CN-122016715-A - Oilfield regional methane monitoring system and method

CN122016715ACN 122016715 ACN122016715 ACN 122016715ACN-122016715-A

Abstract

The application provides a system and a method for monitoring methane in an oil field area. The system comprises a pumping module, an optical signal measuring device and a data acquisition processing module, wherein the pumping module is communicated with the optical signal measuring device, the optical signal measuring device is electrically connected with the data acquisition processing module, the pumping module is used for acquiring a gas sample and transmitting the gas sample to the optical signal measuring device, the optical signal measuring device comprises a laser, a ring-down cavity and a detector, the laser is used for generating laser and injecting the laser into the ring-down cavity so that the laser repeatedly reflects and passes through the gas sample in the ring-down cavity, the light intensity of the laser in the ring-down cavity is attenuated, the detector receives the emergent laser with the attenuated light intensity and converts the optical signal of the emergent laser into an electric signal, and the data acquisition processing module calculates the methane concentration in the gas sample based on the electric signal analysis so as to monitor the methane concentration. The sensitivity and the accuracy of methane monitoring are improved, and long-time online monitoring is realized.

Inventors

ZHANG ZHIQIANG
HU XINYUN
WANG XIAODONG
MA KUN
LI WEI
YUE YU
ZHANG XIAOHAN
SUN DONG
ZOU LIN

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司胜利油田分公司

Dates

Publication Date: 20260512
Application Date: 20241112

Claims (10)

1. The methane monitoring system in the oil field area is characterized by comprising a pumping module, an optical signal measuring device and a data acquisition and processing module; The pumping module is communicated with the optical signal measuring device, and the optical signal measuring device is electrically connected with the data acquisition and processing module; The pumping module is used for collecting a gas sample and conveying the gas sample to the optical signal measuring device; The optical signal measuring device comprises a laser, a ring-down cavity and a detector, wherein the laser is used for generating laser with preset wavelength and injecting the laser into the ring-down cavity so that the laser is repeatedly reflected in the ring-down cavity, a gas sample is contained in the ring-down cavity, the repeatedly reflected laser passes through the gas sample so that methane molecules in the gas sample absorb laser energy to attenuate the light intensity of the laser in the ring-down cavity, and the detector is arranged on an emergent light path of the ring-down cavity so as to receive the emergent laser with the attenuated light intensity and convert an optical signal of the emergent laser into an electric signal; the data acquisition processing module is electrically connected with the detector to analyze and calculate the methane concentration in the gas sample in real time based on the electric signals so as to monitor the methane concentration.
2. The oilfield zone methane monitoring system of claim 1, further comprising a gas flow direction prediction module; The gas flow direction prediction module comprises an environmental information acquisition unit and a gas tracing unit; The environment information acquisition unit is used for acquiring environment information so as to establish a gas flow model based on the environment information; the gas tracing unit is used for analyzing gas flow direction information based on the methane concentration data and the gas flow model so as to obtain an area where a leakage source of methane gas is located.
3. The oilfield zone methane monitoring system of claim 2, wherein the monitoring system further comprises: And the warning module is used for evaluating whether the methane concentration exceeds a set threshold value, recording current methane concentration data and environmental information if the evaluated methane concentration exceeds the threshold value, acquiring an area where a leakage source of methane gas is located based on the gas tracing unit, and triggering concentration abnormality warning.
4. The oilfield regional methane monitoring system of claim 2, further comprising a monitoring site configuration module comprising a sampling tower, a monitoring site room, and a tower site location assessment module; The sampling tower is provided with a sampling port and an environmental information acquisition unit, the sampling port is connected with the pumping module and is used for acquiring a gas sample; the monitoring station room is used for accommodating the optical signal measuring device and the data acquisition processing module; the tower station position assessment module is used for executing one or a combination of the following methods to determine the construction positions of the sampling tower and the monitoring station house: Evaluating mutual interference conditions of the sampling tower, the monitoring station rooms and other monitoring projects in the oil field area, so that the sampling tower, the monitoring station rooms and the other monitoring projects are not interfered with each other to determine a first construction position; Evaluating the safety influence of the sampling tower, the monitoring station rooms and other monitoring projects in the oil field area, so that the sampling tower, the monitoring station rooms and the other monitoring projects meet the safety requirements to determine a second construction position; Evaluating a sampling residence time for collecting the gas sample so that the sampling residence time is less than or equal to 60 seconds to determine a third construction location; evaluating to determine a minimum distance between the sampling tower and a monitoring station room under the condition that only methane gas is monitored so as to determine a fourth construction position; The relative elevation of the geographic locations of the oilfield region is assessed and the geographic location of the highest elevation is selected to determine a fifth construction location.
5. The oilfield regional methane monitoring system of claim 4, wherein the pumping module comprises a plurality of pumping units arranged along the height direction of the sampling tower, each pumping unit comprises a sampling pipe and a sampling pump, the sampling ports are connected with the sampling pipes in a one-to-one correspondence manner, and the sampling pumps are communicated with the optical signal measuring device so as to convey the gas samples collected at the sampling ports to the optical signal measuring device for analysis through the sampling pipes.
6. A method for monitoring methane in an oilfield region comprising the steps of: collecting a gas sample based on a pumping module and conveying the gas sample to the optical signal measurement device; Generating laser with preset wavelength based on a laser and injecting the laser into a ring-down cavity of an optical signal measuring device so that the laser is repeatedly reflected in the ring-down cavity, wherein the repeatedly reflected laser passes through a gas sample in the ring-down cavity so that methane molecules in the gas sample absorb laser energy and the light intensity of the laser in the ring-down cavity is attenuated; Receiving emergent laser light with attenuated light intensity based on a detector, and converting an optical signal of the emergent laser light into an electric signal; And calculating the methane concentration in the gas sample according to the electric signal analysis based on a data acquisition processing module so as to monitor the methane concentration.
7. The oilfield zone methane monitoring method of claim 6, wherein the monitoring method further comprises: Collecting environmental information based on an environmental information collecting unit to establish a gas flow model based on the environmental information; And analyzing the gas flow direction information by utilizing a gas tracing unit based on the methane concentration data and the gas flow model so as to acquire the area where the leakage source of methane gas is located.
8. The oilfield zone methane monitoring method of claim 7, wherein the monitoring method further comprises: And based on a warning module, whether the methane concentration exceeds a set threshold value is evaluated, if the evaluated methane concentration exceeds the threshold value, current methane concentration data and environmental information are recorded, the area where the leakage source of methane gas is located is obtained based on the gas tracing unit, and abnormal concentration warning is triggered.
9. The oilfield zone methane monitoring method of claim 7, further comprising: based on the tower station position assessment module, one or a combination of the following methods are executed to determine the construction positions of the sampling tower and the monitoring station building: Evaluating mutual interference conditions of the sampling tower, the monitoring station rooms and other monitoring projects in the oil field area, so that the sampling tower, the monitoring station rooms and the other monitoring projects are not interfered with each other to determine a first construction position; Evaluating the safety influence of the sampling tower, the monitoring station rooms and other monitoring projects in the oil field area, so that the sampling tower, the monitoring station rooms and the other monitoring projects meet the safety requirements to determine a second construction position; Evaluating a sampling residence time for collecting the gas sample so that the sampling residence time is less than or equal to 60 seconds to determine a third construction location; evaluating to determine a minimum distance between the sampling tower and a monitoring station room under the condition that only methane gas is monitored so as to determine a fourth construction position; Evaluating the relative height of the geographical position of the oilfield region, and selecting the geographical position at the highest position to determine a fifth construction position; a sampling port is arranged on the sampling tower, and a gas sample is collected through a pumping module connected with the sampling port; An environmental information acquisition unit is arranged on the sampling tower to acquire environmental information corresponding to the gas sample; And a monitoring station room is arranged and used for accommodating the optical signal measuring device and the data acquisition processing module.
10. The method of monitoring methane in an oilfield region of claim 9, wherein the installing a sampling port on a sampling tower and collecting a gas sample via a pumping module coupled to the sampling port comprises; A plurality of pumping units are arranged along the height direction of the sampling tower, and each pumping unit comprises a sampling pipe and a sampling pump; the sampling ports are connected with the sampling tubes in a one-to-one correspondence manner so as to collect gas samples through the sampling ports; and conveying the gas sample collected at the sampling port to an optical signal measuring device for analysis through a sampling pipe by a sampling pump.

Description

Oilfield regional methane monitoring system and method Technical Field The invention belongs to the technical field of environmental monitoring, and particularly relates to a methane monitoring system and method for an oilfield region. Background In oilfield production, due to various process operations and geological conditions, volatilization of large amounts of combustible gases, especially methane and ethane, is accompanied, resulting in excessive local area combustible gas concentrations. This phenomenon not only increases the risk of fire and explosion safety accidents, but also causes pollution to the environment. Although the traditional combustible gas monitoring methods, such as a catalytic combustion method, an electrochemical method, a thermal conductivity type and a semiconductor sensor method, can meet certain monitoring requirements to a certain extent, the traditional combustible gas monitoring methods generally have problems, such as low detection sensitivity, difficulty in realizing high-sensitivity monitoring, short service life, performance degradation of monitoring equipment caused by long-term exposure to severe environments, incapability of long-time online monitoring, difficulty in continuously monitoring gas concentration changes, inconvenience in timely discovery of potential safety hazards and the like. Particularly, under the action of complex atmosphere background and wind power, the methods are easy to be interfered by other gases, so that the false alarm rate is increased, and the monitoring result is unreliable. In addition, industrial facilities such as refineries often exist near the oilfield production area, and these facilities also generate combustible gases such as methane during the production process. Under the action of wind force, the gases can diffuse to the oil field production area, and the interference to the existing monitoring equipment is caused, so that the complexity of monitoring is further increased. Disclosure of Invention In order to solve the technical problems, the application provides an oilfield regional methane monitoring system and an oilfield regional methane monitoring method, which are used for solving or relieving the problems existing in the prior art. In order to achieve the above object, the present application provides the following technical solutions: In a first aspect of the application, an oilfield zone methane monitoring system is provided, comprising a pumping module, an optical signal measuring device and a data acquisition and processing module; The pumping module is communicated with the optical signal measuring device, and the optical signal measuring device is electrically connected with the data acquisition and processing module; The pumping module is used for collecting a gas sample and conveying the gas sample to the optical signal measuring device; The optical signal measuring device comprises a laser, a ring-down cavity and a detector, wherein the laser is used for generating laser with preset wavelength and injecting the laser into the ring-down cavity so that the laser is repeatedly reflected in the ring-down cavity, a gas sample is contained in the ring-down cavity, the repeatedly reflected laser passes through the gas sample so that methane molecules in the gas sample absorb laser energy to attenuate the light intensity of the laser in the ring-down cavity, and the detector is arranged on an emergent light path of the ring-down cavity so as to receive the emergent laser with the attenuated light intensity and convert an optical signal of the emergent laser into an electric signal; the data acquisition processing module is electrically connected with the detector to calculate the methane concentration in the gas sample based on the electrical signal analysis to monitor the methane concentration. Optionally, the monitoring system further comprises a gas flow direction prediction module; The gas flow direction prediction module comprises an environmental information acquisition unit and a gas tracing unit; The environment information acquisition unit is used for acquiring environment information so as to establish a gas flow model based on the environment information; the gas tracing unit is used for analyzing gas flow direction information based on the methane concentration data and the gas flow model so as to obtain an area where a leakage source of methane gas is located. Optionally, the monitoring system further comprises a gas flow analysis unit, wherein the gas flow analysis unit is used for building a gas flow model based on computer computing power, the building of the gas flow model comprises building of a gas flow and gas flow direction gradient model based on environment information, and the gas flow direction gradient model is processed based on an error analysis algorithm and a data optimization algorithm so as to improve sensitivity and accuracy of the gas flow model. Optionally, the monitoring system further