Injection-production operation monitoring system and method for salt-cavern gas storage

Abstract

The invention provides a salt-cavern gas storage injection-production operation monitoring system which comprises an optical fiber monitoring module arranged in a target well of a salt-cavern gas storage and used for performing multi-dimensional real-time monitoring on the salt-cavern gas storage; the optical fiber monitoring module comprises an optical fiber shape sensing sensor used for monitoring deformation and damaged parts of a well completion pipe column of an injection and production well, the optical fiber shape sensing sensor comprises an elastic base body, an array fiber grating and an external protective sleeve, the elastic base body adopts a memory metal wire, grooves are formed in the four 90-degree directions of the circle center of the memory metal wire, and the array fiber grating is arranged in the grooves; an array fiber bragg grating is formed by the implanted fiber bragg gratings, and a protective sleeve is extruded on the outer layer of the memory metal wire to serve as an external protective sleeve. According to the method, early warning signals and information of various risks in the operation process of the gas storage can be found in time, and long-term stable and safe operation of the salt-cavern gas storage is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of underground gas storage technology and equipment, and in particular to a salt cavern gas storage injection and production operation monitoring system and method. Background Art

[0002] An underground gas storage is an artificial gas field or reservoir formed by re-injecting extracted natural gas into underground storable gas space. Salt cavern gas storage is based on salt dome or salt rock geological structure and uses salt dissolution technology to form cavern storage space to store natural gas. It is one of the main types of underground gas storage. This type of gas storage has the advantages of high peak-shaving efficiency, large short-term throughput, less bottom gas and complete recovery. It has been well applied both at home and abroad and is an important means to meet peak-shaving needs.

[0003] During the injection and production operation of gas storage salt caverns, the injection and production alternating stress, alternating temperature and creep of salt rock itself are affected. After long-term operation, it is very likely that the salt caverns will experience instability such as creep, settlement, spalling, collapse and leakage. It is also possible that the cement ring sealing will be damaged, the injection and production string will fail and other wellbore damage will occur. In order to ensure the safety of the injection and production operation of salt cavern gas storage, it is necessary to conduct long-term stable monitoring of single well parameters, ground settlement, and deformation of injection and production strings during the injection and production operation of salt cavern gas storage, so as to effectively evaluate the stability of the salt caverns and timely guide the safe operation of the salt caverns.

[0004] At present, the monitoring methods used for the operation and maintenance of salt cavern gas storage mainly include: monitoring of single wellhead pressure, temperature, flow and other data operating parameters, monitoring of underground microseismic events by electric geophones, monitoring of tracer sealing and monitoring of sonar cavity morphology, etc. However, the monitoring methods currently used for the operation and maintenance of salt cavern gas storage are generally electrical sensors and systems, which have the disadvantages of weak adaptability, small capacity, few measurable parameters, large volume and mass, and difficulty in deployment. It is impossible to achieve long-term monitoring of gas storage at multiple scales and all elements. Specifically, each test process is independent, and the dynamic adjustment of injection and production projects is not timely, which increases the cost of manpower and material resources.

[0005] In view of the problems of the prior art, the present invention provides a salt cavern gas storage injection and production operation monitoring system and method. Summary of the invention

[0006] In order to overcome the defects of the prior art, the present invention provides a salt cavern gas storage injection and production operation monitoring system, the system comprising:

[0007] An optical fiber monitoring module is installed in the target well of the salt cavern gas storage reservoir and is used for multi-dimensional real-time monitoring of the salt cavern gas storage reservoir;

[0008] The optical fiber monitoring module includes an optical fiber shape sensing sensor for monitoring deformation and damaged parts of the completion string of the injection and production well, which includes: an elastic matrix, an array optical fiber grating and an external protective cover, wherein the elastic matrix adopts a memory metal wire, and grooves are opened in four directions of 90° from the center of the memory metal wire to implant the optical fiber grating to form the array optical fiber grating, and a protective cover is extruded on the outer layer of the memory metal wire as the external protective cover.

[0009] According to one embodiment of the present invention, the fiber optic monitoring module includes: an injection and production well fiber optic monitoring module, which is arranged on the completion string of the injection and production well of the salt cavern gas storage, and is an armored optical cable composed of multi-parameter multimode optical fibers, wherein the multi-parameter multimode optical fibers include distributed acoustic wave sensing optical fibers, distributed temperature sensing optical fibers, and multiple transmission optical fibers that are serially connected to the optical fiber shape sensing sensors and / or optical fiber pressure sensors.

[0010] According to one embodiment of the present invention, the optical fiber monitoring module includes: a surrounding rock monitoring well optical fiber monitoring module, which is arranged in the surrounding rock monitoring well of the salt cavern gas storage reservoir and is an armored optical cable composed of transmission optical fibers of optical fiber pressure sensors connected in series.

[0011] According to one embodiment of the present invention, the optical fiber monitoring module includes: a subsidence monitoring well optical fiber monitoring module, which is arranged in the subsidence monitoring well of the salt cavern gas storage reservoir and is an armored optical cable composed of transmission optical fibers of optical fiber subsidence displacement sensors connected in series.

[0012] According to one embodiment of the present invention, the optical fiber settlement displacement sensor comprises: a top plate, a shell, a mounting base, a stainless optical measuring rod, and a grouting anchor head, wherein the top plate is connected to the top of the shell as a ground reference point, the bottom of the shell is connected to the mounting base, and the stainless optical measuring rod arranged inside the shell is connected to the grouting anchor head through the mounting base. When settlement or cracks occur on the ground, the displacement of the grouting anchor head can cause the grating sensing signal of the stainless optical measuring rod to change, thereby obtaining real-time measurement data.

[0013] According to one embodiment of the present invention, the system comprises:

[0014] A ground crack monitoring module is arranged at the ground crack of the salt cavern gas storage reservoir, and is a ground crack monitoring optical cable composed of transmission optical fibers of the optical fiber settlement displacement sensor connected in series;

[0015] The underground microseismic monitoring module is arranged in the surrounding rock monitoring well of the salt cavern gas storage reservoir and is an underground three-component geophone array.

[0016] According to one embodiment of the present invention, the system includes: a composite modulation and demodulation instrument, which is connected to the optical fiber monitoring module and is used to modulate and demodulate multi-dimensional real-time monitoring data, wherein the composite modulation and demodulation instrument has the modulation and demodulation function of distributed acoustic wave sensing optical fiber signals, distributed temperature sensing optical fiber signals, optical fiber shape sensing sensor signals, optical fiber settlement displacement sensor signals, and optical fiber pressure sensor signals.

[0017] According to one embodiment of the present invention, the system includes: ground remote monitoring equipment, which is connected to the composite modulation and demodulation instrument, and is used to perform data analysis on the multi-dimensional real-time monitoring data after modulation and demodulation, to achieve long-term real-time dynamic monitoring of the production process parameters of the injection and production wells of the gas storage reservoir, monitoring of the deformation and possible damaged parts of the injection and production well pipes, monitoring of whether there is fault excitation and induction during the injection and production process causing stability, monitoring of ground subsidence data, and monitoring of ground crack data, so as to facilitate intervention measures to maintain the stable operation of the injection and production wells of the gas storage reservoir.

[0018] According to another aspect of the present invention, there is also provided a method for monitoring injection and production operation of a salt cavern gas storage, which is performed by a system as described in any one of the above items, and the method comprises the following steps:

[0019] The salt cavern gas storage is monitored in real time in multiple dimensions by means of the optical fiber monitoring module arranged in the target well of the salt cavern gas storage;

[0020] The optical fiber monitoring module includes an optical fiber shape sensing sensor for monitoring deformation and damaged parts of the completion string of the injection and production well, which includes: an elastic matrix, an array optical fiber grating and an external protective cover, wherein the elastic matrix adopts a memory metal wire, and grooves are opened in four directions of 90° from the center of the memory metal wire to implant the optical fiber grating to form the array optical fiber grating, and a protective cover is extruded on the outer layer of the memory metal wire as the external protective cover.

[0021] According to another aspect of the present invention, a storage medium is provided, which contains a series of instructions for executing the method steps described above.

[0022] The present invention provides a salt cavern gas storage injection and production operation monitoring system and method, which has the following advantages over the prior art:

[0023] The optical fiber sensor used in the present invention can realize long-term, stable, high-precision, and real-time monitoring of micro-leakage, temperature, pressure, and ground subsidence in the cavity or wellbore of the salt cavern gas storage and other injection and production systems, and has the advantages of remote, multi-parameter, large capacity, and multi-sensor fusion. Through the system and method, early warning signals and information of various risks in the operation of the gas storage can be discovered in time, ensuring the long-term stable and safe operation of the salt cavern gas storage.

[0024] The optical fiber shape sensing sensor proposed in the present invention has a simple and sensitive overall structure. Through an array of optical fiber gratings arranged on an elastic substrate, it can sensitively sense the circumferential and axial deformation of the completion string of the injection and production well, and can also perform real-time monitoring of possible damaged locations on the completion string.

[0025] The optical fiber settlement displacement sensor proposed in the present invention has a simple and sensitive overall structure. Through the stainless optical measuring rod and the grouting anchor head connected in sequence, it can sensitively sense the ground settlement and ground cracks in the salt cavern gas storage reservoir, so as to facilitate intervention measures such as well repair and maintain the stable operation of the salt cavern gas storage reservoir.

[0026] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 A schematic diagram of the structure of a salt cavern gas storage injection and production operation monitoring system according to an embodiment of the present invention is shown;

[0029] Figure 2 A schematic diagram of sensor distribution in an injection-production well according to an embodiment of the present invention is shown;

[0030] Figure 3 A schematic diagram of the structure of an optical fiber shape sensing sensor according to an embodiment of the present invention is shown;

[0031] Figure 4 It shows a schematic structural diagram of an optical fiber subsidence displacement sensor according to an embodiment of the present invention;

[0032] Figure 5 A flowchart of the steps of a method for monitoring injection and production operation of a salt cavern gas storage according to an embodiment of the present invention is shown.

[0033] In the accompanying drawings, the same reference numerals are used for the same components. In addition, the accompanying drawings are not drawn according to the actual scale.

[0034] The meanings of the various reference numerals in the accompanying drawings are as follows: 1-injection and production well; 2-armored optical cable; 3-fiber Bragg grating sensor; 4-composite modulation and demodulation instrument; 5-ground crack monitoring cable; 6-surrounding rock monitoring well; 7-sedimentation monitoring well; 8-ground remote monitoring equipment; 11-salt cavern gas storage; 12-brine interface; 21-completion string; 22-fiber optic pressure sensor; 23-fiber optic shape sensing sensor; 24-transmission optical fiber; 25-elastic matrix; 26-arrayed fiber Bragg grating; 27-external protective cover; 31-top plate; 32-transmission optical cable; 33-housing; 34-mounting base; 35-pigtail; 36-stainless steel optical measuring rod; 37-grouting anchor head; 38-ground. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0036] The prior art (CN113588797A) provides a wellbore salt monitoring device and method for gas storage. The prior art (Application of fiber optic displacement sensor in salt rock underground gas storage group model test, Rock and Soil Mechanics, October 2013) provides a fiber optic displacement sensor in a salt rock underground gas storage group model. The prior art (Application of fiber optic technology in oil-water interface monitoring of salt cavern gas storage, Oil and Gas Storage and Transportation, January 2020) provides an application of fiber optic technology in oil-water interface monitoring of salt cavern gas storage. The prior art (Analysis and countermeasures of annular pressure of injection and production wells in hydrogen sulfide gas storage, World Petroleum Industry, April 2022) provides an analysis and countermeasures of annular pressure of injection and production wells in hydrogen sulfide gas storage. The prior art (Application of fiber optic downhole permanent testing technology in gas storage, Zhang Haiyan et al., 2014) provides an application of fiber optic downhole permanent testing technology in gas storage. The prior art (Field test study on wellbore leakage monitoring technology for salt cavern gas storage, An Guoyin et al.) provides a field test study on wellbore leakage monitoring technology for salt cavern gas storage. The prior art (Discussion on fiber optic testing technology for salt cavern gas storage, Journal of Jianghan Petroleum Workers University, May 2018) provides a discussion on fiber optic testing technology for salt cavern gas storage. The prior art (Fiber optic detection of gas-halogen interface in salt cavern gas storage, Oil and Gas Storage and Transportation, July 2017) provides a fiber optic detection of gas-halogen interface in salt cavern gas storage. The prior art (Oil-water interface monitoring in the dissolution process of salt cavern gas storage based on fiber optic technology, Oil and Gas Storage and Transportation, September 2018) provides a monitoring of oil-water interface in the dissolution process of salt cavern gas storage based on fiber optic technology. The prior art (CN112593924A) provides a monitoring system and method for safe operation of underground gas storage. However, none of the above prior arts can achieve long-term monitoring of multi-scale and full-factor salt cavern gas storage. In view of the above-mentioned defects of the prior art, the present invention provides a fiber optic monitoring system for the injection and production operation of a salt cavern gas storage, which can realize real-time monitoring of multi-dimensional data such as micro-leakage of the cavity or wellbore, oil-gas-water interface (brine interface) 12, temperature, pressure, pipe deformation and ground subsidence.

[0037] Figure 1 A schematic structural diagram of an injection and production operation monitoring system for a salt cavern gas storage according to an embodiment of the present invention is shown.

[0038] A salt cavern gas storage injection and production operation monitoring system includes: an optical fiber monitoring module. The optical fiber monitoring module is arranged in a target well of the salt cavern gas storage 11 and is used for multi-dimensional real-time monitoring of the salt cavern gas storage 11.

[0039] In one embodiment, the optical fiber monitoring module includes an optical fiber shape sensing sensor 23 for monitoring deformation and damage of the completion string 21 of the injection and production well 1. Specifically, Figure 3As shown, the optical fiber shape sensing sensor 23 includes: an elastic matrix 25, an array optical fiber grating 26 and an outer protective cover 27, wherein the elastic matrix 25 is made of memory metal wire, grooves are opened in four directions of 90° from the center of the memory metal wire to implant optical fiber gratings to form the array optical fiber grating 26, and a protective cover is extruded on the outer layer of the memory metal wire as the outer protective cover 27.

[0040] The optical fiber shape sensing sensor 23 proposed in the present invention has a simple and sensitive overall structure. Through the array optical fiber grating 26 arranged on the elastic substrate 25, it can sensitively sense the circumferential and axial deformation of the completion string 21 of the injection and production well 1, and can also monitor the possible damaged positions on the completion string 21 in real time.

[0041] In one embodiment, the injection and production well 1 of the salt cavern gas storage reservoir 11 is equipped with an injection and production string 21 (completion string), and an armored optical cable 2 composed of multi-parameter multimode optical fibers is fixed on the outside of the injection and production string. The monitoring well of the salt cavern gas storage reservoir 11 includes a surrounding rock monitoring well 6 and a settlement monitoring well 7, and the monitoring well of the salt cavern gas storage reservoir 11 is also equipped with corresponding armored optical cables. Specifically, the armored optical cables in the injection and production well 1 and the monitoring well are multi-parameter armored optical cables, and there are at least two or more high-temperature resistant single-mode optical fibers in the optical cable. Among them, the armored optical cable 2 in the injection and production well 1 includes a distributed acoustic wave sensing optical fiber, a distributed temperature sensing optical fiber, and a transmission optical fiber 24 for transmitting the signal of the fiber grating sensor 3.

[0042] In one embodiment, the optical fiber monitoring module includes: an injection and production well optical fiber monitoring module, which is arranged on the completion string 21 of the injection and production well 1 of the salt cavern gas storage 11, and is an armored optical cable 2 composed of multi-parameter multimode optical fibers, wherein the multi-parameter multimode optical fibers include distributed acoustic wave sensing optical fibers, distributed temperature sensing optical fibers, and transmission optical fibers 24 of multiple serially connected optical fiber shape sensing sensors 23 and / or optical fiber pressure sensors 22. Among them, the optical fiber shape sensing sensor 23 and the optical fiber pressure sensor 22 constitute the optical fiber Bragg grating sensor 3 in the injection and production well 1. Further, the armored optical cable 2 composed of multi-parameter multimode optical fibers is fixed on the completion string 21 through an annular metal clip, and is lowered into the injection and production well 1 along with the completion string 21. Further, the distributed acoustic wave sensing optical fiber and the distributed temperature sensing optical fiber, in conjunction with the wellhead dynamic production data, can be used for the prediction and evaluation of the stability of the downhole rock formation of a single well and whether there are abnormalities in the injection and production dynamics.

[0043] like Figure 2 As shown, the transmission optical fiber 24 of the injection and production well optical fiber monitoring module is serially connected with an optical fiber shape sensing sensor 23 and an optical fiber pressure sensor 22. Specifically, Figure 2As shown, a plurality of downhole optical fiber pressure sensors 22 and optical fiber shape sensing sensors 23 connected in series are fixed to the outside of the completion string 21 in the injection and production well 1. The optical fiber pressure sensors 22 and optical fiber shape sensing sensors 23 can be connected in series and then welded to the outside of the completion string 21.

[0044] In the present invention, when light waves propagate in optical fibers, their amplitude, phase, and wavelength will change due to external factors (such as pressure, temperature, sound waves, etc.), and the relevant changes in optical signal parameters are detected and then converted to obtain test data. The present invention adopts an optical fiber monitoring module, which has excellent properties such as high precision, good long-term stability, light weight, small size, and resistance to extremely harsh environments. It can accurately measure multiple parameters such as strain, pressure, temperature, vibration, and sound field; and can be transmitted remotely, which can realize long-distance, multi-parameter, large-capacity online monitoring and multi-sensor fusion of gas storage.

[0045] In one embodiment, a plurality of optical fiber shape sensing sensors 23 can be connected in series, so that the optical fiber shape sensing sensors 23 are distributed axially along the completion string 21 to measure the deformation of the completion string 21. The measurement principle is that as the completion string 21 deforms, the array fiber grating 26 of the optical fiber shape sensing sensor 23 will be stretched or compressed, thereby inverting the measurement result through the wavelength change in the optical fiber. The optical signal generated by the optical fiber shape sensing sensor 23 is transmitted to the wellhead of the injection and production well 1 through the transmission optical fiber 24, and the downhole data is transformed by the composite modulation and demodulation instrument 4 and transmitted to the ground remote monitoring device 8. The ground remote monitoring device 8 has a built-in inversion algorithm to realize the real-time inversion of the deformation of the string during the injection and production process.

[0046] In one embodiment, the optical fiber monitoring module includes: a surrounding rock monitoring well optical fiber monitoring module, which is arranged in the surrounding rock monitoring well 6 of the salt cavern gas storage reservoir 11 and is an armored optical cable composed of a transmission optical fiber 24 of a fiber optic pressure sensor 22 in series.

[0047] In one embodiment, a salt cavern gas storage injection and production operation monitoring system includes: a downhole microseismic monitoring module, which is arranged in a surrounding rock monitoring well 6 of the salt cavern gas storage 11 and is a downhole three-component geophone array.

[0048] Specifically, the surrounding rock monitoring well 6 is equipped with an armored optical cable with permanent magnet adsorption or electromagnetic induction adsorption, an optical fiber pressure sensor 22, and a microseismic measurement detector (downhole three-component detector array). The armored optical cable of the surrounding rock monitoring well 6 uses a signal transmission optical fiber 24 to connect the optical fiber pressure sensor 22 in series. At the same time, a downhole three-component detector array is installed in the surrounding rock monitoring well 6, which can perform microseismic monitoring regularly. By collecting downhole pressure and microseismic sound data, it can analyze whether the downhole fault is activated or whether the salt cavern cavity collapses. It is mainly used to measure whether there are abnormalities in the tightness and stability of the downhole salt cavern.

[0049] In one embodiment, the fiber optic pressure sensor 22 is disposed at a specific location underground and can measure the temperature and pressure at that depth. The fiber optic pressure sensor 22 converts the pressure change into wavelength change information and adjusts it to the reflection spectrum. The transmission optical fiber 24 transmits the underground measurement data to the wellhead, and the composite modulation and demodulation instrument 4 detects and analyzes the wavelength change of the reflection spectrum to achieve pressure measurement of the completion string and / or the oil-gas-water interface (brine interface) 12.

[0050] In one embodiment, the optical fiber monitoring module includes: a subsidence monitoring well optical fiber monitoring module, which is arranged in the subsidence monitoring well 7 of the salt cavern gas storage reservoir 11, and is an armored optical cable composed of a transmission optical fiber 24 of a serially connected optical fiber subsidence displacement sensor. Specifically, the armored optical cable of the subsidence monitoring well 7 is connected to the optical fiber subsidence displacement sensor through the signal transmission optical fiber 24, and is installed in the subsidence hole. It has the advantages of high accuracy, shared demodulation equipment and continuous monitoring. Multiple subsidence monitoring wells 7 can be set up, and multi-point measurement and transmission of multi-sensor signals to the composite modulation and demodulation instrument 4 are performed, and the ground subsidence data of different subsidence holes around the salt cavern gas storage reservoir 11 are monitored through the ground remote monitoring equipment 8.

[0051] like Figure 4 As shown, the optical fiber settlement displacement sensor includes: a top plate 31, a shell 33, a mounting base 34, a stainless optical measuring rod 36, and a grouting anchor head 37, wherein the top plate 31 is connected to the top of the shell 33 as a ground reference point, the bottom of the shell 33 is connected to the mounting base 34, a pigtail 35 is provided at the bottom of the mounting base 34, and the stainless optical measuring rod 36 arranged inside the shell 33 is connected to the grouting anchor head 37 through the mounting base 34. When the ground 38 settles or cracks, the displacement of the grouting anchor head 37 can cause the grating sensing signal of the stainless optical measuring rod 36 to change, which is transmitted to the composite modulation and demodulation instrument 4 through the transmission optical cable 32, thereby obtaining real-time measurement data.

[0052] The optical fiber settlement displacement sensor proposed in the present invention has a simple and sensitive overall structure. Through the stainless optical measuring rod 26 and the grouting anchor head 37 connected in sequence, it can sensitively sense the ground settlement and ground cracks in the salt cavern gas storage reservoir, so as to facilitate intervention measures such as well repair and maintain the stable operation of the salt cavern gas storage reservoir.

[0053] In one embodiment, a salt cavern gas storage injection and production operation monitoring system includes: a ground crack monitoring module, which is arranged at the ground crack of the salt cavern gas storage 11, and is a ground crack monitoring optical cable 5 composed of a transmission optical fiber 24 of a serially connected optical fiber settlement displacement sensor. Specifically, the ground crack monitoring optical cable 5 is arranged at the larger ground cracks around the injection and production well 1. Since gas storage leakage and crack expansion may occur, the ground crack monitoring optical cable 5 needs to be arranged to monitor the crack expansion.

[0054] In one embodiment, a salt cavern gas storage injection and production operation monitoring system includes: a composite modulation and demodulation instrument 4, which is connected to the optical fiber monitoring module and is used to modulate and demodulate multi-dimensional real-time monitoring data. Specifically, the composite modulation and demodulation instrument 4 has the modulation and demodulation function of distributed acoustic wave sensing optical fiber signals, distributed temperature sensing optical fiber signals, optical fiber shape sensing sensor signals, optical fiber settlement displacement sensor signals, and optical fiber pressure sensor signals. Further, the composite modulation and demodulation instrument 4 includes modulation and demodulation units of distributed acoustic wave sensing (DAS), distributed temperature sensing (DTS), optical fiber shape sensing sensor, optical fiber pressure sensor, and optical fiber settlement displacement sensor, and the modulation and demodulation instrument 4 is connected to armored optical cables in different wells.

[0055] In one embodiment, a salt cavern gas storage injection and production operation monitoring system includes: a ground remote monitoring device 8, which is connected to a composite modulation and demodulation instrument 4, and is used to perform data analysis on the multi-dimensional real-time monitoring data after modulation and demodulation, to achieve long-term real-time dynamic monitoring of the production process parameters of the injection and production wells of the gas storage, to monitor the deformation and possible damage of the injection and production well pipe strings, to monitor whether there is fault excitation and induction during the injection and production process, resulting in stability, to monitor ground subsidence data, and to monitor ground crack data, so as to facilitate intervention measures to maintain the stable operation of the injection and production wells of the gas storage.

[0056] The salt cavern gas storage injection and production operation monitoring system involved in the present invention includes armored optical cables, optical fiber shape sensing sensors 23, optical fiber settlement displacement sensors, optical fiber pressure sensors 22, downhole detectors, etc., which are arranged in all injection and production wells 1, surrounding rock monitoring wells 6, settlement monitoring wells 7, and ground microcracks, as well as ground monitoring equipment including a composite modulation and demodulation instrument 4 for receiving and processing signals and ground remote monitoring equipment 8. Optical fiber sensing can realize long-term, stable, high-precision, and real-time monitoring of micro-leakage, temperature, pressure, ground cracks, and ground settlement of the injection and production system such as the cavity or wellbore of the salt cavern gas storage, and has the advantages of remote, multi-parameter, large capacity, and multi-sensor fusion. The present invention can timely discover early warning signals and information of various risks in the operation of the gas storage, and ensure the long-term stable and safe operation of the salt cavern gas storage.

[0057] Figure 5 A flowchart of the steps of a method for monitoring injection and production operation of a salt cavern gas storage according to an embodiment of the present invention is shown.

[0058] In one embodiment, Figure 5 A salt cavern gas storage injection and production operation monitoring method is provided, which is executed by a salt cavern gas storage injection and production operation monitoring system.

[0059] like Figure 5As shown, in step S501, the salt cavern gas storage reservoir 11 is monitored in real time in multiple dimensions by means of an optical fiber monitoring module disposed in a target well of the salt cavern gas storage reservoir 11.

[0060] In one embodiment, step S501 includes: in the newly drilled injection and production well 1 of the salt cavern gas storage 11, the completion string 21 and the injection and production well optical fiber monitoring module are lowered, and the injection and production well optical fiber monitoring module is an armored optical cable 2 composed of multi-parameter multi-mode optical fiber, and the armored optical cable 2 composed of multi-parameter multi-mode optical fiber is fixed and protected by a groove at the connection of an annular metal card or a sleeve. Specifically, the armored optical cable 2 composed of multi-parameter multi-mode optical fiber is a multi-parameter multi-mode optical fiber, including a distributed acoustic wave sensing optical fiber, a distributed temperature sensing optical fiber, and a plurality of transmission optical fibers 24 of a series of optical fiber shape sensing sensors 23 and / or an optical fiber pressure sensor 22.

[0061] In one embodiment, step S501 includes: connecting the multimode optical fiber in the armored optical cable 2 composed of multi-parameter multimode optical fibers to the input end of the composite modem instrument 4 at the injection and production wellhead, and the composite modem instrument 4 can distinguish and demodulate different optical fiber signal paths separately.

[0062] In one embodiment, step S501 includes: one or more surrounding rock monitoring wells 6 are arranged around the injection and production well 1, the depth of the surrounding rock monitoring well 6 is close to the depth of the gas storage layer, and the surrounding rock monitoring well fiber optic monitoring module and the downhole microseismic monitoring module are placed, the surrounding rock monitoring well fiber optic monitoring module is an armored optical cable composed of a transmission optical fiber 24 connected in series with an optical fiber pressure sensor 22, and the downhole microseismic monitoring module is a downhole three-component geophone array. The optical fiber downhole pressure sensor 22 and the downhole three-component geophone array are tightly pushed against the inner wall of the casing or the well wall, and the armored optoelectronic composite cable connecting the optical fiber downhole pressure sensor 22 and the downhole three-component geophone array is connected to the composite modulation and demodulation instrument 4 at the wellhead of the surrounding rock monitoring well 6.

[0063] In one embodiment, step S501 includes: arranging a plurality of settlement monitoring wells 7 in the area around the injection and production well 1 to monitor the ground settlement caused by the reduction in the volume of the cavity during the operation of the salt rock gas storage reservoir. The base of the settlement monitoring well 7 is a cement grouting base, and an optical fiber monitoring module for the settlement monitoring well is installed, which is an armored optical cable composed of a transmission optical fiber 24 of a serially connected optical fiber settlement displacement sensor. The optical fiber settlement displacement sensor is connected to the wellhead of the settlement monitoring well 7 through the transmission optical fiber 24, and the signals of multiple optical fiber settlement displacement sensors are integrated into the composite modulation and demodulation instrument 4.

[0064] In one embodiment, step S501 includes: setting a ground crack monitoring module at the ground micro-cracks of the rock cave gas storage reservoir 11, which is a ground crack monitoring optical cable 5 composed of a transmission optical fiber 24 of a serially connected optical fiber settlement displacement sensor, and connecting the ground crack monitoring optical cable 5 to a composite modem instrument 4.

[0065] like Figure 5 As shown, in step S502, the multi-dimensional real-time monitoring data is modulated and demodulated by the composite modulation and demodulation instrument 4 connected to the optical fiber monitoring module.

[0066] In one embodiment, step S502 includes: during normal production operation of the cave gas storage 11, i.e., gas injection or gas production, continuously monitoring and measuring the distributed acoustic wave sensing fiber optic signal and the distributed temperature sensing fiber optic signal in the armored optical cable 2 composed of multi-parameter multimode optical fibers outside the injection and production gas pipe in the well by a composite modem instrument 4 placed next to the injection and production well 1, and continuously monitoring and measuring the optical fiber pressure sensor 22 and the optical fiber shape sensing signal 23 connected in series outside the injection and production gas pipe in the well.

[0067] In one embodiment, step S502 includes: during normal production operation of the cave gas storage 11, i.e., gas injection or production, by placing a composite modulation and demodulation instrument 4 at the wellhead of the surrounding rock monitoring well 6, at the settlement monitoring well 7, and at the ground microcracks, the pressure sensing signal and microseismic signal in the armored optical cable outside the pipe string in the surrounding rock monitoring well 6, the settlement displacement sensing signal in the settlement monitoring well 7, and the displacement sensing signal at the ground microcracks are continuously monitored and measured.

[0068] In one embodiment, step S502 includes: modulating and demodulating the distributed acoustic wave sensing optical fiber signal, distributed temperature sensing optical fiber signal, optical fiber pressure sensor signal, optical fiber shape sensing signal, and optical fiber settlement displacement sensing signal continuously measured by the composite modulation and demodulation instrument 4, converting them into the full-well section noise intensity distribution, temperature distribution, downhole pressure distribution, pipe deformation data, ground settlement data, and ground crack displacement data of all monitoring wells, and transmitting them remotely to the ground remote monitoring equipment 8.

[0069] like Figure 5 As shown, in step S503, the ground remote monitoring device 8 connected to the composite modulation and demodulation instrument 4 performs data analysis on the modulated and demodulated multi-dimensional real-time monitoring data.

[0070] In one embodiment, step S503 includes: the ground remote monitoring equipment 8 monitors and measures the downhole noise, temperature and pressure data of the gas injection well and the gas production well, combines the downhole geophones arranged in the surrounding rock monitoring well 6 to monitor the energy size and spatial distribution law of the underground microseismic events recorded in real time, and uses a multi-parameter comprehensive inversion method to realize real-time large-capacity data remote analysis, long-term real-time dynamic monitoring of production process parameters such as pressure and temperature of the gas storage injection and production wells, monitoring the deformation and possible damaged parts of the injection and production well pipes, monitoring whether there is fault excitation and induction during the injection and production process to cause stability, monitoring ground subsidence data, monitoring ground crack data, etc., so as to facilitate the adoption of intervention measures such as well repair to maintain the stable operation of the injection and production wells 1 of the salt cavern gas storage 11.

[0071] The salt cavern gas storage injection and production operation monitoring system and method provided by the present invention can also be used in conjunction with a computer-readable storage medium, on which a computer program is stored, and the computer program is executed to run a salt cavern gas storage injection and production operation monitoring method. The computer program can run computer instructions, and the computer instructions include computer program code, which can be in source code form, object code form, executable file or some intermediate form.

[0072] Computer-readable storage media may include: any entity or device that can carry computer program code, recording media, USB flash drives, mobile hard disks, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0073] It should be noted that the content contained in computer-readable storage media can be appropriately increased or decreased based on the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, based on legislation and patent practices, computer-readable storage media do not include electrical carrier signals and telecommunications signals.

[0074] In summary, the present invention provides a salt cavern gas storage injection and production operation monitoring system and method, which has the following advantages over the prior art:

[0075] The optical fiber sensor used in the present invention can realize long-term, stable, high-precision, and real-time monitoring of micro-leakage, temperature, pressure, and ground subsidence in the cavity or wellbore of the salt cavern gas storage and other injection and production systems, and has the advantages of remote, multi-parameter, large capacity, and multi-sensor fusion. Through the system and method, early warning signals and information of various risks in the operation of the gas storage can be discovered in time, ensuring the long-term stable and safe operation of the salt cavern gas storage.

[0076] The optical fiber shape sensing sensor proposed in the present invention has a simple and sensitive overall structure. Through an array of optical fiber gratings arranged on an elastic substrate, it can sensitively sense the circumferential and axial deformation of the completion string of the injection and production well, and can also perform real-time monitoring of possible damaged locations on the completion string.

[0077] The optical fiber settlement displacement sensor proposed in the present invention has a simple and sensitive overall structure. Through the stainless optical measuring rod and the grouting anchor head connected in sequence, it can sensitively sense the ground settlement and ground cracks in the salt cavern gas storage reservoir, so as to facilitate intervention measures such as well repair and maintain the stable operation of the salt cavern gas storage reservoir.

[0078] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should be extended to equivalent substitutions of these features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0079] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0080] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0081] Certain terms are used throughout this application document to indicate specific system components. As those skilled in the art will recognize, different names can usually be used to indicate the same components, so this application document is not intended to distinguish those components that are only different in name but not in function. In this application document, the terms "comprise", "include" and "have" are used in an open form, and therefore should be interpreted as meaning "including but not limited to...". In addition, the terms "substantially", "substantially" or "approximately" that may be used in this article relate to the tolerances of the corresponding terms accepted by the industry. The term "coupling" as may be used in this article includes direct coupling and indirect coupling via other components, elements, circuits, or modules, wherein for indirect coupling, the components, elements, circuits, or modules between them do not change the information of the signal but can adjust its current level, voltage level, and / or power level. Inferred coupling (for example, one of the elements is coupled to another element by inference) includes direct and indirect coupling between two elements in the same way as "coupling".

[0082] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0083] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0084] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A salt cavern gas storage injection and production operation monitoring system, characterized in that: The system comprises: An optical fiber monitoring module is installed in the target well of the salt cavern gas storage reservoir and is used for multi-dimensional real-time monitoring of the salt cavern gas storage reservoir; The optical fiber monitoring module includes an optical fiber shape sensing sensor for monitoring deformation and damaged parts of the completion string of the injection and production well, which includes: an elastic matrix, an array optical fiber grating and an external protective cover, wherein the elastic matrix adopts a memory metal wire, and grooves are opened in four directions of 90° from the center of the memory metal wire to implant the optical fiber grating to form the array optical fiber grating, and a protective cover is extruded on the outer layer of the memory metal wire as the external protective cover.

2. A salt cavern gas storage injection and production operation monitoring system as claimed in claim 1, characterized in that: The optical fiber monitoring module includes: an injection and production well optical fiber monitoring module, which is arranged on the completion string of the injection and production well of the salt cavern gas storage, and is an armored optical cable composed of multi-parameter multi-mode optical fibers, wherein the multi-parameter multi-mode optical fibers include distributed acoustic wave sensing optical fibers, distributed temperature sensing optical fibers, and multiple transmission optical fibers serially connected to the optical fiber shape sensing sensors and / or optical fiber pressure sensors.

3. A salt cavern gas storage injection and production operation monitoring system according to any one of claims 1-2, characterized in that: The optical fiber monitoring module comprises: an optical fiber monitoring module for a surrounding rock monitoring well, which is arranged in a surrounding rock monitoring well of a salt cavern gas storage reservoir and is an armored optical cable composed of transmission optical fibers of a serially connected optical fiber pressure sensor.

4. A salt cavern gas storage injection and production operation monitoring system according to any one of claims 1 to 3, characterized in that: The optical fiber monitoring module comprises: a subsidence monitoring well optical fiber monitoring module, which is arranged in the subsidence monitoring well of the salt cavern gas storage reservoir and is an armored optical cable composed of transmission optical fibers of optical fiber subsidence displacement sensors connected in series.

5. A salt cavern gas storage injection and production operation monitoring system as claimed in claim 4, characterized in that: The optical fiber settlement displacement sensor comprises: a top plate, a shell, a mounting base, a stainless optical measuring rod, and a grouting anchor head, wherein the top plate is connected to the top of the shell as a ground reference point, the bottom of the shell is connected to the mounting base, and the stainless optical measuring rod arranged inside the shell is connected to the grouting anchor head through the mounting base. When settlement or cracks occur on the ground, the displacement of the grouting anchor head can cause the grating sensing signal of the stainless optical measuring rod to change, thereby obtaining real-time measurement data.

6. A salt cavern gas storage injection and production operation monitoring system as claimed in any one of claims 4 to 5, characterized in that: The system comprises: A ground crack monitoring module is arranged at the ground crack of the salt cavern gas storage reservoir, and is a ground crack monitoring optical cable composed of transmission optical fibers of the optical fiber settlement displacement sensor connected in series; The underground microseismic monitoring module is arranged in the surrounding rock monitoring well of the salt cavern gas storage reservoir and is an underground three-component geophone array.

7. A salt cavern gas storage injection and production operation monitoring system according to any one of claims 1 to 6, characterized in that: The system includes: a composite modulation and demodulation instrument, which is connected to the optical fiber monitoring module and is used to modulate and demodulate multi-dimensional real-time monitoring data, wherein the composite modulation and demodulation instrument has the modulation and demodulation function of distributed acoustic wave sensing optical fiber signals, distributed temperature sensing optical fiber signals, optical fiber shape sensing sensor signals, optical fiber settlement displacement sensor signals, and optical fiber pressure sensor signals.

8. A salt cavern gas storage injection and production operation monitoring system according to any one of claims 1 to 7, characterized in that: The system includes: ground remote monitoring equipment, which is connected to the composite modulation and demodulation instrument and is used to perform data analysis on the multi-dimensional real-time monitoring data after modulation and demodulation, so as to realize long-term real-time dynamic monitoring of the production process parameters of the injection and production wells of the gas storage reservoir, monitoring of the deformation and possible damaged parts of the injection and production well pipe strings, monitoring of stability caused by fault excitation and induction during the injection and production process, monitoring of ground subsidence data, and monitoring of ground crack data, so as to facilitate the adoption of intervention measures to maintain the stable operation of the injection and production wells of the gas storage reservoir.

9. A method for monitoring injection and production operation of a salt cavern gas storage, characterized in that: Executed by the system according to any one of claims 1 to 8, the method comprises the following steps: The salt cavern gas storage is monitored in real time in multiple dimensions by means of the optical fiber monitoring module arranged in the target well of the salt cavern gas storage; The optical fiber monitoring module includes an optical fiber shape sensing sensor for monitoring deformation and damaged parts of the completion string of the injection and production well, which includes: an elastic matrix, an array optical fiber grating and an external protective cover, wherein the elastic matrix adopts a memory metal wire, and grooves are opened in four directions of 90° from the center of the memory metal wire to implant the optical fiber grating to form the array optical fiber grating, and a protective cover is extruded on the outer layer of the memory metal wire as the external protective cover.

10. A storage medium, characterized in that: It contains a series of instructions for executing the method steps as claimed in claim 9.

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