阅读说明：本技术 防冻堵的天然气集输系统及天然气集输系统防冻堵的方法 (Anti-freezing and anti-blocking natural gas gathering and transportation system and anti-freezing and anti-blocking method for natural gas gathering and transportation system ) 是由 解鲁平 王帅 李岩 王丰 王景辰 李晓磊 于 2018-08-27 设计创作，主要内容包括：本发明提供一种防冻堵的天然气集输系统及天然气集输系统防冻堵的方法。该天然气集输系统包括集气干线和计量干线,集气干线和计量干线的一端通过连接管线导通；集气干线和计量干线朝向连接管线的一端设置有第一集气支线和第一计量支线,第一集气支线和第一计量支线分别用于将集气干线和计量干线与第一单井导通,且第一单井不向集气干线和计量干线中通入井流物；第二集气支线和第二计量支线分别用于将集气干线和计量干线与第二单井导通；第二计量支线与计量干线之间的导通处设有第一控制机构,通过该第一控制机构控制来自于第二单井的井流物在计量干线中的流动方向。该天然气集输系统利用井流物在管线中逆向流动,达到防止冻堵、保护管线的目的。(The invention provides a natural gas gathering and transportation system capable of preventing freezing and blocking and a method for preventing freezing and blocking of the natural gas gathering and transportation system. The natural gas gathering and transporting system comprises a gas collection trunk line and a metering trunk line, wherein one ends of the gas collection trunk line and the metering trunk line are communicated through a connecting pipeline; the gas collection trunk line and the metering trunk line are provided with a first gas collection branch line and a first metering branch line at one end facing the connecting pipeline, the first gas collection branch line and the first metering branch line are respectively used for communicating the gas collection trunk line and the metering trunk line with a first single well, and well fluid is not introduced into the gas collection trunk line and the metering trunk line by the first single well; the second gas collection branch line and the second metering branch line are respectively used for communicating the gas collection trunk line and the metering trunk line with the second single well; and a first control mechanism is arranged at the communication part between the second metering branch line and the metering trunk line, and the flow direction of the well flow from the second single well in the metering trunk line is controlled by the first control mechanism. The natural gas gathering and transportation system achieves the purposes of preventing freezing blockage and protecting pipelines by utilizing the reverse flow of well fluid in the pipelines.)

1. A natural gas gathering and transportation system preventing freezing and blocking comprises a gas collection trunk line and a metering trunk line, wherein one ends of the gas collection trunk line and the metering trunk line are communicated through a connecting pipeline;

the gas collection trunk line and the metering trunk line are provided with a first gas collection branch line and a first metering branch line at one end facing the connecting pipeline, the first gas collection branch line is used for communicating the gas collection trunk line with a first single well, the first metering branch line is used for communicating the metering trunk line with the first single well, and well fluid is not introduced into the gas collection trunk line and the metering trunk line by the first single well;

a second gas collecting branch line and a second metering branch line are arranged on one side, away from the connecting pipeline, of the first gas collecting branch line and one side, away from the connecting pipeline, of the first metering branch line, the second gas collecting branch line is used for conducting the gas collecting trunk line with a second single well, and the second metering branch line is used for conducting the metering trunk line with the second single well;

the communication part between the second metering branch line and the metering trunk line is provided with a first control mechanism, and the flow direction of well flow from the second single well in the metering trunk line is controlled through the first control mechanism.

2. The natural gas gathering system as defined in claim 1 wherein the first control mechanism comprises a first shut-off valve, a second shut-off valve, and a tee for enabling communication between a second metering branch and a metering trunk, wherein:

the first cut-off valve is arranged on the metering main line between the second metering branch line and the connecting pipeline, and the second cut-off valve is arranged on the metering main line on the other side.

3. The natural gas gathering system as defined in claim 2 wherein the first and second shut-off valves are electrically operated ball valves.

4. The natural gas gathering and transportation system as claimed in claim 1 wherein the end of the gas trunk line is adapted to connect to a gas collection station, the gas collection station being connected to a first single well.

5. A natural gas gathering and transportation system as claimed in claim 1 wherein an outbound valve is provided on the second metering branch.

6. A natural gas gathering and transportation system according to any one of claims 1 to 5, wherein a third gas collecting branch line and a third metering branch line are further provided on the sides of the first gas collecting branch line and the first metering branch line, which are away from the connecting pipeline, wherein the third gas collecting branch line is used for conducting the gas collecting trunk line and the third single well, and the third metering branch line is used for conducting the metering trunk line and the third single well;

and a second control mechanism is arranged at the communication position between the third metering branch line and the metering trunk line, and the flow direction of the well fluid from the third single well in the metering trunk line is controlled by the second control mechanism.

7. The natural gas gathering system as defined in claim 6 wherein the second control mechanism comprises a third shut-off valve, a fourth shut-off valve, and a tee for enabling communication between a third metering branch and a metering trunk, wherein:

the third trip valve sets up on the measurement trunk line between third measurement branch line and the connecting line, the fourth trip valve sets up on the measurement trunk line of opposite side.

8. A natural gas gathering and transportation system according to claim 6, wherein the third single well is located on the side of the second single well facing the first single well or on the side of the second single well remote from the first single well.

9. A natural gas gathering and transportation system as claimed in claim 6 wherein an outbound valve is provided on the third metering branch.

10. A method for preventing freezing and blocking of a natural gas gathering and transportation system, which is performed by using the natural gas gathering and transportation system preventing freezing and blocking of any one of claims 1 to 9.

Technical Field

The invention relates to an oil-gas production technology, in particular to an anti-freezing and anti-blocking natural gas gathering and transporting system and an anti-freezing and anti-blocking method for the natural gas gathering and transporting system.

Background

The gathering and transportation system is a system for collecting and transporting well streams (crude oil or natural gas) extracted from oil and gas fields. During production in winter, because the environmental temperature is low, freezing blockage of an oil and gas field gathering and transporting system, particularly a natural gas gathering and transporting system is easy to occur, particularly when a dead end appears on a gas collecting trunk line or a metering trunk line, because natural gas cannot pass through smoothly, and in addition, because the environmental temperature is low, the whole gathering and transporting trunk line is blocked due to generation of hydrate, and great threat is caused to safe production.

Fig. 1 is a schematic structural diagram of a natural gas gathering and transportation system. As shown in figure 1, the natural gas gathering and transportation system adopts single wells to serially collect gas, a gas collecting main line is positioned on the central axis of a gas field, and each single well is connected to the gas collecting main line nearby. The single well A is a planned-to-be-scrapped shut-in well, and a gas gathering station A matched with the single well A has no normal flow of a production well; the single well B and the single well C are single wells which normally operate, wherein blind ends are formed between a metering main line and a gas collecting main line between the single well B and the gas collecting station A, so that the gas collecting main line and the metering main line are easy to freeze and block in winter, and an oval area in figure 1 represents an area easy to freeze and block. And once the metering trunk line and the gas collecting trunk line between the single well B and the gas collecting station A are frozen and blocked, the pressure bearing of the section of pipeline is ultrahigh or ultralow, and the pressure of the gas collecting station A is interlocked and closed. Meanwhile, the ultrahigh pressure-bearing capacity of the pipeline can also cause damage to equipment and facilities such as pipelines, valves, flanges, instruments and the like, and large-area puncture, fire, explosion and other risks exist.

Therefore, how to reform the existing natural gas gathering and transportation system is a problem to be solved at present, and the problems of freezing and blocking of the gathering and transportation trunk line in winter and guaranteeing safe and stable operation of a gas field are solved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a natural gas gathering and transporting system capable of preventing freezing and blocking.

The invention also provides a method for preventing the natural gas gathering and transportation system from being frozen and blocked, and the natural gas gathering and transportation system with the anti-freezing and blocking function is used, so that series problems caused by the fact that the natural gas gathering and transportation system is frozen and blocked at a low temperature can be avoided, and the safe and stable operation of production operation of a gas field is guaranteed.

In order to achieve the aim, the invention provides a natural gas gathering and transportation system capable of preventing freezing and blocking, which comprises a gas collection trunk line and a metering trunk line, wherein one ends of the gas collection trunk line and the metering trunk line are communicated through a connecting pipeline; the gas collection trunk line and the metering trunk line are provided with a first gas collection branch line and a first metering branch line at one end facing the connecting pipeline, the first gas collection branch line is used for communicating the gas collection trunk line with a first single well, the first metering branch line is used for communicating the metering trunk line with the first single well, and well fluid is not introduced into the gas collection trunk line and the metering trunk line by the first single well; a second gas collecting branch line and a second metering branch line are arranged on one side, away from the connecting pipeline, of the first gas collecting branch line and one side, away from the connecting pipeline, of the first metering branch line, the second gas collecting branch line is used for conducting the gas collecting trunk line with a second single well, and the second metering branch line is used for conducting the metering trunk line with the second single well; and a first control mechanism is arranged at the communication part between the second metering branch line and the metering trunk line, and the flow direction of the well flow from the second single well in the metering trunk line is controlled by the first control mechanism.

According to the anti-freezing and anti-blocking natural gas gathering and transportation system provided by the invention, as well fluid is not respectively introduced into the gas collection trunk line and the metering trunk line through the first gas collection branch line and the second metering branch line by the first single well, the first single well can be in failure, production is suspended, and even the first single well is a planned abandonment shut-in well, the metering trunk line and the gas collection trunk line between the first single well and the second single well form blind ends. When the temperature is lower in winter, if no measures are taken, the well flow in the metering main line and the gas collecting main line, especially natural gas, can generate hydrates to cause freezing blockage.

The first control mechanism is arranged at the conduction position between the second metering branch line and the metering trunk line to control the flow direction of the well fluid from the second single well in the metering trunk line, so that the well fluid can reversely flow towards the direction of the connecting pipeline and is finally output through the gas collecting trunk line after entering the metering trunk line through the second metering branch line, or can positively flow against the direction of the connecting pipeline for metering.

When well flow from the second single well flows into the metering trunk and bypasses the connecting pipeline and the gas collecting trunk, the blind end originally formed by the first single well does not exist, and a flow passage is formed. Because the well flow from the second single well has a certain temperature, the problem of freezing and blocking of a gathering and transporting system caused by hydrate formation due to overlong standing time of natural gas in the well flow at low ambient temperature is avoided, and the safe and smooth gathering and transporting of natural gas production is ensured.

Moreover, the reformed natural gas gathering and transportation system does not influence the switching of the metering flow of the second single well, so that the aim of saving the cost is fulfilled.

Specifically, the first control mechanism may include a first cut-off valve, a second cut-off valve, and a tee joint for realizing communication between the second metering branch line and the metering trunk line, wherein: the first cut-off valve is arranged on the metering trunk line between the second metering branch line and the connecting pipeline; the second trip valve sets up on the measurement trunk line of opposite side.

Thus, when the first shut-off valve is in a fully open state and the second shut-off valve is in a fully closed state, well flow from the second single well flows into the metering trunk line through the second metering branch line and the tee joint in sequence, and flows into the gas collecting trunk line through the first shut-off valve and the connecting pipeline in sequence. On the contrary, when the first cut-off valve is in a fully closed state and the second cut-off valve is in a fully opened state, well flow from the second single well sequentially flows into the metering trunk line through the second metering branch line and the tee joint, and is metered after flowing through the second cut-off valve.

The present invention is not particularly limited to the first shut-off valve and the second shut-off valve, as long as the above-described function can be achieved, and the flow direction of the well fluid from the second single well in the metering main line can be controlled. In the implementation process of the invention, the first cut-off valve and the second cut-off valve are ball valves, such as electric ball valves.

Further, the end of the gas collection trunk line is used for connecting with a gas collection station, and the gas collection station is connected with the first single well.

The gas collecting station is a transfer station for collecting and processing natural gas, and is used for throttling and depressurizing the natural gas sent by the first single well, separating free liquid and other mechanical impurities in the gas, measuring the yield of the gas well, and then inputting the gas well into a gas collecting trunk line. In the invention, because the first single well has a fault, stops production or even is about to be scrapped, the shut-in well, a metering trunk line and a gas collecting trunk line between the gas collecting station and the second single well form a blind end. But due to the provision of the first control mechanism, well flow from the second single well is allowed to bypass to the gathering station and ultimately flow into the gathering trunk.

Furthermore, an outbound valve is arranged on the second metering branch line. Specifically, the outbound valve is disposed at an end of the second metering stem proximate the second single well. During operation, the outlet valve can be slowly opened, so that well fluid produced by the second single well enters the second metering trunk line and the metering branch line through the outlet valve.

And the pressure near the outlet valve can be adjusted to adjust the flow and the flow rate of the well fluid, so that the well fluid from the second single well can flow at a sufficient flow rate, particularly flows through the connecting pipeline and finally flows into the gas collecting main line at a sufficient flow rate, and the freezing blockage of the metering main line and the gas collecting main line between the second single well and the first single well is further avoided.

Further, in the anti-freezing and anti-blocking natural gas gathering and transporting system, a third gas collecting branch line and a third metering branch line are further arranged on one side, away from the connecting pipeline, of the first gas collecting branch line and the first metering branch line, wherein the third gas collecting branch line is used for communicating the gas collecting trunk line with a third single well, and the third metering branch line is used for communicating the metering trunk line with the third single well; a second control mechanism is arranged at the communication position between the third metering branch line and the metering trunk line, and the flow direction of the well fluid from the third single well in the metering trunk line is controlled by the second control mechanism.

Through the arrangement of the second control mechanism, after the well fluid from the third single well flows into the metering trunk line through the third metering branch line, the well fluid can reversely flow towards the connecting pipeline and finally enters the gas collecting trunk line to be combined with the well fluid from the second single well, so that the flow speed of the well fluid in the metering trunk line and the gas collecting trunk line between the first single well and the second single well is further increased, and the possibility of freezing and blocking of the natural gas gathering and transportation system is further reduced.

When a third single well needs to be measured, well fluid can flow in the positive direction away from the direction of the connecting pipeline to be measured.

Specifically, the second control mechanism may include a third cut-off valve, a fourth cut-off valve, and a tee joint for realizing communication between the third metering branch line and the metering trunk line, wherein: the third trip valve sets up on the measurement trunk line between third measurement branch line and the connecting line, and the fourth trip valve sets up on the measurement trunk line of opposite side.

Thus, when the third shut-off valve is in a fully open state and the fourth shut-off valve is in a fully closed state, well fluid from the third single well flows sequentially through the third metering branch line and the tee joint into the metering trunk line and sequentially through the third shut-off valve and the connecting line in a reverse direction into the gas collecting trunk line.

On the contrary, when the well fluid of the third single well needs to be measured, the third shut-off valve can be controlled to be in a fully closed state and the fourth shut-off valve is controlled to be in a fully opened state, so that the well fluid from the third single well sequentially flows into the measuring trunk line through the third measuring branch line and the tee joint, and flows through the fourth shut-off valve for measurement.

The third shut-off valve and the fourth shut-off valve are not particularly limited in the present invention, as long as the functions described above can be achieved, and the flow direction of the well fluid from the third single well in the metering main line can be controlled. In the specific implementation process of the invention, the third stop valve and the fourth stop valve are both electric ball valves.

Specifically, the third single well may be located on a side of the second single well facing the first single well, that is, the third single well is located between the second single well and the first single well, or may also be located on a side of the second single well away from the first single well.

Further, similar to the second metering branch, an outlet valve may be provided in the third metering branch to adjust the flow rate and flow rate of the well stream in the third metering branch so that the well stream from the third single well has sufficient momentum to complete the entire flow process.

The invention also provides a method for preventing the natural gas gathering and transportation system from being frozen and blocked, which is carried out by using the natural gas gathering and transportation system. Particularly, by controlling the first control mechanism, well flow from the second single well sequentially flows to the gas collecting trunk line through the second metering branch line and the connecting pipeline, so that a blind end originally formed between the first single well and the second single well is communicated, continuous flow of the well flow is realized, freezing and blocking of the pipeline are avoided, and safety of production operation is guaranteed.

According to the anti-freezing and anti-blocking natural gas gathering and transporting system, the control mechanism for controlling the flow direction of well flow objects in the metering trunk line is arranged at the communication position between the metering branch line and the metering trunk line, so that the blind end originally existing in the natural gas gathering and transporting system is 'broken through' to form a flow passage, the purpose of preventing freezing and blocking is achieved, and the safe and stable operation of a gas field is guaranteed. And the anti-freezing and anti-blocking natural gas gathering and transportation system does not influence the switching of the metering processes of each single well.

And because the flow passage is formed, well fluid remained at the blind end originally is driven to enter the gas collecting main line, and resource waste is avoided.

Meanwhile, the anti-freezing and anti-blocking natural gas gathering and transporting system can be simply transformed on the basis of the existing natural gas gathering and transporting system, the problem that the gathering and transporting system cannot normally operate due to single well failure at the end part of the gathering and transporting system and even well shut-in is avoided, and therefore the purpose of saving production cost is achieved.

According to the method for preventing the natural gas gathering and transportation system from being frozen and blocked, due to the adoption of the natural gas gathering and transportation system, series problems caused by the fact that the natural gas gathering and transportation system is frozen and blocked at a low temperature can be avoided, and the safe and stable operation of production operation of a gas field is guaranteed.

Drawings

FIG. 1 is a schematic diagram of a prior art natural gas gathering and transportation system;

fig. 2 is a first schematic structural diagram of a natural gas gathering and transportation system according to a first embodiment of the present invention;

fig. 3 is a schematic structural diagram of a natural gas gathering and transportation system according to a first embodiment of the present invention;

fig. 4 is a comparison graph of the measured temperature curve and the calculated temperature curve of the pipeline end of the natural gas gathering and transportation system at different environmental temperatures according to the first embodiment of the present invention;

fig. 5 is a schematic structural diagram of a natural gas gathering and transportation system according to a second embodiment of the present invention;

fig. 6 is a schematic structural diagram of a natural gas gathering and transportation system according to a second embodiment of the present invention;

fig. 7 is a schematic structural diagram of a natural gas gathering and transportation system provided in the second embodiment of the present invention.

Description of reference numerals:

1-gas collection trunk line; 2-metering trunk line;

3-connecting a pipeline; 4-a first single well;

41-a first gas collecting branch line; 42-first metering leg;

43-a gas gathering station; 5-a second single well;

51-a second gas collecting branch line; 52-second metering leg;

53-outbound valve; 6-a first control mechanism;

61-a first shut-off valve; 62-a second shut-off valve;

7-a third single well; 71-third gas collecting branch line;

72-third metering branch; 73-an outbound valve;

8-a second control mechanism; 81-a third shut-off valve;

82-fourth shut-off valve.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The embodiments described below and the features of the embodiments can be combined with each other without conflict.