Fractured tight sandstone water-gas reservoir water seal gas resource quantity evaluation method and system

Abstract

The application discloses a kind of fractured tight sandstone water gas reservoir water seal gas resource quantity evaluation method and system, calculate the static resource quantity and dynamic resource quantity of water seal gas of the water flooded well of to be evaluated gas well, and calculate the deviation percentage of the arithmetic mean of static resource quantity and dynamic resource quantity and the static resource quantity and dynamic resource quantity of water seal gas of the water flooded well of to be evaluated gas well, if deviation percentage is within ±10%, then the water seal gas resource quantity evaluation result of the water flooded well of to be evaluated gas well has guiding significance to later water control and production scheme optimization and development benefit evaluation, the quantitative analysis of water seal gas resource quantity in water flooded area is realized after water invasion of fractured tight sandstone water gas reservoir, and supports for later water control and production scheme optimization and development benefit evaluation.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development technology, specifically to a method and system for assessing the water-sealed gas resources in fractured tight sandstone reservoirs with water. Background Technology

[0002] During the development of water-bearing gas reservoirs in fractured tight sandstone, as the pressure in the gas zone continuously decreases, water from the reservoir's periphery intrudes towards higher areas due to the pressure difference between the gas and water zones. Because the resistance to water migration within fractures is much less than that in the matrix, the water rapidly advances along the fractures. Meanwhile, formation water unevenly intrudes along the highly permeable fractures, easily forming "water-sealed gas." This difficult-to-access sealed gas represents a potential area for water management and extraction. Currently, methods for quantitatively assessing the amount of "water-sealed gas" resources are still in the exploratory stage. Commonly used numerical simulation techniques are labor-intensive and highly specialized, and dual-pore, dual-permeability models, local mesh refinement, and unstructured mesh techniques do not have advantages in terms of fracture characteristic scale, mesh component analysis, simulation accuracy, and computational efficiency. Due to inaccurate characterization of fracture linkages in geological modeling, early water intrusion simulations of water-bearing gas reservoirs in fractured tight sandstone show uniform advancement results, resulting in low fit with the actual rapid advancement of intrusive water along fractures, thus hindering the assessment of water management and extraction potential and economic benefits. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a method and system for assessing the water-sealed gas resources in fractured tight sandstone reservoirs with water, enabling quantitative analysis of the water-sealed gas resources in the flooded area after water intrusion into fractured tight sandstone reservoirs with water, thus supporting the optimization of subsequent water management and extraction schemes and the evaluation of development benefits.

[0004] This invention is achieved through the following technical solution: a method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs, the specific steps of which are as follows:

[0005] S1 uses the water flooding degree coefficient k of each development layer of the water-flooded well to be evaluated and the remaining recoverable reserves of each development layer to obtain the "water-sealed gas" resource quantity of each single layer of the water-flooded well. The "water-sealed gas" resource quantity of each single layer is accumulated to obtain the static resource quantity of "water-sealed gas" of the water-flooded gas well to be evaluated.

[0006] S2 establishes the production analysis curves for the water-flooded wells to be evaluated. Based on modern decline analysis methods, curve fitting is performed on the production data of the water-free and water-bearing production periods of the water-flooded gas wells to be evaluated, resulting in decline curves L and L′ for the water-free and water-bearing production periods. Based on the decline curves L and L′, the final recoverable reserves G for the water-free and water-bearing production periods are obtained. p and G p ′, the final recoverable reserves G during the waterless and water-containing production periods p and G pThe difference between ′ is the dynamic resource quantity of “water-sealed gas” in the water-flooded gas well to be evaluated;

[0007] S3 calculates the arithmetic mean of the static and dynamic resource quantities of the water-flooded gas wells to be evaluated, obtained from steps S1 and S2, and calculates the percentage deviation between the static and dynamic resource quantities and the obtained arithmetic mean. If the percentage deviation is within ±10%, the evaluation results of the water-flooded gas wells to be evaluated have guiding significance for the optimization of subsequent water management and extraction schemes and the evaluation of development benefits.

[0008] Furthermore, in step S1, the flooding degree coefficient k of each development layer of the flooded well to be evaluated is calculated using the well control area A of the flooded well to be evaluated in each development layer and the flooded area A′ of the flooded well to be evaluated in each development layer.

[0009] Furthermore, in step S1, the well control area A of the water-flooded well to be evaluated in each development layer is calculated by arithmetic mean or Thiessen polygon.

[0010] Furthermore, in step S1, the water-bearing situation of each development layer is clarified through gas reservoir dynamic analysis, and the water invasion front is characterized, thereby obtaining the water-bearing area A′ of the water-bearing well to be evaluated within the well-controlled area of ​​each development layer.

[0011] Furthermore, in step S1, the remaining recoverable reserves of each development layer are the well-controlled geological reserves G and cumulative production G of the water-flooded wells to be evaluated within each development layer. p The difference, specifically, is calculated using the volumetric method for well-controlled geological reserves G and cumulative production G. p This was obtained based on the production measurement data of the water-flooded wells to be evaluated.

[0012] Furthermore, the formula for calculating the static resource quantity of "water-sealed gas" in water-flooded gas wells to be evaluated is as follows:

[0013]

[0014] Where: i—number of development strata; G—well-controlled geological reserves of a certain stratum, 10 8 m 3 G p —Cumulative output of a certain tier, 10 8 m 3 k—flooding degree coefficient; R—gas reservoir rated recovery rate, %.

[0015] Furthermore, in step S2, a modern decline analysis method is selected for curve fitting based on the geological characteristics and production history of the water-flooded gas well to be evaluated.

[0016] Furthermore, in step S2, modern decline analysis methods include Blasingame and Agarwal-Gardner flow mass equilibrium.

[0017] Furthermore, in step S2, by setting the waste production rate or waste pressure, the final recoverable reserves G for the anhydrous and wet production periods are obtained based on the decline curves L and L′. p and G p ′.

[0018] Furthermore, the method is also applicable to the assessment of "water-sealed gas" resources in well groups or gas reservoirs.

[0019] This invention also discloses a system for assessing the water-sealed gas resources in fractured tight sandstone reservoirs, comprising:

[0020] The static resource calculation module is used to obtain the water-sealed gas resource of each single layer of the water-flooded well by using the water flooding degree coefficient k of each development layer of the water-flooded well to be evaluated and the remaining recoverable reserves of each development layer. The static resource of water-sealed gas of each single layer is accumulated to obtain the static resource of water-sealed gas of the water-flooded well to be evaluated.

[0021] The dynamic resource calculation module is used to establish production analysis curves for water-flooded wells to be evaluated. Based on modern decline analysis methods, it performs curve fitting on the production data of the water-free and water-bearing production periods of the water-flooded gas wells to be evaluated, obtaining decline curves L and L′ for the water-free and water-bearing production periods. Based on the decline curves L and L′, the final recoverable reserves G for the water-free and water-bearing production periods are obtained. p and G p ′, the final recoverable reserves G during the waterless and water-containing production periods p and G p The difference between ′ is the dynamic resource quantity of water-sealed gas in the water-flooded gas well to be evaluated;

[0022] The evaluation module is used to calculate the arithmetic mean of the static and dynamic resources of the water-sealed gas reservoir in the water-flooded well to be evaluated, and to calculate the percentage deviation between the static and dynamic resources and the obtained arithmetic mean. If the percentage deviation is within ±10%, the evaluation result of the water-sealed gas resources in the fractured tight sandstone reservoir is obtained.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention provides a method for assessing the water-sealed gas resources in water-bearing gas reservoirs in fractured tight sandstone. By calculating both the static and dynamic resources of the water-sealed gas in the water-flooded wells to be assessed, the method achieves quantitative analysis of the water-sealed gas resources in the water-flooded area after water intrusion in water-bearing gas reservoirs in fractured tight sandstone. This fills the technical gap in assessing water-sealed gas resources and provides support for optimizing water control and extraction schemes and evaluating development benefits in water-bearing gas reservoirs in fractured tight sandstone. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the well locations in a gas reservoir.

[0026] Figure 2 Blasingame fitting curve of well K2 in a gas reservoir;

[0027] Figure 3 Fitting curve of AG FMB for a certain gas reservoir. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0029] This invention discloses a method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs, the specific steps of which are as follows:

[0030] 1. Calculate the static resource quantity of "water-sealed gas" in the water-flooded well to be evaluated.

[0031] (1) The well control area A of the water-flooded well to be evaluated in each development layer is obtained by using arithmetic mean, Thiessen polygon and other methods.

[0032] (2) By analyzing the dynamics of the gas reservoir, the water-bearing situation of each development layer is clarified, the water invasion front is delineated, and the water-bearing area A′ of the water-bearing well to be evaluated within the well-controlled area of ​​each development layer is calculated.

[0033] (3) Using the data from steps (1) and (2), calculate the flooding degree coefficient k of each development layer of the flooded well to be evaluated, where k is the ratio of A′ / A.

[0034] (4) Calculate the well-controlled geological reserves G of the water-flooded well to be evaluated in each development layer. Specifically, calculate the well-controlled geological reserves G according to the volumetric method in the "Specification for Calculation of Petroleum and Natural Gas Reserves (DZ / T 0217-2005)".

[0035] (5) Based on the production measurement data of the flooded wells to be evaluated, calculate the cumulative production G of each development layer. p Specifically, the cumulative production can be divided based on the weighted average of the effective thickness of the production well sections of each layer.

[0036] (6) Based on the well-controlled geological reserves G and cumulative production G of the water-flooded wells to be evaluated in each development stratum. p The remaining recoverable reserves of each development layer are obtained. The remaining recoverable reserves of each development layer are multiplied by the water flooding coefficient k to calculate the water-sealed gas resource of a single layer. The water-sealed gas resources of each single layer are accumulated to obtain the static water-sealed gas resource of the water-flooded well to be evaluated. The calculation formula is as follows:

[0037]

[0038] Where i—the number of development layers.

[0039] G—Well-controlled geological reserves of a certain stratum (10 8 m 3 )

[0040] G p —Cumulative output of a certain stratum (10 8 m 3 )

[0041] k—Flooding severity coefficient

[0042] R—Certified oil recovery rate of the gas reservoir (%)

[0043] (7) This technology is also applicable to the assessment of the "water-sealed gas" resources of well groups or gas reservoirs.

[0044] 2. Fit the dynamic resource loss of the water-sealed gas in the water-flooded well to be evaluated:

[0045] (1) Based on modern decline analysis methods, and using mature dynamic analysis software such as "Harmony Enterprise" and "FAST", establish production analysis curves for the water-flooded wells to be evaluated;

[0046] (2) Based on the modern decline analysis method, curve fitting was performed on the production data of the waterless production period of the water-flooded gas well to be evaluated and the production data of the water-bearing gas well to be evaluated, so as to obtain the decline curve L of the waterless production period of the water-flooded gas well to be evaluated and the decline curve L′ of the water-bearing gas well to be evaluated.

[0047] Preferably, an appropriate decline analysis method is selected based on the geological characteristics and production history of the water-flooded gas well to be evaluated, and curve fitting is performed. Modern decline analysis methods include Blasingame, NPI (Normalized Pressure Integral), Agarwal-Gardner flow mass balance, etc., as shown in Table 1.

[0048] Table 1. Statistical Table of Applicable Scope of Commonly Used Modern Decline Analysis

[0049]

[0050] (4) Set the abandonment production or abandonment pressure to obtain the final recoverable reserves G during the anhydrous production period and the water-bearing production period, respectively. p and G p ′.

[0051] (5) Calculate the final recoverable reserves G during the anhydrous production period. p And the final recoverable reserves G during the water production period p The difference between ′ and ′ represents the amount of “water-sealed gas” resources in the water-flooded gas well to be evaluated.

[0052] This invention quantifies the resource quantity of "water-sealed gas" in water-flooded wells by fitting the progressive trend of production data at different times before and after water exposure to obtain the difference in the final recoverable reserves.

[0053] (6) This technology is also applicable to the assessment of the "water-sealed gas" resources of well groups or gas reservoirs.

[0054] 3. Compare the static and dynamic resource quantities of "water-sealed gas" obtained in steps 1 and 2.

[0055] (1) Calculate the arithmetic mean of the “water-sealed gas” resource quantity assessed in steps 1 and 2.

[0056] (2) Calculate the percentage deviation between the static and dynamic resource quantities of "water-sealed gas" assessed in Step 1 and Step 2 and the arithmetic mean in Step (1). If the percentage deviation is within ±10%, the assessment results of the "water-sealed gas" resource quantity of this technical gas reservoir are considered to have guiding significance for the optimization of water management and extraction schemes and the assessment of development benefits in the later stage.

[0057] This invention also discloses a system for assessing the water-sealed gas resources in fractured tight sandstone reservoirs, comprising:

[0058] The static resource calculation module is used to obtain the water-sealed gas resource of each single layer of the water-flooded well by using the water flooding degree coefficient k of each development layer of the water-flooded well to be evaluated and the remaining recoverable reserves of each development layer. The static resource of water-sealed gas of each single layer is accumulated to obtain the static resource of water-sealed gas of the water-flooded well to be evaluated.

[0059] The dynamic resource calculation module is used to establish production analysis curves for water-flooded wells to be evaluated. Based on modern decline analysis methods, it performs curve fitting on the production data of the water-free and water-bearing production periods of the water-flooded gas wells to be evaluated, obtaining decline curves L and L′ for the water-free and water-bearing production periods. Based on the decline curves L and L′, the final recoverable reserves G for the water-free and water-bearing production periods are obtained. p and G p ′, the final recoverable reserves G during the waterless and water-containing production periods p and Gp The difference between ′ is the dynamic resource quantity of water-sealed gas in the water-flooded gas well to be evaluated;

[0060] The evaluation module is used to calculate the arithmetic mean of the static and dynamic resources of the water-sealed gas reservoir in the water-flooded well to be evaluated, and to calculate the percentage deviation between the static and dynamic resources and the obtained arithmetic mean. If the percentage deviation is within ±10%, the evaluation result of the water-sealed gas resources in the fractured tight sandstone reservoir is obtained.

[0061] Example

[0062] like Figure 1 As shown, a high-pressure, layered, edge-water dry gas reservoir has only one development layer, at a mid-depth elevation of -4930m, with an original formation pressure of 108.8MPa, a formation temperature of 149.65℃, a pressure coefficient of 1.69, and a natural gas volume factor of 2.29×10⁻⁶ under reservoir conditions. -3 m 3 / (standard)m 3 The deviation factor is 1.710. There are currently three production wells in the gas reservoir. Wells K2 and K3 have successively encountered water and are in the water-bearing production stage. Well K1 is producing stably and is still in the waterless gas production period. First, it is necessary to quantitatively assess the amount of "water-sealed gas" resources in the gas reservoir to provide support for the optimization of water management and production plans and the evaluation of benefits in the later stage.

[0063] 1. Calculate the static resource quantity of "water-sealed gas" in the water-flooded well to be evaluated.

[0064] (1) The well control area of ​​production well K2 was determined to be 9.50 km² using the Thiessen polygon method. 2 .

[0065] (2) A certain gas reservoir has only one development layer, and the fluid nature is dry gas. Therefore, the volumetric method is selected to calculate the geological reserves of dry gas reservoirs. The calculation formula is as follows:

[0066] G = 0.01·A g ·h·Φ·Sgi / Bgi

[0067] in:

[0068] G – Original geological reserves of natural gas, 10 8 m 3 ;

[0069] Ag – Gas-bearing area, km² 2 ;

[0070] H – Average effective thickness, in meters;

[0071] Φ – Average effective porosity, f;

[0072] Sgi – Average initial gas saturation, f;

[0073] Bgi – Original natural gas volume coefficient;

[0074] T – Average formation temperature, K;

[0075] Tsc – Ground standard temperature, K;

[0076] Psc – Standard ground pressure, MPa;

[0077] Pi – the original formation pressure of the average gas reservoir, in MPa;

[0078] Zi – Original gas deviation coefficient.

[0079] Table 2. Values ​​of the original natural gas volume factor for production well K2.

[0080]

[0081] Table 3. Natural Gas Geological Reserve Parameters of Production Well K2

[0082]

[0083] Note: Effective thickness, effective porosity, and gas saturation data can be obtained from well logging interpretation data.

[0084] (3) Based on the dynamic analysis of the gas reservoir and the characterization of the water front, the water-flooded area within the controlled area of ​​well K2 is 7.7900 km². 2 The water intrusion coefficient k was calculated to be 0.82, thus yielding a water-sealed gas resource of 28.3657 × 10⁻⁶ for well K2. 8 m 3 .

[0085] Table 4. Resource data for "water-sealed gas" in production well K2.

[0086]

[0087] (4) Repeat steps (1) to (3) to calculate the "water-sealed gas" resource quantity of production well K3 as 18.2467 × 10 8 m 3 .

[0088] (5) The total "water-sealed gas" resource of a certain gas reservoir is the sum of the resources of individual wells, which is the sum of the resources in steps (3) and (4), 46.6124 × 10 8 m 3 .

[0089] 2. Fit the dynamic resource loss of the water-sealed gas in the water-flooded well to be evaluated:

[0090] Method 1

[0091] (1) Establish the production analysis curve of well K2 within the Harmony Enterprise software platform.

[0092] (2) Based on the fracturing and completion method of K2 well and its variable bottom hole flowing pressure production characteristics, the "Finite Cond Fracture" model of Blasingame was selected for curve fitting.

[0093] (3) such as Figure 2 As shown, the fitting decreasing curve L of the waterless production period of the water-flooded gas well to be evaluated and the fitting decreasing curve L′ of the water-bearing production period of the water-flooded gas well to be evaluated are obtained.

[0094] (4) Set the abandonment pressure and obtain the final recoverable reserves of 47.3459 × 10⁻⁶ based on the fitting decline curve L of the production data during the anhydrous production period and the fitting decline curve L′ of the production data during the water-containing production period. 8 m 3 and 18.3555×10 8 m 3 .

[0095] (5) The fitting difference calculated in step (4) is the resource amount of "water-sealed gas" in well K2, which is 28.9904 × 10⁻⁶. 8 m 3 .

[0096] (6) Repeat steps (1) to (5) to calculate the "water-sealed gas" resource quantity of production well K3 as 19.3269 × 10 8 m 3 .

[0097] (7) The total "water-sealed gas" resource of a certain gas reservoir is the sum of the resources of each individual well, which is the sum of the resources obtained in steps (5) and (6), 48.3173 × 10 8 m 3 .

[0098] Method Two

[0099] (1) Establish production analysis curves for wells K1, K2, and K3 in a gas reservoir within the Harmony Enterprise software platform.

[0100] (2) Taking wells K1, K2 and K3 as well groups, the “Agarwal-Gardner flow material balance” decreasing analysis method was selected and curve fitting was performed.

[0101] (3) such as Figure 3As shown, the final recoverable reserves obtained from the fitted decline curve L during the anhydrous production period and the fitted decline curve L′ during the water-bearing production period are 55.8721 × 10⁻⁶. 8 m 3 and 6.5687×10 8 m 3 ,in Figure 3 In this context, P represents formation pressure, and Z represents the compressibility factor.

[0102] (4) The fitting difference calculated in step (3) is the total "water-sealed gas" resource of a certain gas reservoir, which is 49.3034 × 10⁻⁶. 8 m 3 .

[0103] 3. Compare the static and dynamic resource quantities of "water-sealed gas" obtained in steps 1 and 2.

[0104] Method 1

[0105] The arithmetic mean of the evaluation results from steps 1 and 2 (Method 1) is 47.4649 × 10⁻⁶. 8 m 3 The deviation percentages were -1.83% and 1.76% respectively, therefore the average "water-sealed gas" resource quantity assessed by this technology is considered to be 47.4649 × 10⁻⁶. 8 m 3 This study provides guidance for optimizing water management and extraction schemes and evaluating development benefits in the later stages.

[0106] Table 5. Resource Assessment Table for "Water-Sealed Gas" in a Certain Gas Reservoir

[0107]

[0108] Method Two

[0109] The arithmetic mean of the evaluation results from steps 1 and 2 (Method 2) is 47.9579 × 10⁻⁶. 8 m 3 The deviation percentages were -2.89% and 2.73% respectively, therefore the average "water-sealed gas" resource quantity assessed by this technology is considered to be 47.9579 × 10⁻⁶. 8 m 3 This study provides guidance for optimizing water management and extraction schemes and evaluating development benefits in the later stages.

[0110] Table 6. Resource Assessment Table for "Water-Sealed Gas" in a Certain Gas Reservoir

[0111]

Claims

1. A method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs, characterized in that, The specific steps are as follows: S1 uses the water flooding degree coefficient k of each development layer of the water-flooded well to be evaluated and the remaining recoverable reserves of each development layer to obtain the water-sealed gas resource of each single layer of the water-flooded well. The water-sealed gas resource of each single layer is accumulated to obtain the static water-sealed gas resource of the water-flooded gas well to be evaluated. S2 establishes the production analysis curves for the water-flooded wells to be evaluated. Based on modern decline analysis methods, curve fitting is performed on the production data of the water-free and water-bearing production periods of the water-flooded gas wells to be evaluated, resulting in decline curves L and L′ for the water-free and water-bearing production periods. Based on the decline curves L and L′, the final recoverable reserves G for the water-free and water-bearing production periods are obtained. p and G p ′, the final recoverable reserves G during the waterless and water-containing production periods p and G p The difference between ′ is the dynamic resource quantity of water-sealed gas in the water-flooded gas well to be evaluated; S3 calculates the arithmetic mean of the static and dynamic resources of the water-flooded gas reservoir obtained in steps S1 and S2, and calculates the percentage deviation between the static and dynamic resources and the obtained arithmetic mean. If the percentage deviation is within ±10%, the assessment result of the water-sealed gas resources of the fractured tight sandstone reservoir is obtained.

2. The method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs according to claim 1, characterized in that, In step S1, the flooding degree coefficient k of each development layer of the flooded well to be evaluated is calculated using the well control area A of the flooded well to be evaluated in each development layer and the flooded area A′ of the flooded well to be evaluated in each development layer.

3. The method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs according to claim 2, characterized in that, In step S1, the well control area A of the water-flooded well to be evaluated in each development layer is calculated by arithmetic mean or Thiessen polygon.

4. The method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs according to claim 2, characterized in that, In step S1, the water-bearing situation of each development layer is clarified through gas reservoir dynamic analysis, and the water invasion front is characterized, thereby obtaining the water-bearing area A′ of the water-bearing well to be evaluated within the well-controlled area of ​​each development layer.

5. The method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs according to claim 1, characterized in that, In step S1, the remaining recoverable reserves of each development layer are the well-controlled geological reserves G and the cumulative production G of the water-flooded wells to be evaluated in each development layer. p The difference, specifically, is calculated using the volumetric method for well-controlled geological reserves G and cumulative production G. p This was obtained based on the production measurement data of the flooded wells to be evaluated.

6. The method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs according to claim 1, characterized in that, The formula for calculating the static gas resources of water-flooded wells to be evaluated is as follows: Where: i—number of development strata; G—well-controlled geological reserves of a certain stratum, 10 8 m 3 G p —Cumulative output of a certain tier, 10 8 m 3 k—flooding degree coefficient; R—gas reservoir rated recovery rate, %.

7. The method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs according to claim 1, characterized in that, In step S2, based on the geological characteristics and production history of the water-flooded gas well to be evaluated, a modern decline analysis method is selected for curve fitting. Modern decline analysis methods include Blasingame and Agarwal-Gardner flow material balance.

8. The method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs according to claim 1, characterized in that, In step S2, by setting the waste production rate or waste pressure, the final recoverable reserves G for the anhydrous and wet production periods are obtained based on the decline curves L and L′. p and G p ′.

9. The method for assessing the water-sealed gas resources in fractured tight sandstone reservoirs according to claim 1, characterized in that, The method is also applicable to the assessment of water-sealed gas resources in well groups or gas reservoirs.

10. A system for assessing the water-sealed gas resources in fractured tight sandstone reservoirs, characterized in that, include: The static resource calculation module is used to obtain the water-sealed gas resource of each single layer of the water-flooded well by using the water flooding degree coefficient k of each development layer of the water-flooded well to be evaluated and the remaining recoverable reserves of each development layer. The static resource of water-sealed gas of each single layer is accumulated to obtain the static resource of water-sealed gas of the water-flooded well to be evaluated. The dynamic resource calculation module is used to establish production analysis curves for water-flooded wells to be evaluated. Based on modern decline analysis methods, it performs curve fitting on the production data of the water-free and water-bearing production periods of the water-flooded gas wells to be evaluated, obtaining decline curves L and L′ for the water-free and water-bearing production periods. Based on the decline curves L and L′, the final recoverable reserves G for the water-free and water-bearing production periods are obtained. p and G p ′, the final recoverable reserves G during the waterless and water-containing production periods p and G p The difference between ′ is the dynamic resource quantity of water-sealed gas in the water-flooded gas well to be evaluated; The evaluation module is used to calculate the arithmetic mean of the static and dynamic resources of the water-sealed gas reservoir in the water-flooded well to be evaluated, and to calculate the percentage deviation between the static and dynamic resources and the obtained arithmetic mean. If the percentage deviation is within ±10%, the evaluation result of the water-sealed gas resources in the fractured tight sandstone reservoir is obtained.

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