Gas field double-pressure gas collection method and gas collection system

Abstract

The invention relates to the technical field of natural gas extraction, in particular to a dual-pressure gas collection method and system for a gas field. The gas field dual-pressure gas collection method comprises the steps that the boundary gas amount of a large-gas-amount well cluster is determined, the large-gas-amount well cluster is divided into a large-gas-amount well cluster and a small-gas-amount well cluster, the large-gas-amount well cluster is divided into a large-gas-amount new well site and an expanded large-gas-amount old well site, and the small-gas-amount well cluster is divided into a small-gas-amount new well site and an expanded small-gas-amount old well site; natural gas of the large-air-volume new well site, the large-air-volume old well site and the small-air-volume new well site is conveyed to a gas collection station through medium-pressure gas collection, natural gas of the small-air-volume old well site is conveyed to the gas collection station through low-pressure gas collection, and the natural gas conveyed into the gas collection station through the medium-pressure gas collection and the low-pressure gas collection is treated, metered and output. Medium-pressure gas collection and low-pressure gas collection are carried out according to the gas volumes of different types of well sites, and the requirements of gas wells with different gas volumes can be better met.

Description

Technical Field

[0001] This invention relates to the field of natural gas extraction technology, and in particular to a dual-pressure gas gathering method and gas gathering system for gas fields. Background Technology

[0002] Natural gas is an important energy resource, and its extraction technology has always been a key research area in the oil and gas industry. In the natural gas extraction process, the pressure control system plays a crucial role, effectively regulating and controlling the collection and transportation of natural gas to ensure production safety and efficiency.

[0003] Currently, existing natural gas extraction technologies typically employ a single-pressure system, where all well sites are connected to the same pressure system for gas gathering. However, while simple and easy to implement, this system cannot meet the needs of wells with varying gas volumes. Especially for rolling production in gas fields, the single-pressure system suffers from low production efficiency and may even lead to production accidents. Furthermore, although adjusting the well site pressure to accommodate different gas volume demands has been proposed, this method requires significant equipment modifications and investment, resulting in high costs and extended production cycles. Moreover, adjusting the well site pressure when handling high and low pressure conditions can lead to inconsistent delivery pressures, potentially affecting the quality and performance of the natural gas. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a dual-pressure gas gathering method and gas gathering system for gas fields, so as to solve the problem that the extraction of natural gas in the prior art cannot meet the rolling extraction of gas wells with different gas volumes.

[0005] This invention discloses a dual-pressure gas gathering method for gas fields, comprising: Determine the boundary gas volume of the large-volume well cluster in the target gas field; Based on the determined boundary gas volume, the target gas field's multiple well clusters are divided into large-volume well clusters and small-volume well clusters; Based on the construction status of gas wells in the well clusters, multiple large-volume well clusters are divided into new large-volume well sites and expanded old large-volume well sites, and multiple small-volume well clusters are divided into new small-volume well sites and expanded old small-volume well sites. Natural gas from new high-volume well sites, old high-volume well sites, and new low-volume well sites will be transported to the gas gathering station via medium-pressure gas gathering, while natural gas from old low-volume well sites will be transported to the gas gathering station via low-pressure gas gathering. The natural gas transported to the gas gathering station from medium-pressure and low-pressure gas gathering stations is processed and metered for external export.

[0006] Optionally, the method for determining the boundary gas volume of a large-volume well cluster in the target gas field includes: Establish a simulation model of the gas gathering pipeline of the target gas field, and set the inlet pressure of the gas gathering station for the simulation model of the gas gathering pipeline; Based on the established gas gathering pipeline simulation model, the maximum daily transmission capacity of the gas gathering pipeline of the target gas field under the set inlet pressure is determined. Obtain the statistical statistics of the proportion of gas wells with different gas volumes in the target gas field, and determine the boundary gas volume of the large gas volume well cluster in the target gas field based on the maximum transmission capacity of the gas gathering pipeline and the statistical statistics of the proportion of gas wells with different gas volumes.

[0007] Optionally, the method for establishing a simulation model of the gas gathering pipeline of the target gas field includes: The diameter of the conventional gas gathering pipeline in the target gas field is selected as the pipe diameter input parameter. Obtain the lengths of all gas gathering pipelines in the target gas field, and calculate the average length of the gas gathering pipelines based on the weighted average method as the length input parameter; Based on the selected input pipe diameter and calculated length parameters, a simulation model of the gas gathering pipeline of the target gas field is established using software simulation.

[0008] Optionally, the method for obtaining the percentage statistics of gas wells with different gas volumes in the target gas field, and determining the boundary gas volume of the large-volume well cluster in the target gas field based on the maximum transmission capacity of the gas gathering pipeline and the percentage statistics of gas wells with different gas volumes, includes: Obtain the daily gas production data of all gas wells in a single well cluster within the target gas field, and sort all gas wells in ascending order of gas production data; Each gas volume data point after sorting is used as a calibration data point. The percentage of gas wells with gas volume data less than or equal to the calibration data is calculated out of the total number of gas wells in the well cluster. The calculation is performed step by step starting from the smallest calibration data point. Set a preset threshold for the proportion of gas wells, obtain the percentages that are greater than or equal to the preset threshold, and select the gas volume data corresponding to the percentage that is closest to the preset threshold and whose total gas volume does not exceed the maximum transmission capacity of the gas gathering pipeline as the boundary gas volume of the large-volume well cluster in the target gas field.

[0009] Optionally, it also includes a method for processing and metering the natural gas transported from the low-pressure gas gathering station to the gas gathering station for external export: In response to the low-pressure gas gathering and transportation, natural gas enters the gas gathering station and undergoes low-pressure separation to remove liquid droplets mixed in with the natural gas. The natural gas after low-pressure separation is pressurized; The pressurized natural gas is metered and then transported to the next stage of the system.

[0010] Optionally, it also includes a method for processing and metering the natural gas transported from the medium-pressure gas gathering station to the gas gathering station for external export: In response to the natural gas entering the gas gathering station for medium-pressure gas gathering and transportation, the natural gas undergoes medium-pressure separation to remove liquid droplets mixed in with the natural gas; The natural gas separated under medium pressure is metered and then transported to the next stage of the system.

[0011] Optionally, it also includes gas gathering methods for different well sites in the target gas field at different gas gathering stages: Determine the gas collection stage of a well site based on the gas gathering pressure of different well sites in the target gas field; If the gas collection stage of the well site is determined to be the initial stage of gas collection, the natural gas from the large-volume new well site, the large-volume old well site, and the small-volume new well site will be transported to the gas collection station through medium-pressure gas collection, and the natural gas from the small-volume old well site will be transported to the gas collection station through low-pressure gas collection. If the gas collection stage of the well site is determined to be the later stage of gas collection, the natural gas from the large-volume new well site, the large-volume old well site, and the small-volume new well site will be transported to the gas gathering station through low-pressure gas gathering, and the natural gas from the small-volume old well site will be transported to the gas gathering station through low-pressure gas gathering.

[0012] The present invention also discloses a gas gathering system applied to the above-mentioned dual-pressure gas gathering method in gas fields, including a medium-pressure gas gathering unit and a low-pressure gas gathering unit. The medium-pressure gas gathering unit includes a medium-pressure gas production trunk line connecting a large-volume new well site, a large-volume old well site, and a small-volume new well site to the gas gathering station, respectively. The low-pressure gas gathering unit includes a low-pressure gas production trunk line connecting a small-volume old well site to the gas gathering station.

[0013] Optionally, the medium-pressure gas gathering unit further includes a medium-pressure separator and a first external metering device arranged in sequence within the gas gathering station, and the medium-pressure gas collection main pipe is connected to the medium-pressure separator. The low-pressure gas gathering unit further includes a low-pressure separator, a compressor, and a second external metering device arranged in sequence within the gas gathering station, and the low-pressure gas collection main pipe is connected to the low-pressure separator.

[0014] Optionally, the medium-pressure gas collection trunk line is connected to the low-pressure separator so that the natural gas is subjected to low-pressure processing when the medium-pressure gas collection trunk line switches to low-pressure gas collection.

[0015] Compared with the prior art, the beneficial effects of the dual-pressure gas gathering method and gas gathering system for gas fields provided in this embodiment of the invention are as follows: By determining the boundary gas volume of large-volume well clusters in the target gas field, the gas volume of multiple well clusters in the target gas field is first divided. Then, well clusters with different gas volumes are further divided into new well sites and expanded old well sites according to the construction status of the gas wells. Based on the gas volume of different types of well sites, medium-pressure gas gathering and low-pressure gas gathering are carried out respectively. This can better meet the needs of gas wells with different gas volumes, make full use of the pressure energy of new wells, effectively improve production efficiency, avoid production accidents caused by inconsistent pressure, and thus improve the overall production efficiency and quality of the gas field. Attached Figure Description

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic block diagram illustrating the steps of the dual-pressure gas gathering method for gas fields provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the dual-pressure gas gathering structure in the initial stage of gas collection in a gas field, provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of low-pressure gas gathering in a gas field during the later stage of gas collection, as provided in an embodiment of the present invention.

[0017] The labels for the attached figures are as follows: 1. Medium-pressure gas sampling main; 2. Low-pressure gas sampling main; 3. Medium-pressure separator; 4. First external metering device; 5. Low-pressure separator; 6. Compressor; 7. Second external metering device. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] This invention discloses a dual-pressure gas gathering method for gas fields, such as... Figure 1 and Figure 2 As shown, it includes: S1. Determine the boundary gas volume of the large-volume well cluster in the target gas field; S2. Based on the determined boundary gas volume, the multiple well clusters of the target gas field are divided into large-volume well clusters and small-volume well clusters. S3. Based on the construction status of gas well volume in the well cluster, multiple large-volume well clusters are divided into new large-volume well sites and expanded old large-volume well sites, and multiple small-volume well clusters are divided into new small-volume well sites and expanded old small-volume well sites. S4. Natural gas from large-volume new well sites, large-volume old well sites, and small-volume new well sites will be transported to the gas gathering station via medium-pressure gas gathering, and natural gas from small-volume old well sites will be transported to the gas gathering station via low-pressure gas gathering. S5. Process and meter the natural gas transported to the gas gathering station from medium-pressure and low-pressure gas gathering stations for external export.

[0020] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, the boundary gas volume of large-volume well clusters in the target gas field is first determined. This boundary gas volume is then used to divide the gas volume of multiple well clusters within the target gas field, ensuring that the gas volume of each well cluster can be accurately assessed. Next, well clusters with different gas volumes are further divided into new well sites and expanded old well sites based on the construction status of the gas wells. New well sites refer to recently developed or newly discovered gas well groups, while expanded old well sites refer to well groups where the gas volume has increased after technical upgrades or equipment additions. Based on the gas volume of different types of well sites, medium-pressure and low-pressure gas gathering are carried out separately to better meet the needs of gas wells with different gas volumes and fully utilize the pressure energy of new wells, effectively improving production efficiency. Thus, based on reasonable gas gathering and pressure management, production accidents caused by inconsistent pressure are avoided, thereby improving the overall production efficiency and quality of the gas field.

[0021] As mentioned above, specifically, large-volume new well sites are newly added well sites with high daily gas production, capable of meeting the growing natural gas demand. Small-volume new well sites are also newly added well sites, but their daily gas production is lower, and they are mostly located in areas with fewer resources. Large-volume old well sites are existing well sites that have been expanded, increasing their daily gas production to meet or exceed the standards for large-volume well clusters. Small-volume old well sites are also existing well sites that, after expansion, have seen an increase in gas volume, but their daily gas production remains low.

[0022] Natural gas from large-volume new well sites, large-volume old well sites, and small-volume new well sites is transported to the new well system of the gas gathering station via medium-pressure gathering for medium-pressure gathering. Natural gas from small-volume old well sites is transported to the old well system of the gas gathering station via low-pressure gathering for low-pressure gathering, enabling dual-pressure operation of the new / old well systems. Medium-pressure gathering involves constructing new gathering trunk lines for both medium and low-pressure gathering; low-pressure gathering utilizes existing gathering trunk lines in the gas field. This fully utilizes existing equipment and facilities, improves production efficiency, and shortens the production cycle. Furthermore, by employing dual-pressure gas collection, the pressure energy of new wells is fully utilized, reducing overall investment and maximizing benefits. Preferably, the pressure range for medium-pressure gathering is 1.6 MPa to 10 MPa, and the pressure range for low-pressure gathering is less than 1.6 MPa.

[0023] Furthermore, methods for determining the boundary gas volume of large-volume well clusters in a target gas field include: Establish a simulation model of the gas gathering pipeline of the target gas field, and set the inlet pressure of the gas gathering station for the simulation model of the gas gathering pipeline; Based on the established gas gathering pipeline simulation model, the maximum daily transmission capacity of the gas gathering pipeline of the target gas field under the set inlet pressure is determined. Obtain the statistical statistics of the proportion of gas wells with different gas volumes in the target gas field, and determine the boundary gas volume of the large gas volume well cluster in the target gas field based on the maximum transmission capacity of the gas gathering pipeline and the statistical statistics of the proportion of gas wells with different gas volumes.

[0024] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, by simulating common gas gathering pipelines in the target gas field, and assuming a constant inlet pressure for the natural gas transported by the gas gathering pipeline, the maximum daily throughput of the gas gathering pipeline is accurately determined. Simultaneously, considering the actual deployment of well clusters and the proportion of gas wells with different gas volumes in the target gas field, the boundary gas volume of large-volume well clusters is quickly determined. By determining the boundary gas volume, large-volume well clusters and small-volume well clusters can be distinguished, helping to optimize well site management and resource allocation, ensuring that the production of large-volume well sites is fully utilized, while avoiding excessive resource consumption by small-volume well sites. That is, when the gas volume of a well cluster is greater than the boundary gas volume, the well cluster is a large-volume well cluster; when the gas volume of a well cluster is less than the boundary gas volume, the well cluster is a small-volume well cluster.

[0025] Furthermore, methods for establishing simulation models of gas gathering pipelines for target gas fields include: The diameter of the conventional gas gathering pipeline in the target gas field is selected as the pipe diameter input parameter. Obtain the lengths of all gas gathering pipelines in the target gas field, and calculate the average length of the gas gathering pipelines based on the weighted average method as the length input parameter; Based on the selected input pipe diameter and calculated length parameters, a simulation model of the gas gathering pipeline of the target gas field is established using software simulation.

[0026] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, the software can preferably be professional gas field simulation software, such as PipeSim, OLGA, and GASMOD, which possess powerful computing capabilities and rich databases, enabling accurate simulation of various operating conditions in gas fields. By selecting input parameters for pipe diameter and calculation length, a more accurate data foundation is provided for the gas gathering pipeline simulation model. Through the simulation model, the gas field's gas gathering pipeline system can be optimized, including pipeline layout and flow distribution, thereby improving the overall efficiency of the gas gathering system.

[0027] Furthermore, methods for obtaining the percentage statistics of gas wells with different gas volumes in the target gas field, and determining the boundary gas volume of large-volume well clusters in the target gas field based on the maximum transmission capacity of gas gathering pipelines and the percentage statistics of gas wells with different gas volumes, include: Obtain the daily gas production data of all gas wells in a single well cluster within the target gas field, and sort all gas wells in ascending order of gas production data; Each gas volume data point after sorting is used as a calibration data point. The percentage of gas wells with gas volume data less than or equal to the calibration data is calculated out of the total number of gas wells in the well cluster. The calculation is performed step by step starting from the smallest calibration data point. Set a preset threshold for the proportion of gas wells, obtain the percentages that are greater than or equal to the preset threshold, and select the gas volume data corresponding to the percentage that is closest to the preset threshold and whose total gas volume does not exceed the maximum transmission capacity of the gas gathering pipeline as the boundary gas volume of the large-volume well cluster in the target gas field.

[0028] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, daily gas production data from all gas wells were collected and organized, providing fundamental data for subsequent analysis. The gas production data was sorted in ascending order to make the data more organized and easier to analyze and compare. Calculating the percentage of gas wells corresponding to each gas production data point helps to quickly identify the distribution of gas wells of different production levels within the well cluster. Finally, by progressively calculating and selecting the percentage closest to a preset threshold and matching it with the maximum capacity of the gathering pipeline, the determined boundary gas volume allows for reasonable production planning. This ensures that the production from high-yield wells is prioritized, improving overall production efficiency and preventing the total gas production of the well cluster from exceeding the maximum capacity of the gathering pipeline, thus avoiding waste of some gas.

[0029] Furthermore, it also includes methods for processing and metering the natural gas transported from low-pressure gas gathering stations to external shipments: In response to the low-pressure gas gathering and transportation, natural gas enters the gas gathering station and undergoes low-pressure separation to remove liquid droplets mixed in with the natural gas. The natural gas after low-pressure separation is pressurized; The pressurized natural gas is metered and then transported to the next stage of the system.

[0030] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, low-pressure separation can effectively remove liquid impurities from natural gas, such as water, condensate oil, and particulate matter, preventing these impurities from accumulating in pipelines and causing corrosion, blockages, and reduced efficiency. Simultaneously, the natural gas pressure from low-pressure gathering is relatively low; pressurization can increase the pressure to meet pipeline transportation standards, reducing transportation costs. Furthermore, a precise metering system can accurately record natural gas production and transportation volume.

[0031] Furthermore, it also includes methods for processing and metering the natural gas transported from medium-pressure gas gathering stations to external shipments: In response to the natural gas entering the gas gathering station for medium-pressure gas gathering and transportation, the natural gas undergoes medium-pressure separation to remove liquid droplets mixed in with the natural gas; The natural gas separated under medium pressure is metered and then transported to the next stage of the system.

[0032] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, impurities such as liquid water and condensate oil in natural gas are removed using medium-pressure separation. The accuracy of natural gas production and transportation volume is ensured through a metering system. Because the natural gas from medium-pressure gathering has a higher pressure, it can meet pipeline transportation standards without the need for pressurization.

[0033] Furthermore, combined Figure 2 and Figure 3 As shown, it also includes gas gathering methods for different well sites in the target gas field at different gas gathering stages: Determine the gas collection stage of a well site based on the gas gathering pressure of different well sites in the target gas field; If the gas collection stage of the well site is determined to be the initial stage of gas collection, the natural gas from the large-volume new well site, the large-volume old well site, and the small-volume new well site will be transported to the gas collection station through medium-pressure gas collection, and the natural gas from the small-volume old well site will be transported to the gas collection station through low-pressure gas collection. If the gas collection stage of the well site is determined to be the later stage of gas collection, the natural gas from the large-volume new well site, the large-volume old well site, and the small-volume new well site will be transported to the gas gathering station through low-pressure gas gathering, and the natural gas from the small-volume old well site will be transported to the gas gathering station through low-pressure gas gathering.

[0034] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, the later stage of gas gathering refers to the period when the gas gathering pressure in newly developed well sites and expanded old well sites is below 1.6 MPa. At this time, due to the low gas gathering pressure at the well sites, only low-pressure gas gathering is required for all well sites. That is, the method of medium-pressure gas gathering in the early stage of gas gathering is switched to low-pressure gas gathering in the later stage; and the method of low-pressure gas gathering in the early stage of gas gathering is maintained at low pressure in the later stage. Furthermore, in the later stage of gas gathering, when all the natural gas gathered at low pressure enters the gas gathering station, it first undergoes low-pressure separation to remove liquid droplets carried in the natural gas, then it is pressurized, and finally metered and transported. Because the well site pressure gradually decreases as extraction progresses, switching from medium-pressure to low-pressure gas gathering can collect natural gas more economically. By adapting to changes in well site pressure and optimizing the gas gathering process, the problem of inconsistent extraction times and delivery pressures in rolling development gas fields can be effectively solved, thereby improving the overall extraction efficiency and quality of the gas field.

[0035] The specific application of the dual-pressure gas gathering method in gas fields according to the embodiments of the present invention is further illustrated by taking a common DN80 pipeline in a gas field as an example: A common DN80 pipeline in a gas field was selected, and its average length was calculated to be 5 km using a weighted average method. A simulation of the gas gathering pipeline was then performed, setting the inlet pressure to 0.4 MPa. The maximum daily throughput of the gas gathering pipeline was determined to be 25,000 cubic meters per day through the simulation model. Furthermore, considering the percentage of wells with different gas volumes, for example, in a certain block of the gas field with 400 wells, 75 wells had a gas volume of 3 × 10⁴ m³ / d or less (18.56%), 95 wells had a gas volume of 5 × 10⁴ m³ / d or less (23.51%), and 196 wells had a gas volume of 8 × 10⁴ m³ / d or less (50.24%). Therefore, the boundary gas volume of the large-volume well cluster in this block was confirmed to be 3 × 10⁴ m³ / d.

[0036] Based on the well location layout, the well clusters are divided into four types: large-volume new well sites, large-volume old well sites, small-volume new well sites, and small-volume old well sites. In the initial stage of gas collection, large-volume new well sites, large-volume old well sites, and small-volume new well sites are connected to the new well system for medium-pressure gas collection, and small-volume old well sites are connected to the old well system for low-pressure gas collection, so as to realize the dual-pressure system operation of the new well / old well system. In the later stages of gas collection, all well sites will undergo low-pressure gas collection, and pressurization operations will be carried out at the gas collection station.

[0037] This invention also discloses a gas gathering system applied to the aforementioned dual-pressure gas gathering method for gas fields, comprising a medium-pressure gas gathering unit and a low-pressure gas gathering unit. The medium-pressure gas gathering unit includes a medium-pressure gas production trunk line 1 connecting a large-volume new well site, a large-volume old well site, and a small-volume new well site to the gas gathering station, respectively. The low-pressure gas gathering unit includes a low-pressure gas production trunk line 2 connecting a small-volume old well site to the gas gathering station.

[0038] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, this approach allows for medium-pressure gas gathering via medium-pressure production pipeline 1 and low-pressure gas gathering via low-pressure production pipeline 2, depending on the gas volume of the gas well. This better meets the needs of gas wells with different gas volumes, improves production efficiency, and avoids production accidents caused by inconsistent pressure. Simultaneously, it fully utilizes the pressure energy of new wells, reduces overall investment, and maximizes benefits.

[0039] Furthermore, the medium-pressure gas gathering unit also includes a medium-pressure separator 3 and a first external metering device 4 arranged in sequence within the gas gathering station, and the medium-pressure gas collection main pipe 1 is connected to the medium-pressure separator 3. The low-pressure gas gathering unit also includes a low-pressure separator 5, a compressor 6, and a second external metering device 7 arranged in sequence within the gas gathering station, and the low-pressure gas collection main pipe 2 is connected to the low-pressure separator 5.

[0040] Through the implementation of the above-described dual-pressure gas gathering method embodiment, for the medium-pressure gas gathering unit, the medium-pressure separator 3 can remove impurities such as liquid water and condensate oil from the natural gas. The first export meter 4 ensures the accuracy of natural gas production and delivery volume. For the low-pressure gas gathering unit, the low-pressure separator 5 can effectively remove liquid impurities such as water, condensate oil, and particulate matter from the natural gas, preventing the accumulation of these impurities in the pipeline that could lead to corrosion, blockage, and reduced efficiency. Simultaneously, the natural gas pressure in the low-pressure gathering unit is relatively low; the compressor 6 can increase the natural gas pressure to meet pipeline delivery standards, reducing transportation costs. The second export meter 7 accurately records the natural gas production and delivery volume.

[0041] Furthermore, the medium-pressure gas production trunk line is connected to the low-pressure separator so that the natural gas is processed at low pressure when the medium-pressure gas production trunk line switches to low-pressure gas gathering.

[0042] Through the implementation of the above-described dual-pressure gas gathering method for gas fields, the medium-pressure gas production trunk line 1 is connected to the low-pressure separator 5. During the later stages of gas gathering, as the medium-pressure gathering in the medium-pressure gas production trunk line 1 transitions to low-pressure gathering, the low-pressure separator 5 effectively removes liquid impurities from the natural gas. The compressor 6 then increases the natural gas pressure to meet pipeline transportation standards. Finally, the second external metering device 7 accurately records the natural gas production and transportation volume. By adapting to changes in well site pressure and optimizing the gas gathering process, the problem of inconsistent production times and transportation pressures in rolling development gas fields can be effectively solved, thereby improving the overall production efficiency and quality of the gas field.

[0043] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A dual-pressure gas gathering method for a gas field, characterized in that, The gas field dual-pressure gas gathering method includes: Determine the boundary gas volume of the large-volume well cluster in the target gas field; Based on the determined boundary gas volume, the target gas field's multiple well clusters are divided into large-volume well clusters and small-volume well clusters; Based on the construction status of gas wells in the well clusters, multiple large-volume well clusters are divided into new large-volume well sites and expanded old large-volume well sites, and multiple small-volume well clusters are divided into new small-volume well sites and expanded old small-volume well sites. Natural gas from new high-volume well sites, old high-volume well sites, and new low-volume well sites will be transported to the gas gathering station via medium-pressure gas gathering, while natural gas from old low-volume well sites will be transported to the gas gathering station via low-pressure gas gathering. The natural gas transported to the gas gathering station from medium-pressure and low-pressure gas gathering stations is processed and metered for external export.

2. The gas field dual-pressure gas gathering method according to claim 1, characterized in that, The method for determining the boundary gas volume of a large-volume well cluster in a target gas field includes: Establish a simulation model of the gas gathering pipeline of the target gas field, and set the inlet pressure of the gas gathering station for the simulation model of the gas gathering pipeline; Based on the established gas gathering pipeline simulation model, the maximum daily transmission capacity of the target gas field's gas gathering pipeline under the set inlet pressure is determined. Obtain the statistical statistics of the proportion of gas wells with different gas volumes in the target gas field, and determine the boundary gas volume of the large gas volume well cluster in the target gas field based on the maximum transmission capacity of the gas gathering pipeline and the statistical statistics of the proportion of gas wells with different gas volumes.

3. The gas field dual-pressure gas gathering method according to claim 2, characterized in that, The method for establishing a simulation model of the gas gathering pipeline of the target gas field includes: The diameter of the conventional gas gathering pipeline in the target gas field is selected as the pipe diameter input parameter. Obtain the lengths of all gas gathering pipelines in the target gas field, and calculate the average length of the gas gathering pipelines based on the weighted average method as the length input parameter; Based on the selected input pipe diameter and calculated length parameters, a simulation model of the gas gathering pipeline of the target gas field is established using software simulation.

4. The gas field dual-pressure gas gathering method according to claim 2, characterized in that, The method for obtaining the percentage statistics of gas wells with different gas volumes in the target gas field, and determining the boundary gas volume of large-volume well clusters in the target gas field based on the maximum transmission capacity of the gas gathering pipeline and the percentage statistics of gas wells with different gas volumes, includes: Obtain the daily gas production data of all gas wells in a single well cluster within the target gas field, and sort all gas wells in ascending order of gas production data; Each gas volume data point after sorting is used as a calibration data point. The percentage of gas wells with gas volume data less than or equal to the calibration data is calculated out of the total number of gas wells in the well cluster. The calculation is performed step by step starting from the smallest calibration data point. Set a preset threshold for the proportion of gas wells, obtain the percentages that are greater than or equal to the preset threshold, and select the gas volume data corresponding to the percentage that is closest to the preset threshold and whose total gas volume does not exceed the maximum transmission capacity of the gas gathering pipeline as the boundary gas volume of the large-volume well cluster in the target gas field.

5. The gas field dual-pressure gas gathering method according to claim 1, characterized in that, It also includes methods for processing and metering the natural gas transported from low-pressure gas gathering stations to external transportation: In response to the low-pressure gas gathering and transportation, natural gas enters the gas gathering station and undergoes low-pressure separation to remove liquid droplets mixed in with the natural gas. The natural gas after low-pressure separation is pressurized; The pressurized natural gas is metered and then transported to the next stage of the system.

6. The gas field dual-pressure gas gathering method according to claim 1, characterized in that, It also includes methods for processing and metering the natural gas transported from medium-pressure gas gathering stations to external transportation: In response to the natural gas entering the gas gathering station for medium-pressure gas gathering and transportation, the natural gas undergoes medium-pressure separation to remove liquid droplets mixed in with the natural gas; The natural gas separated under medium pressure is metered and then transported to the next stage of the system.

7. The gas field dual-pressure gas gathering method according to any one of claims 1-6, characterized in that, It also includes gas gathering methods for different well sites in the target gas field at different stages of gas production: Determine the gas collection stage of a well site based on the gas gathering pressure of different well sites in the target gas field; If the gas collection stage of the well site is determined to be the initial stage of gas collection, the natural gas from the large-volume new well site, the large-volume old well site, and the small-volume new well site will be transported to the gas collection station through medium-pressure gas collection, and the natural gas from the small-volume old well site will be transported to the gas collection station through low-pressure gas collection. If the gas collection stage of the well site is determined to be the later stage of gas collection, the natural gas from the large-volume new well site, the large-volume old well site, and the small-volume new well site will be transported to the gas gathering station through low-pressure gas gathering, and the natural gas from the small-volume old well site will be transported to the gas gathering station through low-pressure gas gathering.

8. A gas collection system, characterized in that, The gas field dual-pressure gas gathering method applied to any one of claims 1-7 includes a medium-pressure gas gathering unit and a low-pressure gas gathering unit. The medium-pressure gas gathering unit includes a medium-pressure gas production trunk line connecting a large-volume new well site, a large-volume old well site, and a small-volume new well site to a gas gathering station, respectively. The low-pressure gas gathering unit includes a low-pressure gas production trunk line connecting a small-volume old well site to a gas gathering station.

9. The gas collection system according to claim 8, characterized in that, The medium-pressure gas gathering unit further includes a medium-pressure separator and a first external metering device arranged in sequence within the gas gathering station. The medium-pressure gas collection main pipe is connected to the medium-pressure separator. The low-pressure gas gathering unit further includes a low-pressure separator, a compressor, and a second external metering device arranged in sequence within the gas gathering station. The low-pressure gas collection main pipe is connected to the low-pressure separator.

10. The gas collection system according to claim 9, characterized in that, The medium-pressure gas extraction trunk line is connected to the low-pressure separator so that the natural gas is processed at low pressure when the medium-pressure gas extraction trunk line switches to low-pressure gas collection.

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