Gas reservoir productivity analysis and prediction system and analysis and prediction method based on geological characteristics

Abstract

The present invention provides a gas reservoir capacity analysis and prediction system and an analysis and prediction method based on geological characteristics, and relates to the technical field of gas reservoir and gas well development. The method of the present invention comprises: obtaining historical dynamic reserves and historical gas production per unit time of gas reservoir wells, determining main production wells and calculating production decline rate; generating a prediction formula for future capacity of gas reservoir wells according to the production decline rate of gas reservoir wells; substituting the gas production per unit time and the production decline rate into the prediction formula for future capacity of gas reservoir wells to calculate the future capacity of gas reservoir wells. The present invention first selects gas reservoir wells that are main production wells through dynamic reserves, and then predicts the future capacity of gas reservoir wells based on gas production per unit time and production decline rate. The method of using only production and production time data greatly reduces the calculation workload, and has the effect of high practicality and easy promotion and application.

Description

Technical Field

[0001] The present invention relates to the technical field of gas reservoir and gas well development, and in particular to a gas reservoir capacity analysis and prediction system and an analysis and prediction method based on geological characteristics. Background Art

[0002] In today's international community, gas reservoir resources have always been a hot topic, and the technology for gas reservoir exploitation has also received more and more attention. For example, in the prior art, a complex tight gas reservoir production capacity prediction method with a publication number of "CN109958430A" includes obtaining reservoir physical property parameters of the target layer, the reservoir physical property parameters include effective thickness, effective porosity, permeability, and gas saturation; combining effective porosity with effective thickness; combining gas saturation with effective porosity; combining the daily gas production of the test well with the corresponding similar well. The lithology of each test gas well section is divided into two series: quasi-stratigraphic coefficient and clastic rock, and the relationship diagrams of quasi-stratigraphic coefficient, Φ·Sg and daily gas production are drawn respectively; from the relationship diagram of quasi-stratigraphic coefficient and daily gas production, the abnormal points are found; Step seven: after eliminating the abnormal points, according to the relationship curve between the quasi-stratigraphic coefficient of the test gas well and the initial single well production capacity, the following relationship formulas are regressed for the reservoir and clastic rock reservoir respectively, and the production capacity is predicted by using the quasi-stratigraphic coefficient method, and the predicted gas production is highly consistent with the actual gas production.

[0003] However, the existing technology still has major defects. For example, the gas reservoir structure is complex, and the use of reservoir geological modeling to predict production requires a huge amount of work. In addition, due to the differences in gas well types and the complex structure of gas reservoirs, the prediction model established using reservoir geology is difficult to achieve ideal prediction accuracy. Therefore, for gas wells with stable production, the use of reservoir geological modeling to predict production is not practical and difficult to promote. Summary of the invention

[0004] The purpose of the present invention is to provide a gas reservoir productivity analysis and prediction system and analysis and prediction method based on geological characteristics to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for analyzing and predicting gas reservoir productivity based on geological characteristics comprises the following steps:

[0007] S1, obtain the historical dynamic reserves of gas reservoir wells and the historical gas production per unit time;

[0008] S2, comparing the latest historical dynamic reserves of the gas reservoir well with the reserve threshold. When the latest historical dynamic reserves are greater than the reserve threshold, the gas reservoir well is determined to be a main production well and proceeds to step S3;

[0009] S3, calculate the production decline rate of the gas reservoir well based on the historical gas production per unit time;

[0010] S4, generating a calculation formula for the gas reservoir well production capacity according to the production decline rate of the gas reservoir well;

[0011] S5, converting the calculation formula of the gas reservoir well productivity into a prediction formula of the future productivity of the gas reservoir well;

[0012] S6, substituting the historical gas production per unit time and production decline rate of the gas reservoir well into the prediction formula of the future production capacity of the gas reservoir well to calculate the future production capacity of the gas reservoir well.

[0013] Furthermore, the reserve threshold is set to 2*10 8 m 3 .

[0014] Furthermore, the gas production per unit time at the i-th historical moment is calibrated as q i , where i represents the number of different historical moments, and i = 1, 2, 3, ..., m, and q m Indicates the gas production per unit time at the latest historical moment.

[0015] Furthermore, the calculation formula of the production decline rate is as follows:

[0016]

[0017] Among them, Δt (i,1) represents the time interval from the first historical moment to the i-th historical moment, α i It represents the production decline rate of the gas reservoir well at the i-th historical moment.

[0018] Furthermore, the calculation formula of the production decline rate is as follows:

[0019]

[0020] Among them, α i represents the production decline rate of the gas reservoir well at the i-th historical moment, α1 i represents the first coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α2 i represents the second coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α3 i represents the third coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α4 i represents the fourth coefficient of the production decline rate of the gas reservoir well at the i-th historical moment;

[0021] Among them, λ1, λ2, and λ3 are all preset proportional coefficients, and λ1+λ2+λ3=1, and 0<λ3<λ2<λ1<1.

[0022] Furthermore, the value range of λ1 is 0.5-0.7, the value range of λ2 is 0.2-0.3, and the value range of λ3 is 0.1-0.2.

[0023] Furthermore, according to the production decline rate of the gas reservoir well, the specific logic of the calculation formula for generating the gas reservoir well production capacity is as follows:

[0024]

[0025] Among them, q i+k represents the gas reservoir well production capacity at the i+kth moment, Δt (i+k,i) represents the time interval from the i-th historical moment to the i+k-th moment, n represents the decreasing index, and 0≤n<1;

[0026] Among them, τ1 and τ2 are both preset proportional coefficients, and τ1+τ2=1, and 0≤τ1≤1, 0≤τ2≤1.

[0027] Furthermore, the specific logic of converting the calculation formula of gas reservoir well production capacity into the prediction formula of gas reservoir well future production capacity is as follows:

[0028]

[0029] Among them, q m+k Indicates the future production capacity of gas reservoir wells.

[0030] Furthermore, the specific logic of converting the calculation formula of gas reservoir well production capacity into the prediction formula of gas reservoir well future production capacity is as follows:

[0031]

[0032] Among them, q m+k Indicates the future production capacity of gas reservoir wells, q1 m+k represents the gas production per unit time q at the mth historical moment m and the output decline rate α m , the first coefficient of future production capacity of the gas reservoir well calculated, q2 m+k represents the gas production per unit time q at the mth historical moment m-1 and the output decline rate α m-1 , the second coefficient of future production capacity of the gas reservoir well calculated, q3 m+k represents the gas production per unit time q at the m-2th historical moment m-2 and the output decline rate α m-2 , the third coefficient of future production capacity of the gas reservoir well is calculated.

[0033] A gas reservoir capacity analysis and prediction system based on geological characteristics, used in the above-mentioned gas reservoir capacity analysis and prediction method based on geological characteristics, comprising:

[0034] A data acquisition unit, the data acquisition unit is used to acquire the historical dynamic reserves of the gas reservoir well and the historical gas production per unit time;

[0035] A main production well judgment unit, wherein the main production well judgment unit is used to compare the latest historical dynamic reserves of the gas reservoir well with the reserve threshold, and when the latest historical dynamic reserves are greater than the reserve threshold, the gas reservoir well is judged as the main production well and the process proceeds to step S3;

[0036] A production decline rate calculation unit, wherein the production decline rate calculation unit is used to calculate the production decline rate of the gas reservoir well according to the historical gas production per unit time;

[0037] A calculation formula generating unit, the calculation formula generating unit is used to generate a calculation formula for the production capacity of the gas reservoir well according to the production decline rate of the gas reservoir well;

[0038] A calculation formula conversion unit, the calculation formula conversion unit is used to convert the calculation formula of the gas reservoir well productivity into a prediction formula for the future productivity of the gas reservoir well;

[0039] The future production capacity prediction unit is used to substitute the historical gas production per unit time and production decline rate of the gas reservoir well into the prediction formula of the future production capacity of the gas reservoir well to calculate the future production capacity of the gas reservoir well.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The gas reservoir capacity analysis and prediction system and method based on geological characteristics of the present invention first screen out gas reservoir wells that are main production wells through dynamic reserves, and then predict the future capacity of the gas reservoir wells based on the gas production per unit time and the production decline rate. Compared with the production prediction based on reservoir geological modeling, the method of only using production and production time data greatly reduces the calculation workload, and has the effect of high practicality and easy promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic flow chart of the gas reservoir productivity analysis and prediction method based on geological characteristics of the present invention;

[0043] Figure 2 This is a module unit diagram of the gas reservoir productivity analysis and prediction system based on geological characteristics of the present invention;

[0044] Figure 3 This is the production decline analysis diagram of the DX1418 well in the present invention;

[0045] Figure 4This is the production decline analysis diagram of the DX1428 well in the present invention. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0047] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0048] Embodiment 1:

[0049] See also Figure 1 The present invention provides a method for analyzing and predicting gas reservoir productivity based on geological characteristics, comprising the following steps:

[0050] S1, obtain the historical dynamic reserves of gas reservoir wells and the historical gas production per unit time;

[0051] It should be noted that the dynamic reserves of gas reservoir wells can be calculated and obtained through actual production data, such as wellhead gas production, pressure changes, etc., combined with gas reservoir engineering principles. This is an existing technology and will not be described in detail here. The gas production per unit time can be obtained through the historical production data of the gas reservoir wells.

[0052] Among them, the historical dynamic reserves at the i-th historical moment are calibrated as DTCL i , the gas production per unit time at the i-th historical moment is calibrated as q i , where i represents the number of different historical moments, and i = 1, 2, 3, ..., m, and DTCL m represents the historical dynamic reserves at the latest historical moment, and q m Represents the gas production per unit time at the latest historical moment, and m represents the total number of historical moments, and m≥3,m∈N + ;

[0053] As an implementation method, the historical gas production per unit time may be the daily gas production, and the daily gas production may be obtained through the production log of the gas reservoir well.

[0054] S2, comparing the latest historical dynamic reserves of the gas reservoir well with the reserve threshold. When the latest historical dynamic reserves are greater than the reserve threshold, the gas reservoir well is determined to be a main production well and proceeds to step S3;

[0055] As an implementation method, the reserve threshold is set to 2*10 8 m 3 , when the historical dynamic reserves of the gas reservoir well at the latest historical moment DTCL m Greater than 2*10 8 When the gas reservoir well is determined to be the main production well;

[0056] Furthermore, the historical oil pressure of the gas reservoir well is obtained, and the latest historical oil pressure of the gas reservoir well is compared with the oil pressure threshold, and the gas reservoir well whose historical dynamic reserves are greater than the reserves threshold and whose historical oil pressure is greater than the oil pressure threshold is determined as a main production well of type I, and the gas reservoir well whose historical dynamic reserves are greater than the reserves threshold and whose historical oil pressure is less than the oil pressure threshold is determined as a main production well of type II, and the gas reservoir well whose historical dynamic reserves are less than the reserves threshold and whose historical oil pressure is greater than the oil pressure threshold is determined as an auxiliary production well of type I, and the gas reservoir well whose historical dynamic reserves are less than the reserves threshold and whose historical oil pressure is less than the oil pressure threshold is determined as an auxiliary production well of type II;

[0057] As an implementation method, the oil pressure threshold is set to 8MPa. When the historical oil pressure of a gas reservoir well at the latest historical moment is greater than 8MPa, the gas reservoir well is determined to be a main production well type I well or an auxiliary production well type I well;

[0058] It should be noted that for the main production wells, Class I wells, the oil pressure and dynamic reserves are both high, and the gas wells maintain continuous and stable production, one is to ensure the total gas production of the gas reservoir, and the other is to maintain a certain rate of decrease in the overall formation pressure of the gas reservoir; for the main production wells, Class II wells, the oil pressure is relatively low compared to the main production wells, Class I wells, and is used to cooperate with Class I gas wells to control the production rate and avoid excessive pressure drop;

[0059] For auxiliary production wells of Category 1 and Category 2, due to the influence of geological structures such as reservoirs, the dynamic reserves are low. They mainly cooperate with main production wells of Category 1 and Category 2 to complete the annual production plan, as follows: For auxiliary production wells of Category 1, production is carried out at the minimum liquid carrying rate to avoid excessive decline in production capacity due to liquid accumulation at the bottom of the well; for auxiliary production wells of Category 2, an intermittent production mode is adopted, and the wells are shut down to restore pressure to avoid excessively rapid decreases in production and pressure.

[0060] S3, calculate the production decline rate of the gas reservoir well based on the historical gas production per unit time. The calculation formula is as follows:

[0061]

[0062] It should be noted that Δt (i,1) represents the time interval from the first historical moment to the i-th historical moment, α i represents the production decline rate of the gas reservoir well at the i-th historical moment;

[0063] It should be noted that the gas production per unit time q at the i-th historical moment is i The gas production per unit time q at the first historical moment 1 The smaller the difference between them, the faster the production decline rate of the gas reservoir well is. i The larger the gas production per unit time q at the i-th historical moment i The gas production per unit time q at the first historical moment 1 The larger the difference between them, the slower the production decline rate of the gas reservoir well, and the production decline rate α i The smaller it is;

[0064] Furthermore, the calculation formula for the production decline rate of a gas reservoir well is:

[0065]

[0066] It should be noted that α i represents the production decline rate of the gas reservoir well at the i-th historical moment, α1 i represents the first coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α2 i represents the second coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α3 i represents the third coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α4 i represents the fourth coefficient of the production decline rate of the gas reservoir well at the i-th historical moment;

[0067] It should be noted that the gas production per unit time q at the i-th historical moment is i The gas production per unit time q at the first historical moment 1 The smaller the difference between them, the faster the production decline rate of the gas reservoir well is. i The larger the gas production per unit time q at the i-th historical moment i The gas production per unit time q at the first historical moment 1 The larger the difference between them, the slower the production decline rate of the gas reservoir well. iThe smaller it is, the first coefficient of the production decline rate α1 is obtained by calculation i , is the subsequent calculation of the production decline rate α of the gas reservoir well at the i-th historical moment i Lay the foundation;

[0068] It should be noted that the first coefficient of the output decline rate at the second historical moment, α1 2 , the first coefficient of the output decline rate at the third historical moment α1 3 , ..., and the first coefficient of the output decline rate at the i-th historical moment α1 i The average value of is taken as the second coefficient α2 of the production decline rate of the gas reservoir well at the i-th historical moment i , so as to incorporate the changing trend of the first coefficient of the production decline rate of the gas reservoir well at each historical moment into the production decline rate α of the gas reservoir well at the i-th historical moment i Among the factors considered, the randomness of historical data is weakened, and the subsequent calculation of the production decline rate α of the gas reservoir well at the i-th historical moment is improved. i comprehensiveness and accuracy;

[0069] It should be noted that the first coefficient of the output decline rate at the second historical moment, α1 2 , the first coefficient of the output decline rate at the third historical moment α1 3 , ..., and the first coefficient of the output decline rate at the i-th historical moment α1 i The maximum value of is taken as the third coefficient α3 of the production decline rate of the gas reservoir well at the i-th historical moment i , so as to incorporate the maximum value of the first coefficients of multiple production decline rates into the production decline rate α of the gas reservoir well at the i-th historical moment i Among the factors considered, the subsequent calculation of the production decline rate α of the gas reservoir well at the i-th historical moment is improved. i comprehensiveness and accuracy;

[0070] It should be noted that the first coefficient of the output decline rate at the second historical moment, α1 2 , the first coefficient of the output decline rate at the third historical moment α1 3 , ..., and the first coefficient of the output decline rate at the i-th historical moment α1 i The minimum value of is taken as the fourth coefficient α4 of the production decline rate of the gas reservoir well at the i-th historical moment i , so as to incorporate the minimum value of the first coefficients of multiple production decline rates into the production decline rate α of the gas reservoir well at the i-th historical moment i Among the factors considered, the subsequent calculation of the production decline rate α of the gas reservoir well at the i-th historical moment is improved. i comprehensiveness and accuracy;

[0071] It should be noted that λ1, λ2, and λ3 are all preset proportional coefficients, and λ1 represents the first coefficient of the production decline rate α1 i The weight in the calculation of the production decline rate, λ2 represents the second coefficient of the production decline rate α2 i The weight in the calculation of the production decline rate, λ3 represents the third coefficient of the production decline rate α3 i and the fourth coefficient of output decline rate α4 i The added average value is the weight in the calculation of the production decline rate, and λ1+λ2+λ3=1, and 0<λ3<λ2<λ1<1, and the specific values ​​of λ1, λ2, and λ3 are generally determined by those skilled in the art according to actual conditions;

[0072] As an implementation mode, the value range of λ1 is 0.5-0.7, the value range of λ2 is 0.2-0.3, and the value range of λ3 is 0.1-0.2;

[0073] It should be noted that the first coefficient of the production decline rate of the gas reservoir well at the i-th historical moment is α1 i 、The second coefficient of output decline rate α2 i 、The third coefficient of output decline rate α3 i , and the fourth coefficient of production decline rate α4 i The larger the value is, the faster the production decline rate of the gas reservoir well is. The production decline rate α of the gas reservoir well at the i-th historical moment is i Similarly, the first coefficient of the production decline rate of the gas reservoir well at the i-th historical moment is α1 i 、The second coefficient of output decline rate α2 i 、The third coefficient of output decline rate α3 i , and the fourth coefficient of production decline rate α4 i The smaller it is, the slower the production decline rate of the gas reservoir well is. The production decline rate α of the gas reservoir well at the i-th historical moment is i The smaller it is.

[0074] S4, based on the production decline rate of the gas reservoir well, generates a calculation formula for the gas reservoir well production capacity, as follows:

[0075]

[0076] It should be noted that q i+k represents the gas reservoir well production capacity at the i+kth moment, Δt (i+k,i) represents the time interval from the i-th historical moment to the i+k-th moment, n represents a decreasing index, and 0≤n<1, and the specific value of n is generally determined by those skilled in the art according to actual conditions;

[0077] It should be noted that when the time interval between the i-th historical moment and the i+k-th moment is greater than the time interval between the i-th historical moment and the m-th historical moment, it means that q i+k The future production capacity of the gas reservoir wells is predicted;

[0078] It should be noted that τ1 and τ2 are both preset proportional coefficients, τ1 represents The weight of the gas reservoir well in the calculation of productivity, τ2 represents The weight in the calculation of gas reservoir well productivity, and τ1+τ2=1, and 0≤τ1≤1, 0≤τ2≤1, the specific values ​​of τ1 and τ2 are generally determined by technicians in this field according to actual conditions;

[0079] As an implementation mode, when the decreasing index takes a value of 0, τ1=1, τ2=0;

[0080] As an implementation mode, when the decreasing index takes a value range of 0<n<1, τ1=0, τ2=1.

[0081] S5, convert the calculation formula of gas reservoir well productivity into the prediction formula of future productivity of gas reservoir well, as follows:

[0082]

[0083] Furthermore, the prediction formula for the future production capacity of gas reservoir wells is:

[0084]

[0085] It should be noted that q m+k Indicates the future production capacity of gas reservoir wells, q1 m+k represents the gas production per unit time q at the mth historical moment m and the output decline rate α m , the first coefficient of future production capacity of the gas reservoir well calculated, q2 m+k represents the gas production per unit time q at the mth historical moment m-1 and the output decline rate α m-1 , the second coefficient of future production capacity of the gas reservoir well calculated, q3 m+k represents the gas production per unit time q at the m-2th historical moment m-2 and the output decline rate α m-2 , the third coefficient of future production capacity of the gas reservoir well obtained by calculation;

[0086] It should be noted that the first coefficient q1 of the future production capacity of the gas reservoir well is calculated based on the gas production per unit time and the production decline rate at the mth historical moment, the m-1th historical moment, and the m-2th historical moment. m+k , the second coefficient of future production capacity of gas reservoir wells q2m+k , and the third coefficient of future gas reservoir well production capacity q3 m+k , and then the first coefficient of future gas reservoir well production capacity q1 m+k , the second coefficient of future production capacity of gas reservoir wells q2 m+k , and the third coefficient of future gas reservoir well production capacity q3 m+k Add and average to obtain the future production capacity q of the gas reservoir well m+k Compared with the method of simply using the gas production per unit time and production decline rate at the mth historical moment to calculate the future production capacity of gas reservoir wells, this method weakens the randomness of historical data and improves the calculation of the future production capacity q of gas reservoir wells. m+k accuracy.

[0087] S6, substituting the historical gas production per unit time and production decline rate of the gas reservoir well into the prediction formula of the future production capacity of the gas reservoir well to calculate the future production capacity of the gas reservoir well.

[0088] As an implementation method, taking the DX14 gas reservoir in a certain place as an example, some well parameters of the gas wells in the DX14 gas reservoir are shown in Table 1 below:

[0089] Table 1

[0090]

[0091] The method in step S2 is used to classify each gas well. The classification results are shown in Table 2 below:

[0092] Table 2

[0093]

[0094] The Arps decline analysis module in the RTA software was used to analyze the production decline law of 23 production wells in the whole area. A total of more than 40 production-time and production-cumulative production fittings were performed. The fitting results of some production wells are as follows: Figure 3 , Figure 4 As shown in the figure, according to the fitting results, the production decline types of DX14 gas reservoir are mainly exponential decline and hyperbolic decline. From the perspective of fitting accuracy, the fitting accuracy of the main production wells type 1 and type 2 wells is in line with expectations, and the prediction results are reliable.

[0095] Some fitting calculation results are shown in Table 3 below:

[0096] Table 3

[0097]

[0098] Embodiment 2:

[0099] See also Figure 2The present invention provides a system for analyzing and predicting gas reservoir productivity based on geological characteristics according to an embodiment of the present invention, which is used in the above-mentioned method for analyzing and predicting gas reservoir productivity based on geological characteristics, and comprises:

[0100] A data acquisition unit, the data acquisition unit is used to obtain the historical dynamic reserves of the gas reservoir well and the historical gas production per unit time;

[0101] The main production well judgment unit is used to compare the latest historical dynamic reserves of the gas reservoir well with the reserve threshold. When the latest historical dynamic reserves are greater than the reserve threshold, the gas reservoir well is judged as the main production well and the process proceeds to step S3.

[0102] A production decline rate calculation unit, which is used to calculate the production decline rate of a gas reservoir well according to the historical gas production per unit time;

[0103] A calculation formula generating unit, the calculation formula generating unit is used to generate a calculation formula for the production capacity of a gas reservoir well according to the production decline rate of the gas reservoir well;

[0104] A calculation formula conversion unit, the calculation formula conversion unit is used to convert the calculation formula of the gas reservoir well production capacity into a prediction formula for the future production capacity of the gas reservoir well;

[0105] The future capacity prediction unit is used to substitute the historical gas production per unit time and the production decline rate of the gas reservoir well into the prediction formula of the future capacity of the gas reservoir well to calculate the future capacity of the gas reservoir well.

[0106] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0107] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0108] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0109] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A method for analyzing and predicting gas reservoir productivity based on geological characteristics, characterized in that: The steps include: S1, obtain the historical dynamic reserves of gas reservoir wells and the historical gas production per unit time; S2, comparing the latest historical dynamic reserves of the gas reservoir well with the reserve threshold. When the latest historical dynamic reserves are greater than the reserve threshold, the gas reservoir well is determined to be a main production well and proceeds to step S3; S3, calculate the production decline rate of the gas reservoir well based on the historical gas production per unit time; S4, generating a calculation formula for the gas reservoir well production capacity according to the production decline rate of the gas reservoir well; S5, converting the calculation formula of the gas reservoir well productivity into a prediction formula of the future productivity of the gas reservoir well; S6, substituting the historical gas production per unit time and production decline rate of the gas reservoir well into the prediction formula of the future production capacity of the gas reservoir well to calculate the future production capacity of the gas reservoir well; The gas production per unit time at the i-th historical moment is calibrated as q i , where i represents the number of different historical moments, and i = 1, 2, 3, ..., m, and q m Indicates the gas production per unit time at the latest historical moment; The calculation formula of the production decline rate is as follows: Among them, α i represents the production decline rate of the gas reservoir well at the i-th historical moment, α1 i represents the first coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α2 i represents the second coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α3 i represents the third coefficient of the production decline rate of the gas reservoir well at the i-th historical moment, α4 i represents the fourth coefficient of the production decline rate of the gas reservoir well at the i-th historical moment; Wherein, λ1, λ2, and λ3 are all preset proportional coefficients, and λ1+λ2+λ3=1, and 0<λ3<λ2<λ1<1; According to the production decline rate of gas reservoir wells, the specific logic of the calculation formula for generating gas reservoir well production capacity is as follows: Among them, q i+k represents the gas reservoir well production capacity at the i+kth moment, Δt (i+k,i) represents the time interval from the i-th historical moment to the i+k-th moment, n represents the decreasing index, and 0≤n<1; Wherein, τ1 and τ2 are both preset proportional coefficients, and τ1+τ2=1, and 0≤τ1≤1, 0≤τ2≤1; The specific logic of converting the calculation formula of gas reservoir well productivity into the prediction formula of gas reservoir well future productivity is as follows: Among them, q m+k It indicates the future production capacity of gas reservoir wells; The specific logic of converting the calculation formula of gas reservoir well productivity into the prediction formula of gas reservoir well future productivity is as follows: Among them, q m+k Indicates the future production capacity of gas reservoir wells, q1 m+k represents the gas production per unit time q at the mth historical moment m and the output decline rate α m , the first coefficient of future production capacity of the gas reservoir well calculated, q2 m+k represents the gas production per unit time q at the mth historical moment m-1 and the output decline rate α m-1 , the second coefficient of future production capacity of the gas reservoir well calculated, q3 m+k represents the gas production per unit time q at the m-2th historical moment m-2 and the output decline rate α m-2 , the third coefficient of future production capacity of the gas reservoir well is calculated.

2. The method for analyzing and predicting gas reservoir productivity based on geological characteristics according to claim 1, characterized in that: Set the reserve threshold to 2*10 8 m 3 .

3. The method for analyzing and predicting gas reservoir productivity based on geological characteristics according to claim 1, characterized in that: The calculation formula of the production decline rate is as follows: Among them, Δt (i,1) represents the time interval from the first historical moment to the i-th historical moment, α i It represents the production decline rate of the gas reservoir well at the i-th historical moment.

4. The method for analyzing and predicting gas reservoir productivity based on geological characteristics according to claim 1, characterized in that: The value range of λ1 is 0.5-0.7, the value range of λ2 is 0.2-0.3, and the value range of λ3 is 0.1-0.

2.

5. A gas reservoir productivity analysis and prediction system based on geological characteristics, used in the gas reservoir productivity analysis and prediction method based on geological characteristics according to any one of claims 1 to 4, characterized in that: include: A data acquisition unit, the data acquisition unit is used to acquire the historical dynamic reserves of the gas reservoir well and the historical gas production per unit time; A main production well judgment unit, wherein the main production well judgment unit is used to compare the latest historical dynamic reserves of the gas reservoir well with the reserve threshold, and when the latest historical dynamic reserves are greater than the reserve threshold, the gas reservoir well is judged as the main production well and the process proceeds to step S3; A production decline rate calculation unit, wherein the production decline rate calculation unit is used to calculate the production decline rate of the gas reservoir well according to the historical gas production per unit time; A calculation formula generating unit, the calculation formula generating unit is used to generate a calculation formula for the production capacity of the gas reservoir well according to the production decline rate of the gas reservoir well; A calculation formula conversion unit, the calculation formula conversion unit is used to convert the calculation formula of the gas reservoir well productivity into a prediction formula for the future productivity of the gas reservoir well; The future production capacity prediction unit is used to substitute the historical gas production per unit time and production decline rate of the gas reservoir well into the prediction formula of the future production capacity of the gas reservoir well to calculate the future production capacity of the gas reservoir well.

Images