Method, device and storage medium for real-time monitoring of safety risks of well killing system

Abstract

The application discloses a method for real-time monitoring of safety risk of a well killing system, the system comprising a wellhead blowout preventer, a casing, a formation at a casing shoe and a liquid-gas separator, the method comprising: obtaining a maximum gas apparent flow rate of the liquid-gas separator and an inner diameter of the liquid-gas separator under current input conditions; determining a maximum actual separated gas flow rate of the liquid-gas separator according to the maximum gas apparent flow rate and the inner diameter; determining a first maximum flow rate of gas in the liquid-gas separator in a discharge pipeline and a second maximum flow rate of liquid in the liquid-gas separator in the discharge pipeline, and determining a maximum actual discharge gas flow rate and a maximum actual discharge liquid flow rate of the liquid-gas separator in combination with the inner diameter; and determining a safety index of the liquid-gas separator according to the maximum actual discharge liquid flow rate, the maximum actual discharge gas flow rate, the maximum actual separated gas flow rate, total hydrocarbon content and flow rate of fluid input to the liquid-gas separator. The application can detect the safety risk index in real time during well killing operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of well killing system safety evaluation, in particular to a method and device for real-time monitoring of safety risks of a well killing system and a storage medium. BACKGROUND

[0002] Currently, the technology in the field of oil and gas drilling is gradually developing towards deep water, high temperature and pressure, and dense strata. During drilling, due to the limitations of different construction conditions and the influence of stratum conditions, it is difficult to accurately predict and control the stratum pressure. When the pressure in the wellbore and the stratum pressure are unbalanced, overflow, well kick or even blowout accidents may occur, so well killing operation is needed to rebalance the pressure system in the well to safely circulate the stratum fluid invading the wellbore out of the wellbore, thereby ensuring the safety of drilling operation. During well killing, the pressure in the well should be slightly greater than the stratum pressure to avoid continuous invasion of stratum fluid into the well, while the liquid column pressure in the well should not be too large to cause stratum pollution and loss of well killing fluid by pressing the stratum in the open hole section of the well.

[0003] The existing well killing methods include conventional well killing and unconventional well killing. The conventional well killing methods include driller method well killing and engineer method well killing, and the unconventional well killing methods include displacement method well killing, pressure return method well killing, and overflow and leakage coexistence well killing. During well killing operation, different well killing processes are generally selected according to the well profile conditions, overflow situation and on-site construction conditions of the overflow well. From 1960 to 1990, well killing technology developed from mainly relying on the experience of on-site personnel to a mature theory and systematic operation process, which improved the safety and reliability of well killing operation. Since 1990, well killing technology has developed a more automated and intelligent well killing operation control system, which can monitor a variety of well killing parameters in real time during well killing, improve the interpretability of well killing operation, and further improve the accuracy and reliability of well killing operation. However, when evaluating the safety risks of the well killing system during well killing, the on-site personnel still monitor parameters such as wellhead casing back pressure to manually evaluate whether there is a safety risk in well killing operation. The evaluation of equipment safety risks during well killing is lagging behind, and there is a lack of reliable standards and automated judgment processes. When there is a safety risk in the equipment during well killing, the on-site operation cannot provide accurate and quantitative information about the position and severity of the safety risk of the well killing pressure system, which leads to the inability to timely and effectively eliminate the risk factors, thereby causing a series of well killing construction problems, reducing the construction efficiency, and even causing well killing equipment failure, blowout and other serious construction accidents. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a method and device for real-time monitoring of safety risks of a well killing system, to solve the problem that the safety risks in well killing operation cannot be detected in real time in the prior art.

[0005] To achieve the above object, the first aspect of the present application provides a method for real-time monitoring of safety risks of a well killing system, the system comprising a wellhead blowout preventer, a casing, a formation at a casing shoe, and a liquid-gas separator, the method comprising:

[0006] obtaining a maximum gas superficial velocity of the liquid-gas separator under current input conditions and an inner diameter of the liquid-gas separator;

[0007] determining a maximum actual separated gas flow rate of the liquid-gas separator according to the maximum gas superficial velocity and the inner diameter;

[0008] determining a first maximum flow rate of gas in the liquid-gas separator in a discharge pipeline and a second maximum flow rate of liquid in the liquid-gas separator in the discharge pipeline;

[0009] determining a maximum actual discharge gas flow rate of the liquid-gas separator based on the first maximum flow rate and the inner diameter;

[0010] determining a maximum actual discharge liquid flow rate of the liquid-gas separator based on the second maximum flow rate and the inner diameter;

[0011] determining a total hydrocarbon content and a flow rate of fluid input to the liquid-gas separator;

[0012] determining a safety index of the liquid-gas separator according to the maximum actual discharge liquid flow rate, the maximum actual discharge gas flow rate, the maximum actual separated gas flow rate, the total hydrocarbon content, and the flow rate of fluid input to the liquid-gas separator.

[0013] In the embodiments of the present application, determining the first maximum flow rate of gas in the liquid-gas separator in the discharge pipeline comprises: obtaining a gas density input to the liquid-gas separator and an upper limit of a differential pressure gauge range in a gas outlet pipeline of the liquid-gas separator; and determining the first maximum flow rate based on the gas density and the upper limit of the differential pressure gauge range.

[0014] In the embodiments of the present application, determining the first maximum flow rate based on the gas density and the upper limit of the differential pressure gauge range comprises determining the first maximum flow rate according to formula (1):

[0015]

[0016] wherein P G is the upper limit of the differential pressure gauge range, d G is the gas density, and V G is the first maximum flow rate.

[0017] In the embodiments of the present application, determining the second maximum flow rate of liquid in the liquid-gas separator in the discharge pipeline comprises: obtaining a liquid density input to the liquid-gas separator and an upper limit of a differential pressure gauge range in a liquid outlet pipeline of the liquid-gas separator; and determining the second maximum flow rate based on the liquid density and the upper limit of the differential pressure gauge range.

[0018] In the embodiment of the present application, determining the second maximum flow rate based on the liquid density and the upper limit of the differential pressure measurement range of the outlet pipeline comprises determining the second maximum flow rate according to formula (2):

[0019]

[0020] wherein P L is the upper limit of the differential pressure measurement range of the outlet pipeline, d L is the liquid density, and V L is the second maximum flow rate.

[0021] In the embodiment of the present application, the method further comprises: obtaining the pressure of the fluid in the well killing device acting on the wellhead casing and the upper limit of the safe pressure bearing of the wellhead blowout preventer; and determining the safety index of the wellhead blowout preventer based on the pressure of the fluid in the well killing device acting on the wellhead casing and the upper limit of the safe pressure bearing of the wellhead blowout preventer.

[0022] In the embodiment of the present application, the method further comprises: obtaining the upper limit of the casing pressure bearing of the casing weak position and the first annular pressure of the casing weak position; and determining the safety index of the casing based on the upper limit of the casing pressure bearing of the casing weak position and the first annular pressure of the casing weak position.

[0023] In the embodiment of the present application, the method further comprises: obtaining the fracture pressure of the formation at the casing shoe and the second annular pressure at the casing shoe; and determining the safety index of the formation at the casing shoe based on the fracture pressure of the formation at the casing shoe and the second annular pressure at the casing shoe.

[0024] The second aspect of the present application provides a device for real-time monitoring of safety risks of a well killing system, the device comprising:

[0025] a memory configured to store instructions; and

[0026] a processor configured to call the instructions from the memory and capable of implementing the method for real-time monitoring of safety risks of a well killing system when executing the instructions.

[0027] The third aspect of the present application provides a machine readable storage medium having instructions stored thereon, the instructions being used to cause a machine to execute the method for real-time monitoring of safety risks of a well killing system.

[0028] By the technical solution, the maximum gas superficial velocity of the liquid-gas separator under the current input condition and the inner diameter of the liquid-gas separator are obtained; the maximum actual separated gas flow of the liquid-gas separator is determined according to the maximum gas superficial velocity and the inner diameter; the first maximum flow velocity of the gas in the discharge pipeline in the liquid-gas separator and the second maximum flow velocity of the liquid in the discharge pipeline in the liquid-gas separator are determined; the maximum actual discharge gas flow of the liquid-gas separator is determined based on the first maximum flow velocity and the inner diameter; the maximum actual discharge liquid flow of the liquid-gas separator is determined based on the second maximum flow velocity and the inner diameter; the total hydrocarbon content and the flow of the fluid input to the liquid-gas separator are determined; and the safety index of the liquid-gas separator is determined according to the maximum actual discharge liquid flow, the maximum actual discharge gas flow, the maximum actual separated gas flow, and the total hydrocarbon content and the flow of the fluid input to the liquid-gas separator. The application can detect the safety index in the well killing operation process in real time.

[0029] Other features and advantages of the embodiments of the application will be described in detail in the following specific implementation part. BRIEF DESCRIPTION OF DRAWINGS

[0030] The accompanying drawings are included to provide a further understanding of the embodiments of the application, and constitute a part of the specification, and are used to explain the embodiments of the application together with the specific implementation below, but do not constitute a limitation on the embodiments of the application. In the drawings:

[0031] Figure 1 A flow chart of a method for real-time monitoring of safety risks of a well killing system according to an embodiment of the application is schematically shown;

[0032] Figure 2 A structural diagram of an apparatus for real-time monitoring of safety risks of a well killing system according to an embodiment of the application is schematically shown.

[0033] REFERENCE NUMERALS

[0034] 210 memory 220 processor DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the technical solutions in the embodiments of the application will be clearly and completely described below in combination with the drawings in the embodiments of the application. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiments of the application, and is not used to limit the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the application.

[0036] It should be noted that if the application embodiments have directionality indications (such as up, down, left, right, front, back, etc.), the directionality indications are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directionality indications also change accordingly.

[0037] In addition, if the application embodiments have descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope claimed by the present application.

[0038] Figure 1 A flowchart of a method for real-time monitoring of safety risks of a well killing system according to an embodiment of the present application is schematically shown. As shown in Figure 1 The method for real-time monitoring of safety risks of a well killing system according to an embodiment of the present application can include the following steps:

[0039] Step 101, acquiring the maximum gas superficial velocity of the liquid-gas separator and the inner diameter of the liquid-gas separator under the current input condition;

[0040] Step 102, determining the maximum actual separated gas flow rate of the liquid-gas separator according to the maximum gas superficial velocity and the inner diameter;

[0041] Step 103, determining the first maximum flow rate of the gas in the liquid-gas separator in the discharge pipeline and the second maximum flow rate of the liquid in the liquid-gas separator in the discharge pipeline;

[0042] Step 104, determining the maximum actual discharge gas flow rate of the liquid-gas separator based on the first maximum flow rate and the inner diameter;

[0043] Step 105, determining the maximum actual discharge liquid flow rate of the liquid-gas separator based on the second maximum flow rate and the inner diameter;

[0044] Step 106, determining the total hydrocarbon content and flow rate of the fluid input to the liquid-gas separator;

[0045] Step 107, determining the safety index of the liquid-gas separator according to the maximum actual discharge liquid flow rate, the maximum actual discharge gas flow rate, the maximum actual separated gas flow rate, the total hydrocarbon content, and the flow rate of the fluid input to the liquid-gas separator.

[0046] In one embodiment, the current input conditions are a series of input parameters and conditions considered when operating the liquid-gas separator in an actual production environment. The maximum gas superficial velocity refers to the maximum observed velocity of gas in a pipe or equipment in the liquid-gas separator. The maximum actual separated gas flow rate refers to the maximum gas flow rate that the liquid-gas separator can handle in the liquid-gas separator. The maximum actual vented gas flow rate refers to the maximum gas flow rate that the liquid-gas separator can vent in the liquid-gas separator. The maximum actual vented liquid flow rate refers to the maximum liquid flow rate that the liquid-gas separator can vent in the liquid-gas separator. The total hydrocarbon content refers to the total volume or mass percentage of all hydrocarbon compounds in a fluid. The flow rate refers to the rate of fluid passing through the liquid-gas separator, typically expressed in volumetric or mass flow rate. The present application considers the maximum handling capacity of gas and liquid in the liquid-gas separator under actual operating conditions and the gas and liquid vented from the liquid-gas separator meet the requirements of its design and operation, so that the safety index of the liquid-gas separator in the well killing operation process can be detected in real time.

[0047] In one embodiment, determining the first maximum flow rate of gas in the liquid-gas separator in the venting pipeline can include: obtaining a gas density input into the liquid-gas separator and an upper limit of the differential pressure gauge range in the gas outlet pipeline of the liquid-gas separator; determining the first maximum flow rate based on the gas density and the upper limit of the differential pressure gauge range in the gas outlet pipeline.

[0048] In one embodiment, determining the first maximum flow rate based on the gas density and the upper limit of the differential pressure gauge range in the gas outlet pipeline includes determining the first maximum flow rate according to formula (1):

[0049]

[0050] wherein P G is the upper limit of the differential pressure gauge range in the gas outlet pipeline, d G is the gas density, and V G is the first maximum flow rate.

[0051] In one embodiment, the upper limit of the differential pressure gauge range in the gas outlet pipeline refers to the upper limit of the maximum differential pressure measurement range that the piping system of the gas outlet in the liquid-gas separator can withstand. In the liquid-gas separator, when gas flows in the pipeline, a pressure difference may be generated on both sides of the pipeline due to factors such as resistance, flow rate, etc. The gas density input into the liquid-gas separator refers to the density of the gas entering the separator. Based on the gas density and the upper limit of the differential pressure gauge range in the gas outlet pipeline and formula (1), the first maximum flow rate can be determined. The first maximum flow rate refers to the maximum flow rate of gas in the liquid-gas separator in the venting pipeline. The gas density is directly related to the gas fluid mechanics characteristics and flow behavior, and is crucial for predicting separation efficiency, calculating pressure drop, and determining the working range of the liquid-gas separator.

[0052] In one embodiment, determining the second maximum flow rate of the liquid in the discharge line of the liquid-gas separator can include obtaining a liquid density of the liquid inputted into the liquid-gas separator and an upper limit of differential pressure measurement range in the liquid outlet line of the liquid-gas separator; determining the second maximum flow rate based on the liquid density and the upper limit of differential pressure measurement range in the liquid outlet line.

[0053] In one embodiment, determining the second maximum flow rate based on the liquid density and the upper limit of differential pressure measurement range in the liquid outlet line includes determining the second maximum flow rate according to formula (2):

[0054]

[0055] wherein P L is the upper limit of differential pressure measurement range in the liquid outlet line, d L is the liquid density, and V L is the second maximum flow rate.

[0056] In one embodiment, the upper limit of differential pressure measurement range in the liquid outlet line of the liquid-gas separator refers to the maximum differential pressure range that can be accurately measured in the liquid outlet line of the liquid-gas separator, and the upper limit of measurement range is the maximum differential pressure that can occur in the discharge line of the liquid. The liquid density inputted into the liquid-gas separator refers to the density of the liquid when it enters the separator. The second maximum flow rate can be determined according to formula (2) based on the liquid density and the upper limit of differential pressure measurement range in the liquid outlet line. The second maximum flow rate refers to the maximum flow rate of the liquid in the discharge line of the liquid-gas separator.

[0057] In one embodiment, the method can further include obtaining a pressure of the fluid in the well killing device applied to the wellhead casing and a safety pressure bearing upper limit of the wellhead blowout preventer; and determining a safety index of the wellhead blowout preventer based on the pressure of the fluid in the well killing device applied to the wellhead casing and the safety pressure bearing upper limit of the wellhead blowout preventer.

[0058] In one embodiment, the method for real-time monitoring of safety risk of well killing system further comprises safety monitoring of the wellhead blowout preventer. The pressure of fluid in well killing system applied on wellhead casing refers to the case that the pressure generated by the liquid in the well (such as drilling fluid or well killing fluid) acts on the wellhead casing when the well killing operation is carried out. In oil and gas drilling, well killing operation is usually used to control the formation pressure at the bottom of the well, maintain the stability of the wellbore and carry out other necessary operations. The well killing liquid enters the wellbore through the wellhead casing, which acts to balance the pressure of the formation at the bottom of the well to prevent blowout or other dangerous accidents. In this process, the well killing liquid will exert a certain pressure on the wellhead casing. This pressure is determined by factors such as the density of the liquid, the flow rate, the properties of the formation at the bottom of the well, etc. The upper limit of the safe pressure of the wellhead blowout preventer refers to the maximum pressure that the device can safely withstand under normal operating conditions. In oil and gas drilling, the wellhead blowout preventer is a key safety device for controlling blowout. The wellhead blowout preventer is usually located above the wellhead casing, which acts to block the wellhead when necessary to prevent oil and gas, drilling fluid or other well fluid from being uncontrollably ejected. The present application takes the ratio of the pressure of the fluid in the well killing system applied on the wellhead casing to the upper limit of the safe pressure of the wellhead blowout preventer as the safety index of the wellhead blowout preventer, which can detect the safety risk of the well killing operation process in real time.

[0059] In one embodiment, the method can further comprise: obtaining the upper limit of the casing pressure of the casing weak position and the first annulus pressure of the casing weak position; determining the safety index of the casing based on the upper limit of the casing pressure of the casing weak position and the first annulus pressure of the casing weak position.

[0060] In one embodiment, the method for real-time monitoring of safety risk of well killing system further comprises safety monitoring of casing. The casing pressure limit at casing weak point refers to the maximum pressure that the casing can safely withstand at a certain location in the casing system of the oil and gas well, which is considered to be relatively weak or vulnerable to pressure. In oil and gas drilling, the casing system is used to strengthen the well wall and prevent well wall collapse, while also bearing the pressure from the bottom formation. The casing weak point can be relatively weak in the casing system due to factors such as pipe geometry, material strength, weld quality, etc. The casing pressure limit is designed to ensure that the casing will not be subjected to excessive pressure under normal operation and emergency conditions. This limit is determined by factors such as engineering standards of casing design, material properties, and possible formation pressure. The annulus pressure at the casing weak point refers to the pressure received in the annulus (the space between the casing outside and the wellbore) at a certain weak point of the casing in the casing system of the oil and gas well. This pressure is generated by the bottom formation and is usually used to support the casing system, prevent well wall collapse, and maintain the stability of the wellbore. The annulus pressure is the pressure transmitted to the surface of the casing through the annulus outside the casing under the action of the natural formation pressure of the bottom formation. This pressure not only supports the casing, but also resists the pressure from the formation, and can also be affected by the drilling fluid or other well fluids. The ratio of the casing pressure limit at the casing weak point to the first annulus pressure at the casing weak point is taken as the safety index of the casing, and the safety risk of the well killing operation process can be detected in real time.

[0061] In one embodiment, the method can further comprise: obtaining the fracture pressure of the formation at the casing shoe and the second annulus pressure at the casing shoe; determining the safety index of the formation at the casing shoe based on the fracture pressure of the formation at the casing shoe and the second annulus pressure at the casing shoe.

[0062] In one embodiment, the method for real-time monitoring of safety risks of a well killing system further comprises monitoring the safety of the formation at the casing shoe. The fracture pressure of the formation at the casing shoe refers to the maximum pressure that the formation at the casing shoe can withstand, exceeding which can cause the formation to fracture or other irreversible changes. The casing shoe is usually the end of the casing at the bottom of the well, through which a certain pressure can be applied to the formation to control the formation pressure at the bottom of the well and prevent unsafe conditions such as blowout. The fracture pressure of the formation at the casing shoe needs to consider factors such as the physical properties of the formation, the stress state of the formation, the type of rock in the formation, etc. The fracture pressure is usually estimated or calculated through the analysis of formation mechanics and rock mechanics during the design of the well. The annulus pressure at the casing shoe refers to the pressure in the annulus (the space between the casing and the wellbore) near the casing shoe in the casing system of the oil and gas well. The casing shoe is the bottom of the casing, usually at the end of the casing, used to strengthen the well wall and guide the drill bit. The annulus pressure at the casing shoe is the pressure generated at the bottom of the well, transmitted to the surface of the casing through the annulus near the casing shoe. The annulus pressure at the casing shoe is an important parameter for maintaining wellbore stability, preventing well wall collapse and supporting the casing. This pressure is usually estimated or calculated by considering the natural formation pressure at the bottom of the well, the wellbore stability requirements, the well depth, etc. Its size is affected by many factors such as the properties of the formation, the stability of the formation, the well depth, etc. Proper annulus pressure can prevent well wall collapse, reduce downhole hazards, and ensure that the casing is adequately supported. The ratio of the fracture pressure of the formation at the casing shoe to the second annulus pressure at the casing shoe is taken as the safety index of the casing in this application, which can detect the safety risks of the well killing operation process in real time.

[0063] The technical solutions of the present application are described below with a specific embodiment.

[0064] Data acquisition. Obtain the well profile information, formation fracture pressure test information, wellhead equipment specification parameters, and surface liquid gas separator specification parameters of the well killing operation well as the original equipment data information of the well killing system. The casing pressure, outlet flow and other well killing operation related data obtained in real time at the well killing operation site are taken as the original variable data information for safety verification of the well killing system equipment.

[0065] Equipment safety condition calculation. Calculate the four safety conditions under a certain safety factor: 1. Maximum safe pressure bearing capacity of wellhead well killing device; 2. Minimum internal pressure resistance and maximum pressure bearing position of the lowest level of casing in the well; 3. Formation leakage / fracture pressure of the formation at the casing shoe; 4. Determine the maximum allowable apparent velocity coefficient K of the liquid gas separator according to the API standard and the type and specification parameters of the liquid gas separator; 5. Input the calculated safety conditions of each part of the well killing system into the safety evaluation model as the fixed parameters X1 of the model.

[0066] In the example, the separator structure is a vertical two-phase separator, and the relevant parameters are shown in Table 1:

[0067] Table 1

[0068]

[0069] Variable data processing. The original variable data information of the input model is preprocessed in combination with field experience and related algorithms, mainly including the following steps:

[0070] 1. Use the wavelet decomposition and reconstruction method to remove high-frequency noise in the data, avoid abnormal data affecting the calculation results, and use the haar wavelet basis function to filter the data in the 10min window to 7 levels to remove the highest frequency noise;

[0071] 2. Use the average interpolation method to interpolate the original data into equal time interval time series data, and according to the time interval of the well killing data recorded in the field, the time data is interpolated into equal interval data;

[0072] 3. The wellhead casing pressure data, outlet flow data, outlet fluid density, outlet fluid total hydrocarbon content and other parameters are input into the safety evaluation model as the variable parameters X2 of the model; the safety index of each part of the well killing system calculated by the model is used as the output variable Y of the model.

[0073] In the python language environment, the wavelet decomposition and reconstruction algorithm of the data is realized through the pyWavelet library, the interpolation of the original data is realized through the interpolate library, the model function operation is realized through the numpy library, the formula is converted into program language, the safety factor of each part of the system is calculated in real time according to the input parameters, and finally the real-time dynamic display algorithm of the model safety evaluation result is realized through the FuncAnimation module and the pyplot module in the matplotlib library, the model is built, and the specific construction of the model is as follows.

[0074] The calculation of the safety index of the wellhead well killing equipment involves the calculation of the safety pressure limit of the well killing equipment, which can meet formula (3):

[0075] P max =fP; (3)

[0076] In the formula, P max is the safety pressure limit of the wellhead well killing equipment, MPa; f is the safety margin coefficient of the equipment, dimensionless; P is the maximum pressure limit of the wellhead well killing equipment, MPa.

[0077] At the same time, according to the wellhead casing back pressure obtained in real time during the well killing process, the safety of the wellhead well killing equipment can meet formula (4), and the normalized risk index is used to represent:

[0078]

[0079] In the formula, I a is the safety risk index of the wellhead blowout preventer, the value range is 0-1, the closer to 1, the greater the safety risk; P a is the wellhead casing back pressure, MPa; P max is the safety pressure upper limit of the wellhead well killing equipment, MPa.

[0080] Similarly, the casing weak position safety evaluation module and the casing shoe ground safety evaluation module respectively calculate the casing weak position safety index I c and the casing shoe ground safety index I f according to the casing weak position pressure upper limit, the casing weak position annulus pressure, the casing shoe ground fracture pressure and the casing shoe annulus pressure.

[0081] According to the selection standard of the liquid gas separator in the API standard, the safety conditions that should be met by the liquid gas separator during well killing are:

[0082] ①The gas flow entering the liquid gas separator should be less than the maximum actual separated gas flow to ensure that no liquid droplets are entrained in the gas into the gas pipeline.

[0083] ②The gas flow entering the liquid gas separator should be less than the maximum actual discharged gas flow to ensure that the gas will not accumulate in the separation tank to cause the tank pressure to rise.

[0084] ③The liquid flow entering the liquid gas separator should be less than the maximum actual discharged liquid flow to ensure that the liquid can be discharged from the separation tank in time to ensure that the tank liquid level will not continue to rise to block the input pipeline and the gas discharge pipeline.

[0085] That is, the fluid entering the liquid gas separator can meet formula (5) and formula (6):

[0086] C in Q in ≤min{Q GFmax , Q GPmax}*f; (5)

[0087] and

[0088] (1-C in )Q in ≤Q Lmax *f; (6)

[0089] In the formula, C inQ is the non-dimensional; Q in Q is the current fluid input condition under the liquid gas separator can meet the maximum actual separation gas flow, ft 3 Q is the non-dimensional; Q GFmax Q is the current fluid input condition under the liquid gas separator can meet the maximum actual separation gas flow, ft 3 Q is the non-dimensional; Q GPmax Q is the current fluid input condition under the liquid gas separator can meet the maximum actual separation gas flow, ft 3 Q is the non-dimensional; Q Lmax Q is the current fluid input condition under the liquid gas separator can meet the maximum actual separation gas flow, ft 3 Q is the non-dimensional.

[0090] Where the maximum actual separation gas flow Q GFmax The formula can meet formula (7):

[0091]

[0092]

[0093] In the formula V s The maximum gas superficial velocity of the liquid gas separator under the current input condition, ft / s; A is the internal gas flow area of the liquid gas separator, ft 2 ; K is the maximum gas superficial velocity coefficient of the liquid gas separator (determined by the maximum superficial velocity coefficient K in Table 2 according to API standard reference of different types and sizes of liquid gas separator), non-dimensional; d L The liquid density in the current input fluid, lb / ft 3 ; d G The gas density in the current input fluid, lb / ft 3 ; D is the inner diameter of the separator, ft.

[0094] The maximum superficial velocity coefficient K is shown in Table 2, the separator form is divided into vertical, horizontal, spherical three kinds of separator type, different height or length size of different separator type, corresponding to different K coefficient value range, K coefficient is the maximum gas superficial velocity coefficient of the liquid gas separator, used for calculating the maximum actual separation gas flow of the separator.

[0095] Table 2

[0096]

[0097] Where the maximum actual separation gas flow Q GPmax The formula can meet formula (9):

[0098]

[0099]

[0100] Where V G D is the maximum flow rate of gas in the discharge pipeline of the liquid-gas separator, ft / s; G is the inner diameter of the outlet pipe, ft; P G is the upper limit of the differential pressure meter range in the outlet pipeline, psf. Considering the complexity of fluid flow in the surface manifold, it is assumed here that the gas in the pipeline is a one-dimensional flow, viscosity is ignored, and it is an incompressible steady-state fluid.

[0101] Similarly, the maximum actual discharge liquid flow calculation formula can satisfy formula (10):

[0102]

[0103]

[0104] Where V L D is the maximum flow rate of the liquid in the discharge pipe, ft / s; L is the inner diameter of the liquid outlet pipe, ft; P L The upper limit of the pressure difference measurement range in the liquid outlet pipeline, psf.

[0105] After calculating the safety boundary conditions of the liquid-gas separator, the comprehensive liquid-gas separator safety factor is given based on the safety of the liquid phase pipeline and the gas phase pipeline, which can satisfy formula (11):

[0106]

[0107] Where I L It is the safety index of liquid-gas separator.

[0108] Figure 2 The following schematically shows a structural diagram of a device for real-time monitoring of safety risks of a well killing system according to an embodiment of the present application. Figure 2 As shown, an embodiment of the present application provides a device for real-time monitoring of safety risks of a well killing system, which may include:

[0109] Memory 210 configured to store instructions; and

[0110] The processor 220 is configured to call instructions from the memory 210 and implement the above-mentioned method for real-time monitoring of safety risks of a well killing system when executing the instructions.

[0111] Specifically, in the embodiment of the present application, the processor 220 may be configured to:

[0112] obtaining a maximum gas superficial velocity of the liquid-gas separator under the current input condition and an inner diameter of the liquid-gas separator;

[0113] determining a maximum actual separated gas flow rate of the liquid-gas separator according to the maximum gas superficial velocity and the inner diameter;

[0114] determining a first maximum flow rate of gas in the liquid-gas separator within the discharge pipeline and a second maximum flow rate of liquid in the liquid-gas separator within the discharge pipeline;

[0115] determining a maximum actual discharge gas flow rate of the liquid-gas separator based on the first maximum flow rate and the inner diameter;

[0116] determining a maximum actual discharge liquid flow rate of the liquid-gas separator based on the second maximum flow rate and the inner diameter;

[0117] determining a total hydrocarbon content and a flow rate of fluid input to the liquid-gas separator;

[0118] determining a safety index of the liquid-gas separator according to the maximum actual discharge liquid flow rate, the maximum actual discharge gas flow rate, the maximum actual separated gas flow rate, and the total hydrocarbon content and the flow rate of fluid input to the liquid-gas separator.

[0119] Further, the processor 220 can be further configured to:

[0120] determining the first maximum flow rate of gas in the liquid-gas separator within the discharge pipeline comprises:

[0121] obtaining a gas density input to the liquid-gas separator and an upper limit of a differential pressure gauge range within the gas outlet pipeline of the liquid-gas separator;

[0122] determining the first maximum flow rate based on the gas density and the upper limit of the differential pressure gauge range.

[0123] Further, the processor 220 can be further configured to:

[0124] determining the first maximum flow rate based on the gas density and the upper limit of the differential pressure gauge range comprises determining the first maximum flow rate according to formula (1):

[0125]

[0126] wherein P G is the upper limit of the differential pressure gauge range within the gas outlet pipeline, d G is the gas density, and V G is the first maximum flow rate.

[0127] Further, the processor 220 can be further configured to:

[0128] determining the second maximum flow rate of liquid in the liquid-gas separator within the discharge pipeline comprises:

[0129] Obtain the density of the liquid input to the gas-liquid separator and the upper limit of the differential pressure measurement range in the liquid outlet pipeline of the gas-liquid separator;

[0130] The second maximum flow rate is determined based on the liquid density and the upper limit of the differential pressure meter range in the liquid outlet pipeline.

[0131] Furthermore, the processor 220 may be further configured to:

[0132] Determining the second maximum flow rate based on the liquid density and the upper limit of the differential pressure measurement range in the liquid outlet pipeline includes determining the second maximum flow rate according to formula (2):

[0133]

[0134] Among them, P L The upper limit of the pressure difference measurement range in the outlet pipeline, d L is the liquid density, V L The second maximum flow rate.

[0135] Furthermore, the processor 220 may be further configured to:

[0136] Obtain the pressure exerted by the fluid in the well killing process on the wellhead casing and the upper limit of the safe pressure of the wellhead blowout preventer;

[0137] The safety index of the wellhead blowout preventer is determined based on the pressure exerted on the wellhead casing by the fluid in the well killing process and the upper limit of the safety pressure of the wellhead blowout preventer.

[0138] Furthermore, the processor 220 may be further configured to:

[0139] Obtaining the casing pressure upper limit and the first annular pressure at the casing weak position;

[0140] The safety index of the casing is determined based on the casing pressure upper limit at the casing weak position and the first annular pressure at the casing weak position.

[0141] Furthermore, the processor 220 may be further configured to:

[0142] Obtain the fracture pressure of the formation at the casing shoe and the second annulus pressure at the casing shoe;

[0143] A safety index of the formation at the casing shoe is determined based on a fracture pressure of the formation at the casing shoe and a second annulus pressure at the casing shoe.

[0144] By the technical solution, the processor 220 first acquires the maximum gas superficial velocity of the liquid-gas separator under the current input condition and the inner diameter of the liquid-gas separator; the processor 220 determines the maximum actual separated gas flow of the liquid-gas separator according to the maximum gas superficial velocity and the inner diameter; the processor 220 determines the first maximum flow velocity of the gas in the discharge pipeline in the liquid-gas separator and the second maximum flow velocity of the liquid in the discharge pipeline in the liquid-gas separator; the processor 220 determines the maximum actual discharged gas flow of the liquid-gas separator based on the first maximum flow velocity and the inner diameter; the processor 220 determines the maximum actual discharged liquid flow of the liquid-gas separator based on the second maximum flow velocity and the inner diameter; the processor 220 can determine the total hydrocarbon content and the flow of the fluid input to the liquid-gas separator; and the processor 220 determines the safety index of the liquid-gas separator according to the maximum actual discharged liquid flow, the maximum actual discharged gas flow, the maximum actual separated gas flow, and the total hydrocarbon content and the flow of the fluid input to the liquid-gas separator. The application can detect the safety index in the well killing operation in real time.

[0145] The embodiment of the application further provides a machine readable storage medium, which has instructions stored thereon, and the instructions are used to make the machine execute the method for real-time monitoring of safety risk of a well killing system.

[0146] Those skilled in the art should understand that the embodiments of the application can be provided as a method, a system or a computer program product. Therefore, the application can adopt a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the application can adopt a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0147] The application is described with reference to the flowcharts and / or block diagrams of the method, equipment (system), computer program product according to the embodiments of the application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general purpose computer, a special purpose computer, an embedded processor or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The function specified in one flow or multiple flows and / or blocks Figure 1 The device for implementing the function specified in one block or multiple blocks.

[0148] These computer program instructions can 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 instructions which implement the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0149] These computer program instructions can 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 that are executed on the computer or other programmable apparatus provide steps for implementing the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0150] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0151] The memory can include non-persistent memory and / or volatile memory, such as a random access memory (RAM) including a cache area for the temporary storage of data. The memory can also include non-volatile memory, such as read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, or a combination of non-volatile memories in different forms. The memory is an example of computer readable storage media.

[0152] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as 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 programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0153] It should also be noted that the terms "comprising", "comprises" or other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0154] The above embodiments are only used to illustrate the present application, but not to limit it. Instead of the above, various modifications and changes can be made to the application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall fall into the scope of the claims of the application.

Claims

1. A method for real-time monitoring of safety risks of a well killing system, characterized in that: The system includes a wellhead blowout preventer, casing, a formation at the casing shoe, and a liquid-gas separator, and the method includes: Obtaining the maximum gas superficial flow rate of the liquid-gas separator and the inner diameter of the liquid-gas separator under current input conditions; determining a maximum actual separation gas flow rate of the liquid-gas separator according to the maximum gas superficial velocity and the inner diameter; determining a first maximum flow rate of gas in the liquid-gas separator in the discharge line and a second maximum flow rate of liquid in the liquid-gas separator in the discharge line; determining a maximum actual exhaust gas flow rate of the liquid-gas separator based on the first maximum flow rate and the inner diameter; determining a maximum actual discharge liquid flow rate of the liquid-gas separator based on the second maximum flow rate and the inner diameter; determining the total hydrocarbon content and flow rate of the fluid input to the liquid-gas separator; The safety index of the liquid-gas separator is determined according to the maximum actual discharged liquid flow rate, the maximum actual discharged gas flow rate, the maximum actual separated gas flow rate, the total hydrocarbon content, and the flow rate of the fluid input to the liquid-gas separator.

2. The method according to claim 1, characterized in that Determining a first maximum flow rate of gas in the gas-liquid separator in the exhaust pipeline includes: Obtaining the density of the gas input to the liquid-gas separator and the upper limit of the differential pressure measurement range in the gas outlet pipeline of the liquid-gas separator; The first maximum flow rate is determined based on the gas density and the upper limit of the differential pressure measurement range in the gas outlet pipeline.

3. The method according to claim 2, characterized in that The determining of the first maximum flow rate based on the gas density and the upper limit of the differential pressure measurement range in the gas outlet pipeline includes determining the first maximum flow rate according to formula (1): Among them, P G is the upper limit of the pressure difference measurement range in the outlet pipeline, d G is the gas density, V G is the first maximum flow rate.

4. The method according to claim 1, wherein Determining a second maximum flow rate of the liquid in the discharge line of the liquid-gas separator includes: Obtaining the density of the liquid input into the liquid-gas separator and the upper limit of the differential pressure measurement range in the liquid outlet pipeline of the liquid-gas separator; The second maximum flow rate is determined based on the liquid density and the upper limit of the differential pressure measurement range in the liquid outlet pipeline.

5. The method according to claim 4, characterized in that Determining the second maximum flow rate based on the liquid density and the upper limit of the differential pressure measurement range in the liquid outlet pipeline includes determining the second maximum flow rate according to formula (2): Among them, P L is the upper limit of the pressure difference measurement range in the outlet pipeline, d L is the density of the liquid, V L is the second maximum flow rate.

6. The method according to claim 1, characterized in that The method further comprises: Obtaining the pressure exerted on the wellhead casing by the fluid in the well killing device and the upper limit of the safe pressure of the wellhead blowout preventer; The safety index of the wellhead blowout preventer is determined based on the pressure exerted on the wellhead casing by the fluid in the well killing and the upper limit of the safety pressure of the wellhead blowout preventer.

7. The method according to claim 6, characterized in that The method further comprises: Obtaining the casing pressure upper limit at the casing weak position and the first annular space pressure at the casing weak position; The safety index of the casing is determined based on the casing pressure upper limit at the casing weak position and the first annulus pressure at the casing weak position.

8. The method according to claim 7, characterized in that The method further comprises: obtaining the fracture pressure of the formation at the casing shoe and the second annulus pressure at the casing shoe; A safety index of the formation at the casing shoe is determined based on the fracture pressure of the formation at the casing shoe and the second annulus pressure at the casing shoe.

9. A device for real-time monitoring of safety risks in a well-killing system, characterized in that: include: a memory configured to store instructions; as well as The processor is configured to call the instructions from the memory and implement the method for real-time monitoring of safety risks of a well killing system according to any one of claims 1 to 8 when executing the instructions.

10. A machine-readable storage medium, characterized in that The machine-readable storage medium stores instructions for enabling a machine to execute the method for real-time monitoring of safety risks of a well killing system according to any one of claims 1 to 8.

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