Underground wireless monitoring system and method

Abstract

The invention discloses an underground wireless monitoring system and method, and the system comprises an input device which is used for inputting a detection device into a pipeline for communicating a fracturing pump truck with a fracturing wellhead; the detection device is used for entering a well together with fracturing fluid through an oil pipe or a sleeve channel in the process that the fracturing fluid is pumped into a fracturing wellhead by the fracturing pump truck, collecting underground information representing underground characteristics in the fracturing process in real time and transmitting the collected data to the ground; and the recovery device is used for capturing and recovering the fracturing fluid when the detection device is discharged out of the wellhead along with flowback of the fracturing fluid, and carrying out fracturing process evaluation by analyzing and processing underground information. The problem that in the fracturing process, downhole parameters are difficult to obtain is solved.

Description

Technical Field

[0001] This invention belongs to the field of downhole monitoring technology, and in particular relates to a wireless monitoring system and method for downhole applications. Background Technology

[0002] Currently, commonly used monitoring technologies in the fracturing field include wellbore temperature testing (determining fracture height based on temperature changes caused by post-fracturing flowback), geopotential testing (determining fracture orientation and length based on the effect of ions mixed in the fracturing fluid on potential), microseismic monitoring (estimating reservoir volume based on the response range of microseismic and acoustic emission events caused by fracturing), tracer monitoring (analyzing fracture initiation location and production distribution information after flowback of substances mixed in the fracturing fluid), well test analysis (estimating fracture conductivity based on post-fracturing production and pressure changes), and distributed fiber optic monitoring, etc.

[0003] Hydraulic fracturing primarily involves injecting water and sand into underground formations under high pressure to create a network of fractures, allowing oil and natural gas to flow into the well through these fractures. Based on fiber optic and distributed sensing technologies, using DAS, DTS, and DSS methods, existing technologies can "listen" to nearby hydraulic fracturing operations during the process. This enables real-time continuous monitoring and dynamic tracking of the entire well section throughout the fracturing process, allowing for real-time observation of fracture growth and other information. This facilitates rapid assessment of the fracturing effect and timely adjustments to the fracturing strategy. Microseismic monitoring technology is a valuable tool for understanding underground processes. By monitoring the amplitude attenuation with increasing distance during fracturing using a combination of geophones, information such as fracture height, length, azimuth, symmetry, dip angle, and complexity can be obtained. This information can be used to optimize fracturing design and oil and gas field development.

[0004] However, both fiber optic monitoring and microseismic monitoring require the deployment of numerous downhole or surface monitoring devices. While they can serve as monitoring methods during the deployment of exploratory wells or early development wells, they are costly and the results are difficult to interpret. Therefore, developing convenient, low-cost, and fracturing-resistant wireless downhole monitoring technologies would be beneficial for monitoring complex fracturing wells and would facilitate the acquisition of more downhole data to establish corresponding fracturing learning curves. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a downhole wireless monitoring system, comprising: a deployment device for deploying a detection device into a pipeline connecting a fracturing pump truck and a fracturing wellhead; the detection device, used to enter the downhole via tubing or casing along with the fracturing fluid during the pumping of fracturing fluid into the fracturing well, and to collect downhole information characterizing the downhole fracturing process in real time and transmit the collected data to the surface; and a recovery device for capturing and recovering the detection device as it is discharged from the wellhead with the fracturing fluid, and for evaluating the fracturing process through analysis and processing of the downhole information.

[0006] Preferably, the detection device comprises: an insoluble pressure-bearing layer for forming a hollow cavity inside the detection device, the hollow cavity being filled with a lightweight insulating filler; a soluble pressure-bearing layer, which wraps around the outer surface of the insoluble pressure-bearing layer, for gradually dissolving during the fracturing process to reduce the volume of the detection device and lower the risk of the detection device being trapped; and a data acquisition module for real-time acquisition of downhole information, the data acquisition module being fixed and protected by the lightweight insulating filler.

[0007] Preferably, the soluble pressure-bearing layer is a soluble aluminum-magnesium alloy or a soluble polymer.

[0008] Preferably, the initial outer diameter of the detection device is 2 mm or more larger than the diameter of the perforation hole, wherein after the soluble pressure-bearing layer has completely dissolved, the outer diameter of the detection device is less than or equal to 30 mm.

[0009] Preferably, the density of the detection device remains within a specified density range that corresponds to the actual density of the fracturing fluid from the start of the fracturing process to the end of the well shut-in process after fracturing, wherein the density of the detection device decreases as the soluble pressure-bearing layer dissolves.

[0010] Preferably, the data acquisition module includes: multiple sensors of different types for completing the downhole status acquisition task; a wireless data transmission module for transmitting the downhole information during the downhole status acquisition process; a data storage device for storing the downhole information; a rechargeable battery for supplying power to the electrical equipment in the detection device; and a wireless charging module for providing power to the rechargeable battery.

[0011] Preferably, the detection device further comprises: a pressure transmission through hole, which connects the hollow cavity to the outside of the detection device by penetrating the soluble pressure-bearing layer and the insoluble pressure-bearing layer, for transmitting signals characterizing downhole pressure characteristics and signals characterizing downhole acoustic wave characteristics to corresponding types of sensors.

[0012] Preferably, the pressure transmission through-hole is filled with a pressure-conducting filler, which is used to protect the multiple sensors from damage by materials inside the wellbore.

[0013] Preferably, the recovery device is further configured to determine the fracture characteristics and well runoff characteristics after fracturing based on the temperature information, pressure information and acoustic information during the fracture opening and closing process in the downhole information, and to evaluate the well runoff performance of the current fracturing well.

[0014] Furthermore, this invention also proposes a wireless monitoring method for downhole applications. This method utilizes the wireless monitoring system described in this invention. The wireless monitoring method includes: deploying a detection device into a pipeline connecting a fracturing pump truck and the fracturing wellhead using a deployment device; during the process of the fracturing pump truck pumping fracturing fluid into the fracturing well, the detection device enters the well along with the fracturing fluid through the tubing or casing channel, and collects downhole information characterizing the downhole fracturing process in real time, transmitting the collected data to the surface; when the detection device is discharged from the wellhead with the fracturing fluid, a recovery device captures and recovers the detection device, thereby evaluating the fracturing process through analysis and processing of the downhole information.

[0015] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0016] This invention proposes a wireless monitoring system and method for downhole applications. The system deploys a specifically shaped detection device into the wellbore along with the fracturing fluid. The detection device collects downhole information characterizing the fracturing process in real time. A retrieval device captures and recovers the detection device as it is discharged from the wellhead with the fracturing fluid. The fracturing process is evaluated by analyzing the downhole information throughout the entire fracturing process (or the entire fracturing and post-fracturing well shut-in process). Furthermore, the detection device transmits the collected data to the surface in real time, enabling real-time feedback of downhole information. This invention can be used for downhole parameter monitoring during fracturing and post-fracturing well shut-in processes, solving the problem of difficulty in obtaining downhole parameters during these processes.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 This is a schematic diagram of the specific structure of a wireless monitoring system for underground applications according to an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of the detection device for a wireless monitoring system used in downholes, according to an embodiment of this application.

[0021] Figure 3 This is a step diagram of a wireless monitoring method for downhole applications according to an embodiment of this application.

[0022] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale.

[0023] The list of reference numerals in the attached figures is as follows:

[0024] 1: Detection device

[0025] 2: Input device

[0026] 3: Fracturing pump truck

[0027] 4: Fracturing wellhead

[0028] 5: Annulus between tubing and casing

[0029] 6: Inner passage of oil pipe

[0030] 7: Oil pipe

[0031] 8: Sleeve

[0032] 9: Fracturing fluid

[0033] 10: Fracturing proppant

[0034] 11: Fracturing fracture

[0035] 12: Wellhead Instruments

[0036] 1-1: Pressure transmission through hole

[0037] 1-2: Pressure sensor, acoustic sensor

[0038] 1-3: Soluble bearing layer

[0039] 1-4: Insoluble pressure-bearing layer

[0040] 1-5: Temperature Sensor

[0041] 1-6: Wireless charging module

[0042] 1-7: Data Storage

[0043] 1-8: Rechargeable batteries

[0044] 1-9: Wireless data transmission module

[0045] 1-10: Pressure-conducting filler

[0046] 1-11: Lightweight insulating filler Detailed Implementation

[0047] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0048] Furthermore, the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0049] Currently, commonly used monitoring technologies in the fracturing field include wellbore temperature testing (determining fracture height based on temperature changes caused by post-fracturing flowback), geopotential testing (determining fracture orientation and length based on the effect of ions mixed in the fracturing fluid on potential), microseismic monitoring (estimating reservoir volume based on the response range of microseismic and acoustic emission events caused by fracturing), tracer monitoring (analyzing fracture initiation location and production distribution information after flowback of substances mixed in the fracturing fluid), well test analysis (estimating fracture conductivity based on post-fracturing production and pressure changes), and distributed fiber optic monitoring, etc.

[0050] Hydraulic fracturing primarily involves injecting water and sand into underground formations under high pressure to create a network of fractures, allowing oil and natural gas to flow into the well through these fractures. Based on fiber optic and distributed sensing technologies, using DAS, DTS, and DSS methods, existing technologies can "listen" to nearby hydraulic fracturing operations during the process. This enables real-time continuous monitoring and dynamic tracking of the entire well section throughout the fracturing process, allowing for real-time observation of fracture growth and other information. This facilitates rapid assessment of the fracturing effect and timely adjustments to the fracturing strategy. Microseismic monitoring technology is a valuable tool for understanding underground processes. By monitoring the amplitude attenuation with increasing distance during fracturing using a combination of geophones, information such as fracture height, length, azimuth, symmetry, dip angle, and complexity can be obtained. This information can be used to optimize fracturing design and oil and gas field development.

[0051] However, both fiber optic monitoring and microseismic monitoring require the deployment of numerous downhole or surface monitoring devices. While they can serve as monitoring methods during the deployment of exploratory wells or early development wells, they are costly and the results are difficult to interpret. Therefore, developing convenient, low-cost, and fracturing-resistant wireless downhole monitoring technologies would be beneficial for monitoring complex fracturing wells and would facilitate the acquisition of more downhole data to establish corresponding fracturing learning curves.

[0052] To address the aforementioned problems, this invention proposes a wireless monitoring system and method for downhole applications. The system deploys a specifically shaped detection device into the wellbore along with the fracturing fluid. This device collects downhole information characterizing the fracturing process in real time. A recovery device then captures and retrieves the detection device as it is flushed out of the wellhead with the fracturing fluid. The fracturing process is evaluated by analyzing the downhole information throughout the entire fracturing process (or the entire fracturing and post-fracturing well shut-in process). Furthermore, the detection device transmits the collected data to the surface in real time, enabling real-time feedback of downhole information. This invention can be used for downhole parameter monitoring during fracturing and post-fracturing well shut-in processes, solving the problem of difficulty in obtaining downhole parameters during these processes.

[0053] Example 1

[0054] In this embodiment, the downhole wireless monitoring system includes at least: an insertion device 2, a detection device 1, and a retrieval device (not shown). The insertion device 2 inserts the detection device 1 into the pipeline connecting the fracturing pump truck 3 and the fracturing wellhead 4. Subsequently, as the fracturing pump truck 3 pumps fracturing fluid 9 into the fracturing well, the detection device 1 enters the well along with the fracturing fluid 9 through the tubing 7 or casing 8, and collects downhole information characterizing the fracturing process in real time, transmitting the collected data to the surface. Finally, when the detection device 1 is discharged from the wellhead along with the fracturing fluid 9, the retrieval device captures and retrieves the detection device 1, and performs fracturing process evaluation through analysis and processing of the downhole information.

[0055] Figure 1 This is a schematic diagram of the specific structure of a wireless monitoring system for downhole applications according to an embodiment of this application. The following is in conjunction with… Figure 1 The structure of the wireless monitoring system for downhole applications described in this invention will be described in detail.

[0056] The deployment device 2 deploys the detection device 1 into the pipeline connecting the fracturing pump truck 3 and the fracturing wellhead 4. In this embodiment, the fracturing pump truck 3 and the fracturing wellhead 4 are connected by a pipeline. The fracturing pump truck 3 transmits fracturing fluid 9 to the fracturing wellhead 4 through this pipeline to achieve the purpose of pumping the fracturing fluid 9 into the wellhead. The pipeline is provided with an opening for the detection device 1 to enter the fracturing wellhead 4 along with the fracturing fluid 9. The deployment device 2 deploys the detection device 1 into the pipeline through this opening. The number of detection devices 1 deployed is set according to actual needs. The fracturing pump truck 3 is suitable for various fracturing pumping and pressurization operations in deep, medium-deep, and shallow wells in oil and gas fields. It mainly consists of a chassis, a platform engine, a hydraulic transmission box, a plunger pump, high and low pressure manifolds, and a hydraulic-gas circuit operation control system.

[0057] After the deployment device 2 deploys the detection device 1 into the aforementioned pipeline, the detection device 1, during the process of the fracturing pump truck 3 pumping fracturing fluid 9 into the fracturing well, enters the well along with the fracturing fluid 9 through the tubing 7 or casing 8 channel. It collects downhole information characterizing the downhole features of the fracturing process in real time and transmits the collected data to the surface. The detection device 1 moves along the pipeline towards the fracturing wellhead 4 with the flow of the fracturing fluid 9, and then enters the well along with the fracturing fluid 9 through the channel 6 within the tubing 7 or casing 8 located within the wellbore. Subsequently, the detection device 1 continues to move downhole with the flow of the fracturing fluid 9, simultaneously collecting and storing downhole information related to the fracturing process, such as temperature, pressure, and sound, and transmitting the collected downhole data to the surface in real time. The wireless monitoring system described in this invention is simple to operate, achieving both real-time acquisition of downhole information and real-time feedback of downhole information to the surface via wireless transmission.

[0058] Figure 2 This is a schematic diagram of the detection device for a downhole wireless monitoring system according to an embodiment of this application. The following refers to... Figure 2 The structure of the detection device 1 described in this invention will be described in detail.

[0059] In this embodiment, the detection device 1 is designed with a specific geometric structure such as a capsule or a sphere, which reduces the resistance of the detection device 1 as it moves with the fracturing fluid 9, making it easier to move. Figure 2 As shown, the detection device 1 has an insoluble pressure-bearing layer 1-4, a soluble pressure-bearing layer 1-3, and a data acquisition module.

[0060] The insoluble pressure-bearing layer 1-4 forms a hollow cavity inside the detection device 1, and the hollow cavity is filled with a lightweight insulating filler 1-11. That is to say, the insoluble pressure-bearing layer 1-4 is the boundary of the hollow cavity, and the detection device 1 consists of a soluble pressure-bearing layer 1-3, an insoluble pressure-bearing layer 1-4, and a lightweight insulating filler 1-11 from the outside to the inside. Furthermore, the lightweight insulating filler 1-11 completely fills the hollow cavity formed by the insoluble pressure-bearing layer 1-4 inside the detection device 1.

[0061] The soluble pressure-bearing layer 1-3 is wrapped around the outer surface of the insoluble pressure-bearing layer 1-4. This layer gradually dissolves to reduce the volume of the detection device 1 from the start of the fracturing process to the end of the post-fracturing well shut-in, thereby reducing the risk of the detection device 1 becoming stuck. In this embodiment, the soluble pressure-bearing layer 1-3 is wrapped around the outer surface of the insoluble pressure-bearing layer 1-4. Whether post-fracturing well shut-in is not performed after fracturing, or post-fracturing well shut-in continues after fracturing, and the detection device 1 moves with the fracturing fluid 9 and monitors well shut-in data until it is captured by the recovery device, the soluble pressure-bearing layer 1-3 continuously and gradually dissolves to reduce the volume of the detection device 1. The detection device 1 is heaviest when it first enters the fracturing wellhead 4, and under the influence of gravity, it can quickly reach the downhole. Subsequently, on the one hand, based on the gradual dissolution of the soluble pressure-bearing layer 1-3, as the fracturing process progresses, the volume of the detection device 1 decreases and its density decreases, and the mobility of the detection device 1 gradually increases; on the other hand, after the detection device 1 reaches the wellbore with the fracturing fluid 9, it is subject to the hydraulic action of the wellbore and the throttling effect of the perforation orifice, and there is a risk that the detection device 1 may be stuck in the fracturing proppant 10 in the wellbore or at the perforation orifice. The gradual dissolution of the soluble pressure-bearing layer 1-3 effectively reduces the risk of the detection device 1 being stuck.

[0062] After the detection device 1 reaches the well, the data acquisition module begins real-time acquisition of downhole information. The data acquisition module is fixed and protected by lightweight insulating fillers 1-11. In other words, in this embodiment, the data acquisition module is housed within a hollow cavity, and the lightweight insulating fillers 1-11 ensure the stability and reliability of the data acquisition.

[0063] In the embodiments of this application, the soluble pressure-bearing layer 1-3 is preferably a soluble aluminum-magnesium alloy or a soluble polymer that can dissolve in fracturing fluid 9 under downhole temperature conditions.

[0064] In one specific embodiment of this application, the soluble polymer is selected from materials with similar performance characteristics, such as polyester, polylactic acid, and polyhydroxybutyrate.

[0065] The initial outer diameter of the detection device 1 is at least 2 mm larger than the diameter of the perforation orifice. After the soluble pressure-bearing layer 1-3 has completely dissolved, the outer diameter of the detection device 1 is less than or equal to 30 mm. Specifically, in this embodiment, the initial outer diameter of the detection device 1 (the outer diameter of the detection device 1 before the soluble pressure-bearing layer 1-3 dissolves) is set to be at least 2 mm larger than the diameter of the perforation orifice. This ensures that the soluble pressure-bearing layer 1-3 of the detection device 1 does not completely dissolve when passing through the perforation orifice, thus protecting the internal components of the detection device 1. Furthermore, it is necessary to ensure that the outer diameter of the detection device 1 is less than or equal to 30 mm after the soluble pressure-bearing layer 1-3 has completely dissolved, thereby facilitating recovery and capture by the recovery device.

[0066] The density of the detection device 1 remains within a specified density range that corresponds to the actual density of the fracturing fluid from the start of the fracturing process to the end of the post-fracturing well shut-in. Specifically, the density of the detection device 1 decreases as the soluble pressure-bearing layers 1-3 dissolve. To ensure that the detection device 1 can acquire effective and comprehensive downhole information while flowing with the fracturing fluid, this embodiment sets the density variation range of the detection device 1 from the start of the fracturing process to the end of the post-fracturing well shut-in, according to the actual density of the fracturing fluid (i.e., a specified density range that corresponds to the actual density of the fracturing fluid). This allows the detection device 1 to have an ideal movement state in the fracturing fluid, thereby achieving the acquisition of effective and comprehensive downhole information. Simultaneously, the decrease in the density of the detection device 1 as the soluble pressure-bearing layers 1-3 dissolve makes the detection device 1, after completing its detection, easily carried to the surface by the fracturing fluid 9.

[0067] In one specific embodiment of this application, the initial density of the detection device 1 (the density of the detection device 1 before the soluble pressure-bearing layers 1-3 dissolve) is set to be between 0.95 and 3 g / cm³. 3 This ensures that the detection device 1 can float or will not fall to the bottom of the well due to gravity and become immobile, achieving the purpose of moving with the flow of the fracturing fluid 9. Simultaneously, after the soluble pressure-bearing layer 1-3 has completely dissolved, the density of the detection device 1 is set to be less than or equal to 0.97 g / cm³. 3 This ensures that the detection device 1 floats when it exits the well at the blowout pool along with the fracturing fluid 9, making it easy for the recovery device to capture it.

[0068] In this embodiment, the data acquisition module includes: multiple sensors of different types for completing the downhole status acquisition task; a wireless data transmission module 1-9 for transmitting downhole information during the downhole status acquisition process; a data storage device 1-7 for storing downhole information; a rechargeable battery 1-8 for powering the electrical equipment in the detection device 1; and a wireless charging module 1-6 for providing power to the rechargeable battery 1-8. Specifically, the data acquisition module includes multiple devices, which are connected according to corresponding connection methods. Each device is fixed and protected by a lightweight insulating filler 1-11, effectively avoiding impact and damage from external materials. Multiple sensors of different types (e.g., pressure sensors, temperature sensors 1-5, etc.) complete the downhole status acquisition task by collecting different types of downhole data. The wireless data transmission module 1-9 transmits the downhole information collected by the corresponding sensors in real time during the downhole status acquisition process to provide feedback on the downhole situation to the surface. Data storage devices 1-7 store downhole information. After the recovery device detects the detection device 1, the downhole information stored in data storage devices 1-7 can be extracted to obtain downhole information about the entire fracturing process, thereby enabling the evaluation of the entire fracturing process. Rechargeable batteries 1-8 provide power to the relevant electrical equipment in the detection device 1. Wireless charging modules 1-6 receive wireless charging signals from outside the well and provide power to the aforementioned rechargeable batteries 1-8 wirelessly based on electromagnetic induction, thus ensuring the continuity of power supply to the relevant electrical equipment in the detection device 1.

[0069] Next, the detection device 1 also includes a pressure transmission through-hole 1-1. The pressure transmission through-hole 1-1 connects the hollow cavity to the outside of the detection device 1 by penetrating the soluble pressure-bearing layer 1-3 and the insoluble pressure-bearing layer 1-4, and is used to transmit signals characterizing downhole pressure and downhole acoustic characteristics to corresponding types of sensors. In this embodiment, the detection device 1 is designed with a pressure transmission through-hole 1-1 that connects the hollow cavity to the outside of the detection device 1 by penetrating the soluble pressure-bearing layer 1-3 and the insoluble pressure-bearing layer 1-4, facilitating pressure and acoustic wave transmission. This allows signals characterizing downhole pressure and downhole acoustic characteristics to be transmitted to corresponding types of sensors located within the detection device 1, enabling pressure and acoustic information to directly enter the detection device 1, thus improving the accuracy and convenience of pressure and acoustic information acquisition.

[0070] In this embodiment, the pressure transmission through-hole 1-1 is filled with pressure-conducting filler 1-10, which protects multiple sensors from damage by substances inside the wellbore. The pressure transmission through-hole 1-1 is filled with the elastic pressure-conducting filler 1-10, which effectively transmits pressure and acoustic information while preventing damage to the pressure sensor and acoustic sensor 1-2 from immersion or corrosion by fracturing fluid 9, fracturing proppant 10, and other substances inside the wellbore.

[0071] The recovery device captures and recovers the detection device 1 as it is discharged from the wellhead along with the fracturing fluid 9, and evaluates the fracturing process by analyzing and processing downhole information. During the fracturing flowback process, the detection device 1 returns to the surface from the wellhead at the blowout pool along with the flowback fracturing fluid 9, and is captured and recovered by the recovery device at the blowout pool. Subsequently, the recovery device reads the downhole information such as temperature, pressure, and acoustic waves stored in the data storage devices 1-7 of the detection device 1, and assesses and analyzes the temperature and pressure changes during the downhole fracturing process and the well shut-in process, thereby evaluating the fracturing process.

[0072] Furthermore, the recovery device also determines the fracture characteristics and well-drainage flowback characteristics after fracturing based on the temperature, pressure, and acoustic information from the downhole data, as well as the acoustic information during the fracture opening and closing process. Based on this, the well-drainage flowback performance of the current fracturing well is evaluated. The recovery device, based on the downhole information such as temperature, pressure, and acoustic information stored in the data storage devices 1-7 of the detection device 1, assesses and analyzes the temperature and pressure changes during downhole fracturing and well-drainage processes, and combines this with the acoustic characteristics during fracture opening and closing processes to analyze the fracture characteristics and well-drainage flowback characteristics after fracturing, thereby evaluating the well-drainage flowback performance of the current fracturing well.

[0073] Example 2

[0074] On the other hand, based on the wireless monitoring system for downholes described in Embodiment 1 above, this embodiment of the invention also proposes a wireless monitoring method for downholes. This method utilizes the aforementioned wireless monitoring system for downholes to effectively achieve wireless monitoring of downhole information. Figure 3 This is a step diagram of a wireless monitoring method for downhole applications according to an embodiment of this application. Figure 3As shown, the wireless monitoring method for downhole applications according to the present invention includes the following steps: Step S310: The detection device is deployed into the pipeline connecting the fracturing pump truck and the fracturing wellhead using the deployment device; Step S320: During the process of the fracturing pump truck pumping fracturing fluid into the fracturing well, the detection device enters the well along with the fracturing fluid through the tubing or casing channel, and collects downhole information characterizing the downhole features of the fracturing process in real time and transmits the collected data to the surface; Step S330: When the detection device is discharged from the wellhead with the fracturing fluid, the recovery device captures and recovers the detection device, thereby conducting fracturing process evaluation through the analysis and processing of downhole information.

[0075] This invention proposes a wireless monitoring system and method for downhole applications. The system deploys a specifically shaped detection device into the wellbore along with the fracturing fluid. The detection device collects downhole information characterizing the fracturing process in real time. A retrieval device captures and recovers the detection device as it is discharged from the wellhead with the fracturing fluid. The fracturing process is evaluated by analyzing the downhole information throughout the entire fracturing process (or the entire fracturing and post-fracturing well shut-in process). Furthermore, the detection device transmits the collected data to the surface in real time, enabling real-time feedback of downhole information. This invention can be used for downhole parameter monitoring during fracturing and post-fracturing well shut-in processes, solving the problem of difficulty in obtaining downhole parameters during these processes.

[0076] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0077] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0078] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0079] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A wireless monitoring system for downhole applications, characterized in that, include: The deployment device is used to deploy the detection device into the pipeline that connects the fracturing pump truck to the fracturing wellhead. The detection device is used to enter the well along with the fracturing fluid through the tubing or casing channel during the process of the fracturing pump truck pumping fracturing fluid into the fracturing well, and to collect downhole information that characterizes the downhole features of the fracturing process in real time and transmit the collected data to the surface. A recovery device is used to capture and recover the detection device when it is discharged from the wellhead with the fracturing fluid, and to evaluate the fracturing process by analyzing and processing the downhole information.

2. The wireless monitoring system according to claim 1, characterized in that, The detection device includes: An insoluble pressure-bearing layer is used to form a hollow cavity inside the detection device, the hollow cavity being filled with a lightweight insulating filler. A soluble pressure-bearing layer, which is wrapped around the outer surface of the insoluble pressure-bearing layer, is used to gradually reduce the volume of the detection device by dissolving it from the start of the fracturing process to the end of the well shut-in process after fracturing, so as to reduce the risk of the detection device being stuck. The data acquisition module is used to collect downhole information in real time, and the data acquisition module is fixed and protected by the lightweight insulating filler.

3. The wireless monitoring system according to claim 2, characterized in that, The soluble pressure-bearing layer is preferably a soluble aluminum-magnesium alloy or a soluble polymer.

4. The wireless monitoring system according to claim 2 or 3, characterized in that, The initial outer diameter of the detection device is more than 2 mm larger than the diameter of the perforation hole. After the soluble pressure-bearing layer has completely dissolved, the outer diameter of the detection device is less than or equal to 30 mm.

5. The wireless monitoring system according to any one of claims 2 to 4, characterized in that, The density of the detection device remains within a specified density range that corresponds to the actual density of the fracturing fluid from the start of the fracturing process to the end of the well shut-in process after fracturing. The density of the detection device decreases as the soluble pressure-bearing layer dissolves.

6. The wireless monitoring system according to any one of claims 2 to 5, characterized in that, The data acquisition module includes: multiple sensors of different types for completing downhole status acquisition tasks; a wireless data transmission module for transmitting downhole information during downhole status acquisition; a data storage device for storing the downhole information; a rechargeable battery for powering the electrical equipment in the detection device; and a wireless charging module for providing power to the rechargeable battery.

7. The wireless monitoring system according to any one of claims 2 to 6, characterized in that, The detection device also includes: The pressure transmission through-hole connects the hollow cavity to the outside of the detection device by penetrating the soluble pressure-bearing layer and the insoluble pressure-bearing layer, and is used to transmit signals characterizing downhole pressure characteristics and signals characterizing downhole acoustic wave characteristics to the corresponding type of sensor.

8. The wireless monitoring system according to claim 7, characterized in that, The pressure transmission through-hole is filled with a pressure-conducting filler, which is used to protect the multiple sensors from damage by materials inside the wellbore.

9. The wireless monitoring system according to any one of claims 1 to 8, characterized in that, The recovery device is also used to determine the fracture characteristics and well-drainage characteristics after fracturing based on the temperature information, pressure information and acoustic information during the fracture opening and closing process in the downhole information, and to evaluate the well-drainage performance of the current fracturing well.

10. A wireless monitoring method for downhole applications, characterized in that, The wireless monitoring method is implemented using the wireless monitoring system as described in any one of claims 1 to 9, wherein the wireless monitoring method includes: The detection device is deployed into the pipeline connecting the fracturing pump truck and the fracturing wellhead using the deployment device. During the process of the fracturing pump truck pumping fracturing fluid into the fracturing well, the detection device enters the well along with the fracturing fluid through the tubing or casing channel, and collects downhole information characterizing the downhole features of the fracturing process in real time and transmits the collected data to the surface. When the detection device is discharged from the wellhead along with the fracturing fluid, the recovery device captures and recovers the detection device, thereby evaluating the fracturing process by analyzing and processing the downhole information.

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