RU2506505C1 - Device for gas treatment with remote control terminal and use of software system for automatic flow control - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention pertains to oil and gas industry and it can be used for gas treatment at oil and gas condensate deposits in order to reduce capital and operational costs. Gas treatment installation is equipped with automatic control system (ACS) connected to shutoff and control valves including the first throttle valve at gas feed line, the second throttle valve installed at the line connecting primary and low-temperature separators, the third and fourth throttle valves installed at lines connecting outputs of primary and low-temperature separators for liquid-gas mixture respectively with degasifier, the fifth throttle valve installed at line of liquid discharge from degasifier and the sixth throttle valve installed at line of gas release from degasifier. The installation is equipped with the first flow metre at gas feed line and the second flow metre at line of gas discharge from low-temperature separator connected to ACS and having ability to regulate degree of opening and closure for the first throttle valve, temperature sensor at input of low-temperature separator connected to ACS and having ability to regulate degree of opening and closure for the second throttle valve, liquid level gage in primary and low-temperature separators and degasifier connected to ACS and having ability to regulate degree of opening and closure for the third. Fourth and fifth throttle valves respectively and pressure nozzle in degasifier connected to ACS and having ability to regulate consumption of inhibitor depending on pressure of gas in feed line or its flow rate. ACS uses software system for gas treatment regulation which includes regulation of process parameters in automatic mode.

EFFECT: designing installation for primary treatment of gas supplied from gas wells in clusters that operates in unmanned mode due to use of software system for automatic regulation of gas treatment.

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Description

The invention relates to the gas and oil industries and can be used in the preparation of gas from oil and gas condensate fields to reduce capital and operating costs.

Known methods for the preparation of gas condensate mixtures and installation for their implementation.

A well-known installation of integrated gas preparation for transport (RU 77405 U1), in which gas from gas well clusters is supplied to an inlet separator for the production of gas condensate wells, then to a recuperative gas-gas heat exchanger and an ejector, then to a low-temperature separator, separators of the first and second steps and weathering. At the same time, the installation is additionally equipped with a bypass line on the recuperative gas-gas heat exchanger with a temperature controller installed on it, and the first stage separator is located directly under the inlet separator and is rigidly connected to it by nozzles, forming a single design.

The disadvantage of this installation is that it works only if there are maintenance staff, a support base for the field and a shift housing complex (with a large distance of the hydrocarbon field from urban settlements), which leads to an increase in capital and operating costs.

A known method of operating a gas field (RU 2367782 C1), which consists in the fact that when developing a gas field, remote, automatic and manual control of actuators of the shut-off organs of the wells is used. At the same time, part of the production wells of the bush, field, and field are connected to a station or block of control stations for fountain fittings and an underground shutoff valve.

Each of these stations is equipped with a pump-accumulator unit and a control unit for shutoff organs connected to it via a working fluid. Well control is carried out with automatic provision of the logical sequence of closure: lateral valve-over-valve valve-underground valve-shut-off, produced through slowdown systems.

The disadvantage of this system is that it reduces, but does not exclude the presence of maintenance personnel and, as a result, does not exclude the human factor, which can lead to an accident, and there remains the need to build a support base for the field and a shift housing complex (with a large remoteness of the installation from urban settlements in the Far North). In addition, it does not provide automatic control of the primary gas preparation process after its production.

Closest to the proposed installation is the preparation of oil and natural gas for further processing or for supply to a transport pipeline (RU 2432536 C1, 10.27.2012), which contains a gas supply line connected to the first compressor stage, the outlet of which is connected through the refrigerator to the primary separator whose outlet for gas is connected to the second stage of the compressor, the outlet of which through a refrigerator is connected to a low-temperature separator, the outlet of which for liquid is connected to a container - a three-phase separator, etc. than to the conduit at the outlet of the second stage compressor connected to the conduit supplying hydrate inhibitor - methanol.

In this installation for the preparation of gas, as in others, the presence of maintenance personnel is required.

The objective of the invention is to provide an installation for primary gas treatment from gas well clusters, operating without maintenance personnel through the use of a software package for automatic regulation of gas treatment.

The technical result of the proposed invention is to provide automatic control of the gas preparation process.

The technical result is achieved by the fact that the installation for gas preparation, containing a gas supply line, a primary separator, the gas outlet of which is connected to a low-temperature separator, the outlet of which for a gas-liquid mixture is connected to a degasser, as well as a hydrate formation inhibitor supply system connected to the gas supply line and with a line connecting the primary and low temperature separators, and shut-off and control valves, according to the invention is equipped with an automatic control system (ACS) associated with shut-off and a fitting valve, which is the first control valve on the gas supply line, the second control valve installed on the line connecting the primary and low temperature separators, the third and fourth control valves installed on the lines connecting the outputs of the primary and low temperature separators for gas-liquid mixtures with a degasser, a fifth valve-regulator installed on the line of discharge of liquid from the degasser, and a sixth valve-regulator, installed on the line of discharge of gas from the degasser, The assembly is equipped with a first flow meter on the gas supply line and a second flow meter on the gas exhaust line from the low temperature separator, connected to the ACS with the possibility of controlling the degree of opening-closing of the first valve-regulator, a temperature sensor at the inlet of the low temperature separator connected to the ACS with the possibility of controlling the degree of opening - closing of the second valve-regulator with liquid level sensors in the primary and low-temperature separators and in the degasser associated with self-propelled guns with the possibility of regulation with the degree of opening and closing, respectively, of the third, fourth and fifth control valves, and a pressure sensor in the degasser associated with self-propelled guns with the ability to control the pressure in the degasser, and the hydrate formation inhibitor supply system is connected with self-propelled guns with the ability to control the flow of inhibitor depending on the gas pressure on the line feed or its consumption.

The drawing shows a diagram of the proposed installation.

The installation for primary gas treatment (UPPG) of oil or gas condensate fields contains a primary separator 2 connected to the gas supply line 1 (gas pipeline-shelf), the gas outlet of which is connected to the low-temperature separator 3. The outlet of the separator 3 for the gas-liquid mixture is connected to the degasser 4. System 5, the hydrate inhibitor feed is installed on the gas supply line 1 and on the line connecting the primary and low temperature separators 2 and 3.

The proposed installation employs a software package for automatic regulation of gas preparation, which includes the regulation of process parameters in automatic mode.

The shut-off and control valves of the installation are controlled by an automatic control system (ACS) in the form of a remote control terminal. Stop valves include:

- the first control valves 6 gas flow in the wells;

- a second control valve 7 mounted on a line connecting the primary and low temperature separators 2 and 3 to maintain the temperature in the low temperature separator 3;

- the third valve-regulator 8, installed on the output line of the gas-liquid mixture from the primary separator 2 for its discharge into the degasser 4;

- the fourth valve-regulator 9, installed on the outlet line of the gas-liquid mixture from the low-temperature separator 3 for its discharge into the degasser 4;

- the fifth valve-regulator 10, installed on the line of discharge of liquid from the degasser 4 to a horizontal flare device;

- the sixth valve-regulator 11 installed on the line of gas discharge from the degasser 4 to maintain pressure in the required range.

The installation is equipped with gas and liquid flow meters, pressure and gas temperature sensors connected to self-propelled guns with the ability to control the degree of opening-closing:

- the first valve-regulator 6, depending on the required gas flow, the first flow meter 12 is installed on each well or on a cluster of gas wells as a whole;

- the second control valve 7, depending on the desired separation temperature in the low-temperature separator 3, a temperature sensor 14 is installed on the pipeline between the second control valve 7 and the low-temperature separator 3;

- the third valve-regulator 8 for discharging liquid from the primary separator 2, a level gauge (not shown) is installed in the bottom part of the separator 2;

- the fourth valve-regulator 9 for discharging liquid from the low-temperature separator 3, a level gauge (not shown) is installed in the bottom part of the separator 3;

- the fifth valve-regulator 10 for discharging liquid from the degasser 4, a level gauge (not shown) is installed in the degasser 4;

- the sixth valve-regulator 11 to maintain pressure in the degasser 4, a pressure sensor (not shown) is installed in the upper part of D1;

- the flow meter 13 measures the gas flow after it is dried in a low temperature separator 3.

All sensors are connected to self-propelled guns. The signals from the sensors are sent to the self-propelled guns, in which, in accordance with the programs for regulating the gas flow rate, regulating the temperature of low-temperature separation, regulating the liquid level in the apparatus and regulating the flow of the hydrate inhibitor, control signals are generated that enter the corresponding control valves and are closed or opened until appropriate degree.

Gas from the gas well clusters is supplied to the UPPG, where it undergoes primary preparation, and then through the gas pipeline to the nearest GPP for preparation to commercial quality, while during the entire life of the oil and gas fields, the primary gas treatment unit works without maintenance personnel through the use of software complex automatic regulation of gas treatment.

Automatic regulation is carried out on the basis of the settings according to the following regulation laws:

- discrete regulation;

- PID regulation.

Discrete regulation consists in controlling the control valves when the controlled parameters are reached critical values from the range of permissible, but not yet emergency.

During PID control, the program complex generates a command to control technological equipment (control valves, methanol pumps) based on a comparison of the current value of the controlled parameter received from the analog sensor and the setpoint value (set by the operator or calculated), determined by the operating procedure of the technological section on which regulation is carried out.

The task of the software package for automatic regulation and control of technological processes for gas production and field treatment is to ensure gas supply to the gas pipeline with a given quantity and quality. The problem is solved by subprograms, which are its constituent parts.

At the same time, the subprograms are inextricably interconnected by functions, dependencies, and min / max settings.

ACS control routines include:

1. The subroutine for automatic control of pressure and gas flow at the gas treatment plant and in the gas collection network. The first valve regulator 6 operates by a logical function:

Qplan = Σn threads Q product = Σn wells Qval

under conditions:

1. Qmin <Q fact <Qmax

2. Pmin <Rfact <Pmax

3. Kv is committed to Qoptimal,

where Qplan - the planned task of gas flow;

Σn threads - the number of technological separation threads;

Qtovar - commodity gas consumption after separation;

Σn wells - the number of wells;

Qval - gross gas flow rate (crude gas flow rate);

Qmin - minimum setpoint for flow (minimum gas flow, determined by the geological service);

Qfact - actual, current gas consumption;

Qmax - maximum setpoint for flow rate (minimum gas flow rate, determined by the geological service);

Pmin - set point for minimum pressure;

Rfact - the actual pressure in the gas loop;

Pmax - set point for maximum pressure;

Kv is the degree of valve opening;

Qoptimal is the average gas flow rate between Qmin and Qmax.

Pressure tracking mode (compliance with condition No. 2 - Pmin <Pfact <Pmax):

The control valve 6 maintains the gas pressure in the range of the set pressure min / max depending on the pressure value and the required flow rate in the gas collection network.

R _p - the greatest excess pressure at which the specified mode of operation of the valves, pipeline parts and apparatuses is ensured;

i%, n% - accepted percentages for pressure calculations, where i> n;

- значение минимального давления в системе противоаварийной защиты, при которой происходит отключение аварийного участка;

- the value of the minimum pressure in the emergency protection system at which the emergency section is switched off;

^_ значение максимального давления в системе противоаварийной защиты, при которой происходит отключение аварийного участка;

^_ value of the maximum pressure in the emergency protection system at which the emergency section is switched off;

Calculation of the working settings of the subprogram:

Pmin = (P _{p -} P _p * i%);

Pmax = (P _p -P _p * n%).

и

Provided:

and

To maintain the Rfact in the range from Pmin to Pmax, it is necessary to use the control valve 6 with the adjustment “after itself” according to the PID regulation.

Functions of the ACS software package:

- if Pfact> (P _p -P _p * n%), then a command is issued to close the valve-regulator 6 by Y%;

- waiting time t sec;

- repeated interrogation of primary pressure sensors;

- if Pfact <(P _p -P _p * i%), then a command is issued to open the control valve 6 by Y%;

- waiting time t sec;

- repeated interrogation of primary pressure sensors;

- if (P _p -P _p * i%) <Pfact <(P _p -P _p * n%), then the adjustment is made and the valve-regulator 6 remains in the existing position.

2. Subroutine for automatic temperature control of low-temperature gas separation. It works by a logical function:

Kv preset provides condition 1, i.e., Tmin <Kv preset <Tmax.

under conditions:

1. Tman <Tfact <Tmax

2. Pmin <Rfact <Pmax

,3.

,

Where

Tmin - the minimum value of the temperature of the NTS (determined by the regulations of the installation depending on the conditions of gas transport);

Tmax — maximum temperature of the low temperature switch (determined by the installation regulations depending on the conditions of gas transport);

Tfact - the actual temperature of the NTS (determined by sensors, depends on the throttling of the gas pressure by the valve regulator);

Pmin - the minimum working pressure is determined from the calculation of gas transport;

Pmax - maximum working pressure (determined from the calculation of the strength characteristics of pipelines and devices);

Rfact - the actual pressure after throttling the gas pressure with the control valve (determined by the pressure sensor);

Qmin - minimum allowable gas flow (determined by the geological service);

Qmax - maximum gas flow (determined depending on the performance of the apparatus);

- фактический расход товарного газа.

- actual consumption of commercial gas.

The set valve opening degree (Kv set) should provide (due to throttling, cooling) condition 1, that is, maintain the temperature in a predetermined range between the maximum and minimum values.

The control valve 7 maintains the gas temperature in the low temperature separator 3 by gradually opening or closing in the range of the set temperature min / max depending on the minimum pressure value in the gas pipeline of the external transport and the required flow rate.

3. The subroutine of the hydrate inhibitor - methanol.

The pressure in the methanol pipe and in the hydrate formation inhibitor supply system 5 is maintained automatically by pumps from the existing UKPG (located remotely). The subprogram provides the supply of methanol through the valve regulator of the inhibitor supply system 5, depending on the specific consumption of methanol (kilogram per 1000 m ^{3 of} gas). The specific consumption of methanol is introduced into the software package by the dispatcher periodically, and it is possible to include a subprogram to calculate the specific consumption of methanol based on a constant analysis of the thermobaric parameters of the gas and / or gas flow.

4. The subroutine to maintain the liquid level in the tank-degasser 4 (discrete regulation). It works by a logical function:

Kv preset provides condition 1, that is, X% <Kv preset <Y%, where condition 1: X% <Lact <Y%.

The specified degree of opening of the Kv valve should be set to ensure that the fluid level is maintained in the range from X% to Y%.

Settings, where Lfact is the actual level in the degasser 4;

- the working level is taken in the range from X% - to Y% of the total volume of the tank-degasser 4;

- emergency levels (SPAS settings) are accepted - min (X + z)%, max (Y + i)%.

Functions of the software package:

- the subroutine in real time monitors the readings of the level gauge of the degasser 4;

- if Lfact> Y%, then the command "opening" of the control valve 10 is issued to empty the degasser 4;

- a signal is received from the level gauge - the value of Lfact;

- if Lact <X%, then the command "closing" of the valve regulator 10;

- a signal is received from the level gauge - the value of Lfact;

- if X% <Lfact <Y% MPa, then the command is "normal" and the valve-regulator 10 of the liquid discharge closes.

At the same time, the control valves 8 and 9 work similarly to discharge liquid from the separators 2 and 3 and have the function of emergency closure when the maximum level in the degasser 4 is reached.

The pressure control valve 11 on the line of weathering gases of the degasser 4 has the function of raising the pressure in a certain control range if the liquid level in the capacity of the degasser 4 does not decrease.

This ensures automatic control of the primary gas preparation process without the participation of maintenance personnel.

In addition, the power supply of the gas treatment plant for the operation of actuators (control valves, burners), the organization of the transmission of operation parameters and emergency stop can be carried out through high-capacity batteries from sources of autonomous power supply: wind generator, solar panels, gas-fired power generators.

All equipment is used with increased reliability.

The technological connection of the gas treatment unit with the remote self-propelled gun terminal is based on fiber optic cable.

Outdoor lighting was applied from energy-efficient floodlights with high light output to save electricity.

In addition, measuring instruments are selected with low power consumption.

The proposed installation provides a reduction in operating costs due to the lack of staff and, as a result, the absence of costs for wages and benefits. Capital costs are reduced due to the lack of the need to build a support base for the field and a shift housing complex (with the installation being very far from urban settlements in the Far North).

Claims (1)

A gas preparation installation comprising a gas supply line, a primary separator, the gas outlet of which is connected to a low temperature separator, the outlet of which for the gas-liquid mixture is connected to a degasser, and a hydrate formation inhibitor supply system connected to the gas supply line and to the line connecting the primary and low-temperature separators, and shut-off and control valves, characterized in that it is equipped with an automatic control system (ACS) associated with shut-off and control valves, which represents it is the first regulator valve on the gas supply line, the second regulator valve installed on the line connecting the primary and low temperature separators, the third and fourth regulator valves installed on the lines connecting the outputs of the primary and low temperature separators for the gas-liquid mixture with the degasser, the fifth valve-regulator installed on the line of discharge of liquid from the degasser, and the sixth valve-regulator installed on the line of discharge of gas from the degasser, the installation is equipped with a first flow meter on a gas supply line and a second flow meter on a gas exhaust line from the low temperature separator connected to the ACS with the possibility of controlling the degree of opening-closing of the first valve-regulator, a temperature sensor at the inlet of the low temperature separator connected to the ACS with the possibility of controlling the degree of opening-closing of the second valve-regulator , liquid level sensors in the primary and low temperature separators and in the degasser associated with self-propelled guns with the ability to control the degree of opening and closing, respectively third, fourth and fifth valves, regulators, and the pressure sensor in the degassing associated with the ACS, with pressure control in the degassing and supplying hydrate inhibitor system is associated with ACS, with an inhibitor of flow control, depending on the gas pressure in the supply line or a flow.