CN1297779C - Valve throttle dynamic control method for eliminating serious slug flow - Google Patents

Abstract

The present invention discloses a valve throttling dynamic control method for eliminating serious slug flow. The dynamic control of valve throttling is realized according to an automatic regulating valve which is arranged at the outlet side of an ascending pipe, PID which can receive a valve opening signal, an inlet pressure signal and a pressure signal of the bottom of the ascending pipe, and a logical operation control module. The opening degree of the automatic regulating valve is controlled in real time according to a signal which is output after the collected inlet pressure and the ascending pipe bottom pressure signals and the valve opening signal are analyzed, calculated and converted, and is operated in parallel by three threads. The present invention can react on macrocyclic pressure change and is suitable for fast pressure change. Particularly, a valve can be automatically adjusted according to the flow change of an inlet of a pipeline, so that throttling is stabilized to appropriate extent. Thus, the present invention achieves the aims for realizing serious slug flow repression and solving the problem of over throttling, achieves optimal control for throttling, and has certain automatic adaptive ability.

Description

Eliminate the valve throttle dynamic control method of serious slug flow

Technical field

The invention belongs to throttling dynamical feedback control technique field, relate to a kind of valve throttle dynamic control method, be specifically related to a kind of asending pipe outlet throttling kinetic controlling equation method that the offshore oil rock gas mixes the serious slug flow phenomenon that occurs in the defeated process of eliminating.

Background technique

In marine petroleum exploitation, often run into the situation that gas-liquid is carried simultaneously, when the heterogeneous collector and delivery pipe road in seabed arrives ocean platform or disembarkation, need be connected with asending pipe.Under certain condition, special harmful flow pattern that can occur being called serious slug flow in the system that collector and delivery pipe road and asending pipe are formed, this flow pattern can produce that pressure cycle variation in the liquid plug, collector and delivery pipe road of several times asending pipe height, asending pipe outlet gas-liquid intermittent flow go out, gas ejection at a high speed at short notice, cause outlet liquid plug to enter separator at a high speed, therefore, the serious slug flow phenomenon brings many problems for system design and ordinary production.Carrying out throttling at asending pipe outlet mounted valve is the effective ways that suppress serious slug flow.

" the Oil that on November 12nd, 1979 published; Gas Journal " disclose and utilized the asending pipe outlet that the experimental studies results that serious slug flow is eliminated in the modulating valve throttling is installed, the author utilizes pipeline pressure and asending pipe differential pressure signal to come the inhibition of controlling opening of valve realization to serious slug flow.In Society of Petroleum Engineers (SPE) is numbered the meeting paper of SPE56461, reported and utilized asending pipe base pressure signal to come the control valve throttling to eliminate the method for serious slug flow, specify asending pipe base pressure value in this method, thereby make pressure stability in designated value by the control valve aperture.Because the flow in mixed transporting tube road changes in the field produces, and the pressure set points that can eliminate serious slug flow of different flow correspondence is different, therefore these methods can not adapt to the variation of flow, can only choose higher choke pressure parameter and control, and too high choke pressure can cause the decline of upstream oil well output.

Summary of the invention

The purpose of this invention is to provide a kind of valve throttle dynamic control method of eliminating serious slug flow, can realize suppressing serious slug flow, again can be according to the aperture of entrance changes in flow rate automatic regulating valve door, solve the undue throttling problem that occurs with the control of fixation pressure value, thereby realized the optimization of control.

The technical solution adopted in the present invention is, eliminate the valve throttle dynamic control method of serious slug flow, automatic regulating valve is installed in outlet port at asending pipe, PID by can receiving valve opening signal, inlet pressure P1 signal and asending pipe base pressure P2 signal and logical operation control module realize the dynamic control of valve throttle, the controlling packet vinculum journey 1 of this method, thread 2 and thread 3 executed in parallel

The control circle cycle of thread 1 is 2 seconds, the inlet pressure P1 that collects in real time and signal and the valve opening signal of asending pipe base pressure P2 are carried out Shelving, signal after handling is outputed to thread 2, calculate the mean value MeanP2 ' of the mean value MeanP1 ' of pressure P 1 and pressure P 2 simultaneously respectively and output to thread 3, N is the cycle-index of thread 2, if N is not greater than 0, control thread 1 finishes this circulation, if N greater than 0 for being, then enter PID and logical operation control module, the mean value MeanP2 of the pressure P 2 that circulation on the thread 2 is drawn " calculates valve opening difference u as setting value SP1 ₁(t) and output to thread 3;

The control circle cycle of thread 2 is 200 seconds, the pressure P 1 that collection was handled by thread 1, pressure P 2 signals and valve opening signal and record, when image data reaches 200 seconds, pressure data is carried out waveform analysis, calculate the maximum value MaxP2 of pressure P 2 "; minimum M inP2 ", mean value MeanP2 " and fluctuating range PV2; with mean value MeanP2 " outputs to thread 1 as the pressure set points SP1 of PID computing wherein, with maximum value MaxP2 "; minimum M inP2 ", mean value MeanP2 " and fluctuating range PV2 input PID and logical operation control module; behind the setting value SP2 according to appointment, through PID functional operation output valve aperture difference u ₂(t) and output to thread 3;

The control circle cycle of thread 3 is 100 milliseconds, judge according to the mean value MeanP1 ' of the pressure P 1 that receives and the mean value MeanP2 ' of pressure P 2 whether pressure surpasses the pipeline maximum allowble pressure, if, program is made as the valve opening output value and opens fully and control mode is converted to manual control, provide alarm signal simultaneously, if not, then program is according to the pressure in permission range, when control mode when being automatic, by the valve opening difference u that receives ₁(t) and u ₂(t) sum obtains valve opening, and when control mode when being manual, valve opening is set according to manual input value, this opening value is done P/A conversion back output, by the valve actuator controlling opening of valve.

Setting value SP2 is taken as 30% 〉=SP2 〉=20%.

Controlling method of the present invention is by three thread parallel computings, both can make a response to macrocyclic variation in pressure, also can adapt to variation in pressure fast, especially can realize automatically that according to the variation of entrance flow valve throttle suppresses serious slug flow, ducted pressure mean values is subjected to the control of flow fluctuation to require decision after the throttling, and change automatically with the variation of inlet flow rate, therefore throttling can be stabilized in suitable degree, reach and both realize suppressing serious slug flow, solve the undue throttling problem that prevents again, realized optimal control, had certain adaptive ability throttling.

Description of drawings

Fig. 1 is that the ascending tube system throttling of mixed transporting tube of the present invention road suppresses serious slug flow control schematic representation;

Fig. 2 is the kinetic controlling equation method flow chart that the present invention realizes throttling;

Fig. 3 is control program controlling opening of valve of the present invention and asending pipe base pressure change procedure figure in the experiment;

Fig. 4 is that the pipe outlet trickle entered a measurement jar liquid level uphill process figure after control program was successfully realized throttling;

Fig. 5 measures a jar interior liquid level change procedure chart under the modulating valve complete opening situation, its inlet flow rate is identical with the experiment of Fig. 4.

Among the figure, 1. incoming flow pipe, 2. tipping tube, 3. asending pipe, 4. separator, 5. automatic regulating valve, 6. pressure transducer, 7. pressure transducer, 8.PID and logical operation control module.

Embodiment

The present invention is described in detail below in conjunction with accompanying drawing.

Referring to Fig. 1, the signal of the pressure transducer 6 exportable pressure P 1 that the ingress of incoming flow pipe 1 is provided with, incoming flow pipe 1 is connected with tipping tube 2, the signal of the pressure transducer 7 exportable pressure P 2 that asending pipe 3 bottoms and tipping tube 2 connecting parts are provided with, the outlet port of asending pipe 3 links to each other with separator 4 by automatic regulating valve 5, and PID and logical operation control module 8 can receive valve opening signal, pressure P 1 signal and pressure P 2 signals.

The parameter that can reflect the serious slug flow rule fast is the signal of asending pipe 3 base pressure P2, therefore select the fluctuating range of asending pipe 3 base pressure P2 signals and mean value among the present invention as controlled variable, inlet pressure P1 is the highest in the system, thereby select this point pressure to come the undue throttling support equipment of limiter valve safety, regulate the valve opening that parameter is mounted in the automatic regulating valve 5 of asending pipe 3 outlets.

The gas-liquid mixture fluid that comes from upstream line is than the serious slug flow phenomenon occurring under the low discharge, the big ups and downs of pressure long period, the gas-liquid intermittent flow of outlet.When the start-up control program, referring to Fig. 2 control flow, control thread 1,2,3 is carried out simultaneously,

Cycle period is that 2 seconds thread 1 is gathered inlet pressure P1 signal in real time, asending pipe base pressure P2 signal and valve opening signal also carry out Shelving, signal after handling is outputed to thread 2, calculate the mean value MeanP2 ' of the mean value MeanP1 ' of pressure P 1 and pressure P 2 simultaneously respectively and output to thread 3, N is the cycle-index of thread 2, if N is not greater than 0, control thread 1 finishes this circulation, if N greater than 0 for being, then enter PID and logical operation control module, the mean value MeanP2 of the pressure P 2 that circulation on the thread 2 is drawn " calculates valve opening difference u as setting value SP1 ₁(t) and output to thread 3, valve opening difference

$u_1\left(t\right)=K_c[(\mathrm{SP}1-\mathrm{PV}1)+\frac{1}{T_i}{\∫}_0^t(\mathrm{SP}1-\mathrm{PV}1)\mathrm{dt}+T_d\frac{d(\mathrm{SP}1-\mathrm{PV}1)}{\mathrm{dt}}];$

Wherein, u ₁(t) be the valve opening difference, K _cBe proportional gain, SP1 is a pressure set points, and PV1 is a fluctuating range, T _iBe intergration time, T _dIt is derivative time.

The control circle cycle of thread 2 got 200 seconds, thereby can comprise a plurality of serious slug flow cycles, the pressure P 1 that collection was handled by thread 1, pressure P 2 signals and valve opening signal and record, when image data reaches 200 seconds, pressure data is carried out waveform analysis, calculate the maximum value MaxP2 of pressure P 2 "; minimum M inP2 ", mean value MeanP2 " and fluctuating range PV2; with mean value MeanP2 " outputs to thread 1 as the pressure set points SP1 of PID computing wherein, with maximum value MaxP2 "; minimum M inP2 ", mean value MeanP2 " and fluctuating range PV2 input PID and logical operation control module; behind the given settings value SP2; setting value SP2 is taken as 30% 〉=SP2 〉=20%, through PID functional operation output valve aperture difference u ₂(t) and output to thread 3, valve opening difference

$u_2\left(t\right)=K_c[(\mathrm{SP}2-\mathrm{PV}2)+\frac{1}{T_i}{\∫}_0^t(\mathrm{SP}2-\mathrm{PV}2)\mathrm{dt}+T_d\frac{d(\mathrm{SP}2-\mathrm{PV}2)}{\mathrm{dt}}];$

Wherein, u ₂(t) be the valve opening difference, K _cBe proportional gain, SP2 is a pressure set points, and PV2 is a fluctuating range, T _iBe intergration time, T _dIt is derivative time.

The control circle cycle of thread 3 is 100 milliseconds, judge according to the mean value MeanP1 ' of the pressure P 1 that receives and the mean value MeanP2 ' of pressure P 2 whether pressure surpasses the pipeline maximum allowble pressure, if, program is made as the valve opening output value and opens fully and control mode is converted to manual control, provide alarm signal simultaneously, if not, then program is according to the pressure in permission range, when control mode when being automatic, by the valve opening difference u that receives ₁(t) and u ₂(t) sum obtains valve opening, and when control mode when being manual, valve opening is set according to manual input value, this opening value is done D/A conversion back output, by the valve actuator controlling opening of valve.

More than three thread parallel computings, this kinetic controlling equation case both can be made a response to macrocyclic variation, also can adapt to rapid pressure and change, especially when inlet flow rate changed, control module can make pressure mean values be stabilized in suitable level and avoid excessive throttling.

Referring to Fig. 3, experimental result of the present invention as can be seen.The inlet gas flow is constant in the experimentation, experiment incipient stage automatic regulating valve 5 complete openings, as seen pressure P 2 fluctuating ranges are very big, for accelerating experimentation, manually control automatic regulating valve 5 is closed to 45% in the time of the 245th second, enter automatic control then, automatic regulating valve 5 turns down under the adjusting of control program gradually as can be seen, pressure P 2 fluctuating ranges are reduced near the setting value 25%, during much smaller than automatic regulating valve 5 complete openings 56%, simultaneously valve opening is adjusted to about 24%, among the figure as can be seen valve opening change all the time, and pressure P 2 fluctuating ranges are also changing, in the time of the 3600th second, inlet liquid specific speed increases, and pressure P 2 fluctuating ranges increase as can be seen, under control program is regulated, pressure P 2 mean values increase, but pressure P 2 fluctuating ranges reduce, and valve opening is stabilized in about 25.5%, only increase about 1.5%.

Provided respectively among Fig. 4 and Fig. 5 and used method of the present invention to realize valve throttle and do not use that pipe outlet liquid enters the uphill process of measuring jar liquid level under the throttling situation of the present invention, liquid level is measured by differential pressure transducer, and the slope of curve is represented the speed of pipeline trickle among the figure.Liquid outflow velocity variations is very little as can be seen from Figure 4, can think that substantially liquid at the uniform velocity flows out pipeline.The differential pressure cycle changes among Fig. 5, and the constant time period of differential pressure illustrates that liquid level is constant, does not have liquid to flow out, liquid level can raise suddenly at short notice then, the slope of curve is very big, illustrates that fluid high-speed flows out pipeline, the feature of Here it is when serious slug flow takes place liquid batch flows out pipeline.Above comparative descriptions, the outlet fluid flow is basicly stable after the successful throttling, flow velocity is lower, when not having throttling then liquid batch flow out and instantaneous velocity speed during far above throttling.

Above experimental result finds out that relatively the present invention can suppress the serious slug flow phenomenon well.

Claims (1)

1. eliminate the valve throttle dynamic control method of serious slug flow, automatic regulating valve is installed in outlet port at asending pipe, PID by can receiving valve opening signal, inlet pressure P1 signal and asending pipe base pressure P2 signal and logical operation control module realize the dynamic control of valve throttle, it is characterized in that, the controlling packet vinculum journey 1 of this method, thread 2 and thread 3 executed in parallel

The control circle cycle of thread 1 is 2 seconds, the inlet pressure P1 that collects in real time and signal and the valve opening signal of asending pipe base pressure P2 are carried out Shelving, signal after handling is outputed to thread 2, calculate the mean value MeanP2 ' of the mean value MeanP1 ' of pressure P 1 and pressure P 2 simultaneously respectively and output to thread 3, N is the cycle-index of thread 2, if N is not greater than 0, control thread 1 finishes this circulation, if N greater than 0 for being, then enter PID and logical operation control module, the mean value MeanP2 of the pressure P 2 that circulation on the thread 2 is drawn " calculates valve opening difference u as setting value SP1 ₁(t), u ₁(t) formula is:

$u_1\left(t\right)=K_c[(\mathrm{SP}1-\mathrm{PV}1)+\frac{1}{T_i}{\∫}_0^t(\mathrm{SP}1-\mathrm{PV}1)\mathrm{dt}+T_d\frac{d(\mathrm{SP}1-\mathrm{PV}1)}{\mathrm{dt}}]$

Wherein, u ₁(t) be the valve opening difference, K _cBe proportional gain, SP1 is a pressure set points, and PV1 is a fluctuating range, T _iBe intergration time, T _dBe derivative time, and output to thread 3;

The control circle cycle of thread 2 is 200 seconds, the pressure P 1 that collection was handled by thread 1, pressure P 2 signals and valve opening signal and record, when image data reaches 200 seconds, pressure data is carried out waveform analysis, calculate the maximum value MaxP2 of pressure P 2 "; minimum M inP2 ", mean value MeanP2 " and fluctuating range PV2; with mean value MeanP2 " outputs to thread 1 as the pressure set points SP1 of PID computing wherein, with maximum value MaxP2 "; minimum M inP2 ", mean value MeanP2 " and fluctuating range PV2 input PID and logical operation control module; according to the setting value SP2 of appointment; SP2 is taken as 30% 〉=SP2 〉=20%, through PID functional operation output valve aperture difference u ₂(t), u ₂(t) formula is:

$u_2\left(t\right)=K_c[(\mathrm{SP}2-\mathrm{PV}2)+\frac{1}{T_i}{\∫}_0^t(\mathrm{SP}2-\mathrm{PV}2)\mathrm{dt}+T_d\frac{d(\mathrm{SP}2-\mathrm{PV}2)}{\mathrm{dt}}]$

Wherein, u ₂(t) be the valve opening difference, K _cBe proportional gain,, SP2 is a pressure set points, PV2 is a fluctuating range, T _iBe intergration time, T _dBe derivative time, and output to thread 3;

The control circle cycle of thread 3 is 100 milliseconds, judge according to the mean value MeanP1 ' of the pressure P 1 that receives and the mean value MeanP2 ' of pressure P 2 whether pressure surpasses the pipeline maximum allowble pressure, if, program is made as the valve opening output value and opens fully and control mode is converted to manual control, provide alarm signal simultaneously, if not, then program is according to the pressure in permission range, when control mode when being automatic, by the valve opening difference u that receives ₁(t) and u ₂(t) sum obtains valve opening, and when control mode when being manual, valve opening is set according to manual input value, this opening value is done D/A conversion back output, by the valve actuator controlling opening of valve.

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