Maximum liquid carrying capacity prediction method and device based on coal-bed gas well

Abstract

The invention provides a maximum liquid carrying capacity prediction method and device based on a coal-bed gas well. The maximum liquid carrying capacity prediction method comprises the following steps: determining bottom hole pressure data and bottom hole temperature data according to the maximum liquid carrying capacity of a gas-liquid mixture; determining bottom hole data according to the bottom hole pressure data and the bottom hole temperature data; determining liquid film gas core momentum data according to the maximum liquid carrying amount and the well bottom data; adjusting the maximum liquid carrying amount according to a comparison result of the liquid film gas core momentum data and a preset momentum threshold until a momentum comparison result meets a momentum preset requirement; and determining the maximum liquid carrying amount as a target maximum liquid carrying amount. The method can assist in judgment of the well bottom liquid accumulation problem, and continuity and stability of gas well production are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of coalbed methane extraction, and in particular, to a method and device for predicting the maximum liquid-carrying capacity based on coalbed methane wells. Background Art

[0002] Deep coalbed methane has a high gas saturation, high gas content and is rich in free gas. After fracturing and transformation of some wells, they can rely on their own formation energy for self-flowing production, while the problem of bottom-hole liquid accumulation has gradually become the main problem affecting the production and productivity of self-flowing production gas wells. The bottom-hole liquid accumulation generated during the production process of deep coalbed methane wells mainly comes from formation-produced water. When the gas production of a deep coalbed methane well is higher than the minimum liquid-carrying capacity, the water entering the bottom hole from the formation will be carried out to the wellhead; when the water production is large and the gas volume is not enough to carry more water, it may cause bottom-hole liquid accumulation, which will further affect the inflow dynamics and production dynamics of coalbed methane from the reservoir to the well. Even if a small amount of liquid accumulation is generated, it will have a relatively large impact on the gas well production. If the bottom-hole liquid accumulation is not continuously controlled, it will cause waterlogging of the gas well, thus killing the gas well and making it impossible to produce. Therefore, it is necessary to obtain accurate bottom-hole pressure data and accurately judge the liquid accumulation situation in a timely manner, so as to adjust the production system and take necessary liquid drainage measures.

[0003] At present, for obtaining the bottom-hole pressure of gas wells and diagnosing downhole liquid accumulation, mainly the flowing pressure test method, the echo sounder method for detecting the liquid level, the casing-tubing pressure difference method and the critical liquid-carrying flow rate method are used. The development of deep coalbed methane wells is mainly horizontal wells, and mainly uses annulus self-flowing production between the casing and tubing and tubing self-flowing production.

[0004] The existing technologies have the following problems:

[0005] ① The flowing pressure test method is not applicable to highly deviated horizontal wells. The downhole pressure gauge cannot be lowered to the specified depth, so it is impossible to accurately obtain the bottom-hole pressure and liquid accumulation situation. Moreover, due to problems such as downhole corrosion and scaling, the downhole pressure gauge cannot be monitored for a long time.

[0006] ② The echo sounder method for detecting the liquid level cannot be applied to annulus self-flowing production between the casing and tubing, and it is also impossible to detect an effective liquid level during foam drainage assistance. The on-site application error is large.

[0007] ③ The casing-tubing pressure difference method judges whether there is liquid accumulation through the casing-tubing pressure data, mainly based on experience, and the accuracy is low.

[0008] ④ There are many calculation models for the critical liquid-carrying flow rate method, and the results vary greatly. It is difficult to select a model. The Turner model currently selected by the company has a large on-site application error and low accuracy. Summary of the Invention

[0009] The main purpose of the embodiments of the present invention is to provide a method and device for predicting the maximum liquid-carrying capacity based on coalbed methane wells, so as to assist in judging the problem of bottom-hole liquid accumulation through the maximum liquid-carrying capacity and ensure the continuity and stability of gas well production.

[0010] To achieve the above object, the embodiments of the present invention provide a method for predicting the maximum liquid-carrying capacity based on coalbed methane wells, including:

[0011] Determine the bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture;

[0012] Determine the bottom-hole data according to the bottom-hole pressure data and the bottom-hole temperature data;

[0013] Determine the liquid film-gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data;

[0014] Adjust the maximum liquid-carrying capacity according to the comparison result between the liquid film-gas core momentum data and a preset momentum threshold until the momentum comparison result meets the preset momentum requirement;

[0015] Determine the maximum liquid-carrying capacity as the target maximum liquid-carrying capacity.

[0016] In one of the embodiments, the bottom-hole data includes liquid-phase parameters, gas-phase parameters, and gas-water geometric parameters;

[0017] Determining the liquid film-gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data includes:

[0018] Determine the thickness of the annular flow liquid film according to the maximum liquid-carrying capacity, the liquid-phase parameters, and the gas-phase parameters;

[0019] Determine the gas-water surface tension according to the thickness of the annular flow liquid film;

[0020] Determine the liquid film-gas core momentum data according to the gas-water surface tension, the gas-water geometric parameters, the liquid-phase density in the liquid-phase parameters, and the maximum liquid-carrying capacity.

[0021] In one of the embodiments, determining the gas-water surface tension according to the thickness of the annular flow liquid film includes:

[0022] Determine the dimensionless interfacial shear coefficient according to the thickness of the annular flow liquid film, the liquid-phase density, and the gas-phase density in the gas-phase parameters;

[0023] Determine the gas-water surface tension according to the dimensionless interfacial shear coefficient, the gas-water flow velocity, and the liquid-phase flow velocity.

[0024] In one of the embodiments, determining the gas-water surface tension according to the dimensionless interfacial shear coefficient, the gas-water flow velocity, and the liquid-phase flow velocity includes:

[0025] Determine the gas-water friction coefficient based on the dimensionless interfacial shear coefficient, gas-water flow velocity, and liquid-phase flow velocity;

[0026] Determine the gas-water surface tension based on the gas-water friction coefficient, the gas-water flow velocity, the liquid-phase density, and the gas-core region density.

[0027] In one embodiment, determining the bottom-hole pressure data and the bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture includes:

[0028] Determine the first natural gas deviation coefficient according to the initial bottom-hole pressure and the initial bottom-hole temperature;

[0029] Determine the first bottom-hole pressure according to the first natural gas deviation coefficient, the maximum liquid-carrying capacity, and the initial bottom-hole temperature;

[0030] Determine the bottom-hole temperature according to the specific heat capacity, the initial bottom-hole temperature, and the bottom-hole pressure;

[0031] Determine the second bottom-hole pressure according to the maximum liquid-carrying capacity, the bottom-hole temperature, and the first bottom-hole pressure;

[0032] Determine the bottom-hole pressure data and the bottom-hole temperature data according to the comparison result between the first bottom-hole pressure and the second bottom-hole pressure.

[0033] In one embodiment, determining the first bottom-hole pressure according to the first natural gas deviation coefficient, the maximum liquid-carrying capacity, and the initial bottom-hole temperature includes:

[0034] Determine the intermediate bottom-hole pressure according to the first natural gas deviation coefficient and the maximum liquid-carrying capacity;

[0035] Adjust the initial bottom-hole pressure according to the comparison result between the intermediate bottom-hole pressure and the initial bottom-hole pressure until the pressure comparison result meets the pressure preset requirement.

[0036] In one embodiment, determining the bottom-hole temperature according to the specific heat capacity, the initial bottom-hole temperature, and the bottom-hole pressure includes:

[0037] Determine the intermediate bottom-hole temperature according to the specific heat capacity and the bottom-hole pressure;

[0038] Adjust the initial bottom-hole temperature according to the comparison result between the intermediate bottom-hole temperature and the initial bottom-hole temperature until the temperature comparison result meets the temperature preset requirement.

[0039] An embodiment of the present invention further provides a maximum liquid-carrying capacity prediction device based on a coalbed methane well, including:

[0040] A bottom-hole pressure and temperature module, configured to determine bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture;

[0041] A bottom-hole data determination module, configured to determine bottom-hole data according to the bottom-hole pressure data and the bottom-hole temperature data;

[0042] A liquid film and gas core momentum data module, configured to determine liquid film and gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data;

[0043] A maximum liquid-carrying capacity adjustment module, configured to adjust the maximum liquid-carrying capacity according to the comparison result between the liquid film and gas core momentum data and a preset momentum threshold until the momentum comparison result meets the preset momentum requirement;

[0044] A target maximum liquid-carrying capacity module, configured to determine the maximum liquid-carrying capacity as the target maximum liquid-carrying capacity.

[0045] In one embodiment, the bottom-hole data includes liquid-phase parameters, gas-phase parameters, and gas-water geometric parameters;

[0046] The liquid film and gas core momentum data module includes:

[0047] An annular flow liquid film thickness unit, configured to determine the annular flow liquid film thickness according to the maximum liquid-carrying capacity, the liquid-phase parameters, and the gas-phase parameters;

[0048] A gas-water surface tension unit, configured to determine the gas-water surface tension according to the annular flow liquid film thickness;

[0049] A liquid film and gas core momentum data unit, configured to determine the liquid film and gas core momentum data according to the gas-water surface tension, the gas-water geometric parameters, the liquid-phase density in the liquid-phase parameters, and the maximum liquid-carrying capacity.

[0050] In one embodiment, the gas-water surface tension unit includes:

[0051] A dimensionless interfacial shear coefficient sub-unit, configured to determine the dimensionless interfacial shear coefficient according to the annular flow liquid film thickness, the liquid-phase density, and the gas-phase density in the gas-phase parameters;

[0052] A gas-water surface tension sub-unit, configured to determine the gas-water surface tension according to the dimensionless interfacial shear coefficient, the gas-water flow velocity, and the liquid-phase flow velocity.

[0053] In one embodiment, the gas-water surface tension sub-unit is specifically configured to:

[0054] Determine the gas-water friction coefficient according to the dimensionless interfacial shear coefficient, the gas-water flow velocity, and the liquid-phase flow velocity;

[0055] Determine the gas-water surface tension according to the gas-water friction coefficient, the gas-water flow velocity, the liquid-phase density, and the gas core region density.

[0056] In one embodiment, the bottom-hole pressure and temperature module includes:

[0057] A first natural gas deviation coefficient unit, configured to determine a first natural gas deviation coefficient according to the initial bottom-hole pressure and the initial bottom-hole temperature;

[0058] A first bottom-hole pressure unit, configured to determine a first bottom-hole pressure according to the first natural gas deviation coefficient, the maximum liquid-carrying capacity, and the initial bottom-hole temperature;

[0059] A bottom-hole temperature unit, configured to determine the bottom-hole temperature according to the specific heat capacity, the initial bottom-hole temperature, and the bottom-hole pressure;

[0060] A second bottom-hole pressure unit, configured to determine a second bottom-hole pressure according to the maximum liquid-carrying capacity, the bottom-hole temperature, and the first bottom-hole pressure;

[0061] A bottom-hole pressure and temperature unit, configured to determine the bottom-hole pressure data and the bottom-hole temperature data according to the comparison result between the first bottom-hole pressure and the second bottom-hole pressure.

[0062] In one embodiment, the first bottom-hole pressure unit includes:

[0063] A bottom-hole pressure intermediate quantum unit, configured to determine a bottom-hole pressure intermediate quantity according to the first natural gas deviation coefficient and the maximum liquid-carrying capacity;

[0064] A bottom-hole pressure adjustment sub-unit, configured to adjust the initial bottom-hole pressure according to the comparison result between the bottom-hole pressure intermediate quantity and the initial bottom-hole pressure until the pressure comparison result meets the pressure preset requirement.

[0065] In one embodiment, the bottom-hole temperature unit includes:

[0066] A bottom-hole temperature intermediate quantum unit, configured to determine a bottom-hole temperature intermediate quantity according to the specific heat capacity and the bottom-hole pressure;

[0067] A bottom-hole temperature adjustment sub-unit, configured to adjust the initial bottom-hole temperature according to the comparison result between the bottom-hole temperature intermediate quantity and the initial bottom-hole temperature until the temperature comparison result meets the temperature preset requirement.

[0068] An embodiment of the present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and running on the processor. When the processor executes the computer program, the steps of the maximum liquid-carrying capacity prediction method based on coalbed methane wells are implemented.

[0069] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the maximum liquid-carrying capacity prediction method based on coalbed methane wells are implemented.

[0070] An embodiment of the present invention also provides a computer program product, including a computer program / instructions, and when the computer program / instructions are executed by a processor, the steps of the above-mentioned method for predicting the maximum liquid-carrying capacity based on a coalbed methane well are implemented.

[0071] The method and device for predicting the maximum liquid-carrying capacity based on a coalbed methane well according to the embodiment of the present invention determine bottom-hole pressure data and bottom-hole temperature data based on the maximum liquid-carrying capacity of the gas-liquid mixture to determine bottom-hole data, and determine liquid film and gas core momentum data based on the bottom-hole data to predict the maximum liquid-carrying capacity, which can assist in the judgment of the bottom-hole liquid accumulation problem and ensure the continuity and stability of gas well production. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0073] Figure 1 is a schematic diagram of the method for predicting the maximum liquid-carrying capacity based on a coalbed methane well in an embodiment of the present invention;

[0074] Figure 2 is a schematic diagram of the method for predicting the maximum liquid-carrying capacity based on a coalbed methane well in another embodiment of the present invention;

[0075] Figure 3 is a flowchart of S101 in an embodiment of the present invention;

[0076] Figure 4 is a flowchart of determining bottom-hole pressure data and bottom-hole temperature data in another embodiment of the present invention;

[0077] Figure 5 is a flowchart of S202 in an embodiment of the present invention;

[0078] Figure 6 is a flowchart of S203 in an embodiment of the present invention;

[0079] Figure 7 is a flowchart of S103 in an embodiment of the present invention;

[0080] Figure 8 is a flowchart of S502 in an embodiment of the present invention;

[0081] Figure 9 is a flowchart of S602 in an embodiment of the present invention;

[0082] Figure 10 is a graph of the pressure verification result corresponding to Table 1;

[0083] Figure 11 is the structural block diagram of the maximum liquid-carrying capacity prediction device based on coalbed methane wells in the embodiments of the present invention;

[0084] Figure 12 is the schematic block diagram of the system composition of the electronic device 9600 in the embodiments of the present application. Detailed implementation manners

[0085] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0086] Those skilled in the art know that the implementation manners of the present invention can be realized as a system, a device, a device, a method, or a computer program product. Therefore, the present disclosure can be specifically realized in the following forms, namely: complete hardware, complete software (including firmware, resident software, microcode, etc.), or a combination of hardware and software.

[0087] The present invention takes into account the gas-liquid two-phase flow in the wellbore in the calculation of temperature and pressure, constructs a two-layer cyclic iterative verification of the bottom-hole pressure, makes the predicted bottom-hole pressure more accurate, and thus makes the calculation of the maximum liquid-carrying capacity more precise. The maximum liquid-carrying capacity of coalbed methane wells restricts the water production of gas wells, assists in judging the bottom-hole liquid accumulation problem based on the gas production of gas wells, solves the deviation in judging the bottom-hole liquid accumulation only by using the gas production in the prior art, can adjust the drainage and production system of gas wells earlier, eliminate production failures, and ensure the continuity and stability of gas well production. The following provides a detailed description of the present invention in conjunction with the accompanying drawings.

[0088] Figure 1 is the schematic diagram of the maximum liquid-carrying capacity prediction method based on coalbed methane wells in the embodiments of the present invention. Figure 2 is the schematic diagram of the maximum liquid-carrying capacity prediction method based on coalbed methane wells in another embodiment of the present invention. As Figure 1 - Figure 2 shown, the maximum liquid-carrying capacity prediction method based on coalbed methane wells includes:

[0089] S101: Determine the bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture.

[0090] Figure 3 is the flowchart of S101 in the embodiments of the present invention. Figure 4 is the flowchart of determining the bottom-hole pressure data and bottom-hole temperature data in another embodiment of the present invention. As Figure 3 - Figure 4 shown, S101 includes:

[0091] S201: Determine the first natural gas deviation factor based on the initial bottom-hole pressure and the initial bottom-hole temperature.

[0092] In one embodiment, the calculation formula for the natural gas deviation factor is as follows:

[0093]

[0094]

[0095] T pr = T0 / T lj ;

[0096] where Z jd1 is the first natural gas deviation factor, P pr is the pseudo-reduced pressure, t is the reciprocal of the pseudo-reduced temperature T pr , and y is the iteration parameter. P 0 is the initial bottom-hole pressure, T 0 is the initial bottom-hole temperature, P lj is the critical pressure of the gas well product, T lj is the critical temperature of the gas well product, P lj and T lj need to be determined by analyzing the natural gas composition.

[0097] After iteratively solving for y, the natural gas deviation factor can be calculated. y is solved using the Newton iteration method format:

[0098]

[0099] where k is the number of iterations.

[0100] S202: Determine the first bottom-hole pressure based on the first natural gas deviation factor, the maximum liquid-carrying capacity, and the initial bottom-hole temperature.

[0101] Figure 5 is the flowchart of S202 in the embodiment of the present invention. As Figure 5 shown, S202 includes:

[0102] S301: Determine the intermediate bottom-hole pressure based on the first natural gas deviation factor and the maximum liquid-carrying capacity.

[0103] In one embodiment, the intermediate bottom-hole pressure obtained through the bottom-hole pressure calculation formula is as follows:

[0104]

[0105]

[0106]

[0107]

[0108]

[0109] Among them, P jd is the intermediate quantity of bottom-hole pressure, P 1 is the wellhead pressure, S sz is the dimensionless calculation parameter of the vertical well section, S xq is the dimensionless calculation parameter of the down-dip / horizontal section, θ sz is the correction coefficient related to flow in the vertical section, θ sp is the correction coefficient related to flow in the down-dip / horizontal section, Q is the flow rate of the gas-liquid mixture. The flow rate, density and velocity of the gas-liquid mixture all depend on the maximum liquid-carrying capacity of the gas-liquid mixture.

[0110] γ g is the relative density of the gas phase, ρ m,jt为 is the density of the gas-liquid mixture under the average temperature and pressure of the wellbore, ρ m,sp is the density of the mixture under the average temperature and pressure of the horizontal section, H is the vertical depth at the end of the coalbed methane well, H yg is the depth of the tubing run after the vertical section, Z jt is the gas deviation coefficient of natural gas under the average temperature and pressure of the wellbore, T jt is the temperature under the average temperature and pressure of the wellbore, Z sp is the gas deviation coefficient of natural gas under the average temperature and pressure of the horizontal section, T sp is the temperature under the average temperature and pressure of the horizontal section, λ jt is the flow resistance coefficient under the average temperature and pressure of the wellbore, λ sp is the flow resistance coefficient under the average temperature and pressure of the horizontal section, d is the production pipe diameter, L is the length of the down-dip / horizontal section. Among them, the bottom hole includes the wellbore stage, the horizontal stage and the down-dip stage. Therefore, the first gas deviation coefficient (the first bottom-hole gas deviation coefficient) includes the gas deviation coefficient under the average temperature and pressure of the wellbore and the gas deviation coefficient under the average temperature and pressure of the horizontal section. The bottom-hole temperature includes the temperature under the average temperature and pressure of the wellbore and the temperature under the average temperature and pressure of the horizontal section. In the first iteration, the bottom-hole temperature is the initial bottom-hole temperature.

[0111] S302: Adjust the initial bottom-hole pressure according to the comparison result between the intermediate quantity of bottom-hole pressure and the initial bottom-hole pressure until the pressure comparison result meets the pressure preset requirement.

[0112] Specifically, as Figure 4 shown, calculate (P jd -P 0 ) / P 0Is it less than the specified error value? When the requirement is not met, replace the initial bottom-hole pressure with the intermediate bottom-hole pressure. Otherwise, use the intermediate bottom-hole pressure less than the specified error value as the first bottom-hole pressure.

[0113] S203: Determine the bottom-hole temperature according to the specific heat capacity, the initial bottom-hole temperature, and the bottom-hole pressure.

[0114] Figure 6 It is the flowchart of S203 in the embodiment of the present invention. As Figure 6 shown, S203 includes:

[0115] S401: Determine the intermediate bottom-hole temperature according to the specific heat capacity and the bottom-hole pressure.

[0116] In specific implementation, the intermediate bottom-hole temperature is as follows:

[0117] T jd = T sz + ΔT sp + g T H xq ;

[0118]

[0119]

[0120] C pi = B i + 2C i T + 3D i T 2 + 4E i T 3 + 5F i T 4 ;

[0121]

[0122]

[0123]

[0124] Among them, T jd is the intermediate bottom-hole temperature, T sz is the temperature at the bottom end of the vertical section, ΔT sp is the temperature difference between the two ends of the down-dip / horizontal section, g T is the geothermal gradient, H xq is the vertical depth of the down-dip section, μ jt,sp is the Joule-Thomson coefficient under the average temperature and pressure of the down-dip / horizontal section, P sz is the pressure at the bottom end of the vertical section, P sp is the average pressure of the down-dip / horizontal section, αsp is the shape factor at the average temperature and pressure of the downward / inclined section, C pi is the specific heat capacity at constant pressure of the single-component gas i, B i , C i , D i , E i , F i are all calculation constants related to the pure components, x i is the mole fraction of component i, P is the bottom-hole pressure in the current iteration, T is the bottom-hole temperature in the current iteration, ρ is the density, R is the gas constant, A 0 , B 0 , C 0 , D 0 , E 0 , a, b, c, d, α, γ are all calculation coefficients obtained from the BWRS equation.

[0125] S402: Adjust the initial bottom-hole temperature according to the comparison result between the intermediate bottom-hole temperature and the initial bottom-hole temperature until the temperature comparison result meets the temperature preset requirement.

[0126] Specifically, as Figure 4 shown, calculate whether (T jd -T 0 ) / T 0 is less than the specified error value. When the requirement is not met, replace the initial bottom-hole temperature with the intermediate bottom-hole temperature; otherwise, use the intermediate bottom-hole temperature less than the specified error value as the bottom-hole temperature.

[0127] S204: Determine the second bottom-hole pressure according to the maximum liquid-carrying capacity, the bottom-hole temperature, and the first bottom-hole pressure.

[0128] Specifically, as Figure 4 shown, substitute the maximum liquid-carrying capacity, the bottom-hole temperature, and the first bottom-hole pressure into the natural gas deviation coefficient calculation formula and the bottom-hole pressure calculation formula to obtain the second bottom-hole pressure Pjd*.

[0129] S205: Determine the bottom-hole pressure data and the bottom-hole temperature data according to the comparison result between the first bottom-hole pressure and the second bottom-hole pressure.

[0130] Specifically, as Figure 4 shown, calculate whether (Pjd*-Pjd) / Pjd is less than the specified error value. When the requirement is not met, replace the initial bottom-hole pressure with the second bottom-hole pressure; otherwise, use the second bottom-hole pressure less than the specified error value as the bottom-hole pressure data and the bottom-hole temperature as the bottom-hole temperature data.

[0131] S102: Determine the bottom-hole data according to the bottom-hole pressure data and the bottom-hole temperature data.

[0132] Among them, the bottom-hole data includes liquid-phase parameters, gas-phase parameters, and gas-liquid geometric parameters.

[0133] S103: Determine the liquid film-gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data.

[0134] Figure 7 is the flowchart of S103 in the embodiment of the present invention. As Figure 7 shown, S103 includes:

[0135] S501: Determine the annular flow liquid film thickness according to the maximum liquid-carrying capacity, the liquid-phase parameters, and the gas-phase parameters.

[0136] During specific implementation, the determination formula for annular flow can be determined by the following formula, and the specific expression is:

[0137]

[0138] Among them, χ is the gas volume fraction, v gs is the superficial velocity of the gas, v m is the velocity of the gas-liquid mixture, which depends on the maximum liquid-carrying capacity; g is the acceleration due to gravity, σ L is the surface tension coefficient of the liquid phase, ρ L is the liquid-phase density, ρ g is the gas-phase density. The liquid-phase parameters include the surface tension coefficient and the liquid-phase density of the liquid phase, and the gas-phase parameters include the superficial velocity of the gas and the gas-phase density.

[0139] The liquid-phase surface tension coefficient is calculated according to the following formula:

[0140]

[0141] Among them, P′ is the bottom-hole pressure data in the current iteration, and T′ is the bottom-hole temperature data in the current iteration.

[0142] When the gas volume fraction obtained by actual measurement is greater than or equal to the gas volume fraction obtained by the above calculation, it can be considered that the actual flow pattern is annular flow or mist flow.

[0143] At this time, the liquid film thickness of the bottom-hole critical annular flow is calculated by the following formula:

[0144]

[0145] Among them, h F is the annular flow liquid film thickness, and d is the production pipe diameter.

[0146] When the calculated result is not annular flow and the flow pattern at the bottom of the coalbed methane well is slug flow or bubble flow, it indicates that the volume fraction of the liquid phase in the bottom-hole flow is large and there may be liquid accumulation at the bottom hole. Therefore, the liquid-carrying capacity at critical annular flow is used as the maximum liquid-carrying capacity for the production of coalbed methane wells. When the actual water production is greater than the maximum liquid-carrying capacity, liquid accumulation may have formed at the bottom hole.

[0147] S502: Determine the gas-liquid surface tension according to the thickness of the annular flow liquid film.

[0148] Figure 8 It is the flowchart of S502 in the embodiment of the present invention. As Figure 8 shown, S502 includes:

[0149] S601: Determine the dimensionless interfacial shear coefficient according to the thickness of the annular flow liquid film, the liquid phase density and the gas phase density in the gas phase parameters.

[0150] In one embodiment, the dimensionless interfacial shear coefficient is as follows:

[0151]

[0152] where I is the dimensionless interfacial shear coefficient.

[0153] S602: Determine the gas-liquid surface tension according to the dimensionless interfacial shear coefficient, the gas-water flow velocity and the liquid phase flow velocity.

[0154] Figure 9 It is the flowchart of S602 in the embodiment of the present invention. As Figure 9 shown, S602 includes:

[0155] S701: Determine the gas-water friction coefficient according to the dimensionless interfacial shear coefficient, the gas-water flow velocity and the liquid phase flow velocity.

[0156] Among them, the gas-water friction coefficient includes the liquid film interfacial friction coefficient and the gas core interfacial friction coefficient. In specific implementation, the friction coefficient is determined by the following formula:

[0157]

[0158] f i = f C I;

[0159]

[0160] where f F is the liquid film interfacial friction coefficient, f i is the gas core interfacial friction coefficient, d hF is the hydraulic diameter of the liquid film, d hF = 4h F (d - hF ) / d, v L is the liquid-phase flow rate, v F is the liquid film flow rate, v C is the gas core region flow rate. The gas-liquid flow rate includes the liquid film flow rate and the gas core region flow rate.

[0161] C F , n, C C , m are all calculation empirical coefficients related to the flow regime, and their values are determined by the flow regime, as follows:

[0162]

[0163] S702: Determine the gas-liquid surface tension according to the gas-liquid friction coefficient, the gas-liquid flow rate, the liquid-phase density and the gas core region density.

[0164] Among them, the gas-liquid surface tension includes the wall shear stress and the gas-liquid interface shear stress, as follows:

[0165]

[0166]

[0167] Among them, τ w is the wall shear stress, τ i is the gas-liquid interface shear stress, ρ C is the density of the gas-liquid mixture, which depends on the maximum liquid-carrying capacity of the gas-liquid mixture.

[0168] S503: Determine the liquid film-gas core momentum data according to the gas-liquid surface tension, the gas-liquid geometric parameters, the liquid-phase density in the liquid-phase parameters and the maximum liquid-carrying capacity.

[0169] During specific implementation, the liquid film-gas core momentum data is as follows:

[0170]

[0171] Among them, E is the liquid film-gas core momentum data, S w is the perimeter of the pipe string, S i is the perimeter of the liquid film, A C is the cross-sectional flow area of the gas core region, and A is the cross-sectional flow area of the liquid film region. Among them, the gas-liquid geometric parameters include the perimeter of the pipe string, the perimeter of the liquid film, the cross-sectional flow area of the gas core region and the cross-sectional flow area of the liquid film region.

[0172] S104: Adjust the maximum liquid-carrying capacity according to the comparison result between the liquid film-gas core momentum data and the preset momentum threshold until the momentum comparison result meets the momentum preset requirements.

[0173] Such as Figure 2As shown, when the absolute value of the liquid film-gas core momentum data is greater than the specified error value, it is determined whether the liquid film-gas core momentum data is greater than zero. When it is greater than zero, subtract a specific adjustment value from the maximum liquid-carrying capacity of the gas-liquid mixture. When it is less than zero, add a specific adjustment value to the maximum liquid-carrying capacity of the gas-liquid mixture, and perform iterative calculations again until the absolute value of the liquid film-gas core momentum data is less than the specified error value. At this time, execute S105.

[0174] S105: Determine the maximum liquid-carrying capacity as the target maximum liquid-carrying capacity.

[0175] Figure 1 The execution subject of the maximum liquid-carrying capacity prediction method based on coalbed methane wells shown can be a computer. Figure 1 As can be seen from the flow shown, the maximum liquid-carrying capacity prediction method based on coalbed methane wells in the embodiments of the present invention determines the bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture to determine the bottom-hole data, and determines the liquid film-gas core momentum data according to the bottom-hole data to predict the maximum liquid-carrying capacity, which can assist in the judgment of the bottom-hole liquid accumulation problem and ensure the continuity and stability of gas well production.

[0176] Table 1

[0177]

[0178] Table 1 is a schematic table of the water production and maximum liquid-carrying capacity of different liquid accumulation wells. Figure 10 is the pressure verification result diagram corresponding to Table 1. As shown in Table 1 and Figure 10 As shown, the temperature and pressure parameters of the deep coalbed methane well JS67-P1 in a certain area are selected to verify the bottom-hole temperature and pressure prediction model of coalbed methane wells constructed by the present invention. In the stable production stage, the bottom-hole flowing pressure predicted by the pressure prediction model established by the present invention is basically consistent with the bottom-hole flowing pressure actually measured in the production of this well, and the calculation error is within 15%. The reservoir temperature of this well is 65°C, and the bottom-hole temperature predicted by the temperature prediction model established by the present invention is 70°C, and the calculation error is within 10%. This shows that the prediction model established by the present invention has high accuracy.

[0179] As shown in Table 1, when the water production is greater than the maximum liquid-carrying capacity, the coalbed methane wells are all in the liquid accumulation state. When the coalbed methane well is in the liquid accumulation state, its water production must be greater than its maximum liquid-carrying capacity. Therefore, the maximum liquid-carrying capacity can be used as a necessary condition in the determination problem of coalbed methane well liquid accumulation, and combined with other gas well liquid accumulation determination methods to make a comprehensive determination of whether the gas well accumulates liquid during production. It reduces the determination deviation when only using gas production as the evaluation index for gas well liquid accumulation. The maximum liquid-carrying capacity can more accurately assist other gas well liquid accumulation determination methods, improve the reliability of gas well liquid accumulation determination, so that production failures can be discovered and investigated in time, adjust the drainage and production strategy, and ensure the stability and sustainability of coalbed methane production.

[0180] In summary, the present invention takes into account the gas-liquid two-phase flow in the wellbore in the calculation of temperature and pressure, constructs an iterative verification of two-stage pressure, makes the predicted bottom-hole pressure more accurate, and thus makes the calculation of the maximum liquid-carrying capacity more precise. The maximum liquid-carrying capacity of a coalbed methane well can assist in judging the bottom-hole liquid accumulation problem from the index of water production, so as to adjust the drainage and production system of the gas well and eliminate production faults earlier, ensuring the continuity and stability of gas well production.

[0181] Based on the same inventive concept, an embodiment of the present invention further provides a device for predicting the maximum liquid-carrying capacity of a coalbed methane well. Since the principle of solving problems by this device is similar to that of the method for predicting the maximum liquid-carrying capacity of a coalbed methane well, the implementation of this device can refer to the implementation of the method, and the repeated parts will not be elaborated.

[0182] Figure 11 It is a structural block diagram of the device for predicting the maximum liquid-carrying capacity of a coalbed methane well in an embodiment of the present invention. As Figure 11 shown, the device for predicting the maximum liquid-carrying capacity of a coalbed methane well includes:

[0183] Bottom-hole pressure and temperature module, configured to determine bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture;

[0184] Bottom-hole data determination module, configured to determine bottom-hole data according to the bottom-hole pressure data and the bottom-hole temperature data;

[0185] Liquid film and gas core momentum data module, configured to determine liquid film and gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data;

[0186] Maximum liquid-carrying capacity adjustment module, configured to adjust the maximum liquid-carrying capacity according to the comparison result between the liquid film and gas core momentum data and a preset momentum threshold until the momentum comparison result meets the preset momentum requirement;

[0187] Target maximum liquid-carrying capacity module, configured to determine the maximum liquid-carrying capacity as the target maximum liquid-carrying capacity.

[0188] In one embodiment, the bottom-hole data includes liquid-phase parameters, gas-phase parameters, and gas-water geometric parameters;

[0189] The liquid film and gas core momentum data module includes:

[0190] Annular flow liquid film thickness unit, configured to determine the annular flow liquid film thickness according to the maximum liquid-carrying capacity, the liquid-phase parameters, and the gas-phase parameters;

[0191] Gas-water surface tension unit, configured to determine the gas-water surface tension according to the annular flow liquid film thickness;

[0192] A liquid film and gas core momentum data unit for determining the liquid film and gas core momentum data based on the gas-water surface tension, the gas-water geometric parameters, the liquid phase density in the liquid phase parameters, and the maximum liquid carrying capacity.

[0193] In one embodiment, the gas-water surface tension unit includes:

[0194] A dimensionless interfacial shear coefficient sub-unit for determining a dimensionless interfacial shear coefficient based on the annular flow liquid film thickness, the liquid phase density, and the gas phase density in the gas phase parameters;

[0195] A gas-water surface tension sub-unit for determining the gas-water surface tension based on the dimensionless interfacial shear coefficient, the gas-water flow velocity, and the liquid phase flow velocity.

[0196] In one embodiment, the gas-water surface tension sub-unit is specifically configured to:

[0197] Determine a gas-water friction coefficient based on the dimensionless interfacial shear coefficient, the gas-water flow velocity, and the liquid phase flow velocity;

[0198] Determine the gas-water surface tension based on the gas-water friction coefficient, the gas-water flow velocity, the liquid phase density, and the gas core region density.

[0199] In one embodiment, the bottom hole pressure and temperature module includes:

[0200] A first natural gas deviation coefficient unit for determining a first natural gas deviation coefficient based on the initial bottom hole pressure and the initial bottom hole temperature;

[0201] A first bottom hole pressure unit for determining a first bottom hole pressure based on the first natural gas deviation coefficient, the maximum liquid carrying capacity, and the initial bottom hole temperature;

[0202] A bottom hole temperature unit for determining the bottom hole temperature based on the specific heat capacity, the initial bottom hole temperature, and the bottom hole pressure;

[0203] A second bottom hole pressure unit for determining a second bottom hole pressure based on the maximum liquid carrying capacity, the bottom hole temperature, and the first bottom hole pressure;

[0204] A bottom hole pressure and temperature unit for determining the bottom hole pressure data and the bottom hole temperature data based on the comparison result of the first bottom hole pressure and the second bottom hole pressure.

[0205] In one embodiment, the first bottom hole pressure unit includes:

[0206] A bottom hole pressure intermediate quantity sub-unit for determining a bottom hole pressure intermediate quantity based on the first natural gas deviation coefficient and the maximum liquid carrying capacity;

[0207] The bottom-hole pressure adjustment sub-unit is used to adjust the initial bottom-hole pressure according to the comparison result between the intermediate bottom-hole pressure and the initial bottom-hole pressure until the pressure comparison result meets the pressure preset requirement.

[0208] In one embodiment, the bottom-hole temperature unit includes:

[0209] The bottom-hole temperature intermediate quantity sub-unit is used to determine the bottom-hole temperature intermediate quantity according to the specific heat capacity and the bottom-hole pressure;

[0210] The bottom-hole temperature adjustment sub-unit is used to adjust the initial bottom-hole temperature according to the comparison result between the bottom-hole temperature intermediate quantity and the initial bottom-hole temperature until the temperature comparison result meets the temperature preset requirement.

[0211] In summary, the maximum liquid-carrying capacity prediction device based on a coalbed methane well according to the embodiments of the present invention determines the bottom-hole pressure data and the bottom-hole temperature data based on the maximum liquid-carrying capacity of the gas-liquid mixture to determine the bottom-hole data, and determines the liquid film and gas core momentum data based on the bottom-hole data to predict the maximum liquid-carrying capacity, which can assist in judging the problem of bottom-hole liquid accumulation and ensure the continuity and stability of gas well production.

[0212] Figure 12 It is a schematic block diagram of the system composition of the electronic device 9600 according to the embodiments of the present application. As Figure 12 shown, the electronic device 9600 may include a central processing unit 9100 and a memory 9140; the memory 9140 is coupled to the central processing unit 9100. It should be noted that this Figure 12 is exemplary; other types of structures can also be used to supplement or replace this structure to achieve telecommunication functions or other functions.

[0213] In one embodiment, the function of the maximum liquid-carrying capacity prediction method based on a coalbed methane well can be integrated into the central processing unit 9100. Among them, the central processing unit 9100 can be configured to perform the following controls:

[0214] Determine the bottom-hole pressure data and the bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture;

[0215] Determine the bottom-hole data according to the bottom-hole pressure data and the bottom-hole temperature data;

[0216] Determine the liquid film and gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data;

[0217] Adjust the maximum liquid-carrying capacity according to the comparison result between the liquid film and gas core momentum data and a preset momentum threshold until the momentum comparison result meets the momentum preset requirement;

[0218] Determine the maximum liquid-carrying capacity as the target maximum liquid-carrying capacity.

[0219] As can be seen from the above description, the maximum liquid-carrying capacity prediction method based on coalbed methane wells provided by the present application determines bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture to determine bottom-hole data, and determines liquid film gas core momentum data according to the bottom-hole data to predict the maximum liquid-carrying capacity, which can assist in the judgment of bottom-hole liquid accumulation problems and ensure the continuity and stability of gas well production.

[0220] In another embodiment, the maximum liquid-carrying capacity prediction device based on coalbed methane wells can be separately configured from the central processing unit 9100. For example, the maximum liquid-carrying capacity prediction device based on coalbed methane wells can be configured as a chip connected to the central processing unit 9100, and the functions of the maximum liquid-carrying capacity prediction method based on coalbed methane wells are realized through the control of the central processing unit.

[0221] As Figure 12 shown, the electronic device 9600 may further include: a communication module 9110, an input unit 9120, an audio processor 9130, a display 9160, and a power supply 9170. It should be noted that the electronic device 9600 does not necessarily have to include Figure 12 all the components shown in Figure 12 ; in addition, the electronic device 9600 may further include

[0222] As Figure 12 shown, the central processing unit 9100 is sometimes also referred to as a controller or an operation control, and may include a microprocessor or other processor devices and / or logic devices. The central processing unit 9100 receives inputs and controls the operations of the various components of the electronic device 9600.

[0223] Among them, the memory 9140, for example, may be one or more of a buffer, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory, or other suitable devices. The above information related to failures can be stored, and in addition, programs for executing relevant information can also be stored. And the central processing unit 9100 can execute the programs stored in the memory 9140 to implement information storage or processing, etc.

[0224] The input unit 9120 provides inputs to the central processing unit 9100. The input unit 9120 is, for example, a key or a touch input device. The power supply 9170 is used to provide power to the electronic device 9600. The display 9160 is used to display display objects such as images and texts. The display may be, for example, an LCD display, but is not limited thereto.

[0225] The memory 9140 may be a solid-state memory, for example, a read-only memory (ROM), a random access memory (RAM), a SIM card, etc. It may also be a memory that stores information even when power is off, can be selectively erased and has more data. Examples of such a memory are sometimes referred to as EPROMs, etc. The memory 9140 may also be some other type of device. The memory 9140 includes a buffer 9141 (sometimes referred to as a buffer memory). The memory 9140 may include an application / function storage unit 9142 for storing application programs and function programs or the processes for operating the electronic device 9600 by the central processing unit 9100.

[0226] The memory 9140 may also include a data storage unit 9143 for storing data such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit 9144 of the memory 9140 may include various drivers of the electronic device for communication functions and / or for performing other functions of the electronic device (such as a messaging application, an address book application, etc.).

[0227] The communication module 9110 is a transmitter / receiver 9110 that transmits and receives signals via the antenna 9111. The communication module (transmitter / receiver) 9110 is coupled to the central processing unit 9100 to provide input signals and receive output signals, which may be the same as in the case of a conventional mobile communication terminal.

[0228] Based on different communication technologies, multiple communication modules 9110 may be provided in the same electronic device, such as a cellular network module, a Bluetooth module, and / or a wireless local area network module, etc. The communication module (transmitter / receiver) 9110 is also coupled to the speaker 9131 and the microphone 9132 via the audio processor 9130 to provide an audio output via the speaker 9131 and receive an audio input from the microphone 9132, thereby implementing normal telecommunication functions. The audio processor 9130 may include any suitable buffers, decoders, amplifiers, etc. Additionally, the audio processor 9130 is also coupled to the central processing unit 9100, so that recording can be performed on the local machine through the microphone 9132 and the sound stored on the local machine can be played through the speaker 9131.

[0229] An embodiment of the present invention also provides a computer-readable storage medium that can implement all steps of the maximum liquid-carrying capacity prediction method for coalbed methane wells with the execution subject being a server or a client in the above embodiments. A computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, all steps of the maximum liquid-carrying capacity prediction method for coalbed methane wells in the above embodiments are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0230] Determine bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture;

[0231] Determine bottom-hole data according to the bottom-hole pressure data and the bottom-hole temperature data;

[0232] Determine liquid film gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data;

[0233] Adjust the maximum liquid-carrying capacity according to the comparison result between the liquid film gas core momentum data and a preset momentum threshold until the momentum comparison result meets the preset momentum requirement;

[0234] Determine the maximum liquid-carrying capacity as the target maximum liquid-carrying capacity.

[0235] In summary, the computer-readable storage medium of the embodiment of the present invention determines bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture to determine bottom-hole data, and determines liquid film gas core momentum data according to the bottom-hole data to predict the maximum liquid-carrying capacity, which can assist in judging the problem of bottom-hole liquid accumulation and ensure the continuity and stability of gas well production.

[0236] An embodiment of the present invention also provides a computer program product that can implement all steps of the maximum liquid-carrying capacity prediction method for coalbed methane wells with the execution subject being a server or a client in the above embodiments. The computer program product includes computer programs / instructions, and when the computer programs / instructions are executed by a processor, all steps of the maximum liquid-carrying capacity prediction method for coalbed methane wells in the above embodiments are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0237] Determine bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture;

[0238] Determine bottom-hole data according to the bottom-hole pressure data and the bottom-hole temperature data;

[0239] Determine liquid film gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data;

[0240] Adjust the maximum liquid-carrying capacity according to the comparison result between the liquid film gas core momentum data and a preset momentum threshold until the momentum comparison result meets the preset momentum requirement;

[0241] Determine the maximum liquid-carrying capacity as the target maximum liquid-carrying capacity.

[0242] In summary, the computer program product of the embodiment of the present invention determines the bottom-hole pressure data and the bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture to determine the bottom-hole data, and determines the liquid film and gas core momentum data according to the bottom-hole data to predict the maximum liquid-carrying capacity, which can assist in the judgment of the bottom-hole liquid accumulation problem and ensure the continuity and stability of gas well production.

[0243] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the hardware + program type embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments.

[0244] The specific embodiments of this specification have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0245] Although this application provides method operation steps as described in the embodiments or flowcharts, based on routine or non-creative labor, there may be more or fewer operation steps. The step order listed in the embodiments is only one way among the numerous step execution orders and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order shown in the embodiments or the figures or in parallel (such as in an environment with parallel processors or multi-threaded processing).

[0246] Although the embodiments of this specification provide method operation steps as described in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-creative means. The order of steps listed in the embodiments is only one way among the execution orders of numerous steps and does not represent the only execution order. When the actual device or terminal product executes, it can be executed in the order of the method shown in the embodiments or the drawings or executed in parallel (for example, in an environment of parallel processors or multi-threaded processing, or even in a distributed data processing environment). The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, product or device comprising a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, product or device. Without more limitations, it does not exclude the existence of additional identical or equivalent elements in the process, method, product or device comprising the said elements.

[0247] For the convenience of description, when describing the above device, it is divided into various modules according to functions for separate description. Of course, when implementing the embodiments of this specification, the functions of each module can be implemented in the same or multiple software and / or hardware, or the modules implementing the same function can be realized by a combination of multiple sub-modules or sub-units, etc. The device embodiments described above are only illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0248] Those skilled in the art also know that in addition to implementing the controller in the form of pure computer-readable program code, the method steps can be logically programmed to enable the controller to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. to achieve the same function. Therefore, such a controller can be regarded as a hardware component, and the devices included therein for implementing various functions can also be regarded as the structures within the hardware component. Or even, the devices for implementing various functions can be regarded as both software modules for implementing the method and the structures within the hardware component.

[0249] The present invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each flow and / or block in the flowchart illustrations and / or block diagrams, and combinations of flows and / or blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing apparatus create means for implementing the functions specified in the flowchart Figure 1 for one or more flows and / or blocks Figure 1 for one or more blocks.

[0250] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means that implement the functions specified in the flowchart Figure 1 for one or more flows and / or blocks Figure 1 for one or more blocks.

[0251] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart Figure 1 for one or more flows and / or blocks Figure 1 for one or more blocks.

[0252] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and memory.

[0253] The memory may include non-permanent memory in the form of computer-readable media, random access memory (RAM), and / or non-volatile memory such as read-only memory (ROM) or flash memory (flash RAM). The memory is an example of computer-readable media.

[0254] A computer-readable medium includes both permanent and non-permanent, removable and non-removable media and can implement information storage by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tapes, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer-readable medium does not include transitory computer-readable media such as modulated data signals and carrier waves.

[0255] Those skilled in the art should understand that the embodiments of this specification can be provided as a method, a system, or a computer program product. Therefore, the embodiments of this specification can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of this specification can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0256] The embodiments in this specification can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The embodiments of this specification can also be practiced in a distributed computing environment where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0257] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts can refer to the description of the method embodiments. In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of this specification. In this specification, the schematic expression of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0258] The above is only the embodiments of the embodiments of this specification and is not used to limit the embodiments of this specification. For those skilled in the art, various changes and modifications can be made to the embodiments of this specification. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the embodiments of this specification shall be included within the scope of the claims of the embodiments of this specification.

Claims

1. A method for predicting the maximum liquid - carrying capacity of a coal - bed methane well, characterized in that, it includes: Determine the bottom - hole pressure data and bottom - hole temperature data according to the maximum liquid - carrying capacity of the gas - liquid mixture; Determine the bottom - hole data according to the bottom - hole pressure data and the bottom - hole temperature data; Determine the liquid - film gas - core momentum data according to the maximum liquid - carrying capacity and the bottom - hole data; Adjust the maximum liquid - carrying capacity according to the comparison result between the liquid - film gas - core momentum data and a preset momentum threshold until the momentum comparison result meets the preset momentum requirement; Determine the maximum liquid - carrying capacity as the target maximum liquid - carrying capacity.

2. The method for predicting the maximum liquid - carrying capacity of a coal - bed methane well according to claim 1, characterized in that, the bottom - hole data includes liquid - phase parameters, gas - phase parameters and gas - water geometric parameters; Determining the liquid - film gas - core momentum data according to the maximum liquid - carrying capacity and the bottom - hole data includes: Determine the annular - flow liquid - film thickness according to the maximum liquid - carrying capacity, the liquid - phase parameters and the gas - phase parameters; Determine the gas - water surface tension according to the annular - flow liquid - film thickness; Determine the liquid - film gas - core momentum data according to the gas - water surface tension, the gas - water geometric parameters, the liquid - phase density in the liquid - phase parameters and the maximum liquid - carrying capacity.

3. The method for predicting the maximum liquid - carrying capacity of a coal - bed methane well according to claim 2, characterized in that, Determining the gas - water surface tension according to the annular - flow liquid - film thickness includes: Determine the dimensionless interfacial shear coefficient according to the annular - flow liquid - film thickness, the liquid - phase density and the gas - phase density in the gas - phase parameters; Determine the gas - water surface tension according to the dimensionless interfacial shear coefficient, the gas - water flow velocity and the liquid - phase flow velocity.

4. The method for predicting the maximum liquid - carrying capacity of a coal - bed methane well according to claim 3, characterized in that, Determining the gas - water surface tension according to the dimensionless interfacial shear coefficient, the gas - water flow velocity and the liquid - phase flow velocity includes: Determine the gas - water friction coefficient according to the dimensionless interfacial shear coefficient, the gas - water flow velocity and the liquid - phase flow velocity; Determine the gas - water surface tension according to the gas - water friction coefficient, the gas - water flow velocity, the liquid - phase density and the gas - core region density.

5. The method for predicting the maximum liquid - carrying capacity of a coal - bed methane well according to claim 1, characterized in that, Determining the bottom - hole pressure data and bottom - hole temperature data according to the maximum liquid - carrying capacity of the gas - liquid mixture includes: Determine the first natural - gas deviation coefficient according to the initial bottom - hole pressure and the initial bottom - hole temperature; Determine the first bottom - hole pressure according to the first natural - gas deviation coefficient, the maximum liquid - carrying capacity and the initial bottom - hole temperature; Determine the bottom - hole temperature according to the specific heat capacity, the initial bottom - hole temperature and the bottom - hole pressure; Determine the second bottom - hole pressure according to the maximum liquid - carrying capacity, the bottom - hole temperature and the first bottom - hole pressure; Determine the bottom - hole pressure data and the bottom - hole temperature data according to the comparison result between the first bottom - hole pressure and the second bottom - hole pressure.

6. The method for predicting the maximum liquid - carrying capacity of a coal - bed methane well according to claim 5, characterized in that, Determining the first bottom - hole pressure according to the first natural - gas deviation coefficient, the maximum liquid - carrying capacity and the initial bottom - hole temperature includes: Determine the intermediate bottom - hole pressure according to the first natural - gas deviation coefficient and the maximum liquid - carrying capacity; Adjust the initial bottom-hole pressure according to the comparison result between the intermediate bottom-hole pressure and the initial bottom-hole pressure until the pressure comparison result meets the pressure preset requirement.

7. The method for predicting the maximum liquid-carrying capacity based on a coalbed methane well according to claim 5, wherein, determining the bottom-hole temperature according to the specific heat capacity, the initial bottom-hole temperature and the bottom-hole pressure includes: determining an intermediate bottom-hole temperature according to the specific heat capacity and the bottom-hole pressure; adjusting the initial bottom-hole temperature according to the comparison result between the intermediate bottom-hole temperature and the initial bottom-hole temperature until the temperature comparison result meets the temperature preset requirement.

8. A device for predicting the maximum liquid-carrying capacity based on a coalbed methane well, wherein, comprising: a bottom-hole pressure and temperature module, configured to determine bottom-hole pressure data and bottom-hole temperature data according to the maximum liquid-carrying capacity of the gas-liquid mixture; a bottom-hole data determination module, configured to determine bottom-hole data according to the bottom-hole pressure data and the bottom-hole temperature data; a liquid film and gas core momentum data module, configured to determine liquid film and gas core momentum data according to the maximum liquid-carrying capacity and the bottom-hole data; a maximum liquid-carrying capacity adjustment module, configured to adjust the maximum liquid-carrying capacity according to the comparison result between the liquid film and gas core momentum data and a preset momentum threshold until the momentum comparison result meets the momentum preset requirement; a target maximum liquid-carrying capacity module, configured to determine the maximum liquid-carrying capacity as the target maximum liquid-carrying capacity.

9. The device for predicting the maximum liquid-carrying capacity based on a coalbed methane well according to claim 8, wherein, the bottom-hole data includes liquid phase parameters, gas phase parameters and gas-water geometric parameters; the liquid film and gas core momentum data module includes: an annular flow liquid film thickness unit, configured to determine the annular flow liquid film thickness according to the maximum liquid-carrying capacity, the liquid phase parameters and the gas phase parameters; a gas-water surface tension unit, configured to determine the gas-water surface tension according to the annular flow liquid film thickness; a liquid film and gas core momentum data unit, configured to determine the liquid film and gas core momentum data according to the gas-water surface tension, the gas-water geometric parameters, the liquid phase density in the liquid phase parameters and the maximum liquid-carrying capacity.

10. The device for predicting the maximum liquid-carrying capacity based on a coalbed methane well according to claim 9, wherein, the gas-water surface tension unit includes: a dimensionless interfacial shear coefficient sub-unit, configured to determine a dimensionless interfacial shear coefficient according to the annular flow liquid film thickness, the liquid phase density and the gas phase density in the gas phase parameters; a gas-water surface tension sub-unit, configured to determine the gas-water surface tension according to the dimensionless interfacial shear coefficient, the gas-water flow velocity and the liquid phase flow velocity.

11. The device for predicting the maximum liquid-carrying capacity based on a coalbed methane well according to claim 10, wherein, the gas-water surface tension sub-unit is specifically configured to: determine a gas-water friction coefficient according to the dimensionless interfacial shear coefficient, the gas-water flow velocity and the liquid phase flow velocity; determine the gas-water surface tension according to the gas-water friction coefficient, the gas-water flow velocity, the liquid phase density and the gas core region density.

12. The device for predicting the maximum liquid-carrying capacity based on a coalbed methane well according to claim 8, wherein, the bottom-hole pressure and temperature module includes: The first natural gas deviation coefficient unit is used to determine the first natural gas deviation coefficient according to the initial bottom hole pressure and the initial bottom hole temperature; The first bottom hole pressure unit is used to determine the first bottom hole pressure according to the first natural gas deviation coefficient, the maximum liquid-carrying capacity and the initial bottom hole temperature; The bottom hole temperature unit is used to determine the bottom hole temperature according to the specific heat capacity, the initial bottom hole temperature and the bottom hole pressure; The second bottom hole pressure unit is used to determine the second bottom hole pressure according to the maximum liquid-carrying capacity, the bottom hole temperature and the first bottom hole pressure; The bottom hole pressure and temperature unit is used to determine the bottom hole pressure data and the bottom hole temperature data according to the comparison result between the first bottom hole pressure and the second bottom hole pressure.

13. The maximum liquid-carrying capacity prediction device based on a coalbed methane well according to claim 12, wherein, the first bottom hole pressure unit includes: The bottom hole pressure intermediate quantum unit is used to determine the bottom hole pressure intermediate quantity according to the first natural gas deviation coefficient and the maximum liquid-carrying capacity; The bottom hole pressure adjustment sub-unit is used to adjust the initial bottom hole pressure according to the comparison result between the bottom hole pressure intermediate quantity and the initial bottom hole pressure until the pressure comparison result meets the pressure preset requirement.

14. The maximum liquid-carrying capacity prediction device based on a coalbed methane well according to claim 12, wherein, the bottom hole temperature unit includes: The bottom hole temperature intermediate quantum unit is used to determine the bottom hole temperature intermediate quantity according to the specific heat capacity and the bottom hole pressure; The bottom hole temperature adjustment sub-unit is used to adjust the initial bottom hole temperature according to the comparison result between the bottom hole temperature intermediate quantity and the initial bottom hole temperature until the temperature comparison result meets the temperature preset requirement.

15. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and running on the processor, wherein, when the processor executes the computer program, the steps of the maximum liquid-carrying capacity prediction method based on a coalbed methane well according to any one of claims 1 to 7 are implemented.

16. A computer-readable storage medium, on which a computer program is stored, wherein, when the computer program is executed by a processor, the steps of the maximum liquid-carrying capacity prediction method based on a coalbed methane well according to any one of claims 1 to 7 are implemented.

17. A computer program product, comprising a computer program / instructions, wherein, when the computer program / instructions are executed by a processor, the steps of the maximum liquid-carrying capacity prediction method based on a coalbed methane well according to any one of claims 1 to 7 are implemented.

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