Method for automatic load distribution between low-temperature separation process lines at integrated gas treatment plants of oil and gas condensate fields in the far north

Abstract

FIELD: oil and gas.SUBSTANCE: invention relates to the field of production and preparation of natural gas from Valanginian deposits for long-distance transportation at integrated gas treatment units (IGTU) of oil and gas condensate fields (OGCF) in the Far North of the Russian Federation, in particular to the automatic distribution of load between process lines (PL) of low-temperature separation with simultaneous maintenance of the level in three-phase liquid separators (LS), flow rate and density of unstable gas condensate (UGC) at the IGTU, fed into the main condensate pipeline (MCP). The purpose of the invention is to ensure automatic load distribution between the IGTU PL, maintaining the flow rate of dried gas and the density of the OGC at the IGTU, taking into account the state of the equipment involved in the process of preparing natural gas for long-distance transport, with simultaneous monitoring of the filling level of the LS, while observing the standards and restrictions stipulated by the process regulations of the unit for various modes of its operation.EFFECT: fulfilling the adjusted planned task for the preparation of dry gas at times of peak demand and preparation of OGC with a given density from natural gas at all stages of the operation of the OGCF, in compliance with the standards and restrictions according to the process regulations of the unit, maintaining the specified quality of the preparation of OGC supplied to consumers while simultaneously taking into account the actual condition of the equipment of each process line of the IGTU.4 cl, 2 dwg

Description

[0001] The invention relates to the field of production and preparation of natural gas from Valanginian deposits (hereinafter referred to as natural gas) for long-distance transportation at integrated gas treatment units (IGTU) of oil and gas condensate fields (OGCF) in the Far North of the Russian Federation, in particular, to the automatic distribution of the load between process lines (PL) of low-temperature separation with simultaneous maintenance of the level in three-phase liquid separators, hereinafter referred to as RL, the flow rate and density of unstable gas condensate (OGC) at the IGTU, fed into the main condensate pipeline (MCP).

[0002] A known method for automating a low-temperature gas separation unit includes automatically maintaining set temperatures and pressures in the unit [see, for example, p. 406, R.Ya. Isakovich, V.I. Loginov, V.E. Popadko. Automation of Production Processes in the Oil and Gas Industry. Textbook for Universities, Moscow, Nedra, 1983, 424 p.]. The degree of degassing of the oil and gas condensate in this method is maintained by heating it using a heating coil installed in the tank of the degasser-separator.

[0003] The disadvantage of this method is that, due to the inertia of the heating process and the lack of control over the density of the natural gas supplied to the MCP, the degree of degassing and the maintenance of the natural gas density during its supply to the MCP are carried out virtually "blindly," significantly reducing the quality of the natural gas supplied to consumers. Furthermore, when distributing the load between the low-temperature separation lines of the gas treatment plant, the condition of the equipment involved in preparing the natural gas for long-distance transport, which affects the quality of the product supplied to consumers, is completely ignored. There is also no control over the fill level of the three-phase liquid separators (hereinafter RL), which is a potential source of emergency situations associated with both overfilling and underfilling.

[0004] The closest in technical essence to the claimed invention is a method for automatic load distribution between low-temperature gas separation TLs at the OGCF UKPG in the North of the Russian Federation [RU Patent No. 2743870], which includes monitoring by means of the automated process control system (APCS) of the CGTP of the flow rate of dried gas entering the main gas pipeline (MGP), the flow rate of OGK entering the MCP, automatic maintenance of the gas separation temperature in the low-temperature separator of each TL at a given gas flow rate through it by changing the gas throttling degree at the nozzle located upstream of this separator. The task of the gas production enterprise (GPE) dispatcher for the volume of OGK preparation is sent to the APCS, which executes the task using a proportional-integral-differentiating (PID) controller for maintaining the flow rate of OGK in the MCP.The APCS sends the GDP dispatcher's setpoint signal to the SP input of this PID controller, and the current flow rate of the gas turbine unit in the MCP to the PV feedback input. The PID controller compares these parameters and generates a setpoint signal at its CV output, which is sent to the SP input of the PID controllers of all the TPs. Simultaneously, the APCS sends the actual flow rate of dry gas through the gas treatment plant to the PV feedback input of these PID controllers. This is also simultaneously sent to the input. The PID controller of each TL is fed a signal of the proportionality coefficient value (where i is the TL number), which determines the degree of influence of this PID controller on the gas flow control valve (GV) controlled by it according to its TL. In this case, the value of the proportionality coefficient is determined for each TL by its proportionality coefficient calculation unit depending on the current temperature in the low-temperature separator of this line according to the readings recorded by the APCS using the corresponding temperature sensor.

[0005] A significant disadvantage of this method is that due to the lack of control over the density value of the NGK supplied to the MCP, the degree of degassing and maintaining the density of the NGK in the TL is carried out practically “blindly”, without precise process control, which reduces the quality of the NGK supplied to consumers and there is no control over the filling level of the RZ, which is a potential source of emergency situations associated with both its overfilling and insufficient filling.

[0006] According to the technological process of collecting and preparing natural gas for long-distance transportation, natural gas from the production well clusters enters the UKPG - the switching valve building, from where it is distributed through a common raw gas collector to several (up to 8, and in the future - even more) identical TL [see p. 361, Andreev E.B. et al. Automation of technological processes for oil and gas production and preparation: a textbook for universities. - M .: OOO Nedra-Business Center, 2008. - 399 p.]. For example, at the Zapolyarnoye OGCF, UKPG-1V and UKPG-2V use four TL each.

[0007] During operation, for various reasons, such as sudden water discharges and sand production in natural gas wells, equipment corrosion, etc., the condition of the gas treatment plant equipment changes, leading to deterioration in the performance of the separators. This results in increased carryover of liquid droplets and mechanical impurities, which reduces the efficiency of the recuperative heat exchangers (RHEs) due to fouling of the heat exchange tube surfaces. The formation of hydrate and other deposits in the GPP units leads to changes in the pressure drop across them, which ultimately impacts their performance, i.e., the quality of the recovered natural gas, specifically its density.

[0008] It is clear that the condition of the gas pipeline equipment at the gas treatment plant (GTP) varies unevenly. Therefore, the actual performance of each pipeline will differ. Therefore, to improve the efficiency of the natural gas preparation process for long-distance transportation, it is necessary to distribute the load between the GTP pipelines in real-time, taking into account the actual condition of each line. This will significantly improve the quality of natural gas preparation for long-distance transportation while adhering to the standards and limitations of the GTP process regulations.

[0009] In practice, it is necessary to shut down and restart producing gas condensate wells, for example, during gas-hydrodynamic studies, when refining the reservoir pressure at a given site, etc., which leads to changes in the operating mode of the unit and, accordingly, to a change in the actual flow rate of gas condensate entering the gas condensate from the unit. This may result in situations of overfilling or underfilling of the gas condensate, which may lead to a halt in the process or cause gas locks and their accumulation in the gas condensate wellhead. Such changes may entail a number of adverse consequences and become a source of serious complications and accidents in the gas field. In some cases, these factors can lead to material, human, and environmental losses [see, for example, A.A. Korshak, A.I. Zabaznov, V.V. Novoselov et al. Pipeline transportation of unstable gas condensate. - M: VNIIOENG, 1994, p. 224].

[0010] The purpose of the invention is the automatic distribution of the load between the TL of the UKPG, maintaining the flow rate of dried gas and the density of the NGK at the UKPG, taking into account the state of the equipment involved in the process of preparing natural gas for long-distance transport, with simultaneous monitoring of the filling level of the RZh, while observing the standards and restrictions stipulated by the technological regulations of the installation for various modes of its operation.

[0011] The technical result achieved by implementing the invention is the automatic distribution of the load between the TL of the UKPG, ensuring control and maintenance of the level in the RZ, the flow rate of the dried gas and the density of the NGK at the UKPG, taking into account the state of the equipment involved in the process of preparing natural gas for long-distance transport, while observing the standards and restrictions stipulated by the technological regulations of the installation for various modes of its operation.

[0012] The claimed method ensures automatic load distribution between the liquefied natural gas pipelines of the gas treatment plant, maintaining a specified flow rate of dried gas and the density of the liquefied natural gas supplied to the microprocessor unit. This method controls the degassing pressure in the degasser-separator, taking into account the equipment status of each pipeline, and monitors the fill level of the liquefied natural gas. This improves the quality of the liquefied natural gas supplied to consumers and prevents the formation of gas locks and their accumulation in the microprocessor unit, increasing its operational reliability and reducing the risk of complications and accidents that could lead to serious environmental, human, and material losses.

[0013] The stated problem is solved, and the technical result is achieved due to the fact that the method of automatic load distribution between low-temperature separation process lines at integrated gas treatment plants at oil and gas condensate fields in the Far North includes control of the flow rate of dried gas by means of the automated process control system of the integrated gas treatment plant. , coming into the MGP, the consumption of oil and gas , entering the MCP. The automated process control system automatically maintains the gas separation temperature in the low-temperature separator of each TL at a given gas flow rate by varying the gas throttling degree at the nozzle located before this separator, and fulfills the task of the GDP dispatcher regarding the volume of dried gas preparation. The task for the volume of dry gas preparation is entered as a setpoint in the database (DB) of the automated process control system, which implements the plan for the preparation of dry gas by monitoring the observance of equality using PID controllers to maintain the flow rate of dried gas in the gas distribution system. For this purpose, the automated process control system sends a setpoint signal to the SP input of these PID controllers. , and at the same time, the PV feedback input of these PID controllers of the APCS sends a signal of the actual flow rate of the dried gas by the gas condensate treatment plant, comparing which each PID controller generates a control signal at its CV output - the value of the gas condensate mixture flow rate for its TL, at which the total contribution of all TL will ensure the specified planned volume of dry gas preparation according to the UKPG. Also, at the same time, a signal of the proportionality coefficient value is fed to the Kp input of the PID controller of each TL , which determines the degree of contribution of the i-th TL, where i is the TL number, to the process of maintaining a given volume of dry gas preparation at the gas treatment plant in real time. This proportionality coefficient sets the degree of influence of the PID controller on the controlled KR of the gas condensate mixture flow rate according to its TL, located before the low-temperature separator. In this case, the value of the proportionality coefficient is determined for each TL by its proportionality coefficient calculation unit.

[0014] The automated process control system of the gas treatment plant, when executing the adjusted planned task for the preparation of dry gas at moments of peak load for its consumption, automatically maintains the density of the NGK prepared by each TL individually, ensuring its compliance with the task - the density setpoint This is achieved by controlling the vented gas pressure in its gas handling system, implemented by a cascade of two PID controllers. To achieve this, the process control system sends a setpoint signal to the SP input of the first controller. , common to all TL, and to its feedback input PV it supplies an individual signal of the density value of the NGC , recorded by the density sensor measuring the oil and gas component, coming from the i-th TL's RJ to the MCP. As a result of processing these signals, the first PID controller of the cascade generates a pressure setpoint value at its CV output. , which must be maintained in the RZh of the i-th TL to achieve the specified density of the NGC at the output of the i-th TL. The signal of this setting is fed to the SP input of the second PID controller of the pressure maintenance cascade in the IL of the i-th TL. At this time, the ventilated gas pressure signal is fed to its PV feedback input. in the pressure gauge of the i-th TL, recorded by the pressure sensor installed on its output line. As a result of processing these signals, the second PID controller generates a control signal at its CV output , which is fed as a control signal to the KR, which regulates the pressure of the exhaust gases in the RZh i-th TL.

[0015] In each measurement cycle, the process parameter compliance control unit for the i-th TL checks the compliance of the actual values ​​of the process parameters with the established limits: the level of the NGK in RZh; degrees of opening - the position of the working element of the KR regulating the pressure of the exhaust gases in the RZh; the flow rate of the dried gas ; temperatures in the low-temperature separator of the i-th TL. This control unit performs this check by assessing the compliance of the controlled parameters with the specified limits, using the following inequalities, which represent a complex individual condition for the normal operation of the i-th TL's technological process:

[0016]

[0017] where And - settings for the minimum and maximum values ​​of the oil and gas level in the RZh, respectively; And - settings for the minimum and maximum degree of opening of the valve regulating the pressure of exhaust gases in the hydraulic fluid, respectively; And - settings of the minimum and maximum flow rate of dried gas of the i-th TL, respectively; And - minimum and maximum temperature settings in the low-temperature separator of the i-th TL, respectively. Maintenance personnel set these setpoints based on the equipment manufacturer's specifications and the requirements of the process regulations for the unit.

[0018] If, as a result of checking the condition for normal operation of the technological process, the i-th control unit establishes that it is observed in the given measurement cycle simultaneously for all the inequalities that make it up, then it generates a logical “zero” signal at its output O, which is then fed to the start / stop input of the PID controller that controls the volume of preparation of the dried gas at the i-th TL, allowing it to control the KR flow rate of the gas condensate mixture through it.

[0019] But if during the technological process at least one of the values , , And If the i-th TL reaches its preset limit value or exceeds its specified limits during the next measurement cycle, this control unit generates a logical "one" signal at its output O, which is fed to the "start / stop" input of the PID controller, which controls the dry gas processing volume at the i-th TL. As soon as this PID controller receives this signal, it pauses its operation, storing the previous control signal value calculated in the previous calculation cycle at its CV output. As a result, the i-th TL is excluded from the control process, but it continues to operate with the process parameters recorded at the time of its exclusion from the control process.

[0020] When the i-th TL is removed from the control process, all changes in the gas dehydration load are automatically distributed among the operating TLs whose operating parameters correspond to their individual normal process conditions. This operating mode continues until maintenance personnel eliminate the cause of the process disruption that caused the i-th TL to be removed from the control process. Once compliance with the integrated normal process conditions for the i-th TL is restored, its control unit sets a logical "zero" signal at its output O. This signal is fed to the "start / stop" input of the PID controller, which controls the volume of dehydrated gas preparation at the i-th TL, permitting its inclusion in the overall control system for automatic load distribution among the CGTP TLs.

[0021] Proportionality coefficient value calculates an individual block for calculating the proportionality coefficient for the PID controller that controls the volume of dry gas preparation at the i-th TL, using the following formulas:

[0022] - if the performance of the TL needs to be increased, i.e. , then the value he calculates using the formula:

[0023]

[0024] - and if the TL performance needs to be reduced, i.e. , then the value he calculates using the formula:

[0025]

[0026] where - the current value of the oil and gas level in the liquid phase of the i-th TL, controlled by a level sensor, the signal of which is fed to the input I2 of the proportionality coefficient calculation block for the PID controller of the i-th TL;

[0027] And - the minimum and maximum levels of the NGK in the RP of the i-th TL are set according to the RP passport, and their signals are fed to the inputs I1 and I3 of the proportionality coefficient calculation block for the PID controller of the i-th TL, respectively;

[0028] And - the settings of the minimum and maximum values ​​of the proportionality coefficient for the PID controller of the i-th TL, which are assigned based on the state of the process equipment of this TL, taking into account the technological standards and restrictions provided for by the technological regulations of the installation, and their signals are fed to inputs I4 and I5 of the proportionality coefficient calculation block for the PID controller of this line, respectively.

[0029] All specified settings for all TL are entered by the operating personnel into the DB of the automated process control system of the gas treatment plant before putting the plant into operation, and during operation all calculations according to the given formulas, they are limited by the following condition:

[0030]

[0031] If all the TL units have exhausted their capabilities to comply with their individual conditions for the normal conduct of the technological process, the APCS generates a message to the unit operator about the impossibility of maintaining the specified values ​​of the flow rate and density of the NGK for the GPP and the need to change its operating mode.

[0032] When implementing the adjusted planned task for the preparation of dry gas at times of peak load for its consumption, the resulting surplus of NGK preparation is sent to the NGK tank farms of the GDP and / or the NGK processing complex with subsequent adjustment of the NGK supply plan to consumers under the MCP.

[0033] Fig. 1 shows a high-level schematic flow diagram of a gas treatment plant with gas throttling at the nozzle to achieve low temperatures. To simplify the presentation of the application, Fig. 1 shows the sensor and control system connections for only one – the first – gas line. Fig. 2 shows a block diagram of the automatic control of load distribution between the gas treatment plant's gas lines, maintaining the level, flow rate, and density of the crude oil supplied to the microprocessor unit in the gas pressure regulator.

[0034] The following notations are used in Fig. 1:

[0035] 1 - raw gas collector;

[0036] 2 - collector of aqueous inhibitor solution (AIC);

[0037] 3 i - separator of the first stage of separation of the i-th TL, (i = 1, 2, …, n, where n is the number of TL at the gas treatment plant);

[0038] 4 i - RZ i-th TL;

[0039] 5 i - pressure sensor of venting gases in the i-th TL;

[0040] 6 i - oil level sensor in the i-th TL;

[0041] 7 i- sensor for measuring the flow rate and density of the i-th TL oil and gas complex;

[0042] 8 i - KR of the pressure of the weathering gases of the i-th TL;

[0043] 9 - automated process control system of the gas treatment plant;

[0044] 10 i - TO "gas-gas" i-th TL;

[0045] 11 i - TO "gas condensate" i-th TL;

[0046] 12 - vented gas collector;

[0047] 13 i - intermediate separator of the i-th TL;

[0048] 14 i - KR of gas condensate mixture flow rate of the i-th TL;

[0049] 15 i - low-temperature separator of the i-th TL;

[0050] 16 i - dry gas flow sensor of the i-th TL;

[0051] 17 i - temperature sensor in low-temperature separator 15 i i-th TL;

[0052] 18 - IGP;

[0053] 19 - Manual transmission.

[0054] The following notations are used in Fig. 2:

[0055] 20 i - vented gas pressure signal in RZh 4 i i-th TL (comes from sensor 5 i);

[0056] 21 i - signal of actual density of oil and gas (comes from sensor 7 i ) i-th TL;

[0057] 22 - setpoint signal - density of the oil and gas complex by the gas treatment plant (comes from the automated process control system 9 to the input of the SP task of all PID controllers 23);

[0058] 23 i - PID controller for maintaining the density of the i-th TL oil and gas pipeline;

[0059] 24 i - PID controller for maintaining the pressure of the venting gas of the i-th TL;

[0060] 25 i - control signal sent to KR 8 i i-th TL;

[0061] 26 i - setpoint signal - minimum level of NGC in RZh 4 i i-th TL;

[0062] 27 i - actual value signal level of NGK in RZh 4 i i-th TL (comes from sensor 6 i );

[0063] 28 i - setpoint signal - the maximum level of NGC in the RZh 4 i i-th TL;

[0064] 29 i - setpoint signal - minimum opening degree of the KR 8 i i-th TL;

[0065] 30 i - actual signal degree of opening of the KR 8 i i-th TL;

[0066] 31 i - setpoint signal - maximum opening degree of the KR 8 i i-th TL;

[0067] 32 i - setpoint signal - minimum flow rate of dried gas of the i-th TL;

[0068] 33 i - actual consumption signal dried gas of the i-th TL (comes from sensor 16 i );

[0069] 34 i - setpoint signal - maximum flow rate of dried gas of the i-th TL;

[0070] 35 i - setpoint signal - minimum temperature in the low-temperature separator 15 i i-th TL;

[0071] 36 i - actual temperature signal in low-temperature separator 15 i i-th TL (comes from sensor 17 i );

[0072] 37 i- setpoint signal - maximum temperature in the low-temperature separator 15 i i-th TL;

[0073] 38 i - a block for monitoring the compliance of the technological process parameters with the established boundaries of the i-th TL;

[0074] 39 - plan setpoint signal preparation of dried gas for the gas treatment plant (comes from the automated process control system 9 to the input of the SP PID controllers 44);

[0075] 40 - actual consumption signal dried gas according to the gas treatment plant (APCS 9 is determined by summing up the readings of sensors 16 i );

[0076] 41 i - setpoint signal - minimum value of the proportionality coefficient for the PID controller 44 i i-th TL;

[0077] 42 i - setpoint signal - maximum value of the proportionality coefficient for the PID controller 44 i i-th TL;

[0078] 43 i- block for calculating the proportionality coefficient for PID controller 44 i i-th TL;

[0079] 44 i - PID controller that controls the volume of dry gas preparation by the i-th TL;

[0080] 45 i - control signal sent to KR 14 i consumption of gas condensate mixture of the i-th TL.

[0081] The process of preparing natural gas for long-distance transportation at the gas processing plant, the process flow diagram of which is shown in Fig. 1, includes:

[0082] Primary separation of natural gas in inlet separators 3 i ;

[0083] Cooling the inlet flow of gas condensate mixture in TO 10 i "gas-gas" with a flow of cooled gas and in TO 11 i "gas-condensate" with a flow of cooled condensate mixture with VRI;

[0084] intermediate separation of gas condensate mixture in separators 13 i for its subsequent division;

[0085] Cooling the gas condensate mixture by throttling the flow at KR 14 i;

[0086] final separation of cooled gas condensate mixture in low-temperature separators 15 i .

[0087] Maintaining a given density of NGK by controlling the process of its degassing in RZh 4 i .

[0088] PID controllers 231…, 23 n , 241…, 24 n , 441…, 44 n , control units 381…, 38 n , as well as calculation blocks 431…, 43 n , implemented on the basis of APCS 9.

[0089] The method of automatic load distribution between low-temperature separation process lines at integrated gas treatment plants at oil and gas condensate fields in the Far North is implemented as follows.

[0090] Natural gas from production well clusters enters the gas treatment plant (GTP) in the switching valve building, from where it is distributed through raw gas manifold 1 via inlet lines to the gas transfer lines. For simplicity, we will consider the operating principle of only one gas transfer line, the i-th gas transfer line, since all gas transfer lines operate in the same manner.

[0091] Natural gas is fed through the inlet line to the first stage separator 3 i , in which the liquid phase (formation water with dissolved inhibitor and condensed hydrocarbon condensate) is separated, which enters the RZh 4 i The separated gas condensate mixture is sent to TO 10 i "gas-gas" and TO 11 i "gas-condensate" for cold recovery from the throttled (cooled) gas flow and the separated condensate mixture with the VRI, removed from separators 13 i and 15 i, respectively. To prevent hydrate formation, a hydrate inhibitor (not shown in Fig. 1) is injected into the mixture flow before the TO. Then, the cooled gas-liquid mixture flows from the TO 10 outlets i "gas-gas" and TO 11 i "gas-condensate" are combined and fed to the input of the intermediate separator 13 i , where further separation of the liquid phase occurs. From the outlet of the intermediate separator 13 i gas-liquid mixture through the flow control valve 14 i enters the low-temperature separator 15 i , where condensed liquid hydrocarbons and VRI are finally separated from the gas condensate mixture flow.

[0092] Automatic maintenance of gas separation temperature in low-temperature separator 15 i The automated process control system TP 9 carries out the control at a given value of gas flow rate by changing the degree of gas throttling at the nozzle KR 14 i consumption of gas condensate mixture of the i-th TL.

[0093] Dried gas from low-temperature separator 15 i passes through maintenance 10 i "gas-gas", where it is heated and through a pipeline equipped with a dry gas flow sensor 16 i , enters the MGP 18. The liquid phase is a mixture of NGK and VRI from the low-temperature 15 i and intermediate separator 13 i , passing through TO 11 i "gas-condensate" gives off cold to the oncoming flow of gas-condensate mixture, after which it mixes with the liquid phase removed from separator 3 i , and then goes to RZh 4 i .

[0094] The set density of the NGK is automatically maintained by regulating the gas pressure in the RZh 4 i using KR 8 i , installed at its outlet. For this purpose, the vented gas, which is a mixture of low-density hydrocarbons, is removed through KR 8 iinto the exhaust gas collector 12 and sent for compression for further feeding to the MGP 18, or for disposal. The exhaust gas discharged from the lower part of the RZh 4 i , through the VRI 2 collector, it is sent for regeneration to the inhibitor regeneration shop of the UKPG. The NGK flow is diverted through a pipeline equipped with a Coriolis flow meter 7 i With the ability to measure the density of NGK. NGK flows from all TLs are combined and fed to MKP 19 for further transportation to consumers.

[0095] When peak demand for dry gas occurs, for example due to severe cold weather at its consumers, especially in winter, the Valanginian gas treatment plants typically switch to supporting the adjusted dry gas preparation target. At such times, the volume of dry gas preparation at the NGK , as a rule, exceeds the specified planned supply volume of oil and gas to consumers via the MCP. In this situation, excess NGK preparation is sent to the NGK GDP tank farms and / or the NGK processing complex, with subsequent adjustment of the NGK supply plan. to consumers via the MCP. At such times, the preparation of dry gas occurs as follows.

[0096] The traffic controller sets an adjusted training plan dried gas according to the UKPG setpoint, which is entered into the APCS 9 database, and it supports the implementation of this planned task using PID controllers 44. For this, the APCS 9 sends a common signal 39 - the setpoint value - to the SP input of all these PID controllers - a plan for preparing dry gas for the gas treatment plant, and at the same time, a signal 40 is sent to their PV feedback input - the value of the actual flow rate of dry gas according to the gas treatment plant, which is determined by summing the readings of the gas flow sensors 16 i for all TL.

[0097] 44 PID controllers continuously monitor the compliance of the actual dry gas preparation all TL UKPG plan specified by the setpoint If the compliance check reveals that:

[0098] ,

[0099] Then PID controllers 44 generate a control signal at their output to increase the passage of the prepared dried gas through the gas treatment plant.

[0100] If it is found that:

[0101] ,

[0102] Then PID controllers 44 generate a control signal at their output to reduce the flow of treated dry gas through the gas treatment plant. As a result, the flow rate of dry gas through the gas treatment plant will be increased in the first case, or decreased in the second case, by all PID controllers 44 controlling their KR 14 simultaneously. This increase or decrease in TL performance is carried out until the gas treatment plant reaches its planned target. upon supply of dried gas to the MGP, i.e. until the compliance condition is met:

[0103] .

[0104] Load distribution between TL is carried out taking into account the state of the process equipment by applying to the Kp input of the PID controller 44 i signal of the value of the proportionality coefficient K п_i , which is calculated individually for each i-th TL by its calculation block 43 i according to the following formulas:

[0105] - if the performance of the TL needs to be increased, i.e. , then the value is determined by the formula:

[0106]

[0107] - if the TL performance needs to be reduced, i.e. , then, meaning is determined by the formula:

[0108]

[0109] where - current value of the level of NGC in RZh 4 i , which comes from level sensor 6 i, installed on RZh 4 i ; , - settings - minimum and maximum level of NGK in RZh 4 i , respectively, are installed by service personnel in accordance with their passport; , - settings - the minimum and maximum values ​​of the proportionality coefficient, also set by the operating personnel. Values , are determined based on the state of the technological equipment of each TL at the time of starting up the installation, taking into account the technological standards and restrictions stipulated by the technological regulations of the installation.

[0110] Calculation according to formulas (1) and (2) are limited by the following conditions:

[0111]

[0112] When the dry gas capacity of the gas treatment plant needs to be increased, the TLs with the highest capacity reserve will be activated first. Conversely, if the dry gas capacity of the gas treatment plant decreases, attention will be given to unloading the TLs operating at or near maximum capacity.

[0113] To maintain the set value of the NGK density, the maintenance personnel sets the set value , which is loaded into the APCS 9 database. From it, the setpoint in the form of signal 22, the APCS 9 sends to the input of the SP tasks of all PID controllers 23, each of which maintains the density of the NGK in the RZh 4 of its TL. Simultaneously, to the feedback input PV of each of these PID controllers 23 i ACS TP 9 sends an individual signal 21 i - the value of the density of the NGC , recorded by sensor 7 i , measuring the density of the NGK coming from RZh 4 iin the MCP 19. As a result of processing these signals, each PID controller 23 i generates a pressure setpoint value at its CV output , which must be maintained in RZh 4 i to achieve the specified density of the NGK at the output of the i-th TL. The signal from each of these settings is then fed to the SP input of the PID controller 24 i maintaining pressure in the RZh 4 i . Simultaneously, 24 PID controllers are fed to the PV feedback input. i give signal 20 i pressure of weathered gas in RZh 4 i , recorded by sensor 5 i , installed on its output line.

[0114] As a result, at its output, the CV PID controller 24 i generates a control signal , which serves as a control signal 25 i arrives at KR 8 i , maintaining the pressure of the flash gas in RZh 4 i i-th TL.

[0115] Control unit 38 iin each measurement cycle, it checks the compliance of the actual values ​​with the requirements of the technological process: the level of the NGC in RZh 4 i (signal 27 i , comes from level sensor 6 i ); degrees of opening for KR 8 i (signal 30 i , issued by the automated process control system based on monitoring the actual position of the working body of the KR 8 i ); consumption of dried gas (signal 33 i , comes from sensor 16 i ); temperatures in low-temperature separator 15 i (signal 36 i , comes from sensor 17 i ) i-th TL. This check is carried out by control unit 38 i is carried out by assessing the compliance of the controlled parameters with the specified limits, using for this the following inequalities, which represent a complex individual condition for the normal conduct of the technological process of the i-th TL:

[0116]

[0117] where - setting the minimum value of the NGK level in RZh 4 i ;

[0118] - setting the maximum value of the NGK level in RZh 4 i ;

[0119] - setting of the minimum degree of opening of KR 8 i ;

[0120] - setting the maximum degree of opening of KR 8 i ;

[0121] - setting of the minimum flow rate of dried gas of the i-th TL;

[0122] - setting of the maximum flow rate of dried gas of the i-th TL;

[0123] - setting the minimum temperature in the low-temperature separator to 15 i ;

[0124] - setting the maximum temperature in the low-temperature separator to 15 i .

[0125] Setting values , , , , , , And - the service personnel sets the parameters based on the passport data provided by the manufacturer of this equipment, as well as the requirements of the technological regulations for this installation.

[0126] If, as a result of checking the normal process conditions, control unit 38 i establishes that it is observed in a given measurement cycle simultaneously for all the inequalities that make it up, then at its output O it generates a logical “zero” signal, which is then fed to the start / stop input of the PID controller 44 i , controlling the volume of preparation of dried gas at the i-th TL, allowing it to control KR 14 i consumption of gas condensate mixture through it.

[0127] If during the technological process at least one of the values , , And The i-th TL reaches its set limit value or goes beyond the specified boundaries, then control unit 38 igenerates a logical "one" signal at its output O. This signal is fed to the "start / stop" input of PID controller 44 i , which controls the volume of dry gas preparation at the i-th TL. Having received this signal, PID controller 44 i pauses its operation, storing at its CV output the previous value of the control signal, which was calculated in the previous calculation cycle.

[0128] When such a situation occurs, the APCS 9 generates a message to the plant operator, informing them of the problem on the i-th TL, and this line is excluded from the control process. However, it continues to operate with the process parameters recorded at the time it was excluded from the control process.

[0129] During the i-th TL's removal from the control process, all changes in the gas dehydration load will be automatically distributed among operating TLs whose operating parameters correspond to their individual process conditions. This operating mode will continue until maintenance personnel eliminate the cause of the process disruption that caused the i-th TL's removal from the control process.

[0130] As soon as compliance with the complex condition for normal operation of the technological process for the i-th TL is restored, control unit 38 i sets a logical “zero” signal at its output O, which is fed to the “start / stop” input of PID controller 44 i , allowing its inclusion in the general control system for automatic load distribution between the TL UKPG.

[0131] If all TLs have exhausted their capabilities to comply with their individual conditions for the normal conduct of the technological process, the APCS 9 generates a message to the plant operator about the impossibility of maintaining the specified values ​​of the flow rate of dried gas and the density of the NGK at the GPP and the need to change its operating mode.

[0132] The adjustment of the PID controllers used is carried out by the maintenance personnel at the moment of starting the system for a specific operating mode of the installation according to the method described, for example, in the “Encyclopedia of APCS”, section 5.5, PID controller, resource: http: / / www.bookasutp.ru / Chapter5_5.aspx#HandTuning.

[0133] A method for automatically distributing the load between low-temperature separation process lines at integrated gas treatment units at oil, gas, and condensate fields in the Far North has been implemented at Gazprom PJSC and Gazprom Dobycha Yamburg LLC at the Zapolyarnoye oil, gas, and condensate field at UKPG 1V and UKPG 2V. Operational results have demonstrated its high efficiency. The claimed invention can be widely used at other operating and newly developed gas condensate fields in the northern Russian Federation.

[0134] The use of this method allows the gas treatment plant to provide a specified volume of dry gas preparation and obtain NGK with the required quality characteristics from natural gas at all stages of the NGKM operation, while adhering to the standards and limitations of the plant's process regulations. Moreover, all specified product characteristics supplied to consumers are achieved while simultaneously taking into account the actual condition of the equipment at each process line of the CGTU.

Claims

1. A method for automatically distributing the load between process lines – low-temperature separation lines at integrated gas treatment plants – UKPG of oil and gas condensate fields in the Far North, including control by means of an automated process control system – ACS TP UKPG of the flow rate of dried gas , entering the main gas pipeline - MGP, the flow rate of unstable gas condensate - NGK , entering the main condensate pipeline - MCP, automatic maintenance of the gas separation temperature in the low-temperature separator of each TL at a given value of gas flow through it by changing the degree of gas throttling at the nozzle located in front of this separator, and fulfilling the task of the gas production enterprise dispatcher - GPE for the volume of preparation of dried gas , which is entered as a setpoint in the database – the APCS DB, which implements the plan for preparing dry gas, monitoring the observance of equality using proportional-integral-differentiative (PID) controllers for maintaining the flow rate of dried gas, each of which controls the flow rate of the gas condensate mixture according to its TL, to the input of the SP task of which the automated process control system sends a setpoint signal , and the actual flow rate of dried gas is sent to the PV feedback input of these PID controllers of the APCS by the gas condensate treatment plant, comparing which, each PID controller generates a control signal at its CV output - the value of the gas condensate mixture flow rate for its TL, at which the total contribution of all TL will ensure the specified planned volume of dry gas preparation according to the UKPG, and also simultaneously a signal of the proportionality coefficient value is fed to the Kp input of the PID controller of each TL , which determines the degree of contribution of the given i-th TL, where i is the TL number, to the process of maintaining a given volume of dry gas preparation at the gas treatment plant in real time by setting the degree of influence of this PID controller on the valve-regulator controlled by it – the KR of the gas condensate mixture flow rate at its TL, located in front of the low-temperature separator, while the value of the proportionality coefficient is determined for each TL by its proportionality coefficient calculation unit, characterized in that the automated process control system of the gas treatment plant, when executing the adjusted planned task for the preparation of dry gas at moments of peak load for its consumption, automatically maintains the density of the NGK prepared by each TL individually, achieving its compliance with the task - the density setpoint The NGK for the UKPG, by controlling the pressure of the vented gas in its three-phase liquid separator, hereinafter referred to as the LS, implemented by a cascade of two PID controllers, and for this purpose the APCS sends a setpoint signal to the input of the SP task of the first of them , common to all TL, and to its feedback input PV it supplies an individual signal of the density value of the NGC , recorded by the density sensor measuring the NGK, coming from the RZh i-th TL to the MCP, and as a result of processing these signals, the first PID controller of the cascade generates a pressure setpoint value at its CV output , which must be maintained in the RF of the i-th TL to achieve the specified density of the NGK at the output of the i-th TL, and this signal is fed to the input of the SP setting of the second PID controller of the cascade for maintaining pressure in the RF of the i-th TL, and at this time the signal of the ventilated gas pressure is fed to its feedback input PV in the pressure of the i-th TL, recorded by the pressure sensor installed on its output line, and as a result of processing these signals, the second PID controller generates a control signal at its CV output , which is sent as a control signal to the control unit that regulates the pressure of the exhaust gases in the RZh of the i-th TL, and in each measurement cycle, the control unit for the compliance of the process parameters with the established limits for the i-th TL checks the compliance of the actual values ​​of the level of the NGK with the requirements of the process in RZh; degrees of opening - the position of the working element of the KR regulating the pressure of the exhaust gases in the RZh; the flow rate of the dried gas ; temperatures in the low-temperature separator of the i-th TL, and this control unit carries out the specified check by assessing the compliance of the controlled parameters with the specified limits, using for this the following inequalities, which represent a complex individual condition for the normal conduct of the technological process of the i-th TL: Where And – settings for the minimum and maximum values ​​of the oil and gas level in the RZh, respectively; And – settings for the minimum and maximum degree of opening of the valve regulating the pressure of exhaust gases in the hydraulic fluid, respectively; And – settings of the minimum and maximum flow rate of dried gas of the i-th TL, respectively; And – the minimum and maximum temperature settings in the low-temperature separator of the i-th TL, respectively, and the values ​​of these settings are set by the operating personnel based on the passport data provided by the manufacturer of this equipment, as well as the requirements of the process regulations for this installation, and if, as a result of checking the condition for normal operation of the technological process, the i-th control unit establishes that it is observed in this measurement cycle simultaneously for all the inequalities that make it up, then at its output O it generates a logical “zero” signal, which is then fed to the start / stop input of the PID controller that controls the volume of preparation of dried gas at the i-th TL, allowing it to control the KR flow rate of the gas condensate mixture through it, but if during the technological process at least one of the values , , And If the i-th TL in the next measurement cycle reaches its set limit value or goes beyond the specified boundaries, then this control unit generates a logical "one" signal at its output O, and this signal is fed to the "start\stop" input of the PID controller that controls the volume of dry gas preparation at the i-th TL, and as soon as this PID controller receives this signal, it suspends its operation, storing at its CV output the previous value of the control signal, which was calculated in the previous calculation cycle, as a result of which this i-th TL is excluded from the control process, but it continues to function with the process parameters recorded at the time of its exclusion from the control process, and during the removal of the i-th TL from the control process, all changes in the gas drying load are automatically distributed between the operating TL,the technological operating parameters of which correspond to their individual condition of normal technological process management, and this mode of their operation continues until the maintenance personnel eliminate the cause of the disruption of the technological process that caused the withdrawal of the i-th TL from the control process, and as soon as compliance with the complex condition of normal technological process management for the i-th TL is restored, its control unit sets a logical "zero" signal at its output O, which feeds into the "start / stop" input of the PID controller that controls the volume of dry gas preparation at the i-th TL, allowing its inclusion in the general control system of automatic load distribution between the TL of the UKPG.

2. The method according to paragraph 1, characterized in that the value of the proportionality coefficient calculates an individual block for calculating the proportionality coefficient for the PID controller that controls the volume of dry gas preparation at the i-th TL, using the following formulas: - if the productivity of the TL needs to be increased, i.e. , then the value he calculates using the formula: - and if the productivity of the TL needs to be reduced, i.e. , then the value he calculates using the formula: Where – the current value of the oil and gas level in the RZh of the i-th TL, controlled by the level sensor, the signal of which is fed to the input I2 of the proportionality coefficient calculation block for the PID controller of the i-th TL; And – the minimum and maximum levels of the NGK in the RP of the i-th TL are set according to the RP passport, and their signals are fed to the inputs I1 and I3 of the proportionality coefficient calculation block for the PID controller of the i-th TL, respectively; And – the settings of the minimum and maximum values ​​of the proportionality coefficient for the PID controller of the i-th TL, which are assigned based on the state of the process equipment of this TL taking into account the technological standards and limitations provided for by the technological regulations of the installation, and their signals are fed to the inputs I4 and I5 of the block for calculating the proportionality coefficient for the PID controller of this line, respectively, and all the specified settings for all TL are entered by the maintenance personnel into the DB of the automated process control system of the gas treatment plant before putting the installation into operation, and during operation all calculations according to the given formulas, they are limited by the following condition:

3. The method according to paragraph 1, characterized in that the automated process control system generates a message to the plant operator about the impossibility of maintaining the specified values ​​of the flow rate and density of the NGK at the gas treatment plant and the need to change its operating mode if all the TL of the plant have exhausted their capabilities to comply with their individual conditions for the normal conduct of the technological process.

4. The method according to paragraph 1, characterized in that when the adjusted planned task for the preparation of dry gas is carried out at times of peak load for its consumption, the resulting surplus of NGK preparation is sent to the NGK tank farms of the GDP and / or the NGK processing complex with subsequent adjustment of the NGK supply plan. to consumers under the MCP.

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