Gas cap reservoir type gas storage multi-cycle dynamic water invasion amount calculation method and system

Abstract

The invention belongs to the technical field of underground gas storage water invasion amount calculation, and discloses a gas cap reservoir type gas storage multi-cycle dynamic water invasion amount calculation method and a gas cap reservoir type gas storage multi-cycle dynamic water invasion amount calculation system. The method comprises the following steps: establishing a total substance amount conservation equation based on a multi-cycle fluid injection and production change rule of the gas cap reservoir type gas storage; deriving to obtain calculation equations of the amount of original formation fluid substances, the amount of extracted formation fluid substances, the amount of injected natural gas substances and the amount of residual formation fluid substances, and substituting the derived calculation equations into the total substance amount conservation equation to establish a dynamic water invasion amount calculation model; and the formation fluid high-pressure physical property, the reverse condensation liquid saturation degree and the natural gas deviation factor change rule in the multi-period injection and production process are obtained, and the multi-period dynamic water invasion amount is obtained through calculation. The calculation result is high in accuracy, the calculation process is simple, and the method can be suitable for the condensate gas cap reservoir type gas storage where a general material balance method is not suitable.

Description

Technical Field

[0001] This invention belongs to the field of underground gas storage water intrusion calculation technology, and relates to a multi-period dynamic water intrusion calculation method and system for gas cap oil reservoir type gas storage. Background Technology

[0002] Compared to the ever-increasing natural gas consumption, the peak-shaving capacity of underground gas storage facilities in most regions is severely insufficient. Furthermore, in areas with high natural gas peak-shaving demand, the number of depleted gas reservoirs suitable for storage site selection is limited. Therefore, vigorously developing oil-type gas storage facilities is of great significance for enriching the types of underground gas storage facilities, rapidly and significantly improving the peak-shaving capacity of regional gas storage facilities, and ensuring regional energy security. Gas-capped oil reservoirs are one of the important types of oil and gas reservoirs, and their excellent formation sealing and native natural gas caps make them ideal locations for underground gas storage. However, edge and bottom water intrusion can greatly affect the storage capacity and capacity utilization rate of gas storage facilities. Therefore, accurately predicting the water intrusion volume during multi-cycle injection and production processes of gas storage facilities is fundamental to evaluating storage capacity parameters and ensuring efficient operation of gas storage facilities. Commonly used methods for calculating gas storage water intrusion volume mainly include the area method, volume method, reservoir numerical simulation methods, and material balance methods. While the area and volume methods are relatively simple to use, they fail to adequately consider the heterogeneity, phase changes, and stress sensitivity of gas storage facilities, resulting in significant errors in the calculations. They are only suitable for rough calculations of water intrusion in gas storage facilities. Numerical simulation methods for oil reservoirs offer high accuracy in calculating water intrusion in gas storage facilities; however, high-precision numerical simulation modeling of gas storage facilities is difficult, time-consuming, and costly, posing significant challenges for practical field applications. Currently, the mass balance method is beginning to be applied to the calculation of water intrusion in gas-type gas storage facilities. For example, the paper "Multi-cycle Injection-Production Water Intrusion Calculation Model for Edge-Water Condensate Gas Storage Facilities" published by Beijing University of Science and Technology establishes a multi-cycle water intrusion calculation model for condensate gas storage facilities, considering the anti-condensation changes in condensate gas reservoirs, based on the mass balance principle. However, this method cannot calculate water intrusion in complex gas-cap oil storage facilities. For gas-cap oil storage facilities, the fluid distribution and phase changes during multi-cycle injection-production are particularly complex, posing significant challenges to water intrusion calculation.

[0003] In summary, current research on water intrusion calculation methods for gas storage facilities is relatively limited, with existing reports focusing primarily on gas reservoir-type facilities. A theoretical framework for evaluating water intrusion in complex oil reservoir-type gas storage facilities, such as those with condensate gas caps containing edge and bottom water, has not yet been established, severely hindering the optimal design and operation of these facilities. Therefore, there is an urgent need to develop a multi-cycle injection-production water intrusion calculation method for complex oil reservoir-type gas storage facilities. Summary of the Invention

[0004] The purpose of this invention is to address the technical problem that the existing technology lacks a theoretical system for evaluating water intrusion in complex gas storage reservoirs such as condensate gas cap reservoirs with edge and bottom water, and to provide a multi-period dynamic water intrusion calculation method and system for gas cap reservoirs.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a method for calculating the dynamic water intrusion of a gas cap reservoir type gas storage facility over multiple periods, including:

[0007] Based on the multi-cycle fluid injection and production variation law of gas cap reservoir type gas storage, a total material quantity conservation equation is established;

[0008] The calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material are derived. The derived calculation equations are then substituted into the total material conservation equation to establish a dynamic water intrusion calculation model.

[0009] Based on indoor experiments and equation of state, the variation patterns of formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production were obtained.

[0010] The basic parameters and dynamic operation data of the gas cap reservoir are obtained, and the basic parameters, dynamic operation data, formation fluid high pressure properties, anticondensate saturation and natural gas deviation factor are substituted into the dynamic water intrusion calculation model to calculate the multi-period dynamic water intrusion.

[0011] Further improvements are made in the following aspects:

[0012] After calculating the multi-cycle dynamic water intrusion, reliability verification is also included, specifically:

[0013] A numerical simulation model was established based on the basic parameters, operational dynamic data, and high-pressure properties of formation fluids of the gas cap reservoir type gas storage facility.

[0014] Reliability verification was performed based on the numerical simulation model and the calculated multi-period dynamic water intrusion.

[0015] The specific equation for the conservation of total amount of substance is as follows:

[0016] n ig +n il +n inj =n pg +n po +n ro +n rg (1)

[0017] Where, nig n represents the amount of the original hydrocarbon gas, expressed in kmol; il n represents the amount of the original hydrocarbon liquid substance, in kmol; inj The amount of hydrocarbon gas injected during the depletion development phase of a gas reservoir or the operation phase of a gas storage facility, expressed in kmol; n pg The amount of hydrocarbon gas produced, expressed in kmol; n po The amount of hydrocarbon liquid produced, in kmol; n ro n represents the amount of residual hydrocarbon liquid in the current formation, in kmol; rg This represents the amount of residual hydrocarbon gaseous substances in the current formation, expressed in kmol.

[0018] The calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material derived are as follows:

[0019] The amount of the original formation fluid material includes the amount of original hydrocarbon gas material n. ig The amount of the original hydrocarbon liquid substance n il The amount of extracted formation fluid includes the amount of hydrocarbon gas produced (n). pg and the amount of hydrocarbon liquid produced, n pl The amount of injected natural gas includes the amount of hydrocarbon gas injected during the reservoir depletion development phase or the gas storage facility operation phase. inj The amount of remaining formation fluid material includes the amount of residual hydrocarbon liquid material in the current formation, n. ro and the amount of residual hydrocarbon gaseous substances in the current formation, n rg ;

[0020] The equation for calculating the amount of original hydrocarbon gas is:

[0021]

[0022] Where, p i The original formation pressure is MPa; p sc Z represents the pressure under standard conditions, in MPa; cgi Z represents the condensate gas deviation factor under the original formation conditions. sc R is the gas deviation factor under surface conditions; T is the universal gas constant; and T is the formation temperature in K.

[0023] The equation for calculating the amount of the original hydrocarbon liquid substance is:

[0024]

[0025]

[0026] Among them, Vg The original pore volume of the gas cap region is m. 3 G represents the original condensate gas reserves in the gas cap region, in m³. 3 B cgi S is the original condensate gas volume coefficient; wcg The initial water saturation of the gas cap region; m is the gas cap index; S wco ρ represents the water saturation of the oil ring region under the original formation conditions. oi Density of oil rings under original formation conditions, kg / m³ 3 M oi The molecular weight of the oil ring oil liquid under the original formation conditions is expressed in kg / mol.

[0027] The equation for calculating the amount of substance of the surface-separated condensate gas is as follows:

[0028]

[0029] Among them, G cp The amount of natural gas extracted from the gas cap area, in m 3 ;

[0030] The equation for calculating the amount of dissolved gas in the extracted oil ring is as follows:

[0031]

[0032] Among them, V pbo m represents the amount of oil extracted from the oil ring. 3 ;R p For the oil-to-gas ratio in oil-ring oil production, m 3 / m 3 ;

[0033] The amount of oil separated from the produced gas top condensate is:

[0034]

[0035] Among them, V pco The amount of condensate oil extracted from the gas cap area, in m 3 ;ρ co The density of the condensate oil extracted from the gas cap area, kg / m³ 3 M co The molecular weight of condensate oil extracted from the gas cap area under surface conditions, in kg / mol.

[0036] The equation for calculating the amount of oil produced in the oil ring is as follows:

[0037]

[0038] Where, ρ bo The density of the oil extracted from the oil ring region, kg / m³3 M bo is the molecular weight of the liquid under oil ring surface conditions, in kg / mol;

[0039] The equation for calculating the amount of hydrocarbon gas produced is as follows:

[0040] n pg =n pcg +n pdg (10)

[0041] The equation for calculating the amount of hydrocarbon liquid produced is as follows:

[0042] n po =n pco +n pbo (11)

[0043] Equations for calculating the amount of hydrocarbon gas injected during the depletion development phase of a gas reservoir or the operation phase of a gas storage facility:

[0044]

[0045] Among them, G inj The amount of natural gas extracted from the gas cap area, in m 3 ;

[0046] The equation for calculating the amount of remaining hydrocarbon gas is:

[0047]

[0048] Where, p c Z represents the current formation pressure, in MPa; c V is the gas deviation factor under current formation conditions. rcg m is the pore volume occupied by the remaining hydrocarbon gas. 3 W e The current water intrusion in the gas cap reservoir is m. 3 W p To accumulate water production, m 3 W i To calculate the cumulative water injection volume, m 3 B w The volume factor of formation water; C w C is the formation water compressibility coefficient. f Δp is the compressibility coefficient of the formation rock; Δp is the pressure difference, MPa.

[0049] The equation for calculating the amount of remaining oil ring material is as follows:

[0050]

[0051] Among them, V rbo The pore volume occupied by the oil ring under the current pressure is m.3 B boc ρ is the oil ring volume coefficient under the current pressure; boc The density of the oil ring is kg / m³. 3 M boc The molecular weight of the oil ring oil liquid is given in kg / mol.

[0052] The equation for calculating the amount of residual condensate oil is:

[0053]

[0054] V rco =V g (1-S wcg )S coc (18)

[0055] Among them, V rco The pore volume occupied by condensate oil under the current formation conditions is expressed in m. 3 S coc ρ represents the saturation of condensate oil under the current formation conditions. coc Density of residual condensate oil, kg / m³ 3 M coc The molecular weight of the remaining condensate oil is kg / mol.

[0056] The equation for calculating the amount of remaining hydrocarbon liquid material in the current formation is as follows:

[0057] n ro =n rbo +n rco (19)

[0058] The equation for calculating the amount of residual hydrocarbon gas in the current formation is as follows:

[0059] n rg =n rcg (20).

[0060] The specific steps for establishing a dynamic water intrusion calculation model by substituting the derived calculation equations into the total mass conservation equation are as follows:

[0061] Substituting formulas (2) to (13) and formulas (15) to (20) into formula (1), we get:

[0062]

[0063] get:

[0064]

[0065] Among them, W e The current water intrusion in the gas cap reservoir is m. 3;p sc Pressure under standard conditions, MPa;

[0066] G represents the original condensate gas reserves in the gas cap region, m 3 Z sc R is the gas deviation factor under surface conditions; T is the universal gas constant; B is the formation temperature in K; cgi S is the original condensate gas volume coefficient; wco ρ represents the water saturation of the oil ring region under the original formation conditions. oi Density of oil rings under original formation conditions, kg / m³ 3 m is the gas cap index; M oi The molecular weight of the oil ring oil liquid under the original formation conditions is given in kg / mol; S wcg G represents the initial water saturation level of the gas cap region. inj The amount of natural gas extracted from the gas cap area, in m 3 G cp The amount of natural gas extracted from the gas cap area, in m 3 V pbo m represents the amount of oil extracted from the oil ring. 3 ;R p For the oil-to-gas ratio in oil-ring oil production, m 3 / m 3 V pco The amount of condensate oil extracted from the gas cap area, in m 3 ;ρ co The density of the condensate oil extracted from the gas cap area, kg / m³ 3 M co For condensate oil extracted from the gas cap area, the molecular weight of the liquid under surface conditions is kg / mol; ρ bo The density of the oil extracted from the oil ring region, kg / m³ 3 M bo The liquid molecular weight of the oil extracted from the oil ring region, in kg / mol; ρ boc The density of the oil ring under current conditions, kg / m³ 3 M boc B represents the molecular weight of the oil-ring oil liquid under current conditions, in kg / mol. boc This represents the oil ring volume coefficient under current conditions;

[0067] S coc ρ represents the saturation of condensate oil in the current formation; coc The density of formation condensate oil under current conditions, in kg / m³ 3 M coc The molecular weight of formation condensate oil under current conditions is given in kg / mol; p c Z represents the current formation pressure, in MPa; c W represents the gas deviation factor under current formation conditions.p To accumulate water production, m 3 W i To calculate the cumulative water injection volume, m 3 B w The volume factor of formation water; C w C is the formation water compressibility coefficient. f Δp is the rock compressibility coefficient of the formation; Δp is the pressure difference, MPa.

[0068] The specific laws governing the changes in formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production, based on indoor experiments and equations of state, are as follows:

[0069] The relationship between the high-pressure physical properties of oil ring oil and the amount of natural gas injected was obtained through indoor experiments; the change law of condensate saturation during the gas injection process of gas cap oil reservoir was obtained through phase state experiments.

[0070] The natural gas deviation factor is calculated using the DPR method, specifically as follows:

[0071]

[0072] ρ pr =0.27p pr / (ZT pr ) (twenty four)

[0073]

[0074] Among them, T pr For apparent contrast temperature; T pc Let p be the apparent critical temperature, in K; pr See contrast pressure; p pc ρ is the apparent critical pressure, MPa; pr It is a dimensionless contrast density.

[0075] Substituting the aforementioned basic parameters, operational dynamic data, formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor into the dynamic water intrusion calculation model, the multi-cycle dynamic water intrusion is calculated as follows:

[0076]

[0077] Secondly, the present invention provides a multi-period dynamic water intrusion calculation system for gas cap reservoirs, comprising:

[0078] The module for establishing the total mass conservation equation is used to establish the total mass conservation equation based on the multi-cycle fluid injection and production variation law of gas cap reservoirs.

[0079] The dynamic water intrusion calculation model establishment module is used to derive calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material. The derived calculation equations are then substituted into the total material conservation equation to establish the dynamic water intrusion calculation model.

[0080] The parameter determination module is used to obtain the variation patterns of formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production based on indoor experiments and equations of state.

[0081] The dynamic water intrusion calculation module is used to obtain the basic parameters and dynamic operation data of the gas cap reservoir type gas storage, and to substitute the basic parameters, dynamic operation data, formation fluid high pressure properties, anticondensate saturation and natural gas deviation factor into the dynamic water intrusion calculation model to calculate the multi-period dynamic water intrusion.

[0082] Compared with the prior art, the present invention has the following beneficial effects:

[0083] This invention discloses a multi-cycle dynamic water intrusion calculation method for gas-cap reservoirs. By establishing a total mass conservation equation based on multi-cycle injection-production patterns, it can more accurately describe the mass exchange process in gas-cap reservoirs during long-term, multi-cycle injection-production processes, providing a solid theoretical foundation for the optimized operation of the gas storage facility. This equation considers the interaction between formation fluids and injected natural gas during the injection-production process, making the prediction of dynamic changes in the gas storage facility more comprehensive and scientific, and contributing to the formulation of more reasonable injection-production plans and inventory management strategies. By collecting and calculating detailed basic parameters, operating parameters, and fluid property parameters of the gas storage facility, the accuracy and reliability of the input data for subsequent models are ensured, thereby improving the accuracy and credibility of model predictions. Accurate calculation of the mass of original formation fluids, produced fluids, injected natural gas, and remaining formation fluids provides a comprehensive mass balance analysis basis for subsequent dynamic water intrusion calculations. Furthermore, by deriving a dynamic water intrusion calculation model, real-time monitoring and prediction of water intrusion during multi-cycle injection and production processes in gas storage facilities are achieved. This helps in the timely detection and response to water intrusion issues, ensuring the safe and stable operation of gas storage facilities. The model can guide gas storage facility managers to adjust injection and production strategies based on dynamic changes in water intrusion, optimizing the operational efficiency and lifespan of gas storage facilities and reducing operating costs. Finally, considering the high-pressure properties of formation fluids and the deviation factor of natural gas, the calculation of dynamic water intrusion is made closer to reality, improving calculation accuracy and practicality. Through refined parameter settings and calculations, gas storage facility managers can conduct more refined management of gas storage facilities, including developing targeted water intrusion prevention measures and gas storage expansion plans. In summary, based on the principle of material balance, by obtaining the basic parameters, injection and production operation parameters, and fluid property parameters of the utilized gas cap reservoir type gas storage facility, it is possible to predict the multi-cycle dynamic water intrusion of complex condensate gas cap reservoir gas storage facilities. The method in this invention takes into account the effects of gas cap anti-condensation changes, natural gas dissolution and escape, and rock and bound water deformation. The calculation results are highly accurate, the calculation process is simple, and it can be applied to condensate gas cap reservoir-type gas storage facilities where general material balance methods are not applicable. Attached Figure Description

[0084] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0085] Figure 1 This is a flowchart of a multi-period dynamic water intrusion calculation method for a gas cap reservoir type gas storage facility according to the present invention;

[0086] Figure 2This is a PVT data graph of crude oil-to-natural gas injection in an embodiment of the present invention; Figure 2 (a) is a graph showing the relationship between saturation pressure; Figure 2 (b) is a graph showing the dissolved gas-oil ratio; Figure 2 (c) is a diagram showing the formation oil volume factor relationship; Figure 2 (d) is a diagram showing the formation oil density relationship;

[0087] Figure 3 This is a graph showing the change in saturation of the condensate during the development and injection process of condensate gas exhaustion in an embodiment of the present invention. Figure 3 (a) A graph showing the relationship between saturation and pressure of the depletion-induced condensate; Figure 3 (b) is a graph showing the relationship between the saturation of the condensate and the pressure after the injection of dry gas;

[0088] Figure 4 This is a comparison chart of the multi-cycle water injection and extraction volume and the numerical simulation calculation results in an embodiment of the present invention;

[0089] Figure 5 This is a block diagram of a multi-period dynamic water intrusion calculation system for a gas cap reservoir type gas storage facility according to the present invention.

[0090] Figure 6 This is a diagram of the electronic device used in this invention. Detailed Implementation

[0091] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0092] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0093] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0094] The present invention will now be described in further detail with reference to the accompanying drawings:

[0095] See Figure 1 This invention discloses a method for calculating the dynamic water intrusion of a gas cap reservoir type gas storage facility over multiple periods, comprising the following steps:

[0096] S1. Based on the variation law of multi-cycle fluid injection and production in gas-capped gas storage tanks, a total material conservation equation is established.

[0097] S2, derive the calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material and the amount of remaining formation fluid material, and substitute the derived calculation equations into the total material conservation equation to establish a dynamic water intrusion calculation model.

[0098] S3, based on indoor experiments and equation of state, obtains the variation law of formation fluid high pressure properties, condensate saturation and natural gas deviation factor during multi-cycle injection and production;

[0099] S4. Obtain the basic parameters and dynamic operation data of the gas cap reservoir type gas storage, and substitute the basic parameters, dynamic operation data, formation fluid high pressure properties, anticondensate saturation and natural gas deviation factor into the dynamic water intrusion calculation model to calculate the multi-cycle dynamic water intrusion.

[0100] This invention discloses a multi-cycle dynamic water intrusion calculation method for gas-cap reservoirs. By establishing a total mass conservation equation based on multi-cycle injection-production patterns, it can more accurately describe the mass exchange process in gas-cap reservoirs during long-term, multi-cycle injection-production processes, providing a solid theoretical foundation for the optimized operation of the gas storage facility. This equation considers the interaction between formation fluids and injected natural gas during the injection-production process, making the prediction of dynamic changes in the gas storage facility more comprehensive and scientific, and contributing to the formulation of more reasonable injection-production plans and inventory management strategies. By collecting and calculating detailed basic parameters, operating parameters, and fluid property parameters of the gas storage facility, the accuracy and reliability of the input data for subsequent models are ensured, thereby improving the accuracy and credibility of model predictions. Accurate calculation of the mass of original formation fluids, produced fluids, injected natural gas, and remaining formation fluids provides a comprehensive mass balance analysis basis for subsequent dynamic water intrusion calculations. Furthermore, by deriving a dynamic water intrusion calculation model, real-time monitoring and prediction of water intrusion during multi-cycle injection and production processes in gas storage facilities are achieved. This helps in the timely detection and response to water intrusion issues, ensuring the safe and stable operation of gas storage facilities. The model can guide gas storage facility managers to adjust injection and production strategies based on dynamic changes in water intrusion, optimizing the operational efficiency and lifespan of gas storage facilities and reducing operating costs. Finally, considering the high-pressure properties of formation fluids and the deviation factor of natural gas, the calculation of dynamic water intrusion is made closer to reality, improving calculation accuracy and practicality. Through refined parameter settings and calculations, gas storage facility managers can conduct more refined management of gas storage facilities, including developing targeted water intrusion prevention measures and gas storage expansion plans. In summary, based on the principle of material balance, by obtaining the basic parameters, injection and production operation parameters, and fluid property parameters of the utilized gas cap reservoir type gas storage facility, it is possible to predict the multi-cycle dynamic water intrusion of complex condensate gas cap reservoir gas storage facilities. The method in this invention takes into account the effects of gas cap anti-condensation changes, natural gas dissolution and escape, and rock and bound water deformation. The calculation results are highly accurate, the calculation process is simple, and it can be applied to condensate gas cap reservoir-type gas storage facilities where general material balance methods are not applicable.

[0101] The present invention will be described in detail below with reference to specific embodiments:

[0102] Step 1: Based on the multi-cycle fluid injection and production variation law of gas cap reservoir type gas storage, establish the total mass conservation equation.

[0103] The multi-cycle operation of a gas-capped reservoir with condensate at the edge and bottom water is essentially a process of material exchange involving alternating reverse condensation and reverse evaporation, repeated hydrocarbon dissolution and escape, and the reciprocating shift of the gas-oil and oil-water interfaces. Therefore, the total mass conservation equation for multi-cycle injection and production in a gas-capped reservoir is: Amount of original hydrocarbons + Amount of injected hydrocarbons = Amount of produced hydrocarbons + Amount of remaining hydrocarbons, i.e.:

[0104] n ig +n il +n inj =n pg +n po +n ro +n rg (1)

[0105] Where, n ig n represents the amount of the original hydrocarbon gas, expressed in kmol; il n represents the amount of the original hydrocarbon liquid substance, in kmol; inj The amount of hydrocarbon gas injected during the depletion development phase of a gas reservoir or the operation phase of a gas storage facility, expressed in kmol; n pg The amount of hydrocarbon gas produced, expressed in kmol; n po The amount of hydrocarbon liquid produced, in kmol; n ro n represents the amount of residual hydrocarbon liquid in the current formation, in kmol; rg This represents the amount of residual hydrocarbon gaseous substances in the current formation, expressed in kmol.

[0106] Step 2: Based on the multi-cycle fluid injection and production variation law of gas cap reservoir type gas storage, the calculation equations for the amount of original formation fluid, the amount of produced formation fluid, the amount of injected natural gas, and the amount of remaining formation fluid are derived respectively.

[0107] The amount of the original formation fluid material includes the amount of original hydrocarbon gas material n. ig The amount of the original hydrocarbon liquid substance n il The amount of extracted formation fluid includes the amount of hydrocarbon gas produced (n). pg and the amount of hydrocarbon liquid produced, n pl The amount of injected natural gas includes the amount of hydrocarbon gas injected during the reservoir depletion development phase or the gas storage facility operation phase. inj The amount of remaining formation fluid material includes the amount of residual hydrocarbon liquid material in the current formation, n. ro and the amount of residual hydrocarbon gaseous substances in the current formation, n rg ;

[0108] The amount of the original hydrocarbon gaseous substance is:

[0109]

[0110] Where, p i The original formation pressure is MPa; p sc Z represents the pressure under standard conditions, in MPa; cgi Z represents the condensate gas deviation factor under the original formation conditions. scR is the gas deviation factor under surface conditions; T is the universal gas constant; and T is the formation temperature in K.

[0111] The original amount of hydrocarbon liquid substance was:

[0112]

[0113] Among them, V g The original pore volume of the gas cap region is m. 3 G represents the original condensate gas reserves in the gas cap region, in m³. 3 B cgi S is the original condensate gas volume coefficient; wcg The initial water saturation of the gas cap region; m is the gas cap index; S wco ρ represents the water saturation of the oil ring region under the original formation conditions. oi Density of oil rings under original formation conditions, kg / m³ 3 M oi The molecular weight of the oil ring oil liquid under the original formation conditions is expressed in kg / mol.

[0114] The amount of condensate gas separated from the surface is:

[0115]

[0116] Among them, G cp The amount of natural gas extracted from the gas cap area, in m 3 ;

[0117] The amount of dissolved gas in the extracted oil ring is:

[0118]

[0119] Among them, V pbo m represents the amount of oil extracted from the oil ring. 3 ;R p For the oil-to-gas ratio in oil-ring oil production, m 3 / m 3 ;

[0120] The amount of oil separated from the produced gas top condensate is:

[0121]

[0122] Among them, V pco The amount of condensate oil extracted from the gas cap area, in m 3 ;ρ co The density of the condensate oil extracted from the gas cap area, kg / m³ 3 M co The molecular weight of condensate oil extracted from the gas cap area under surface conditions, in kg / mol.

[0123] The amount of oil ring produced is:

[0124]

[0125] Where, ρ bo The density of the oil extracted from the oil ring region, kg / m³ 3 M bo is the molecular weight of the liquid under oil ring surface conditions, in kg / mol;

[0126] The amount of hydrocarbon gaseous substances produced is:

[0127] n pg =n pcg +n pdg (10)

[0128] The amount of hydrocarbon liquid substance produced is:

[0129] n po =n pco +n pbo (11)

[0130] The amount of hydrocarbon gas injected during the gas reservoir depletion development phase or the gas storage facility operation phase:

[0131]

[0132] Among them, G inj The amount of natural gas extracted from the gas cap area, in m 3 ;

[0133] The amount of remaining hydrocarbon gaseous substances is:

[0134]

[0135] Where, p c Z represents the current formation pressure, in MPa; c V is the gas deviation factor under current formation conditions. rcg m is the pore volume occupied by the remaining hydrocarbon gas. 3 W e The current water intrusion in the gas cap reservoir is m. 3 W p To accumulate water production, m 3 W i To calculate the cumulative water injection volume, m 3 B w The volume factor of formation water; C w C is the formation water compressibility coefficient. f Δp is the compressibility coefficient of the formation rock; Δp is the pressure difference, MPa.

[0136] The amount of remaining oil ring material is:

[0137]

[0138] Among them, V rbo The pore volume occupied by the oil ring under the current pressure is m. 3 B boc ρ is the oil ring volume coefficient under the current pressure; boc The density of the oil ring is kg / m³. 3 M boc The molecular weight of the oil ring oil liquid is given in kg / mol.

[0139] The amount of residual condensate oil is:

[0140]

[0141] V rco =V g (1-S wcg )S coc (18)

[0142] Among them, V rco The pore volume occupied by condensate oil under the current formation conditions is expressed in m. 3 S coc ρ represents the saturation of condensate oil under the current formation conditions. coc Density of residual condensate oil, kg / m³ 3 M coc The molecular weight of the remaining condensate oil is kg / mol.

[0143] The current amount of residual hydrocarbon liquid in the formation is:

[0144] n ro =n rbo +n rco (19)

[0145] The current amount of residual hydrocarbon gaseous material in the formation is:

[0146] n rg =n rcg (20).

[0147] Step 3: Substitute the derived calculation equations into the total amount of substance conservation equation to establish a dynamic water intrusion calculation model.

[0148] Substituting equations (2) to (13) and equations (15) to (20) into equation (1), we get:

[0149]

[0150] get,

[0151]

[0152] Substituting formula (22) into formula (14) and transforming the formula, we obtain the final formula for calculating the dynamic water intrusion of a gas cap reservoir:

[0153]

[0154] Among them, W e The current water intrusion in the gas cap reservoir is m. 3 ;p sc Pressure under standard conditions, MPa; G is the original condensate gas reserve in the gas cap area, m³. 3 Z sc R is the gas deviation factor under surface conditions; T is the universal gas constant; B is the formation temperature in K; cgi S is the original condensate gas volume coefficient; wco ρ represents the water saturation of the oil ring region under the original formation conditions. oi Density of oil rings under original formation conditions, kg / m³ 3 m is the gas cap index; M oi The molecular weight of the oil ring oil liquid under the original formation conditions is given in kg / mol; S wcg G represents the initial water saturation level of the gas cap region. inj The amount of natural gas extracted from the gas cap area, in m 3 G cp The amount of natural gas extracted from the gas cap area, in m 3 V pbo m represents the amount of oil extracted from the oil ring. 3 ;R p For the oil-to-gas ratio in oil-ring oil production, m 3 / m 3 V pco The amount of condensate oil extracted from the gas cap area, in m 3 ;ρ co The density of the condensate oil extracted from the gas cap area, kg / m³ 3 M co For condensate oil extracted from the gas cap area, the molecular weight of the liquid under surface conditions is kg / mol; ρ bo The density of the oil extracted from the oil ring region, kg / m³ 3 M bo The liquid molecular weight of the oil extracted from the oil ring region, in kg / mol; ρ boc The density of the oil ring under current conditions, kg / m³ 3 M boc B represents the molecular weight of the oil-ring oil liquid under current conditions, in kg / mol. boc S is the volumetric coefficient of the oil ring under current conditions; coc ρ represents the saturation of condensate oil in the current formation;coc The density of formation condensate oil under current conditions, in kg / m³ 3 M coc The molecular weight of formation condensate oil under current conditions is given in kg / mol; p c Z represents the current formation pressure, in MPa; c W represents the gas deviation factor under current formation conditions. p To accumulate water production, m 3 W i To calculate the cumulative water injection volume, m 3 B w The volume factor of formation water; C w C is the formation water compressibility coefficient. f Δp is the rock compressibility coefficient of the formation; Δp is the pressure difference, MPa.

[0155] Equation (23) can be derived to calculate the dynamic water intrusion during the development and operation of gas cap and bottom water reservoirs, taking into account factors such as bottom water intrusion, condensate gas recondensation, dissolved gas escape, bound water, and rock deformation. The parameters involved in the formula, except for high-pressure fluid properties, are known for a specific gas cap reservoir or can be obtained from reservoir data testing.

[0156] Step four: Based on indoor experiments and equations of state, obtain the variation patterns of formation fluid high-pressure properties, anti-condensate saturation, and natural gas deviation factor during multi-cycle injection and production. Obtain the basic parameters and dynamic operation data of the gas cap reservoir type gas storage. Substitute the basic parameters, dynamic operation data, formation fluid high-pressure properties, anti-condensate saturation, and natural gas deviation factor into the final calculation formula of the dynamic water intrusion of the gas cap reservoir type gas storage to calculate the multi-cycle dynamic water intrusion.

[0157] The relationship between the high-pressure properties of oil-ring oil and the amount of natural gas injected was obtained through indoor experiments. The high-pressure property variation patterns in the embodiments of this specification are as follows: Figure 2 As shown. The change law of condensate saturation during the gas injection process of the gas storage tank was determined through phase state experiments. The change law of condensate saturation in the embodiments of this specification is as follows: Figure 3 As shown.

[0158] The accuracy of the gas deviation factor has a significant impact on the calculation results of the mass balance equation. Given the relatively low absolute pressure of natural gas in the target gas storage facility, the DPR method is used to calculate the deviation factor.

[0159]

[0160] ρ pr =0.27p pr / (ZT pr (25)

[0161]

[0162] Among them, T pr For apparent contrast temperature; T pc Let p be the apparent critical temperature, in K; pr See contrast pressure; p pc ρ is the apparent critical pressure, MPa; pr It is a dimensionless contrast density.

[0163] Step 5: Reliability verification.

[0164] A numerical simulation model was established based on the basic parameters, injection and production operation parameters, and fluid property parameters of the gas cap reservoir. The reliability of the gas cap reservoir was verified based on the numerical simulation model and the calculated multi-cycle dynamic water intrusion volume.

[0165] Example 1

[0166] The S-type gas cap reservoir was selected for multi-cycle dynamic water intrusion calculation. First, the basic parameters, injection and production operation parameters, and fluid properties of the gas cap reservoir were obtained, as shown in Table 1.

[0167] Table 1

[0168]

[0169]

[0170] Then, dynamic data on the injection and production patterns of the S-type gas cap reservoir over four cycles were obtained, as shown in Table 2:

[0171] Table 2

[0172]

[0173]

[0174] Based on the data in Tables 1 and 2, the amount of original hydrocarbon gaseous material in each injection and production cycle of the S gas-top reservoir can be calculated by formula (2), the amount of original hydrocarbon liquid material can be calculated by formula (3), the amount of produced hydrocarbon gaseous material can be calculated by formulas (6) and (7), the amount of produced hydrocarbon liquid material can be calculated by formulas (8) and (9), the amount of injected hydrocarbon gaseous material can be calculated by formula (12), the amount of remaining hydrocarbon gaseous material can be calculated by formula (13), and the amount of remaining hydrocarbon liquid material can be calculated by formulas (15) and (17).

[0175] Calculate the water intrusion W under the construction conditions of the gas cap reservoir based on formula (23). e=751.81×10 4 m 3 ;

[0176] The water intrusion W at the end of the first gas injection cycle of the gas cap reservoir is calculated according to formula (23). e =564.90×10 4 m 3 ;

[0177] The water intrusion W at the end of the first gas production cycle of the gas cap reservoir is calculated according to formula (23). e =595.99×10 4 m 3 ;

[0178] The water intrusion W at the end of the second gas injection cycle of the gas cap reservoir is calculated according to formula (23). e =511.32×10 4 m 3 ;

[0179] The water intrusion W at the end of the second gas production cycle of the gas cap reservoir is calculated according to formula (23). e =584.60×10 4 m 3 ;

[0180] The water intrusion W at the end of the third gas injection cycle of the gas cap reservoir is calculated according to formula (23). e =487.33×10 4 m 3 ;

[0181] The water intrusion W at the end of the third gas production cycle of the gas cap reservoir is calculated according to formula (23). e =557.30×10 4 m 3 ;

[0182] The water intrusion W at the end of the fourth gas injection cycle of the gas cap reservoir is calculated according to formula (23). e =476.57×10 4 m 3 ;

[0183] The water intrusion W at the end of the fourth gas production cycle of the gas cap reservoir is calculated according to formula (23). e =557.71×10 4 m 3 .

[0184] Finally, the reliability of the calculation results is verified.

[0185] See Figure 4Based on the numerical simulation model of the gas cap reservoir, the water intrusion volume at each stage of the gas storage facility's operation was obtained. The water intrusion volume calculated in the example was compared with the reservoir water intrusion volume calculation results after historical fitting of the numerical simulation. The water intrusion volume variation patterns obtained by the two methods are basically consistent, and the maximum error in the multi-cycle water intrusion volume calculation is within 8.06%. This indicates that the present invention can accurately predict the dynamic water intrusion volume during the multi-cycle operation of the gas cap reservoir.

[0186] See Figure 5 This invention discloses a multi-period dynamic water intrusion calculation system for gas cap reservoirs, comprising:

[0187] The module for establishing the total mass conservation equation is used to establish the total mass conservation equation based on the multi-cycle fluid injection and production variation law of gas cap reservoirs.

[0188] The dynamic water intrusion calculation model establishment module is used to derive calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material. The derived calculation equations are then substituted into the total material conservation equation to establish the dynamic water intrusion calculation model.

[0189] The parameter determination module is used to obtain the variation patterns of formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production based on indoor experiments and equations of state.

[0190] The multi-period dynamic water intrusion calculation module is used to obtain the basic parameters and dynamic operation data of the gas cap reservoir type gas storage, and to substitute the basic parameters, dynamic operation data, formation fluid high pressure properties, anticondensate saturation and natural gas deviation factor into the dynamic water intrusion calculation model to calculate the multi-period dynamic water intrusion.

[0191] See Figure 6 The third objective of this invention is to provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method for calculating the multi-period dynamic water intrusion of a gas cap reservoir.

[0192] The method for calculating multi-period dynamic water intrusion in a gas cap reservoir includes the following steps:

[0193] Based on the multi-cycle fluid injection and production variation law of gas cap reservoir type gas storage, a total material quantity conservation equation is established;

[0194] The calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material are derived. The derived calculation equations are then substituted into the total material conservation equation to establish a dynamic water intrusion calculation model.

[0195] Based on indoor experiments and equation of state, the variation patterns of formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production were obtained.

[0196] The basic parameters and dynamic operation data of the gas cap reservoir are obtained, and the basic parameters, dynamic operation data, formation fluid high pressure properties, anticondensate saturation and natural gas deviation factor are substituted into the dynamic water intrusion calculation model to calculate the multi-period dynamic water intrusion.

[0197] The fourth objective of this invention is to provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method for calculating the multi-period dynamic water intrusion of a gas cap reservoir.

[0198] The method for calculating multi-period dynamic water intrusion in a gas cap reservoir includes the following steps:

[0199] Based on the multi-cycle fluid injection and production variation law of gas cap reservoir type gas storage, a total material quantity conservation equation is established;

[0200] The calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material are derived. The derived calculation equations are then substituted into the total material conservation equation to establish a dynamic water intrusion calculation model.

[0201] Based on indoor experiments and equation of state, the variation patterns of formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production were obtained.

[0202] The basic parameters and dynamic operation data of the gas cap reservoir are obtained, and the basic parameters, dynamic operation data, formation fluid high pressure properties, anticondensate saturation and natural gas deviation factor are substituted into the dynamic water intrusion calculation model to calculate the multi-period dynamic water intrusion.

[0203] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0204] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0205] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0206] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0207] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calculating multi-period dynamic water intrusion in a gas cap reservoir, characterized in that, include: Based on the multi-cycle fluid injection and production variation law of gas cap reservoir type gas storage, a total material quantity conservation equation is established; The calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material are derived. The derived calculation equations are then substituted into the total material conservation equation to establish a dynamic water intrusion calculation model. Based on indoor experiments and equation of state, the variation patterns of formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production were obtained. The basic parameters and dynamic operation data of the gas cap reservoir are obtained, and the basic parameters, dynamic operation data, formation fluid high pressure properties, anticondensate saturation and natural gas deviation factor are substituted into the dynamic water intrusion calculation model to calculate the multi-period dynamic water intrusion.

2. The method for calculating multi-period dynamic water intrusion in a gas-capped oil reservoir according to claim 1, characterized in that, After calculating the multi-cycle dynamic water intrusion, reliability verification is also included, specifically: A numerical simulation model was established based on the basic parameters, operational dynamic data, and high-pressure properties of formation fluids of the gas cap oil reservoir type gas storage facility. Reliability verification was performed based on the numerical simulation model and the calculated multi-period dynamic water intrusion.

3. The method for calculating multi-period dynamic water intrusion in a gas-capped oil reservoir according to claim 1, characterized in that, The specific equation for the conservation of total amount of substance is as follows: n ig +n il +n inj =n pg +n po +n ro +n rg (1) Where, n ig n represents the amount of the original hydrocarbon gas, expressed in kmol; il n represents the amount of the original hydrocarbon liquid substance, in kmol; inj The amount of hydrocarbon gas injected during the depletion development phase of a gas reservoir or the operation phase of a gas storage facility, expressed in kmol; n pg The amount of hydrocarbon gas produced, expressed in kmol; n po The amount of hydrocarbon liquid produced, in kmol; n ro n represents the amount of residual hydrocarbon liquid in the current formation, in kmol; rg This represents the amount of residual hydrocarbon gaseous substances in the current formation, expressed in kmol.

4. The method for calculating multi-period dynamic water intrusion in a gas-capped oil reservoir according to claim 3, characterized in that, The calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material derived are as follows: The amount of the original formation fluid material includes the amount of original hydrocarbon gas material n. ig The amount of the original hydrocarbon liquid substance n il The amount of extracted formation fluid includes the amount of hydrocarbon gas produced (n). pg and the amount of hydrocarbon liquid produced, n pl The amount of injected natural gas includes the amount of hydrocarbon gas injected during the reservoir depletion development phase or the gas storage facility operation phase. inj The amount of remaining formation fluid material includes the amount of residual hydrocarbon liquid material in the current formation, n. ro and the amount of residual hydrocarbon gaseous substances in the current formation, n rg ; The equation for calculating the amount of original hydrocarbon gas is: Where, p i The original formation pressure is MPa; p sc Z represents the pressure under standard conditions, in MPa; cgi Z represents the condensate gas deviation factor under the original formation conditions. sc R is the gas deviation factor under surface conditions; T is the universal gas constant; and T is the formation temperature in K. The equation for calculating the amount of the original hydrocarbon liquid substance is: Among them, V g The original pore volume of the gas cap region is m. 3 G represents the original condensate gas reserves in the gas cap region, in m³. 3 B cgi S is the original condensate gas volume coefficient; wcg The initial water saturation of the gas cap region; m is the gas cap index; S wco ρ represents the water saturation of the oil ring region under the original formation conditions. oi Density of oil rings under original formation conditions, kg / m³ 3 M oi The molecular weight of the oil ring oil liquid under the original formation conditions is expressed in kg / mol. The equation for calculating the amount of substance of the surface-separated condensate gas is as follows: Among them, G cp The amount of natural gas extracted from the gas cap area, in m 3 ; The equation for calculating the amount of dissolved gas in the extracted oil ring is as follows: Among them, V pbo m represents the amount of oil extracted from the oil ring. 3 ;R p For the oil-to-gas ratio in oil-ring oil production, m 3 / m 3 ; The amount of oil separated from the produced gas top condensate is: Among them, V pco The amount of condensate oil extracted from the gas cap area, in m 3 ;ρ co The density of the condensate oil extracted from the gas cap area, kg / m³ 3 M co The molecular weight of condensate oil extracted from the gas cap area under surface conditions, in kg / mol. The equation for calculating the amount of oil produced in the oil ring is as follows: Where, ρ bo The density of the oil extracted from the oil ring region, kg / m³ 3 M bo is the molecular weight of the liquid under oil ring surface conditions, in kg / mol; The equation for calculating the amount of hydrocarbon gas produced is as follows: n pg =n pcg +n pdg (10) The equation for calculating the amount of hydrocarbon liquid produced is as follows: n po =n pco +n pbo (11) Equations for calculating the amount of hydrocarbon gas injected during the depletion development phase of a gas reservoir or the operation phase of a gas storage facility: Among them, G inj The amount of natural gas extracted from the gas cap area, in m 3 ; The equation for calculating the amount of remaining hydrocarbon gas is: Where, p c Z represents the current formation pressure, in MPa; c V is the gas deviation factor under the current formation conditions. rcg m is the pore volume occupied by the remaining hydrocarbon gas. 3 W e The current water intrusion in the gas cap reservoir is m. 3 W p To accumulate water production, m 3 W i To calculate the cumulative water injection volume, m 3 B w The volume factor of formation water; C w C is the formation water compressibility coefficient. f Δp is the compressibility coefficient of the formation rock; Δp is the pressure difference, MPa. The equation for calculating the amount of remaining oil ring material is: Among them, V rbo The pore volume occupied by the oil ring under the current pressure is m. 3 B boc ρ is the oil ring volume coefficient under the current pressure; boc The density of the oil ring is kg / m³. 3 M boc The molecular weight of the oil ring oil liquid is given in kg / mol. The equation for calculating the amount of residual condensate oil is: V rco =V g (1-S wcg )S coc (18) Among them, V rco The pore volume occupied by condensate oil under the current formation conditions is expressed in m. 3 S coc ρ represents the saturation of condensate oil under the current formation conditions. coc Density of residual condensate oil, kg / m³ 3 M coc The molecular weight of the remaining condensate oil is kg / mol. The equation for calculating the amount of remaining hydrocarbon liquid material in the current formation is as follows: n ro =n rbo +n rco (19) The equation for calculating the amount of residual hydrocarbon gas in the current formation is as follows: n rg =n rcg (20)。 5. The method for calculating multi-period dynamic water intrusion in a gas-capped oil reservoir according to claim 4, characterized in that, The specific steps for establishing a dynamic water intrusion calculation model by substituting the derived calculation equations into the total mass conservation equation are as follows: Substituting equations (2) to (13) and (15) to (20) into equation (1), we get: get: Among them, W e The current water intrusion in the gas cap reservoir is m. 3 ;p sc Pressure under standard conditions, MPa; G represents the original condensate gas reserves in the gas cap region, m 3 Z sc R is the gas deviation factor under surface conditions; T is the universal gas constant; B is the formation temperature in K; cgi S is the original condensate gas volume coefficient; wco ρ represents the water saturation of the oil ring region under the original formation conditions. oi Density of oil rings under original formation conditions, kg / m³ 3 m is the gas cap index; M oi The molecular weight of the oil ring oil liquid under the original formation conditions is given in kg / mol; S wcg G represents the initial water saturation level of the gas cap region. inj The amount of natural gas extracted from the gas cap area, in m 3 G cp The amount of natural gas extracted from the gas cap area, in m 3 V pbo m represents the amount of oil extracted from the oil ring. 3 ;R p For the oil-to-gas ratio in oil-ring oil production, m 3 / m 3 V pco The amount of condensate oil extracted from the gas cap area, in m 3 ;ρ co The density of the condensate oil extracted from the gas cap area, kg / m³ 3 M co For condensate oil extracted from the gas cap area, the molecular weight of the liquid under surface conditions is kg / mol; ρ bo The density of the oil extracted from the oil ring region, kg / m³ 3 M bo The liquid molecular weight of the oil extracted from the oil ring region, in kg / mol; ρ boc The density of the oil ring under current conditions, kg / m³ 3 M boc B represents the molecular weight of the oil-ring oil liquid under current conditions, in kg / mol. boc S is the volumetric coefficient of the oil ring under current conditions; coc ρ represents the saturation of condensate oil in the current formation; coc The density of formation condensate oil under current conditions, in kg / m³ 3 M coc The molecular weight of formation condensate oil under current conditions is given in kg / mol; p c Z represents the current formation pressure, in MPa; c W represents the gas deviation factor under current formation conditions. p To accumulate water production, m 3 W i To calculate the cumulative water injection volume, m 3 B w The volume factor of formation water; C w C is the formation water compressibility coefficient. f Δp is the rock compressibility coefficient of the formation; Δp is the pressure difference, MPa.

6. The method for calculating multi-period dynamic water intrusion in a gas-capped oil reservoir according to claim 5, characterized in that, The specific laws governing the changes in formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production, based on indoor experiments and equations of state, are as follows: The relationship between the high-pressure physical properties of oil ring oil and the amount of natural gas injected was obtained through indoor experiments; the change law of condensate saturation during the gas injection process of gas cap oil reservoir was obtained through phase state experiments. The natural gas deviation factor is calculated using the DPR method, specifically as follows: r pr =0.27p pr / (ZT pr ) (24) Among them, T pr For apparent contrast temperature; T pc Let p be the apparent critical temperature, K; pr See contrast pressure; p pc ρ is the apparent critical pressure, MPa; pr It is a dimensionless contrast density.

7. The method for calculating multi-period dynamic water intrusion in a gas-capped oil reservoir according to claim 6, characterized in that, Substituting the aforementioned basic parameters, operational dynamic data, formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor into the dynamic water intrusion calculation model, the multi-cycle dynamic water intrusion is calculated as follows:

8. A multi-period dynamic water intrusion calculation system for a gas cap reservoir, characterized in that, include: The module for establishing the total mass conservation equation is used to establish the total mass conservation equation based on the multi-cycle fluid injection and production variation law of gas cap reservoirs. The dynamic water intrusion calculation model establishment module is used to derive calculation equations for the amount of original formation fluid material, the amount of extracted formation fluid material, the amount of injected natural gas material, and the amount of remaining formation fluid material. The derived calculation equations are then substituted into the total material conservation equation to establish the dynamic water intrusion calculation model. The parameter determination module is used to obtain the variation patterns of formation fluid high-pressure properties, condensate saturation, and natural gas deviation factor during multi-cycle injection and production based on indoor experiments and equations of state. The dynamic water intrusion calculation module is used to obtain the basic parameters and dynamic operation data of the gas cap reservoir type gas storage, and to substitute the basic parameters, dynamic operation data, formation fluid high pressure properties, anticondensate saturation and natural gas deviation factor into the dynamic water intrusion calculation model to calculate the multi-period dynamic water intrusion.

Images