Distinguishing method for determining shutdown of low-efficiency gas well of fractured-porous gas reservoir

Abstract

The invention discloses a judgment method for determining shutdown of a low-efficiency gas well of a fractured-pore type gas reservoir, which belongs to the technical field of oil and gas reservoir development, and is characterized by comprising the following steps: a, carrying out profit and loss balance analysis on the low-efficiency gas well; b, performing input-output linear profit and loss balance analysis on the low-efficiency gas well, and judging sales income; c, the cost of low-efficiency gas well production operation, oil gas treatment operation, maintenance operation and natural gas purification operation is calculated; and d, according to the gas well type, a low-efficiency gas well shutdown limit yield model is established, the gas well limit gas production rate is calculated, and then low-efficiency gas well shutdown judgment is conducted. According to the method, shutdown of different types of low-efficiency gas wells can be rapidly judged, the method has guiding significance on benefit evaluation of different types of gas wells of carbonate rocks, and the purpose of improving quality and efficiency of gas field development is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas reservoir development, and in particular to a method for determining the shutdown of inefficient gas wells in fracture-pore type gas reservoirs. Background Art

[0002] Carbonate gas reservoirs contribute about 50% to my country's total natural gas production. However, due to various geological factors such as complex structure, formation water distribution and water intrusion intensity, low permeability, degree of fracture development, and fracture-cavity matching, different types of gas reservoirs have different development technical policies. As a result, many inefficient gas wells are shut down during gas field development due to low production capacity, low formation pressure, waterlogging, difficulty in producing water treatment, and poor efficiency.

[0003] Individual well performance evaluation plays a crucial role in decision-making during oil well production and operations, particularly in demonstrating oilfield production and operations status, monitoring and managing high-cost wells, making risk-based decisions about well measures, and optimizing production and cost allocation. Under the prevailing low oil prices, individual well performance evaluation has become a comprehensive component of oil and gas field companies' efforts to increase revenue, reduce costs, and increase efficiency, becoming a crucial component of production well management. However, its applicability to gas well performance evaluation is limited.

[0004] A Chinese patent document with publication number CN113537655A, published on October 22, 2021, discloses a method for determining the restart potential of a gas well, characterized in that the method includes:

[0005] Obtaining a plurality of evaluation indicators for judging the restart potential of a target gas well, wherein the target gas well is a shut-in gas well;

[0006] Determine the first indicator score of each evaluation indicator using a preset evaluation method;

[0007] For each evaluation indicator, compare the importance of the evaluation indicator with any other evaluation indicator in the multiple evaluation indicators to obtain a weight corresponding to the evaluation indicator;

[0008] determining a restart index of the target gas well according to a first indicator score of the evaluation indicator and a corresponding weight thereof;

[0009] Determining the restart potential of the target gas well according to a magnitude relationship between the restart index and a first preset threshold and a second preset threshold;

[0010] When the evaluation indicator is the remaining dynamic reserves, the predetermined evaluation method is used to determine the first indicator score of each evaluation indicator, including:

[0011] Obtaining a remaining value of the remaining dynamic reserves of the target gas well in the previous year before it was shut down;

[0012] Obtaining a limit value of the remaining dynamic reserves that the target gas well should have when it is restarted;

[0013] determining whether a ratio of the residual value to the limit value is less than a third preset threshold;

[0014] When the ratio is less than the third preset threshold, taking the ratio of the remaining value to the limit value as the first indicator score of the evaluation indicator;

[0015] When the ratio is not less than the third preset threshold, the third preset threshold is used as the first indicator score of the evaluation indicator.

[0016] The patent document discloses a method for determining the potential for restarting a gas well. Compared to relying solely on subjective judgment based on personnel experience, this method improves accuracy and expands its scope of application. However, its accuracy in determining the potential for shutting down different types of inefficient gas wells is poor, hindering the effectiveness of gas field development. Summary of the Invention

[0017] In order to overcome the above-mentioned defects of the prior art, the present invention provides a method for determining the shutdown of inefficient gas wells in fracture-pore type gas reservoirs. The present invention can quickly determine the shutdown of different types of inefficient gas wells, has guiding significance for the efficiency evaluation of different types of carbonate gas wells, and achieves the purpose of improving the quality and efficiency of gas field development.

[0018] The present invention is achieved through the following technical solutions:

[0019] A method for determining whether to shut down an inefficient gas well in a fracture-pore gas reservoir is characterized by comprising the following steps:

[0020] a. Conduct break-even analysis on inefficient gas wells;

[0021] b. Conduct input-output linear break-even analysis on inefficient gas wells to determine sales revenue;

[0022] c. Calculate the cost of inefficient gas well recovery operations, oil and gas processing operations, maintenance operations, and natural gas purification operations;

[0023] d. According to the type of gas well, establish the shutdown limit production model of inefficient gas wells, calculate the limit gas production of the gas wells, and then determine the shutdown of inefficient gas wells.

[0024] In step a, the break-even analysis refers to conducting a break-even analysis of the input and output of the gas well to determine the maximum gas production of the gas well.

[0025] The maximum gas production of a gas well refers to the gas production of the gas well when the gas production is reduced to the point where the input and output offset each other in the middle and late stages of gas well development.

[0026] In step b, determining sales revenue specifically refers to calculating and determining by formula 1;

[0027] STC≥0 Formula 1

[0028] Among them, S is sales revenue, T is tax, and C is cost.

[0029] In step c, the cost includes direct material costs, direct fuel costs, direct power costs, oil and gas processing costs, natural gas purification costs, and maintenance and repair costs.

[0030] In step d, the shutdown judgment of inefficient gas wells means that when the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down; when the gas pipeline is broken and the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down.

[0031] In step d, the gas well types include gas lift wells, non-water-producing wells and unpressurized wells.

[0032] The shut-in limit production model of the inefficient gas well of the gas lift well is shown in Equation 2:

[0033]

[0034] Among them, q g is the maximum gas production of the gas well, G is the fixed cost, C 回注 is the unit water production reinjection cost, q w is the daily water production, s is the production hour rate, P is the gas price, R is the natural gas commodity rate, T is the tax rate, C 增压 is the pressurization cost per unit gas output, C 脱硫 is the purification cost per unit gas output, C 脱水 is the reinjection cost per unit water production.

[0035] The shut-in limit production model of the low-efficiency gas well that does not produce water is as follows:

[0036]

[0037] The shut-in limit production model of the unpressurized low-efficiency gas well is shown in Equation 4.

[0038]

[0039] The beneficial effects of the present invention are mainly manifested in the following aspects:

[0040] 1. The present invention, a. performs a break-even analysis on inefficient gas wells; b. performs an input-output linear break-even analysis on the inefficient gas wells to determine sales revenue; c. calculates the cost of production operations, oil and gas processing operations, maintenance operations, and natural gas purification operations for the inefficient gas wells; d. establishes a shutdown limit production model for the inefficient gas wells based on the gas well types, calculates the limit gas production of the gas wells, and then determines the shutdown of the inefficient gas wells. Compared with the existing technology, the present invention can quickly determine the shutdown of different types of inefficient gas wells, has guiding significance for the benefit evaluation of different types of carbonate gas wells, and achieves the purpose of improving the quality and efficiency of gas field development.

[0041] 2. The present invention targets most inefficient gas wells, combines the profit-and-loss balance principle, and uses the typical process flow of natural gas production to analyze the various operating costs involved in gas extraction, gathering, and purification. It converts various cost parameters into functions with technical parameters such as gas production and water production as variables, thereby establishing a calculation method for the maximum gas production of three major types of gas wells: gas lift wells, non-water-producing wells, and unpressurized wells. This can improve the calculation results of single-well efficient development and help increase the well opening rate of gas reservoirs.

[0042] 3. The present invention can accurately and timely identify loss-making gas wells and realize effective development. By actively taking corresponding treatment measures for loss-making gas wells, it can reduce mining costs and improve the overall development efficiency of the gas field. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0044] Figure 1 It is a flowchart of the present invention;

[0045] Figure 2 This is a chart under different gas price conditions for the gas lift well in the present invention;

[0046] Figure 3 This is a chart of different gas price conditions for non-water-producing gas wells in the present invention;

[0047] Figure 4 This is a chart showing different gas price conditions for the unpressurized gas well in the present invention. DETAILED DESCRIPTION

[0048] Example 1

[0049] See also Figure 1 A method for determining whether to shut down an inefficient gas well in a fracture-pore gas reservoir comprises the following steps:

[0050] a. Conduct break-even analysis on inefficient gas wells;

[0051] b. Conduct input-output linear break-even analysis on inefficient gas wells to determine sales revenue;

[0052] c. Calculate the cost of inefficient gas well recovery operations, oil and gas processing operations, maintenance operations, and natural gas purification operations;

[0053] d. According to the type of gas well, establish the shutdown limit production model of inefficient gas wells, calculate the limit gas production of the gas wells, and then determine the shutdown of inefficient gas wells.

[0054] This embodiment is the most basic implementation method, which includes: a. performing a break-even analysis on inefficient gas wells; b. performing an input-output linear break-even analysis on inefficient gas wells to determine sales revenue; c. calculating the cost of production operations, oil and gas processing operations, maintenance operations, and natural gas purification operations for inefficient gas wells; and d. establishing a shutdown limit production model for inefficient gas wells based on the type of gas wells, calculating the limit gas production of the gas wells, and then determining the shutdown of inefficient gas wells. Compared with the existing technology, this embodiment can quickly determine the shutdown of different types of inefficient gas wells, has guiding significance for the benefit evaluation of different types of carbonate gas wells, and achieves the goal of improving the quality and efficiency of gas field development.

[0055] Example 2

[0056] See also Figure 1 A method for determining whether to shut down an inefficient gas well in a fracture-pore gas reservoir comprises the following steps:

[0057] a. Conduct break-even analysis on inefficient gas wells;

[0058] b. Conduct input-output linear break-even analysis on inefficient gas wells to determine sales revenue;

[0059] c. Calculate the cost of inefficient gas well recovery operations, oil and gas processing operations, maintenance operations, and natural gas purification operations;

[0060] d. According to the type of gas well, establish the shutdown limit production model of inefficient gas wells, calculate the limit gas production of the gas wells, and then determine the shutdown of inefficient gas wells.

[0061] Furthermore, in step a, the break-even analysis refers to conducting an input-output break-even analysis of the gas well to determine the maximum gas production of the gas well.

[0062] The maximum gas production of a gas well refers to the gas production of the gas well when the gas production is reduced to the point where the input and output offset each other in the middle and late stages of gas well development.

[0063] In step b, determining sales revenue specifically refers to calculating and determining by formula 1;

[0064] STC≥0 Formula 1

[0065] Among them, S is sales revenue, T is tax, and C is cost.

[0066] In step c, the cost includes direct material costs, direct fuel costs, direct power costs, oil and gas processing costs, natural gas purification costs, and maintenance and repair costs.

[0067] Example 3

[0068] See also Figure 1 A method for determining whether to shut down an inefficient gas well in a fracture-pore gas reservoir comprises the following steps:

[0069] a. Conduct break-even analysis on inefficient gas wells;

[0070] b. Conduct input-output linear break-even analysis on inefficient gas wells to determine sales revenue;

[0071] c. Calculate the cost of inefficient gas well recovery operations, oil and gas processing operations, maintenance operations, and natural gas purification operations;

[0072] d. According to the type of gas well, establish the shutdown limit production model of inefficient gas wells, calculate the limit gas production of the gas wells, and then determine the shutdown of inefficient gas wells.

[0073] Furthermore, in step a, the break-even analysis refers to conducting an input-output break-even analysis of the gas well to determine the maximum gas production of the gas well.

[0074] The maximum gas production of a gas well refers to the gas production of the gas well when the gas production is reduced to the point where the input and output offset each other in the middle and late stages of gas well development.

[0075] In step b, determining sales revenue specifically refers to calculating and determining by formula 1;

[0076] STC≥0 Formula 1

[0077] Among them, S is sales revenue, T is tax, and C is cost.

[0078] Furthermore, in step c, the cost includes direct material costs, direct fuel costs, direct power costs, oil and gas processing costs, natural gas purification costs, and maintenance and repair costs.

[0079] In step d, the shutdown judgment of inefficient gas wells means that when the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down; when the gas pipeline is broken and the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down.

[0080] In the step d, the gas well type is a gas lift well.

[0081] The shut-in limit production model of the inefficient gas well of the gas lift well is shown in Equation 2:

[0082]

[0083] Among them, q g is the maximum gas production of the gas well, G is the fixed cost, C 回注 is the unit water production reinjection cost, q w is the daily water production, s is the production hour rate, P is the gas price, R is the natural gas commodity rate, T is the tax rate, C 增压 is the pressurization cost per unit gas output, C 脱硫 is the purification cost per unit gas output, C 脱水 is the reinjection cost per unit water production.

[0084] Example 4

[0085] See also Figure 1 A method for determining whether to shut down an inefficient gas well in a fracture-pore gas reservoir comprises the following steps:

[0086] a. Conduct break-even analysis on inefficient gas wells;

[0087] b. Conduct input-output linear break-even analysis on inefficient gas wells to determine sales revenue;

[0088] c. Calculate the cost of inefficient gas well recovery operations, oil and gas processing operations, maintenance operations, and natural gas purification operations;

[0089] d. According to the type of gas well, establish the shutdown limit production model of inefficient gas wells, calculate the limit gas production of the gas wells, and then determine the shutdown of inefficient gas wells.

[0090] In step a, the break-even analysis refers to conducting a break-even analysis of the input and output of the gas well to determine the maximum gas production of the gas well.

[0091] The maximum gas production of a gas well refers to the gas production of the gas well when the gas production is reduced to the point where the input and output offset each other in the middle and late stages of gas well development.

[0092] In step b, determining sales revenue specifically refers to calculating and determining by formula 1;

[0093] STC≥0 Formula 1

[0094] Among them, S is sales revenue, T is tax, and C is cost.

[0095] In step c, the cost includes direct material costs, direct fuel costs, direct power costs, oil and gas processing costs, natural gas purification costs, and maintenance and repair costs.

[0096] In step d, the shutdown judgment of inefficient gas wells means that when the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down; when the gas pipeline is broken and the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down.

[0097] In the step d, the gas well type is a non-water-producing well.

[0098] The shut-in limit production model of the low-efficiency gas well that does not produce water is as follows:

[0099]

[0100] This embodiment is a preferred implementation method. For most inefficient gas wells, combined with the break-even principle, through the typical process flow of natural gas production, the various operating costs involved in gas extraction, gas gathering and purification are constructed, and various cost parameters are converted into functions with technical parameters such as gas production and water production as variables. In this way, the calculation of the maximum gas production of three types of gas wells, namely gas lift wells, non-water-producing wells and unpressurized wells, is established. This can improve the calculation results of the efficient development of single wells and help increase the well opening rate of gas reservoirs.

[0101] Example 5

[0102] See also Figure 1 A method for determining whether to shut down an inefficient gas well in a fracture-pore gas reservoir comprises the following steps:

[0103] a. Conduct break-even analysis on inefficient gas wells;

[0104] b. Conduct input-output linear break-even analysis on inefficient gas wells to determine sales revenue;

[0105] c. Calculate the cost of inefficient gas well recovery operations, oil and gas processing operations, maintenance operations, and natural gas purification operations;

[0106] d. According to the type of gas well, establish the shutdown limit production model of inefficient gas wells, calculate the limit gas production of the gas wells, and then determine the shutdown of inefficient gas wells.

[0107] In step a, the break-even analysis refers to conducting a break-even analysis of the input and output of the gas well to determine the maximum gas production of the gas well.

[0108] The maximum gas production of a gas well refers to the gas production of the gas well when the gas production is reduced to the point where the input and output offset each other in the middle and late stages of gas well development.

[0109] In step b, determining sales revenue specifically refers to calculating and determining by formula 1;

[0110] STC≥0 Formula 1

[0111] Among them, S is sales revenue, T is tax, and C is cost.

[0112] In step c, the cost includes direct material costs, direct fuel costs, direct power costs, oil and gas processing costs, natural gas purification costs, and maintenance and repair costs.

[0113] In step d, the shutdown judgment of inefficient gas wells means that when the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down; when the gas pipeline is broken and the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down.

[0114] In the step d, the gas well type is an unpressurized well.

[0115] The shut-in limit production model of the unpressurized low-efficiency gas well is shown in Equation 4.

[0116]

[0117] This embodiment is the best implementation method, which can accurately and timely identify loss-making gas wells and achieve effective development. By actively taking corresponding treatment measures for loss-making gas wells, it can reduce mining costs and improve the overall development efficiency of the gas field.

[0118] Gas lift well parameter setting: single well is considered as a manned well, with 3 employees and personnel cost calculated at RMB 160,000 / year; daily water production is 100m3 3 Utilizing a pressurized gas lift dewatering process, a reinjection system has been established. Gas quality is low to medium sulfur. Because gas lift wells are pressurized individually, operating costs for lubricants, low-value consumables, pressurization accessories, and power are high. Consequently, basic maintenance and repair costs for individual wells are high, and the production process involves multiple steps. Furthermore, due to the inherent gas loss of the compressors, the commercialization rate of natural gas is low.

[0119] Parameter settings for non-water-producing wells: These are typically low-pressure, low-yielding wells in the late stages of production. Individual wells are considered unattended, with no personnel costs involved. Since these wells produce virtually no water, there are no gas field water reinjection costs, and basic maintenance and repair costs are also low. Due to the low wellhead pressure, these non-water-producing wells utilize a pressurized delivery process. The model considers block-level pressurization, with pressurization costs allocated to each well based on gas production.

[0120] Unpressurized Well Parameter Settings: Single wells are also considered unattended and do not involve personnel costs. They produce a small amount of water, which involves gas field water reinjection costs, but basic maintenance and repair costs are also low.

[0121] Calculate the maximum gas production of the gas well. Table 1 is the calculation table of the maximum gas production of the gas well for low-efficiency gas wells.

[0122] Table 1

[0123]

[0124] As shown in Table 1, Well HS4, due to a ruptured gas pipeline, could only be vented for pressure relief. Furthermore, due to its low production rate and high pressure, it presented potential risks and was therefore shut down. Wells YH2 and QL024-2 are drainage wells, maintaining relatively stable production from the main gas wells and effectively slowing the advance of formation water into the reservoir, playing a crucial role in protecting the reservoir and maintaining production. Wells TD15, S13, S25, and X2, had fallen below their maximum gas production rates and were shut down.

[0125] Gas prices have an impact on the ultimate gas production of gas wells, but the increase in gas prices is difficult to predict. The ultimate gas production of gas wells formed at different gas prices also varies with the increase in gas prices. It is necessary to determine it at any time based on gas prices in order to accurately predict the potential of gas wells and achieve effective development. To calculate the ultimate gas production of gas wells at different gas prices, consider the ultimate gas production of gas wells under different water production conditions. Figure 2 、 Figure 3 and Figure 4 .

[0126] It can be seen that the invention can quickly identify the shutdown of different types of inefficient gas wells, and has guiding significance for the efficiency evaluation of different types of carbonate gas wells.

Claims

1. A method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs, characterized by: The following steps are involved: a. Conduct break-even analysis on inefficient gas wells; b. Conduct input-output linear break-even analysis on inefficient gas wells to determine sales revenue; c. Calculate the cost of inefficient gas well recovery operations, oil and gas processing operations, maintenance operations, and natural gas purification operations; d. According to the type of gas well, establish the shutdown limit production model of inefficient gas wells, calculate the limit gas production of the gas wells, and then determine the shutdown of inefficient gas wells.

2. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 1, characterized in that: In step a, the break-even analysis refers to conducting a break-even analysis of the input and output of the gas well to determine the maximum gas production of the gas well.

3. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 2, characterized in that: The maximum gas production of a gas well refers to the gas production of the gas well when the gas production is reduced to the point where the input and output offset each other in the middle and late stages of gas well development.

4. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 1, characterized in that: In step b, determining sales revenue specifically refers to calculating and determining by formula 1; STC≥0 Formula 1 Among them, S is sales revenue, T is tax, and C is cost.

5. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 1, characterized in that: In step c, the cost includes direct material costs, direct fuel costs, direct power costs, oil and gas processing costs, natural gas purification costs, and maintenance and repair costs.

6. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 1, characterized in that: In step d, the shutdown judgment of inefficient gas wells means that when the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down; when the gas pipeline is broken and the gas production of the gas well is less than the limit gas production of the gas well, the inefficient gas well is shut down.

7. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 1, characterized in that: In step d, the gas well types include gas lift wells, non-water-producing wells and unpressurized wells.

8. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 7, characterized in that: The shut-in limit production model of the inefficient gas well of the gas lift well is shown in Equation 2: Among them, q g is the maximum gas production of the gas well, G is the fixed cost, C 回注 is the unit water production reinjection cost, q w is the daily water production, s is the production hour rate, P is the gas price, R is the natural gas commodity rate, T is the tax rate, C 增压 is the pressurization cost per unit gas output, C 脱硫 is the purification cost per unit gas output, C 脱水 is the reinjection cost per unit water production.

9. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 7, characterized in that: The shut-in limit production model of the low-efficiency gas well that does not produce water is as follows:

10. The method for determining the shutdown of inefficient gas wells in fracture-pore gas reservoirs according to claim 7, characterized in that: The shut-in limit production model of the unpressurized low-efficiency gas well is shown in Equation 4.

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