inversion mathematical model, and a linear form analytical solution is obtained; solving the matrix seepage mathematical model by using a separation variable method and a Duhamel principle to obtain the matrix-to-crack fluid channeling amount; simultaneously solving the fracture and matrix material balance equation to determine the change relation of the average pressure in the fracture and the matrix along with the time and the change relation of the average saturation along with the time; and performing inversion iteration on the fracture parameters based on the linear form analytical solution, the average pressure and the change relation of the average saturation along with time so as to determine the fracture parameters of the shale oil and gas reservoir. According to the scheme, the fracture parameters of the shale oil and gas reservoir can be accurately and timely solved.

The embodiment of the invention provides a prediction method and device for reserves and water invasion of a water-drive gas reservoir. The method comprises the following steps: acquiring reservoir physical property parameters of a gas reservoir and production dynamic data of the gas reservoir; determining the substance balance equation of the gas reservoir based on the elastic expansion effect ofbound water and rock particles, and establishing a first linear regression model; establishing a second linear regression model according to the material balance equation and the first linear regression model; and predicting the reserves and the water invasion amount of the gas reservoir according to the reservoir physical property parameters, the production dynamic data, the first linear regression model and the second linear regression model, thereby improving the prediction efficiency and accuracy of the reserves and the water invasion amount.

The invention relates to a determination method of hot-water drive physical simulation similarity criterion of fracture thickened oil deposit. The determination method includes steps of 1) establishing basic assumption conditions according to hot-water drive seepage of fracture thickened oil deposit; 2) establishing a hot-water drive mathematical model of fracture thickened oil deposit according to the material balance equation and the energy balance equation in fracture and pressure, initial temperature and internal and external boundary conditions; 3) non-dimensionalizing relevant variables in the hot-water drive mathematical model of fracture thickened oil deposit, and simplifying the non-dimensionalized mathematical model of fracture thickened oil deposit; 4) listing physical variables in the hot-water drive mathematical model and the hot-water drive non-dimensionalized mathematical model of fracture thickened oil deposit; 5) listing basic dimensions included in all physical variables of step 4); 6) acquiring similarity criterion combined with analysis of Pi theory and similarity theory according to the hot-water drive non-dimensionalized mathematical model of fracture thickened oil deposit.

The invention provides a shale gas well dynamic production allocation method. The shale gas well dynamic production allocation method comprises the steps of step 1, constructing a shale gas well single well material balance equation; step 2, establishing a single-well actual material balance equation in combination with the step 1 according to actual shale gas well related reservoir properties, and establishing a relation function about accumulated gas production and formation pressure; step 3, calculating the accumulated gas production according to the current formation pressure; step 4, establishing a binomial productivity equation through productivity well testing, and performing production allocation according to unchoked flow; step 5, drawing a plate of the accumulated gas production,the formation pressure and the single well production allocation according to the production allocation result obtained in the step 4; and step 6, according to different oil deposit accumulated gas production of a shale gas well, searching the obtained plate for production allocation. By the adoption of the scheme, rapid production allocation can be achieved, in the gas well production process, the reasonable production allocation can be rapidly determined by searching the plate according to the current accumulated gas production of the gas well, time factors do not need to be considered in the production allocation process, and the method is very convenient, efficient and practical.

The invention relates to the field of sewage treatment, and provides an A2O biological tank process model building method. The method comprises the following steps: setting input parameters and output parameters; building an A2O biological tank process model according to the input parameters, the output parameters, an ASM2D (Activated Sludge Model No.2D) model and a material balance equation, wherein the A2O biological tank process model comprises an anaerobic tank process model, an anoxic tank process model and an aerobic tank process model; the output parameters represent the concentration variation rate of components. According to the A2O biological tank process model building method, the A2O biological tank process model is simple and can be built through Matlab simulation software; the A2O biological tank process model can be used for simulating the A2O biological tank process, so as to provide foundation for later control strategy study; meanwhile, purchase of foreign ASMs-like series simulation software which is high in price can be avoided, so that the cost of sewage treatment of the A2O biological tank process can be reduced.

The invention relates to a dynamic modeling method for a reacting furnace in the Claus sulfur recovery process. The method is a novel method for dynamic modeling of the reacting furnace in the Claus sulfur recovery process and firstly shows that including the heat loss into the energy conservation equation for performing iterative computation to judge whether the temperature in the reacting furnace is reasonable so as to calculate the ingredients in the reacting furnace according to the atomic material conservation, minimization of Gibbs free energy and energy conservation calculation; when calculating, the temperature in the reacting furnace and the quantity of each ingredient in the reacting furnace the Claus sulfur recovery process are assumed, the contents of the ingredients in the reacting furnace are calculated according to the material balance equation and the minimization of Gibbs free energy, and then whether the assumed temperature is reasonable can be determined according to the energy-balance equation. The dynamic modeling method for the reacting furnace in the Claus sulfur recovery process is the first time proposed, and brings a novel path for the dynamic modeling calculation of the Claus sulfur recovery process.

The invention discloses a method for calculating single-well controlled reserves of a water-producing gas well. The method comprises the steps that a relation model of gas-water two-phase relative permeability and water saturation of a to-be-measured well is established, wherein the gas-water two-phase relative permeability includes gas-phase relative permeability and water-phase relative permeability; according to the relation model of the gas-water two-phase relative permeability and the water saturation, a relation model of current formation pressure and water saturation is determined, anda single-well controlled reserve calculation model is deduced by combining a water-drive reservoir material balance equation; and a pressure value and a water saturation value of the to-be-measured well are collected, and according to the collected pressure value, water saturation value and state parameters of the to-be-measured well, the single-well controlled reserves of the to-be-measured wellare solved through the single-well controlled reserve calculation model. Through the method, the complex water invasion amount calculation process in the dynamic reserve calculation process is avoided, the calculation process is simple, data requirements are simple, collection is easy, and adaptability is wider; and the method is high in calculation precision and has high popularization value.

The invention discloses a method and a system for partitioning total output of a single shaft gas-steam combined cycle generating set. The method comprises the following steps: (a) establishing a mathematical model of a gas compressor, a combustion chamber and a gas turbine; (b) acquiring a real-time production parameter of the generating set; (c) calculating the power of the gas turbine and the consumed power of the gas compressor according to the results of the steps (a) and (b); (d) deducting the consumed power of the gas compressor from the generated power of the gas turbine to obtain theoutput of the gas turbine; (e) listing a material balance equation and an energy balance equation for a waste heat boiler; and (f) establishing a mathematical model of a steam turbine, listing a heatbalance equation for the waste heat boiler, and calculating the output of the steam turbine through the mathematical model of the steam turbine. The method and the system can master the contributionsof the gas turbine and the steam turbine to the total output of the set and the performance of each key part in real time so as to perform effective adjustment and control according to the actual conditions of the set.

The invention discloses a method for determining water drive gas reservoir parameters under the conditions of rock pore shrinkage and bound water expansion. The method comprises the steps that S1, a material balance equation of a water drive gas reservoir considering the conditions of rock pore shrinkage and bound water expansion is converted into a material balance equation after deformation; S2,a calculation formula of the water influx rate of the gas reservoir to be measured is substituted into the material balance equation after deformation, and a water influx material balance indicationcurve equation is obtained; S3, a water body multiple of the gas reservoir to be measured is set to be 10, and a water influx material balance indication curve is drawn under the water body multiple;S4, the water body multiple of the gas reservoir to be measured is set to be 20, 30, 50 and 150 separately, and the step S3 is repeated to obtain water influx material balance indication curves underdifferent water body multiples; and S5, the water body multiple corresponding to the indication curve with the largest correlation coefficient is the water body multiple of the water drive gas reservoir to be measured, the slope of the curve is a water influx constant of the gas reservoir to be measured, and the intercept of the curve is the dynamic reserve of the gas reservoir to be measured. Themethod is reliable in principle and simple and convenient to operate, and data support and theoretical basis are provided for gas reservoir development.

The invention discloses an activated sludge model and solving method used for nitrification stage steady state solution. The method comprises the following steps: (1) carrying out reasonable reduction on an ASM3 (Activated Sludge Model 3) model, and constructing the chemometrics model and the process rate equation of the ASM3 model; (2) coupling an oxidation process of NO2<-> with a growth attenuation process of NOB (Nitrite Oxidizing Bacteria), and constructing the chemometrics model and the process rate equation of the ASM3 model by using the ASM3 model as a reference; and (3) according to the model, constructing the mass balance equation of each component according to the model, utilizing MATLAB mathematical software to obtain the analytical solution of each component, and substituting each class of parameters and working conditions, and finally, determining the concentration of each component in the model. The method can be used for the nitrification stage steady state solution, and also can be used for determining an initial value during dynamic simulation. Therefore, the activated sludge model constructed by the method is high in practicality.

The invention discloses an optimization method for efficiently laying propping agents in hydraulic fracturing operation. The optimization method comprises the following steps that 1, a rock deformation control equation and a fracturing fluid flowing and propping agent migration material balance equation in the fracturing process are constructed; 2, a model used for representing the pumping volume fraction of the propping agents is constructed; 3, parameters are given, and the corresponding fracture geometric dimension and propping agent volume concentration distribution are obtained through calculation; 4, the laying efficiency of each group of propping agents is calculated; 5, the average propping agent laying efficiency of each group is calculated; 6, optimization parameters are selected; and 7, the propping agent pumping volume fraction changing along with time is calculated; and the result is substituted into the model in the step 1 for calculation, the calculated propping agent laying efficiency after fracturing is obtained, and whether the optimization parameters are optimal or not is verified. The optimization method has the advantages that the hydraulic fracturing propping agent laying effect can be improved, and the oil and gas productivity can be improved.

The invention relates to a method for calculating the productivity of a shale gas well. According to the characteristics of fracturing and non-fracturing stimulation areas in the single well control area of ​​shale gas reservoirs, the present invention comprehensively considers the influence of adsorbed gas desorption diffusion and fracturing and non-fracturing stimulation areas on the productivity of shale gas wells, A material balance equation for dual-zone composite shale gas reservoirs considering adsorbed gas is established, combined with the gas well productivity equation and the channeling equation between the two zones, a fast and accurate calculation method for shale gas well productivity is established. This method does not require complex geological models of shale gas reservoirs, nor does it require many geological and fracturing dynamic parameters. The calculation results are suitable for various applications such as rational production allocation of shale gas wells, development technology policy and development plan optimization.

The invention provides a method for predicting the solubility of CO2 in a NaCl aqueous solution based on a CPA state equation. On the basis of a CPA-SRK state equation, a WS mixing rule, an NRTL activity coefficient model, a material balance equation, a thermodynamic balance equation set and a miscible phase function, an inert association scheme more suitable for CO2 is selected, and a phase state simulation step-by-step iteration numerical calculation method is established. The method is high in calculation speed, high in precision and wide in application range, can guide development of the gas reservoir with high CO2 content and carbon capture and storage, and provides technical support for improving natural gas recovery efficiency and coping with global CO2 emission.

The invention discloses a natural gas hydrate reservoir reserve accounting method based on a substance energy balance principle. The natural gas hydrate reservoir reserve accounting method comprises the following steps: 1) collecting basic geological parameters and development parameters of a natural gas hydrate reservoir; 2) assuming the decomposition rate of the hydrate and calculating the original reserves of the hydrate according to a material balance equation; 3) calculating the total decomposition enthalpy of the hydrate according to the obtained original reserves of the hydrate and an energy conservation principle; 4) obtaining the decomposition rate of the new hydrate according to the decomposition kinetics of the hydrate; and 5) judging whether the decomposition rate of the hydrate and the assumed decomposition rate meet error requirements or not, and if not, performing iterative calculation by adopting the decomposition rate obtained by calculation until the error requirements are met. The method combines a material balance equation, an energy conservation principle and hydrate decomposition dynamics to calculate the original reserves of the natural gas hydrate reservoir, has the characteristics of high calculation speed and high practicability, and can provide technical support for reasonable development of the natural gas hydrate reservoir.