Analysis and determination method for production allocation of water-containing tight gas reservoir
By comprehensively evaluating and analyzing the decreasing changes of factors affecting gas wells, unreasonable results are eliminated, and reasonable production capacity values for gas wells are determined. This solves the problem that geological factors are not considered in traditional methods, and improves the stable production period and production potential of gas wells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-10-29
- Publication Date
- 2026-05-01
AI Technical Summary
Traditional methods fail to fully consider actual geological conditions and multiple geological influencing factors when calculating the production capacity of gas reservoirs and gas wells, resulting in low production accuracy. Both excessive and insufficient initial production can damage the reservoir and affect the stable production period and production efficiency of gas wells.
By collecting and comprehensively evaluating the factors affecting gas wells, the first production allocation optimization conditions and production capacity value are determined. Combined with the decreasing change analysis, the second production allocation capacity value is calculated. By processing the difference rate to eliminate unreasonable results, the comprehensive production allocation capacity value is obtained to determine the stable production period.
It enables accurate assessment of factors affecting production allocation in water-bearing tight gas reservoirs, forms a scientific and reasonable data range for production allocation results, ensures that gas wells have reasonable production capacity and stable production period, and enhances the production potential of gas wells.
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Figure CN121961008A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of oil and gas reservoir development technology, specifically to an analytical method for determining the production of water-bearing tight gas reservoirs. Background Technology
[0002] Oil and gas reservoir development plays a crucial role in energy security, with increasing natural gas development being particularly important. Rational production allocation of gas reservoirs and wells is a key factor in achieving efficient and stable natural gas extraction. Initial production capacity will affect the entire lifecycle of gas reservoirs and wells, including the decline and stable production phases.
[0003] As can be seen from the above, the rational allocation of gas wells in gas reservoirs has become an important research topic. For example, Wang Fengbiao's master's thesis, "Research on the Dynamic Characteristics of Production and Rational Production Allocation Methods of Water-Bearing Tight Gas Reservoirs," published by China University of Petroleum in 2016, recorded the analysis of production characteristics, parameter determination, and decline analysis of gas wells and gas fields. In 2017, Jiang Chao of Sinopec North China Oil and Gas Branch published a journal article, "Research on the Method for Determining Rational Production Allocation of Gas Wells in the D66 Well Area of the Daniudi Gas Field," which recorded various methods for analyzing gas production, including empirical methods, gas production indicator curve methods, flow material balance methods, and software simulation methods, and discussed and compared the advantages and disadvantages of various methods.
[0004] In addition, a Chinese patent application filed by Cheng Youyou et al. of Xi'an Petroleum University with publication number CN114893154B discloses a dynamic optimization method for production allocation of horizontal wells in edge-bottom water gas reservoirs. This method establishes a horizontal well production allocation optimization model based on an improved genetic algorithm, realizing dynamic optimization of production allocation of horizontal wells in edge-bottom water gas reservoirs. It fully considers the dynamics of formation inflow and the engineering and technical conditions of the wellbore and wellhead, thus fully reflecting the optimization concept of underground-surface integration. At the same time, the key constraints such as the production capacity equation and the critical fluid carrying flow rate are all derived and optimized specifically for the development of horizontal wells in edge-bottom water gas reservoirs, and have good representativeness and adaptability.
[0005] Traditional methods for calculating the production capacity of gas reservoirs and wells include the unobstructed flow rate method and the gas production indicator curve method. However, these methods do not take into account actual geological conditions and multiple geological influencing factors, resulting in low accuracy in production capacity allocation. When the initial production allocation is too high, the production pressure differential is large, which can damage the reservoir. After entering the decline period, the production decreases more rapidly, and the corresponding stable production period is also shorter. When the initial production allocation is too low, the natural gas flow rate is too low, which cannot carry the liquid to the surface, causing liquid accumulation at the bottom of the well. This leads to a sharp drop in gas well production or even shutdown due to liquid accumulation. How to more scientifically and rationally determine the production capacity and stable production period, and to develop a program to guide technical personnel in decision-making for efficient development and application, has become an urgent problem to be solved. Summary of the Invention
[0006] The purpose of this invention is to provide an analytical method for determining the production allocation of water-bearing tight gas reservoirs, aiming to improve the problem that traditional methods for calculating the production capacity of gas reservoirs and gas wells do not take into account actual geological conditions and multiple geological influencing factors.
[0007] This invention is achieved as follows: an analytical method for determining the production of water-bearing tight gas reservoirs, comprising:
[0008] Step 1: Collect and summarize the influencing factors of gas wells, and comprehensively evaluate the influencing factors of gas wells to obtain the first production optimization conditions and the first production capacity value;
[0009] Step Two: Collect the production allocation data set, perform a decreasing change analysis based on the production allocation data set, determine the decreasing formula, and derive the second production allocation capacity values W1, W2, W3, ..., W k ;
[0010] Step 3: Compare the capacity values of multiple second-level production allocations with the capacity values of the first-level production allocations to obtain multiple difference rates;
[0011] Step 4: If the difference rate is greater than the preset value, return to collect production allocation data again to form a set; if the difference rate is less than the preset value, retain the first production allocation capacity value and the second production allocation capacity value respectively, and output the average of the two as one or more comprehensive production allocation capacity values to determine multiple stable production periods.
[0012] Preferably, the gas well influencing factors in step one include topographic factors, geological factors, gas well type, gas well pressure differential, fluid properties, production data, and gas reservoir economic indicators.
[0013] Preferably, the influence ratio of a certain factor on the comprehensive evaluation is determined based on the ratio influence factor, and then the first production optimization condition is determined based on the influence ratio.
[0014] Preferably, the coupling analysis conditions included in the first production optimization conditions are the water production of the gas well, the critical liquid carrying capacity, and the liquid accumulation characteristics. The first production capacity value is obtained by coupling based on the first production optimization conditions.
[0015] Preferably, the production allocation data set in step two includes multiple historical production allocation data, which are paired one-to-one with multiple gas wells. The production allocation capacity is related to the stable production period, output per unit time, etc.
[0016] Preferably, based on the production allocation data set, a decreasing change analysis is performed to determine the decreasing formula as follows:
[0017] When producing at a given output, the length of the decline period can be calculated:
[0018] The second production capacity value can be calculated:
[0019] Preferably, multiple historical production allocation data are input into a decreasing formula to obtain a second production allocation data set p1, p2, p3, ..., p j The second production allocation data set is analyzed conditionally one by one. If the second production allocation capacity values W1, W2, W3, ..., W are obtained... k If no result is found, delete it directly.
[0020] Preferably, the conditional judgment includes: considering the actual geological conditions to exclude obviously unreasonable second production allocation data sets p1, p2, p3, ..., p j The second production allocation data set is iterated, and / or, multiple historical production allocation data corresponding to the second production allocation data set converge.
[0021] Preferably, the gas well production capacity formula is derived based on the unobstructed flow rate value and the fitting formula for the second production capacity:
[0022]
[0023] Unobstructed flow rate:
[0024]
[0025] Unobstructed flow rate: ΔP 2 =AQ+BQ 2 .
[0026] Preferably, the preset value is 10%, that is, the difference rate is ≥10% and it is an unqualified value. The first and second production capacity values obtained by comparison are discarded, and the historical production data is collected again to form a new production data set. The difference rate is <10% and it is a qualified value. The first and second production capacity values are retained respectively, and the average value of the two is output as one or more comprehensive production capacity values to determine multiple stable production periods.
[0027] Compared with existing technologies, the beneficial effects of this invention are: it enables the evaluation and analysis of factors affecting production allocation in water-bearing tight gas reservoirs, effectively utilizes geological data, obtains a first production capacity value and multiple second production capacity values through different methods, summarizes and processes the differences to eliminate some unreasonable results, making the results more accurate and able to reflect the actual production allocation of water-bearing tight gas reservoirs, and finally forms multiple production allocation results for technical personnel to make decisions and consider. The resulting production allocation result data range is scientific and reasonable, which can ensure that the gas reservoir and gas wells have relatively reasonable production capacity and stable production period, thereby improving the production potential of the gas reservoir and gas wells. Attached Figure Description
[0028] Figure 1 Flowchart for determining the analytical method for production allocation in water-bearing tight gas reservoirs;
[0029] Figure 2 A schematic diagram illustrating the specific analytical judgment method for determining the production of water-bearing tight gas reservoirs;
[0030] Figure 3 A schematic diagram of the curves showing the relationship between different stable production years and the reserve-production ratio for water-bearing tight gas reservoirs;
[0031] Figure 4 A schematic diagram of the production capacity and reserve-production ratio for different production allocations in a water-bearing tight gas reservoir. Detailed Implementation
[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0033] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details:
[0034] Example 1
[0035] refer to Figure 1 and Figure 2 As shown, embodiments of this application provide an analytical method for determining the production allocation of a water-bearing tight gas reservoir, including a first production capacity value and a second production capacity value.
[0036] S101: Based on the summary of factors affecting gas wells, these factors include gas well type, gas well pressure differential, fluid properties, production data, and gas reservoir economic indicators.
[0037] S102: Based on a comprehensive evaluation of the factors affecting gas wells, the first production optimization conditions and the first production capacity value are derived.
[0038] S103: The first production capacity value is obtained by coupling the first production optimization conditions.
[0039] In this embodiment, specifically, the gas well influencing factors refer to the limitations imposed by specific locations, such as topographical, geological, economic, and development factors, which have a certain impact on the determination of production allocation for water-bearing tight gas reservoirs. A comprehensive consideration and evaluation of multiple factors, including gas well type, gas well pressure differential, fluid properties, production data, and reservoir economic indicators, is conducted. A proportionate influencing factor is used to determine the percentage of influence of a particular factor on the overall evaluation. Based on this percentage, the first production allocation optimization condition is determined, and the first production capacity value is obtained by coupling historical production capacity, such as production data, with the first production allocation optimization condition. Preferably, the coupling analysis conditions included in the first production allocation optimization condition include gas well water production, critical fluid carrying capacity, and fluid accumulation characteristics.
[0040] S201: Collect production data set, which includes multiple historical production data, each corresponding to a gas well.
[0041] S202: Based on the production allocation data set, perform a decreasing change analysis to determine the decreasing formula and derive the second production allocation capacity values W1, W2, W3, ..., W k The first production capacity value is compared with multiple second production capacity values to obtain multiple difference rates.
[0042] S203: When the difference rate is greater than the preset value, the system will return to collect historical production data to form different production data sets. When the difference rate is less than the preset value, the system will retain the first production capacity value and the second production capacity value respectively, and output the average of the two as one or more comprehensive production capacity values to determine multiple stable production periods.
[0043] It should be noted that when the proven reserves controlled by a gas well are fixed, a higher gas production rate and a higher recovery rate result in greater energy consumption and a faster decline effect. In other words, the higher the production capacity of a gas well, the shorter its stable production period and the higher its output per unit time. Conversely, a lower production capacity corresponds to a longer stable production period. A longer stable production period leads to a longer well lifespan and higher cumulative gas production. Production capacity is also affected by the casing pressure of the gas well.
[0044] In this embodiment, specifically, a production allocation data set is collected, which includes multiple historical production allocation data points. Each historical production allocation data point corresponds to a specific gas well. The collection of corresponding historical production allocation data and corresponding stable production periods ensures that the subsequently calculated second production capacity value can more accurately and objectively reflect the comprehensive production capacity of the gas well. Based on the production allocation data set, a decreasing change analysis is performed to determine the decreasing formula:
[0045] When producing at a given output, the length of the decline period can be calculated:
[0046] The second production capacity value can be calculated:
[0047] Preferably, each historical production allocation data point is input into a decreasing formula to calculate the corresponding second production allocation data set p1, p2, p3, ..., p j The second set of production allocation data is p1, p2, p3, ..., p j After judging each condition, if it is true, the second production capacity values W1, W2, W3, ..., W are obtained. k If not, delete directly.
[0048] Preferably, based on the measured bottom pressure and end-of-flow bottom pressure of the gas well, the historical production allocation data are coupled, considering the decreasing trend and decreasing parameters, to obtain a second production allocation data set p1, p2, p3, ..., p i .
[0049] Preferably, the condition judgment includes: excluding obviously unreasonable second production allocation data sets p1, p2, p3, ..., p j The second production allocation data set is iterated, and / or, multiple historical production allocation data corresponding to the second production allocation data set converge.
[0050] In this embodiment, specifically, the second production allocation data set p1, p2, p3, ..., p j Considering the actual geological conditions, obviously unreasonable data are excluded, and multiple second production capacity values are determined by methods including but not limited to the gas production indicator curve method or the unobstructed flow method. The second production data set is dynamically fitted through iteration and / or coarsened by converging to the historical production data.
[0051] The gas well production capacity formula is derived based on the fitting relationship between the unobstructed flow rate and the second production capacity:
[0052]
[0053] Unobstructed flow rate:
[0054]
[0055] Unobstructed flow rate: ΔP 2 =AQ+BQ 2 .
[0056] In this embodiment, specifically, the second production capacity values W1, W2, W3, ..., W are obtained. kThe first production capacity value is compared with multiple second production capacity values to obtain multiple difference rates. When the difference rate is greater than a preset value, the process returns to collect historical production data to form different production data sets. When the difference rate is less than the preset value, the first and second production capacity values are retained, and the average of the two is output as one or more comprehensive production capacity values to determine multiple stable production periods. Preferably, the preset value is 10%, that is, a difference rate ≥ 10% is considered an unqualified value, and the first and second production capacity values obtained from the comparison are discarded. The process returns to S201 to collect historical production data to form a new production data set. The first and second production capacity values in the new production data set are different from the original ones. Correspondingly, a difference rate < 10% is considered a qualified value, and the first and second production capacity values are retained, and the average of the two is output as one or more comprehensive production capacity values to determine multiple stable production periods.
[0057] In this embodiment, preferably, the average of the first production capacity value and the second production capacity value is output as the comprehensive production capacity value. The method for obtaining the average value includes, but is not limited to, the arithmetic mean, the harmonic mean, the ensemble mean, and the weighted average.
[0058] In this embodiment, specifically, when there are multiple stable production periods, the variation law of different stable production years and reserve-production ratio is established. That is, there is a functional correspondence between different stable production years and reserve-production ratio, which can reflect the actual production allocation of water-bearing tight gas reservoirs. Finally, multiple production allocation results are formed for technical personnel to make decisions and consider. The resulting production allocation result data range is scientific and reasonable, which can ensure that the gas reservoir and gas wells have relatively reasonable production capacity and stable production period, thereby improving the production potential of the gas reservoir and gas wells.
[0059] It should be noted that the reserve-to-production ratio is the ratio of remaining recoverable reserves to the current year's production in an oil (gas) field. The reserve-to-production ratio is an indicator of an oil and gas field's production capacity and must be considered when formulating oil and gas production plans and programs. When the oil field's reserve-to-production ratio falls within a certain range, production begins to decline, making it difficult to maintain stable production; to maintain stable production, additional recoverable reserves must be added. Therefore, such a reserve-to-production ratio is often referred to as the critical reserve-to-production ratio for stable production; however, this value can vary considerably across different regions and oil fields, depending on the specific circumstances.
[0060] refer to Figure 3 As shown, this example uses different stable production years and reserve-to-production ratios of a certain gas reservoir.
[0061]
[0062] refer to Figure 4 As shown, this example illustrates different production capacities and reserve-to-production ratios for a gas reservoir.
[0063]
[0064] In this embodiment, preferably, when there are multiple stable production periods in the historical production data, the variation law of different stable production years and reserve-production ratio is established; or when there are declining periods in the historical production data, the variation law of reserve-production ratio under different initial production and different declining laws is established. Accordingly, the reasonable relationship between the comprehensive production capacity and the stable production time can also obtain the reasonable production under different stable production time requirements. The size of the production capacity and the length of the stable production time reflect the production capacity and stable production level of the gas well.
[0065] In this embodiment, specifically, a three-dimensional pipeline network model of the gas reservoir is constructed based on the gas well influencing factors. The first production allocation optimization condition includes processing the first production allocation capacity value using the three-dimensional pipeline network model of the gas reservoir to obtain the cumulative production allocation output and the reserve-production ratio; and determining the first production allocation capacity value corresponding to the reserve-production ratio based on the determination that the reserve-production ratio meets the first production allocation optimization condition.
[0066] In this embodiment, preferably, the first production optimization conditions include gas well reserves, monthly gas well production, monthly decline rate, gas well type, gas well pressure difference, simulated economic production of gas well, and production optimization conditions updated dynamically based on the above factors.
[0067] In this embodiment, the analysis and determination method can evaluate and analyze the factors affecting the production allocation of water-bearing tight gas reservoirs, effectively utilize geological data, apply different methods to obtain the first production capacity value and multiple second production capacity values, summarize and process the difference rate to eliminate some unreasonable results so that the result data is more accurate and can reflect the actual production allocation of water-bearing tight gas reservoirs, and finally form multiple production allocation results for technical personnel to make decisions and consider. The resulting production allocation result data range is scientific and reasonable, which can ensure that the gas reservoir and gas wells have relatively reasonable production capacity and stable production period, thereby improving the production potential of the gas reservoir and gas wells.
[0068] Example 2
[0069] Based on Example 1, this example further provides a device for determining the production allocation of a water-bearing tight gas reservoir, including a first production allocation capacity unit, a second production allocation capacity unit, a summarization unit, and a processing unit.
[0070] In this embodiment, specifically, the first production capacity unit is used to determine the first production optimization conditions based on the received gas well influencing factors to obtain the first production capacity value.
[0071] In this embodiment, specifically, the second production capacity unit is used to determine multiple second production capacity values that meet the judgment conditions based on the production data set, and each second production capacity value corresponds to the production historical data.
[0072] In this embodiment, specifically, the summarizing unit is used to summarize the data obtained from the first production capacity unit and the second production capacity unit and transmit it to the processing unit.
[0073] In this embodiment, specifically, the processing unit receives the data from the aggregation unit and performs comparative analysis to obtain a comprehensive production capacity value to determine multiple stable production periods for technical personnel to make decisions.
[0074] The device for determining the production of water-bearing tight gas reservoirs provided by the present invention can be used to execute the processing flow of the analysis and determination method for the production of water-bearing tight gas reservoirs in Example 1. Its function will not be repeated here, but can be referred to the detailed description of the above method embodiments.
[0075] The present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the analytical determination method for the production of water-bearing tight gas reservoirs according to any of the above possible embodiments.
[0076] A fourth aspect of the present invention is a computer-readable storage medium storing a computer program that, when run on a processor, executes the analytical determination method for the production of water-bearing tight gas reservoirs according to any of the above possible embodiments.
[0077] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. 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. An analytical method for determining the production of water-bearing tight gas reservoirs, characterized in that, include Step 1: Collect and summarize the influencing factors of gas wells, and comprehensively evaluate the influencing factors of gas wells to obtain the first production optimization conditions and the first production capacity value; Step Two: Collect the production allocation data set, perform a decreasing change analysis based on the production allocation data set, determine the decreasing formula, and derive the second production allocation capacity values W1, W2, W3, ..., W k ; Step 3: Compare the capacity values of multiple second-level production allocations with the capacity values of the first-level production allocations to obtain multiple difference rates; Step 4: If the difference rate is greater than the preset value, return to collect production allocation data again to form a set; If the difference rate is less than the preset value, the first production capacity value and the second production capacity value are retained respectively, and the average value of the two is output as one or more comprehensive production capacity values to determine multiple stable production periods.
2. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 1, characterized in that, The factors influencing gas wells in step one include topographic factors, geological factors, gas well type, gas well pressure differential, fluid properties, production data, and gas reservoir economic indicators.
3. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 2, characterized in that, The influence ratio of a certain factor on the comprehensive evaluation is determined based on the influencing factors of the ratio, and then the first production optimization condition is determined based on the influence ratio.
4. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 3, characterized in that, The first production optimization conditions include coupling analysis conditions such as gas well water production, critical fluid carrying capacity, and fluid accumulation characteristics. The first production capacity value is obtained by coupling based on the first production optimization conditions.
5. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 1, characterized in that, Step two's production allocation data set includes multiple historical production allocation data sets, each paired with a specific gas well. The production allocation capacity is related to factors such as the stable production period and output per unit time.
6. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 5, characterized in that, Based on the production allocation data set, a decreasing change analysis was performed, and the decreasing formula was determined to be: Q = Q i e -Dt When producing at a given output, the length of the decline period can be calculated: The second production capacity value can be calculated:
7. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 6, characterized in that, By inputting multiple historical production allocation data into a decreasing formula, a second production allocation data set p1, p2, p3, ..., p is obtained. j The second production allocation data set is analyzed conditionally one by one. If the second production allocation capacity values W1, W2, W3, ..., W are obtained... k If no result is found, delete it directly.
8. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 7, characterized in that, Conditional judgments include: considering actual geological conditions to exclude obviously unreasonable second production allocation data sets p1, p2, p3, ..., p j The second production allocation data set is iterated, and / or, multiple historical production allocation data corresponding to the second production allocation data set converge.
9. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 8, characterized in that, The gas well production capacity formula is derived based on the fitting relationship between the unobstructed flow rate and the second production capacity: Unobstructed flow rate: Unobstructed flow rate: ΔP 2 =AQ+BQ 2 .
10. The analytical method for determining the production of a water-bearing tight gas reservoir according to claim 9, characterized in that, The preset value is 10%, meaning that a difference rate of ≥10% is considered an unqualified value. The first and second production capacity values obtained from the comparison are discarded, and the historical production data is collected again to form a new production data set. A difference rate of less than 10% is considered acceptable. The first and second production capacity values will be retained separately, and the average of the two values will be output as one or more comprehensive production capacity values to determine multiple stable production periods.
Citation Information
Patent Citations
A Dynamic Optimization Method for Production Allocation of Horizontal Wells in Edge-Bottom Water-Gas Reservoirs
CN114893154B