Classification method, device, medium and equipment for low-yield and low-efficiency gas wells

Abstract

The invention discloses a low-yield and low-efficiency gas well classification method, device, medium and equipment, and relates to the technical field of oil-gas field development. The method comprises the following steps: firstly, acquiring historical production data of a plurality of typical low-yield and low-efficiency gas wells, then analyzing the historical production data, and determining a historical production characteristic change rule of each typical low-yield and low-efficiency gas well, so that each typical low-yield and low-efficiency gas well is classified, and the low-yield and low-efficiency type of each typical low-yield and low-efficiency gas well is determined; and finally, classifying the low-yield and low-efficiency gas wells to be classified by taking the classification of each typical low-yield and low-efficiency gas well as a reference. According to the method, the typical low-yield and low-efficiency gas wells are analyzed based on the production data of the typical low-yield and low-efficiency gas wells, the causes of the low-yield and low-efficiency gas wells are determined, and different conditions are classified, so that the unclassified low-yield and low-efficiency gas wells are classified based on the causes, and subsequent production recovery measures can be performed on the low-yield and low-efficiency gas wells in a targeted manner.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas field development, and particularly relates to a classification method, device, medium, and equipment for low-production and low-efficiency gas wells. Background Art

[0002] Currently, with the deepening of the development of oil and gas fields in China, the number and proportion of low-production and low-efficiency gas wells are showing a gradually increasing trend, the increasing rate is accelerating year by year, the management and protection costs are rising day by day, the comprehensive decline rate of the gas field remains high, the contradictions in the development of old gas fields are becoming increasingly prominent, the stable production situation is becoming increasingly severe, and the development efficiency of the gas field is seriously affected.

[0003] However, the existing technology lacks an understanding of the causes of low-production and low-efficiency gas wells, making it difficult to classify low-production and low-efficiency gas wells, and thus it is difficult to take targeted measures to resume production for low-production and low-efficiency gas wells. Summary of the Invention

[0004] Based on this, it is necessary to provide a classification method, device, medium, and equipment for low-production and low-efficiency gas wells in view of the above technical problems.

[0005] The present specification adopts the following technical solutions:

[0006] The present specification provides a classification method for low-production and low-efficiency gas wells, including:

[0007] Obtain the historical pressure data and historical production data of multiple low-production and low-efficiency gas wells, and calculate the production decline rate according to the historical production data;

[0008] Respectively determine the variation laws of the historical pressure data and production decline rate of each low-production and low-efficiency gas well as the production characteristic variation laws;

[0009] Analyze the low-production and low-efficiency mechanisms of each low-production and low-efficiency gas well to determine the low-production and low-efficiency types of each low-production and low-efficiency gas well; among them, the low-production and low-efficiency gas wells with the same low-production and low-efficiency type show the same production characteristic variation laws;

[0010] Obtain the pressure data and production data during the production process of the low-production and low-efficiency gas well to be classified, and analyze the variation laws of the pressure data and production data to determine the low-production and low-efficiency type of the low-production and low-efficiency gas well to be classified.

[0011] Optionally, the calculating the production decline rate according to the historical production data specifically includes:

[0012] Taking time as the abscissa and historical production data as the ordinate, draw a production scatter plot of the low-production and low-efficiency gas well;

[0013] Perform polynomial curve fitting according to the production scatter plot, and the form of the polynomial curve is:

[0014] y = A + B1X + B2X 2 + B3X 3 ;

[0015] Calculate the production decline rate according to the obtained fitting curve through the following formula:

[0016]

[0017] where A, B1, B2, and B3 are curve coefficients, D is the instantaneous production decline rate, D i is the initial decline rate at the beginning of production, t is the production time in the production decline stage, and Q is the production volume of the low - yield and inefficient gas well within the production time t in the production decline stage.

[0018] Optionally, respectively determining the historical pressure data and the variation law of the production decline rate of each low - yield and inefficient gas well as the production characteristic variation law specifically includes:

[0019] Determine the production characteristic variation law of the first - type gas wells whose production shows a straight - line downward trend;

[0020] Determine the production characteristic variation law of the second - type gas wells whose pressure shows a two - stage downward trend with the pressure decline rate in the initial production stage greater than that in the later production stage and has a low - pressure stable production stage;

[0021] Determine the production characteristic variation law of the third - type gas wells whose production shows an upward trend in the initial production stage, gradually tends to be stable, and shows a downward trend in the middle production stage;

[0022] Determine the production characteristic variation law of the fourth - type gas wells whose production shows an upward trend in the initial production stage, a downward trend in the middle production stage and the production pressure difference change range is greater than the preset upper threshold value, and shows a stable production trend in the later production stage;

[0023] Determine the production characteristic variation law of the fifth - type gas wells whose production in the initial production stage and the later production stage is less than that in the middle production stage, and the water production volume during the production period is less than the production volume;

[0024] Determine the production characteristic variation law of the sixth - type gas wells that produce water in the initial production stage, and whose production shows a downward trend after water production and the production pressure difference change range is less than the preset lower threshold value.

[0025] Optionally, analyzing the low - yield and inefficient mechanism of each low - yield and inefficient gas well specifically includes:

[0026] For the first - type gas wells, with the continuous deepening of production, the recovery degree gradually increases, the formation energy deficit, the formation pressure decreases, the remaining movable reserves are small, and the production capacity is exhausted, resulting in low production or shut - down of the gas well;

[0027] With the increase of production time in Class II gas wells, the sulfur blockage area in the gas wells gradually expands to the formation around the wellbore, the formation pressure gradually decreases, the solubility of elemental sulfur in natural gas decreases and precipitates, attaching to the gas transmission equipment to cause sulfur deposition blockage, resulting in low production or shut - down of the gas wells;

[0028] With the increase of production time in Class III gas wells, the combined action of corrosion inhibitor cracking residues, pipe string corrosion and scaling products, and various well - injection agents in the well - produced fluid of the gas wells causes blockage and throttling in the gas wellbore, resulting in low production or shut - down of the gas wells;

[0029] Affected by reservoir geological factors, wellbore conditions and production factors, Class IV gas wells have wellbore failure problems, resulting in low production or shut - down of the gas wells;

[0030] In the middle and late production stage of Class V gas wells, one or more of the phenomena such as scaling, water blocking, water plugging and reservoir damage occur, resulting in low production or shut - down of the gas wells;

[0031] In the production process of Class VI gas wells, the external water cannot be effectively discharged by the gas flow, causing liquid accumulation in the wellbore. The bottom hole back - pressure on the formation continuously rises, resulting in an increasing amount of liquid accumulation in the formation, an expanding liquid accumulation range, an increasing formation water saturation, a decrease in gas - phase permeability, blocking the channels for natural gas production in the formation pores, causing reservoir water plugging, and resulting in low production or shut - down of the gas wells.

[0032] Optionally, determining the low - production and low - efficiency types of each low - production and low - efficiency gas well specifically includes:

[0033] Determine Class I gas wells as the type of gas well reservoir energy depletion; determine Class II gas wells as the type of gas well sulfur - containing; determine Class III gas wells as the type of gas well blockage; determine Class IV gas wells as the type of gas well wellbore failure; determine Class V gas wells as the type of reservoir water blocking; determine Class VI gas wells as the type of gas well liquid accumulation.

[0034] This specification provides a classification device for low - production and low - efficiency gas wells, including:

[0035] An acquisition module, used to acquire the historical pressure data and historical production data of multiple low - production and low - efficiency gas wells, and calculate the production decline rate according to the historical production data;

[0036] A pre - classification module, used to respectively determine the change rules of the historical pressure data and production decline rate of each low - production and low - efficiency gas well as the production characteristic change rules;

[0037] An analysis module, used to analyze the low - production and low - efficiency mechanisms of each low - production and low - efficiency gas well, and determine the low - production and low - efficiency types of each low - production and low - efficiency gas well; among them, low - production and low - efficiency gas wells with the same low - production and low - efficiency type present the same production characteristic change rules;

[0038] A classification module, configured to obtain pressure data and production data during the production process of low - yield and low - efficiency gas wells to be classified, analyze the variation laws of the pressure data and the production data, so as to determine the low - yield and low - efficiency types of the low - yield and low - efficiency gas wells to be classified.

[0039] This specification provides a computer - readable storage medium, which stores a computer program. When the computer program is executed by a processor, the classification method of the above - mentioned low - yield and low - efficiency gas wells is implemented.

[0040] This specification provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the classification method of the above - mentioned low - yield and low - efficiency gas wells is implemented.

[0041] The above - mentioned at least one technical solution adopted in this specification can achieve the following beneficial effects:

[0042] First, obtain the historical production data of multiple low - yield and low - efficiency gas wells, including historical pressure data and historical production data. Then, analyze the historical production data to determine the variation laws of the historical production characteristics of each low - yield and low - efficiency gas well, so as to classify each low - yield and low - efficiency gas well and determine its low - yield and low - efficiency type. Finally, the classification of each low - yield and low - efficiency gas well can be used as a benchmark to classify the low - yield and low - efficiency gas wells to be classified.

[0043] The present invention analyzes the variation laws of production characteristics of low - yield and low - efficiency gas wells based on their historical production data, and classifies the low - yield and low - efficiency types of each low - yield and low - efficiency gas well based on the low - yield and low - efficiency mechanism. Since low - yield and low - efficiency gas wells of the same low - yield and low - efficiency type often show the same variation laws of production characteristics, it is possible to classify the low - yield and low - efficiency types of unclassified low - yield and low - efficiency gas wells based on the pressure data and production data of the unclassified low - yield and low - efficiency gas wells, so as to facilitate subsequent targeted measures for resuming production of low - yield and low - efficiency gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation to the present application. In the drawings:

[0045] Figure 1 is a schematic flowchart of a classification method for low - yield and low - efficiency gas wells provided by this specification;

[0046] Figure 2 is a schematic diagram of a fitting curve of annual production of a typical type of gas well provided by this specification;

[0047] Figure 3Schematic diagram of the fitting curves of the annual production of a typical type II gas well provided in this specification;

[0048] Figure 4 Schematic diagram of the fitting curves of the annual production of a typical type III gas well provided in this specification;

[0049] Figure 5 Schematic diagram of the fitting curves of the annual production of a typical type IV gas well provided in this specification;

[0050] Figure 6 Schematic diagram of the fitting curves of the annual production of a typical type V gas well provided in this specification;

[0051] Figure 7 Schematic diagram of the fitting curves of the annual production of a typical type VI gas well provided in this specification;

[0052] Figure 8 Schematic diagram of the annual water production of a typical type VI gas well provided in this specification;

[0053] Figure 9 Schematic diagram of the change of production data of a target gas well provided in this specification;

[0054] Figure 10 Schematic diagram of the reservoir plugging removal effect provided in this specification;

[0055] Figure 11 Schematic diagram of the classification device for low - production and low - efficiency gas wells provided in this specification;

[0056] Figure 12 Schematic diagram of a computer device for implementing the classification method of low - production and low - efficiency gas wells provided in this specification. Detailed implementation manners

[0057] To make the purpose, technical solutions and advantages of this specification clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this specification and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of them. Based on the embodiments in the specification, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0058] In view of the unclear understanding of the causes of low - production and low - efficiency gas wells and the lack of targeted stimulation and transformation measures, it is urgent to use the comprehensive research of the existing dynamic and static data in the gas field to clarify the development characteristics of low - production wells, analyze the main cause types of low - production wells, and establish a classification method for low - production and low - efficiency wells starting from the mechanism of gas well low - production, which can efficiently and quickly identify the low - production types of gas wells, thus facilitating subsequent targeted measures for the rejuvenation of old wells.

[0059] The technical solutions provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0060] Figure 1 It is a schematic flow chart of a classification method for low-yield and low-efficiency gas wells in this specification, specifically including the following steps:

[0061] S101: Obtain the historical pressure data and historical production data of multiple low-yield and low-efficiency gas wells, and calculate the production decline rate according to the historical production data.

[0062] Generally, when classifying low-yield and low-efficiency gas wells, typical low-yield and low-efficiency gas wells over the years can be analyzed first. According to the characteristics of their production and development processes, each typical low-yield and low-efficiency gas well can be classified, and multiple different low-yield and low-efficiency standard types can be established based on their causes. Subsequently, when facing new low-yield and low-efficiency gas wells, they can be classified based on each standard type, so as to take targeted rehabilitation measures for low-yield and low-efficiency gas wells.

[0063] When judging the production situation of a gas well, it can be judged based on the pressure drop rate method. Usually, the pressure drop rate needs to be controlled within a certain value range at least half a year after the gas well is put into production. For a gas well after production, its pressure drop rate standard can be calculated by the following formula:

[0064]

[0065] Wherein, P * is the pressure drop rate standard, P i is the original inlet pressure of the gas well, P w is the lowest export pressure of the gas well, a is the set stable production period, and 330 is the stable production days.

[0066] When the pressure drop rate of a gas well after production is less than its corresponding pressure drop rate standard, it is a low-yield and low-efficiency gas well. A typical low-yield and low-efficiency gas well may refer to a gas well whose pressure drop rate after production is much less than the corresponding pressure drop rate standard. An offset threshold between the actual pressure drop rate and the pressure drop rate standard can be set according to experience. When the offset is greater than this offset threshold, it is determined as a typical low-yield and low-efficiency gas well.

[0067] Based on this, in one or more embodiments of this specification, the server of the service platform may first obtain the production static data and production dynamic data of multiple typical low-yield and low-efficiency gas wells. The production static data and production dynamic data may include historical pressure data, historical production data, and historical production measures during their production process. Thus, the differences in production characteristics between ordinary gas wells and low-yield and low-efficiency gas wells can be clarified. The so-called typical low-yield and low-efficiency gas wells may be gas wells with large changes in oil pressure, casing pressure, and production and obvious change trends in one or more target areas. Starting from the stimulation measures implemented in the target area over the years, analysis can be carried out on each type of low-yield and low-efficiency gas well, and gas wells with early production start time and long production time can be selected as typical low-yield and low-efficiency gas wells for research.

[0068] After obtaining the data of typical low-yield and low-efficiency gas wells, the server can further analyze the data. That is, the server can calculate the production decline rate according to the historical production data. Specifically, the server can first take time as the abscissa and historical production data as the ordinate to plot the production scatter plot of typical low-yield and low-efficiency gas wells. Here, it can specifically take days, months, or years as the abscissa and the corresponding historical production data as the ordinate. Of course, it is also possible to first plot the production change graph of typical low-yield and low-efficiency gas wells on a daily basis, and then plot the production scatter plots of each year at annual intervals based on the production change graph. How to specifically obtain the production scatter plot can be determined according to needs, and this specification does not limit this.

[0069] Then, polynomial curve fitting is performed according to the production scatter plot. The form of the polynomial curve can be:

[0070] y = A + B1X + B2X 2 + B3X 3

[0071] In the formula, A, B1, B2, and B3 are curve coefficients. The production decline rate is calculated through the following formula based on the obtained fitting curve:

[0072]

[0073] In the formula, D is the instantaneous decline rate (month -1 or year -1 ), generally expressed as % / month or % / year, t is the production time in the production decline stage, D i is the initial decline rate at the beginning of production, Q is the production of typical low-yield and low-efficiency gas wells within the time t in the production decline stage, is the production change rate per unit time.

[0074] In addition, the relationship between production and decline rate can also be obtained through the following formula:

[0075]

[0076] where n is a decreasing exponent with a value range of 0 ≤ n ≤ 1, D i is the initial decline rate in the initial production stage, q i is the production rate at the initial decline, and q(t) is the production rate within time t in the production decline stage. The corresponding decline type of the production rate can be determined through the relationship between the production rate and the decline rate.

[0077] When a gas well is exploited, measures such as opening the well, shutting down the well, and intermittently opening the well are usually implemented for the gas well according to the actual exploitation situation. For gas wells under different conditions, their own production rates and production pressure differences will have different changes during exploitation, and there will also be different changes during the adjustment of various production measures. Then, the server can determine the well opening and shutting measures in the historical production measures of each typical low - production and low - efficiency gas well to assist in subsequent classification and attribution judgment.

[0078] The server mentioned in this specification can be a server set up on the business platform or devices such as desktop computers and laptop computers that can execute the solutions in this specification. For the convenience of description, only the server is used as the execution subject for description below.

[0079] S102: Respectively determine the historical pressure data and the variation law of the production decline rate of each low - production and low - efficiency gas well as the variation law of production characteristics.

[0080] S103: Analyze the low - production and low - efficiency mechanisms of each low - production and low - efficiency gas well to determine the low - production and low - efficiency types of each low - production and low - efficiency gas well; among them, the low - production and low - efficiency gas wells with the same low - production and low - efficiency type show the same variation law of production characteristics.

[0081] Through the above - mentioned analysis of historical pressure data and historical production data, the server can combine the well opening and shutting measures for analysis to determine the corresponding variation law of production characteristics under different conditions.

[0082] Table 1 Schematic table of annual production parameters of a typical type of gas well

[0083]

[0084] Table 1 is a schematic table of annual production parameters of a typical type of gas well. Figure 2 is a schematic diagram of the annual production fitting curve of a typical type of gas well in this specification. As can be seen from Table 1 and Figure 2 it can be seen that the annual production shows a linear downward trend. For a type of gas well, there may be no water production and formation voidage in the later production stage. This type of low - production and low - efficiency gas well may be a gas well with high casing pressure - bearing capacity, good cementing quality, and relatively light wellbore corrosion. Most of this type of low - production and low - efficiency gas wells have good productivity in adjacent wells in the same production horizon. Figure 2 The polynomial fitting equation of the corresponding type of gas well is as follows:

[0085] y = 930.6 - 85.2X + 4.14X 2 - 0.26X 3

[0086] It can be seen from its production decline curve that its production shows a linear downward trend. It is determined as a type-I gas well. For type-I gas wells, usually due to the continuous deepening of gas well production, the recovery degree gradually increases, the formation energy deficit is serious, the tubing head pressure and casing head pressure change significantly, the formation pressure decreases, the remaining movable reserves are small, and the productivity is exhausted, resulting in low production or shutdown of the gas well. Its main characteristics are manifested in the weakening of formation seepage energy, relatively poor reservoir physical properties, and small formation coefficient. It can be determined that type-I gas wells are of the type of gas well reservoir energy exhaustion.

[0087] Table 2 Schematic table of production parameters of a typical type-II gas well over the years

[0088]

[0089] Table 2 is a schematic table of production parameters of a typical type-II gas well over the years. Figure 3 This is a schematic diagram of the polynomial fitting curve of the annual production of a typical type-II gas well in this specification. From Table 2 and Figure 3 it can be seen that the annual production shows a two-stage downward trend, and the decline is fast in the early production stage, and the production increases after the stimulation measures are taken in the later production stage. For type-II gas wells, with the extension of the gas well production time, various problems and failures usually occur in the wellbore, and there will also be failures such as fishing neck breakage, sand burial, non-unsealing, and jamming of the throttler. Conventional fishing operations have failed many times on site. The production of this type of low-yield and low-efficiency gas well has a typical "two-stage" characteristic in production. The initial production and pressure decline rapidly, but according to the observation of the stimulation measures effect on site, the productivity of this type of gas well will increase to a certain extent after the wellbore treatment work is carried out, and the effect is obvious and the change is rapid. Figure 3 The corresponding polynomial fitting equation of the type-II gas well is as follows:

[0090] y = 127.54 + 358.27X - 70.42X 2 + 3.4X 3

[0091] From the historical pressure data of Class II gas wells, it can be seen that the pressure of Class II gas wells shows a two-stage downward trend in which the pressure drop rate in the early stage of production is greater than the pressure drop rate in the later stage of production. Combined with the production decline curve, it can be obtained that there is a low-pressure stable production stage. This type of low-yield and low-efficiency gas well can be identified as a Class II gas well. Class II gas wells usually have a sulfur blockage area that gradually expands to the outer formation of the wellbore as the production time of the gas well increases, the formation pressure gradually decreases, the solubility of elemental sulfur in natural gas decreases and precipitates, and adheres to the gas transmission equipment to cause sulfur deposition blockage. Its main characteristics are that it has a larger daily gas production of the gas well, reservoir (initial) water saturation, non-Darcy flow constant, smaller reservoir effective thickness, reservoir (initial) porosity and permeability, and bottom hole flow pressure, which can cause more serious sulfur deposition blockage in the gas well. Class II gas wells can be determined as sulfur-containing gas wells.

[0092] Table 3 Schematic diagram of production parameters of a typical three-type gas well over the years

[0093]

[0094] Table 3 is a diagram showing the production parameters of a typical three-type gas well over the years. Figure 4 This is a typical three-type gas well production fitting curve diagram in this specification. Figure 4 It can be seen that for the three types of gas wells, as the production time increases and the operation frequency increases, the corrosion inhibitor interacts with the impurities, output fluids, corrosion products, etc. in the well to form a variety of blockages in the wellbore, thereby blocking the wellbore. When this type of low-yield and low-efficiency gas well is blocked, the production oil pressure and casing pressure change significantly, the gas production and water production will drop significantly, and some gas wells will stop production. Figure 4 The corresponding polynomial fitting equations for the three types of gas wells are as follows:

[0095] y=517.2+25.76X-7.12X 2 +0.19X 3

[0096] Combined with the production decline curves of the three types of gas wells, it can be seen that the production of the three types of gas wells shows an upward trend in the early stage of production, and gradually tends to be stable, and shows a downward trend in the middle stage of production. This type of low-yield and low-efficiency gas wells can be identified as type three gas wells. For type three gas wells, usually with the extension of gas well production time, the combined effects of corrosion inhibitor cracking residues, tubing corrosion scaling products, gas well production fluids and other well-injecting agents cause serious blockage and throttling of the gas well bore, resulting in the inability of the gas well to produce normally, or even forced to shut down the well. Its main characteristics are salt scaling caused by high mineralization of formation water, corrosion scaling caused by CO2 and H2S corrosion, and accumulation of corrosion inhibitor residues and foaming agent denatured products in the well bore. Type three gas wells can be identified as gas well blockage types.

[0097] Table 4 Schematic diagram of production parameters of four typical gas wells over the years

[0098]

[0099] Table 4 is a schematic table of the production parameters of a typical four - type gas well over the years. Figure 5 This is a schematic diagram of the fitting curve of the annual production of a typical four - type gas well in this specification. From Table 4 and Figure 5 it can be seen that for the four - type gas wells, when the gas well is blocked, the wellbore friction coefficient increases, the production tubing - casing pressure difference increases significantly, the production becomes relatively difficult, the gas production and water production will drop significantly, and some gas wells will stop production in the later stage. The increase in the seepage resistance of natural gas makes the drainage effect worse and worse, and the near - well liquid accumulation becomes more and more serious, seriously affecting the normal production of gas wells. Among them, the water - lock invasion depth severely restricts the ability of the effective reservoir pressure to discharge the retained water. The deeper the invasion depth, the more difficult it is to discharge the retained water, and the more serious the damage caused by the water - lock effect. Figure 5 The polynomial fitting equation for the corresponding four - type gas wells is as follows:

[0100] y = 306.08 - 65.17X + 2.31X 2 + 0.11X 3

[0101] For the four - type gas wells, according to the following Poiseuille formula:

[0102] In the formula, q is the flow rate of the discharged liquid, ΔP is the driving pressure difference, r is the radius, P c is to overcome the capillary force, μ is the viscosity of the liquid, and L is the length of the capillary.

[0103] By converting the flow rate in the above formula to the linear velocity and then integrating with respect to time, the expression for the time t required to discharge a liquid column of length L from a capillary with a radius of r can be obtained. Then, according to the Kozeny - Carman formula, substituting it into the formula, the calculation formula for the water - lock depth of the near - well formation of the condensate gas well is as follows:

[0104]

[0105] In the formula, L is the water - lock invasion depth of the near - well formation, θ is the wetting angle on the capillary wall, T is the time required to discharge the fluid, σ is the surface tension of the fluid, τ is the pore tortuosity, K is the rock permeability, and Φ is the porosity.

[0106] Combining the production and pressure data of the four types of gas wells, it can be seen that the production of the four types of gas wells shows an upward trend in the initial production stage, a downward trend in the middle production stage, and the change range of the production pressure difference is greater than the preset upper threshold value. In the late production stage, it shows a stable production trend. Such low-yield and low-efficiency gas wells can be determined as the four types of gas wells. The four types of gas wells usually have varying degrees of wellbore failure problems due to the influence of reservoir geological factors, wellbore conditions, and production factors, resulting in low production or shutdown of the gas wells. The four types of gas wells can be determined as the gas well wellbore failure type.

[0107] Table 5 is a schematic table of the production parameters of a typical five types of gas wells over the years. Figure 6 This is a schematic diagram of the fitting curve of the annual production of a typical five types of gas wells in this specification. From Table 5 and Figure 6 it can be seen that for the five types of gas wells, due to the changes in pressure and temperature in the formation, the geometric shapes of the reservoir storage space and seepage channels will be deformed, resulting in a decrease in porosity and permeability. As a result, the energy loss generated by gas seepage during the production of gas wells is more serious, which exacerbates the precipitation of elemental sulfur from the saturated gas flow, thereby triggering more sulfur deposition, causing the sulfur content of the gas wells to increase, and thus leading to a large and rapid decline in the productivity of the gas wells. Figure 6 The corresponding polynomial fitting equation for the five types of gas wells is as follows:

[0108] y = 232.12 - 408.78X - 85.98X 2 + 4.36X 3

[0109] Table 5 Schematic table of the production parameters of a typical four types of gas wells over the years

[0110]

[0111] From the production and water production of the five types of gas wells, it can be seen that the production of the five types of gas wells is less in the initial production stage and the late production stage than in the middle production stage, and the water production during the production period is less than the production. Such low-yield and low-efficiency gas wells can be determined as the five types of gas wells. For the five types of gas wells, usually in the middle and late stages of development and production, one or more of the phenomena such as scaling, water blocking, water plugging, and reservoir damage will occur, resulting in low production or shutdown of the gas wells. Its main characteristics are water blocking caused by capillary effect and water blocking caused by Jamin effect. Its main influencing factors are reservoir permeability, water saturation, production pressure difference, and wettability of the rock, etc. The five types of gas wells can be determined as the reservoir water blocking type.

[0112] Table 6 is a schematic table of the production parameters of a typical six types of gas wells over the years, Figure 7 This is a schematic diagram of the fitting curve of the annual production of a typical six types of gas wells in this specification, Figure 8 This is a schematic diagram of the annual water production of a typical six types of gas wells in this specification. From Table 6, Figure 7 and Figure 8It can be seen that for the six types of gas wells, as production progresses, the water production of the gas wells gradually increases. The water production leads to an increase in pressure loss in the wellbore, and a higher liquid-carrying lifting bottomhole pressure is required to achieve the same production rate. As the pressure and production rate further decrease, the gas production of the gas well is less than the minimum liquid-carrying flow rate, and the liquid in the wellbore cannot be completely carried out of the wellbore, resulting in liquid accumulation in the gas well, gradually leading to a reduction in production and even well shutdown due to waterlogging. Wellbore liquid accumulation may occur in the early stage and the middle and late stages of production. Figure 7 The polynomial fitting equations for the corresponding six types of gas wells are as follows:

[0113] y = 438.9 + 361.1X + 48.61X 2 - 5.55X 3

[0114] Table 6 Schematic Table of Production Parameters of a Typical Six-Type Gas Well over the Years

[0115]

[0116] Among them, the calculation formula for the critical liquid-carrying flow velocity of F-type gas wells generally adopts the droplet model, mainly including the Turner model, the Li Min model, and the Wang Yizhong model. Among the three droplet models, the assumed conditions are three states of droplets: spherical, ellipsoidal, and spherical cap-shaped.

[0117] Generally, the critical liquid-carrying flow velocity can be expressed by the following formula:

[0118]

[0119] In the formula: v g is the critical liquid-carrying flow velocity, a is the equation coefficient of the three models, σ is the gas-water interfacial tension, ρ1 is the density of formation water, and ρ g is the density of natural gas.

[0120] Judging from the production, water production and pressure drop rates of six types of gas wells, they produce water in the initial production stage. After water production, the production rate shows a rapid decline and the change range of the production pressure difference is less than the preset lower threshold value. This type of low-yield and low-efficiency gas well can be determined as a type-six gas well. For type-six gas wells, usually, during the production process, the gas flow cannot effectively discharge the external water, resulting in difficulty in liquid carrying by the gas well. On the one hand, it causes liquid accumulation in the wellbore. As the liquid accumulation increases, the bottomhole backpressure on the formation continuously rises, leading to continuous increase in the formation liquid accumulation amount, continuous expansion of the liquid accumulation range, and continuous increase in the formation water saturation, and the decline of gas-phase permeability. Its main characteristics are the decline of gas-phase permeability, which blocks the channels for natural gas production in the formation pores, causing water blockage in the reservoir and gradually reducing the gas well production rate, and finally resulting in water flooding and production suspension. The main influencing factor is that after the gas well produces water, due to the capillary force, the invading water imbibes into the pore medium of the branch fracture network on both sides of the main fracture, reducing the ability of the main fracture to supply gas flow and the relative permeability of gas, causing the gas well production rate to rapidly decline and the critical liquid-carrying ability of the gas to decrease, thus reducing the gas well production rate. The type-six gas well can be determined as the gas well liquid accumulation type.

[0121] In one or more embodiments of the present specification, 300 typical low-yield and low-efficiency gas wells are obtained for classification analysis, their low-yield and low-efficiency types are determined, and a proportion analysis is carried out, as shown in Table 7.

[0122] Table 7 Proportion of Different Types of 300 Low-Yield and Low-Efficiency Gas Wells

[0123] Gas well classification Reservoir energy depletion type Sulfur content type Blockage type Wellbore failure Reservoir water block Gas well liquid loading type Proportion 0.13 0.19 0.39 0.08 0.09 0.22

[0124] S104: Obtain the pressure data and production data of the low-yield and low-efficiency gas well to be classified during the production process, and analyze the variation laws of the pressure data and production data to determine the low-yield and low-efficiency type of the low-yield and low-efficiency gas well to be classified.

[0125] After classifying the typical low-yield and low-efficiency gas wells and determining their low-yield and low-efficiency types respectively through the above methods, the server can use this as a benchmark to analyze the low-yield and low-efficiency gas wells to be classified, so as to determine their low-yield and low-efficiency types and complete the classification.

[0126] The server can first obtain the pressure data and production data of the low-yield and low-efficiency gas well to be classified during the production process. This production process can be the entire production process or a partial production process selected according to a preset time period. Then, analyze the variation laws of the production characteristics based on the pressure data and production data, and thus determine the low-yield and low-efficiency type of the low-yield and low-efficiency gas well to be classified according to the corresponding relationship between the production characteristic variation laws and the low-yield and low-efficiency types.

[0127] For example, an analysis was conducted on a low - production and low - efficiency target gas well in a certain development block of a low - permeability gas reservoir in China. The target gas well was put into production in September 2010. In the initial stage, the production status was relatively stable, with the gas production fluctuating between 0.6×10⁴ m³ / day. The tubing head pressure and casing head pressure were relatively high, fluctuating in the range of 9.2 - 10.9 MPa, but without large fluctuations. From the end of 2010 to 2014, it was in the high - production stage, and during this period, the gas production was stable at over 1.6×10⁴ m³ / day. In 2016, the gas production decreased year by year. During the years from 2016 to 2020, the gas production varied between 0.64 - 1.13×10⁴ m³ / day, and the production rate and decline rate remained at a relatively low level for a long time. In 2021, the gas production decreased to 0.112×10⁴ m³ / day, reaching a minimum value. At the end of 2021, the corresponding stimulation measures were improved and strengthened. In 2022, the gas production reached 2.435×10⁴ m³ / day, and the tubing head pressure and casing head pressure changed stably, with significant stimulation effects. As Figure 9 shown, Figure 9 it is a schematic diagram of the production data change of a target gas well in this specification.

[0128] Based on the actual production characteristics of the gas field and the changes in some production data such as gas production, water production, tubing head pressure, and casing head pressure, it can be determined that the change law of the production characteristics of its production data conforms to the change laws of three types of gas wells and gas well blockage types.

[0129] Further clarify the time nodes since the well was put into production, clarify the downhole operation history after production, and combine relevant geological and production dynamic data. The reasons for the decline in the productivity of the target gas well are summarized and analyzed as follows:

[0130] (1) The fluid salinity of the gas well is high or it contains sulfur.

[0131] (2) There is no throttler or other tools in the wellbore, but the productivity has decreased, and some conventional wellbore potential tapping measures cannot be taken.

[0132] (3) The tubing - casing pressure difference of the gas well production is large (not affected by liquid column).

[0133] (4) During well flushing, there is a phenomenon of encountering resistance, and the well flushing data shows that there is dirt or blockage in the gas wellbore.

[0134] (5) Chemical agents such as corrosion inhibitors were added during the previous production.

[0135] Combined with the actual production dynamics on site and the shut - in well law, the main low - production factors and their low - production mechanisms of the target gas well are analyzed. During the operation of the gas well, with the extension of the gas well production time, the combined action of corrosion inhibitor cracking residues, pipe string corrosion and scaling products, gas well produced fluid and other well - entering agents causes serious blockage and throttling in the gas wellbore, resulting in the abnormal production of the gas well. The low - production mechanism of this type of low - production gas well is as follows:

[0136] In the middle and late stages of gas well production, the fluid seepage channels of some gas wells are blocked, resulting in the characteristics of "sudden abnormal drop in casing pressure and rapid decline in production". After the gas well enters the middle and late stages of production, the decline in natural gas production leads to a decrease in the liquid-carrying capacity, which in turn causes liquid accumulation in the wellbore and an increase in the water saturation of the reservoir near the wellbore. The liquid droplets in the gas flow are mainly affected by two forces: the downward gravity of the liquid droplets themselves and the upward drag force of the gas flow on the liquid droplets. The critical velocity of gas carrying liquid is:

[0137]

[0138] In the formula, Vg is the critical velocity of gas carrying liquid (m / s), ρ L is the liquid density (kg / m 3 ), ρ g is the natural gas density (kg / m 3 ), and σ is the gas-liquid surface tension (mN / m).

[0139] The critical liquid-carrying flow rate is:

[0140]

[0141] In the formula, Q is the critical liquid-carrying flow rate (m 3 d -1 ), P is the wellhead pressure (MPa), A is the cross-sectional area of the tubing in the wellbore (m 2 ), Z is the gas deviation coefficient, uc is the critical liquid-carrying velocity of natural gas (m·s -1 ), and T is the wellhead temperature (K).

[0142] After the liquid column exceeds a certain height, the gas well cannot continue to produce due to the small pressure difference. The main reason for the water lock effect caused by liquid phase retention is the capillary pressure, and its magnitude can be expressed by the Laplace equation:

[0143]

[0144] In the formula, P C is the capillary pressure (mN), σ is the interfacial tension (mN / m), and R1, R2 are the radii of curvature (m).

[0145] It can be seen from the above formula that the capillary pressure is inversely proportional to the radius of curvature of the porous medium. The smaller the radius of curvature of the pores, the relatively larger the capillary pressure. When bottom-hole liquid accumulation occurs in the gas well, the stagnant water at the bottom hole is likely to accumulate and is not easily discharged, and it is more likely to produce a serious water lock effect.

[0146] Due to the blockage of the fluid seepage channels in some gas wells, which results in the characteristics of "sudden abnormal drop in casing pressure and rapid decline in production", aiming at "unclogging the blockage, improving diversion, and expanding the drainage area", the target gas wells generally adopt measures such as reservoir deep acidification (Lower Paleozoic) and near-wellbore plug removal (Upper Paleozoic) to restore and improve the production of gas wells. The mechanism of reservoir plug removal is as Figure 10 shown Figure 10 and is a schematic diagram of the reservoir plug removal effect in this specification.

[0147] Taking into account the static and dynamic characteristics of gas wells, combining the main factors causing low production and the low-production mechanism, to identify the types of low-efficiency gas wells. The target gas wells conform to the characteristics of three types of gas wells, that is, the target gas wells are indeed of the gas well blockage type.

[0148] Based on Figure 1 the classification method of low-production and low-efficiency gas wells shown, first obtain the historical production data of multiple low-production and low-efficiency gas wells including historical pressure data and historical production data, then analyze the historical production data to determine the changing rules of the historical production characteristics of each low-production and low-efficiency gas well, so as to classify each low-production and low-efficiency gas well and determine its low-production and low-efficiency type. Finally, the classification of each low-production and low-efficiency gas well can be used as a benchmark to classify the low-production and low-efficiency gas wells to be classified.

[0149] The present invention analyzes the changing rules of production characteristics of low-production and low-efficiency gas wells based on their historical production data, and classifies the low-production and low-efficiency types of each low-production and low-efficiency gas well based on the low-production and low-efficiency mechanism of low-production and low-efficiency gas wells. Since low-production and low-efficiency gas wells of the same low-production and low-efficiency type often show the same changing rules of production characteristics, it is possible to classify the low-production and low-efficiency types of unclassified low-production and low-efficiency gas wells based on the pressure data and production data of unclassified low-production and low-efficiency gas wells, so as to facilitate subsequent targeted rehabilitation measures for low-production and low-efficiency gas wells.

[0150] The present invention fully considers the main factors causing low production and the low-production mechanism, compares and references the production images and production characteristics studied, and can preliminarily classify some low-production gas wells, so as to carry out targeted production-increasing transformation measures.

[0151] When applying the classification method of low-production and low-efficiency gas wells provided in this specification, it is not necessary to execute according to the Figure 1 sequence of each step shown. The specific execution sequence of each step can be determined according to needs, and this specification does not limit this.

[0152] The above is the classification method of low-production and low-efficiency gas wells provided by one or more embodiments of this specification. Based on the same idea, this specification also provides a corresponding classification device for low-production and low-efficiency gas wells, as Figure 11 shown.

[0153] Figure 11Schematic diagram of a classification device for low - production and low - efficiency gas wells provided in this specification, including:

[0154] An acquisition module 201, configured to acquire historical pressure data and historical production data of multiple low - production and low - efficiency gas wells, and calculate the production decline rate according to the historical production data;

[0155] A pre - classification module 202, configured to respectively determine the variation laws of the historical pressure data and the production decline rate of each low - production and low - efficiency gas well as the production characteristic variation laws;

[0156] An analysis module 203, configured to analyze the low - production and low - efficiency mechanisms of each low - production and low - efficiency gas well to determine the low - production and low - efficiency types of each low - production and low - efficiency gas well; among them, the low - production and low - efficiency gas wells with the same low - production and low - efficiency type present the same production characteristic variation laws;

[0157] A classification module 204, configured to acquire the pressure data and production data during the production process of the low - production and low - efficiency gas well to be classified, and analyze the variation laws of the pressure data and the production data to determine the low - production and low - efficiency type of the low - production and low - efficiency gas well to be classified.

[0158] Optionally, the calculation module 202 takes time as the abscissa and historical production data as the ordinate to draw a production scatter plot of typical low - production and low - efficiency gas wells;

[0159] Perform polynomial curve fitting according to the production scatter plot, and the form of the polynomial curve is:

[0160] y = A + B1X + B2X 2 + B3X 3

[0161] Calculate the production decline rate through the following formula according to the obtained fitting curve:

[0162]

[0163] where A, B1, B2, and B3 are curve coefficients, D is the instantaneous production decline rate, D i is the initial decline rate at the beginning of production, t is the exploitation time in the production decline stage, and Q is the production of a typical low - production and low - efficiency gas well within the exploitation time t in the production decline stage.

[0164] Optionally, the pre-classification module 202 determines the production characteristic change rules of Class I gas wells for low-yield and low-efficiency gas wells with a linearly decreasing production rate, determines the production characteristic change rules of Class II gas wells for low-yield and low-efficiency gas wells with a two-stage decreasing trend where the pressure drop rate in the initial production stage is greater than that in the later production stage and has a low-pressure stable production stage, determines the production characteristic change rules of Class III gas wells for low-yield and low-efficiency gas wells where the production rate shows an increasing trend in the initial production stage, gradually tends to be stable, and shows a decreasing trend in the middle production stage, determines the production characteristic change rules of Class IV gas wells for low-yield and low-efficiency gas wells where the production rate shows an increasing trend in the initial production stage, a decreasing trend in the middle production stage and the production pressure differential change amplitude is greater than the preset upper threshold value, and shows a stable production trend in the later production stage, determines the production characteristic change rules of Class V gas wells for low-yield and low-efficiency gas wells where the production rate in the initial production stage and the later production stage is less than that in the middle production stage, and the water production volume during the production period is less than the production rate, and determines the production characteristic change rules of Class VI gas wells for low-yield and low-efficiency gas wells where water is produced in the initial production stage, and after water production, the production rate shows a decreasing trend and the production pressure differential change amplitude is less than the preset lower threshold value.

[0165] Optionally, for the analysis module 203, as the production of Class I gas wells continues to deepen, the recovery degree gradually increases, the formation energy deficit occurs, the formation pressure decreases, the remaining movable reserves are small, and the production capacity is exhausted, resulting in low production or shutdown of the gas wells. For Class II gas wells, as the production time increases, the sulfur blockage area of the gas wells gradually expands to the formation outside the wellbore, the formation pressure gradually decreases, the solubility of elemental sulfur in natural gas decreases and precipitates, and adheres to the gas transmission equipment to cause sulfur deposition blockage, resulting in low production or shutdown of the gas wells. For Class III gas wells, as the production time increases, the combined action of corrosion inhibitor cracking residues, pipe string corrosion and scaling products, and various well-injected agents in the gas well produced fluid causes blockage and throttling of the gas well wellbore, resulting in low production or shutdown of the gas wells. For Class IV gas wells, affected by reservoir geological factors, wellbore conditions and production factors, wellbore failure problems occur, resulting in low production or shutdown of the gas wells. For Class V gas wells, in the middle and later production stages, one or more of the phenomena such as scaling, water lock, water blockage and reservoir damage occur, resulting in low production or shutdown of the gas wells. For Class VI gas wells, during the production process, the gas flow cannot effectively discharge the external water, causing wellbore liquid accumulation, the bottom hole backpressure on the formation continuously rises, resulting in continuous increase of the formation liquid accumulation volume, continuous expansion of the liquid accumulation range, continuous increase of the formation water saturation, and decrease of the gas-phase permeability, blocking the channels for natural gas production in the formation pores, resulting in reservoir water blockage and low production or shutdown of the gas wells.

[0166] Optionally, the analysis module 203 determines Class I gas wells as the type of gas well reservoir energy exhaustion, determines Class II gas wells as the type of gas well sulfur content, determines Class III gas wells as the type of gas well blockage, determines Class IV gas wells as the type of gas well wellbore failure, determines Class V gas wells as the type of reservoir water lock, and determines Class VI gas wells as the type of gas well liquid accumulation.

[0167] For the specific limitations of the classification device for low - production and low - efficiency gas wells, reference can be made to the limitations of the classification method for low - production and low - efficiency gas wells in the above text, which will not be elaborated here. Each module in the above - mentioned classification device for low - production and low - efficiency gas wells can be implemented in whole or in part by software, hardware, or a combination thereof. The above - mentioned modules can be embedded in the processor of the computer device in hardware form or be independent of it, or can be stored in the memory of the computer device in software form, so as to facilitate the processor to call and execute the operations corresponding to each of the above - mentioned modules.

[0168] This specification also provides a computer - readable storage medium, which stores a computer program that can be used to execute the above - mentioned Figure 1 classification method for low - production and low - efficiency gas wells.

[0169] This specification also provides Figure 12 the structural schematic diagram of the computer device shown in, as Figure 12 described, at the hardware level, this computer device includes a processor, an internal bus, a network interface, a memory, and a non - volatile memory. Of course, it may also include other hardware required for other services. The processor reads the corresponding computer program from the non - volatile memory into the memory and then runs it to implement the above - mentioned Figure 1 classification method for low - production and low - efficiency gas wells.

[0170] Those of ordinary skill in the art can understand that all or part of the processes in the above - mentioned method embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non - volatile computer - readable storage medium. When the computer program is executed, it can include the processes of the above - mentioned method embodiments. Among them, any reference to the memory, storage, database, or other media used in the various embodiments provided in this application can include at least one of non - volatile and volatile memories. Non - volatile memory can include read - only memory (ROM), magnetic tape, floppy disk, flash memory, or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0171] The technical features of the above - mentioned embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above - mentioned embodiments are described. However, as long as these combinations of technical features do not conflict, they should be considered as the scope described in this specification.

Claims

1. A classification method for low-yield and low-efficiency gas wells, characterized in that, Including: Obtain the historical pressure data and historical production data of multiple low - yield and low - efficiency gas wells, and calculate the production decline rate according to the historical production data; Respectively determine the variation laws of the historical pressure data and production decline rate of each low - yield and low - efficiency gas well as the production characteristic variation laws; Analyze the low - yield and low - efficiency mechanisms of each low - yield and low - efficiency gas well to determine the low - yield and low - efficiency types of each low - yield and low - efficiency gas well; among them, the low - yield and low - efficiency gas wells with the same low - yield and low - efficiency type present the same production characteristic variation laws; Obtain the pressure data and production data of the low - yield and low - efficiency gas well to be classified during the production process, and analyze the variation laws of the pressure data and production data to determine the low - yield and low - efficiency type of the low - yield and low - efficiency gas well to be classified.

2. The classification method for low-production and low-efficiency gas wells according to claim 1, wherein The calculation of the production decline rate according to the historical production data specifically includes: Taking time as the abscissa and historical production data as the ordinate, draw the production scatter plot of the low - yield and low - efficiency gas well; Perform polynomial curve fitting according to the production scatter plot, and the form of the polynomial curve is: y = A + B1X + B2X 2 + B3X 3 ; Calculate the decline rate D through the following formula according to the obtained fitting curve: Among them, A, B1, B2, and B3 are curve coefficients, D is the instantaneous production decline rate, D i is the initial decline rate at the initial stage of production, t is the production time in the production decline stage, and Q is the production of low-production and low-efficiency gas wells within the production time t in the production decline stage.

3. The classification method for low-yield and low-efficiency gas wells according to claim 1, characterized in that, The respective determination of the variation laws of the historical pressure data and production decline rate of each low - yield and low - efficiency gas well as the production characteristic variation laws specifically includes: Determine the production characteristic variation law of a type of gas well for the low - yield and low - efficiency gas well with a linearly decreasing production; Determine the production characteristic variation law of a type - two gas well for the low - yield and low - efficiency gas well with a two - stage decreasing trend where the pressure decline rate in the initial production stage is greater than that in the later production stage and there is a low - pressure stable production stage; Determine the production characteristic variation law of a type - three gas well for the low - yield and low - efficiency gas well where the production shows an increasing trend in the initial production stage, gradually tends to be stable, and shows a decreasing trend in the middle production stage; Determine the production characteristic variation law of a type - four gas well for the low - yield and low - efficiency gas well where the production shows an increasing trend in the initial production stage, a decreasing trend in the middle production stage and the production pressure difference change amplitude is greater than the preset upper threshold value, and shows a stable production trend in the later production stage; Determine the production characteristic variation law of a type - five gas well for the low - yield and low - efficiency gas well where the production in the initial production stage and the later production stage is less than that in the middle production stage, and the produced water volume during the production period is less than the production volume; Determine the production characteristic variation law of a type - six gas well for the low - yield and low - efficiency gas well that produces water in the initial production stage, and the production shows a decreasing trend after water production and the production pressure difference change amplitude is less than the preset lower threshold value.

4. The classification method for low-yield and low-efficiency gas wells according to claim 3, characterized in that The analysis of the low - yield and low - efficiency mechanisms of each low - yield and low - efficiency gas well specifically includes: For a type - one gas well, with the continuous progress of production, the recovery degree gradually increases, the formation energy deficit occurs, the formation pressure decreases, the remaining movable reserves are small, and the production capacity is exhausted, resulting in low production or shutdown of the gas well; For a type - two gas well, with the increase of production time, the sulfur - plugging area of the gas well gradually expands to the formation outside the wellbore, the formation pressure gradually decreases, the solubility of elemental sulfur in natural gas decreases and precipitates, and adheres to the gas - transmission equipment to cause sulfur deposition blockage, resulting in low production or shutdown of the gas well; For a type - three gas well, with the increase of production time, the combined action of corrosion inhibitor cracking residues, pipe string corrosion and scaling products, and various well - entering agents in the gas well output liquid causes blockage and throttling of the gas well wellbore, resulting in low production or shutdown of the gas well; Four types of gas wells are affected by reservoir geological factors, wellbore conditions and production factors, resulting in wellbore failure problems, leading to low production or shutdown of gas wells; In the middle and late stages of production, five types of gas wells have one or more of the phenomena of scaling, water blockage, water plugging and reservoir damage, resulting in low production or shutdown of gas wells; In the production process of six types of gas wells, the gas flow cannot effectively discharge the external water, causing liquid accumulation in the wellbore. The bottom hole backpressure on the formation continuously rises, resulting in an increasing liquid accumulation volume, an expanding liquid accumulation range, an increasing formation water saturation, a decrease in gas phase permeability, and blocking the channels for natural gas production in the formation pores, resulting in reservoir water plugging and leading to low production or shutdown of gas wells.

5. The classification method of low-yield and low-efficiency gas wells according to claim 1, characterized in that, The determination of the low-production and low-efficiency types of each low-production and low-efficiency gas well specifically includes: Determine the first type of gas well as the type of gas well with depleted reservoir energy; determine the second type of gas well as the sulfur-containing type of gas well; determine the third type of gas well as the blocked type of gas well; determine the fourth type of gas well as the wellbore failure type of gas well; determine the fifth type of gas well as the reservoir water blockage type; determine the sixth type of gas well as the gas well liquid accumulation type.

6. A classification device for low-yield and low-efficiency gas wells, characterized in that, Including: An acquisition module for acquiring the historical pressure data and historical production data of multiple low-production and low-efficiency gas wells, and calculating the production decline rate according to the historical production data; A pre-classification module for respectively determining the change rules of the historical pressure data and production decline rate of each low-production and low-efficiency gas well as the change rules of production characteristics; An analysis module for analyzing the low-production and low-efficiency mechanisms of each low-production and low-efficiency gas well to determine the low-production and low-efficiency types of each low-production and low-efficiency gas well; among them, the low-production and low-efficiency gas wells with the same low-production and low-efficiency type show the same change rules of production characteristics; A classification module for acquiring the pressure data and production data during the production process of the low-production and low-efficiency gas well to be classified, and analyzing the change rules of the pressure data and production data to determine the low-production and low-efficiency type of the low-production and low-efficiency gas well to be classified.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described in any one of claims 1 to 5 above is implemented.

8. A computer device, characterized in that, Including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the method described in any one of claims 1 to 5 above is implemented.

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