Sleeve deformation monitoring simulation device and method based on distributed strain sensing
The downhole environment is simulated through distributed strain sensing technology, and the error and operation complexity of casing deformation monitoring are solved, and high-precision and real-time strain monitoring is achieved, which is suitable for high-temperature and high-pressure environments.
Patent Information
- Application Number
- CN202411442848.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2024-12-20
AI Technical Summary
The existing casing deformation monitoring technology has problems such as large errors, complex operations, and inability to monitor online in real time. Especially in harsh environments of high temperature and high pressure, it is difficult for traditional methods to accurately measure strain and perform temperature compensation.
Using a casing deformation monitoring and simulation device based on distributed strain sensing, including a distributed strain monitoring system, a high-temperature and high-pressure casing deformation simulation system and a pressure control system, the strain coefficient calibration and temperature compensation scheme verification are carried out by simulating the downhole environment to achieve real-time , accurate strain monitoring.
It improves measurement accuracy and safety, realizes continuous and real-time monitoring of casing deformation, has good applicability and low cost, and is suitable for harsh environments with high temperature and high pressure.
Smart Images
Figure CN119164309A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of casing monitoring in oil and gas production, and in particular to a casing deformation monitoring simulation device and method based on distributed strain sensing. Background Art
[0002] During the exploration and development of oil fields, the casing plays an important role in supporting the wellbore and protecting the oil pipe on the outer layer of the pumping pipe. The outermost layer of the entire oil production pipeline is in direct contact with crude oil or formations. The currently commonly used hydraulic oil recovery method causes the underground rock formation to be impacted and flowed by high-pressure water flow. The stress conditions of the downhole casing are complex and the service environment is harsh, which leads to a significant increase in the probability of casing deformation and damage. On the one hand, casing damage directly affects the safety and reliability of oil and gas production, and there is a risk of unexpected failure; on the other hand, it also affects the output of oil and gas. In severe cases, it may even cause the casing to break and the drilling to be scrapped, resulting in waste of resources and property losses. Therefore, it is of great significance to monitor the deformation of the casing.
[0003] Common casing damage monitoring technologies include ultrasonic television, optical equipment imaging, and multi-arm wellbore calculation. Ultrasonic television continuously transmits ultrasonic signals to the inner wall of the casing, and uses ultrasonic reflection imaging to display the deformation information of the casing. However, this method cannot distinguish between oil stains and casing structural damage, so it has a large error. Optical equipment imaging uses a camera to take photos along the casing downhole, which can intuitively show information such as casing deformation, leakage, and fracture, but the flow of downhole media will affect the imaging effect. Multi-arm wellbore calculation spreads multiple detection arms in the casing. The detection arms undergo radial displacement as the casing diameter changes to obtain casing shape information, but the detection arm operation was complicated at that time, and the electrical signal downhole was not conducive to production safety.
[0004] The above common methods are time-consuming and complicated to operate, and the sensor probe needs to be lowered into the well along the casing, which makes it impossible to perform real-time online monitoring. Compared with traditional monitoring methods, distributed fiber optic sensing monitoring has the characteristics of small sensor size, high measurement point density, controllable spacing, corrosion resistance, and no electromagnetic interference. With the increasing maturity of distributed fiber optic sensing technology, distributed strain sensing (DSS) based on fiber Brillouin scattering has comparable performance to traditional methods in terms of measurement accuracy, linearity, and repeatability. In addition, combined with the downhole high-temperature and high-pressure resistant armored oil well optical cable, the distributed strain sensing technology is capable of handling harsh working environments such as high temperature, high pressure, strong corrosion, and narrow space, and can better meet the needs of downhole casing deformation monitoring.
[0005] However, there are still some problems in the actual use of distributed strain sensing technology: the armored oil well optical cable used to withstand the harsh environment of high temperature and high pressure underground is significantly different from the traditional strain optical cable in terms of structure, and its strain coefficient is also different from that of the traditional strain optical cable. The high temperature and high pressure environment underground and the coupling between the optical cable and the casing will also affect the strain measurement. In addition, the distributed strain sensing technology based on Brillouin scattering also has the problem of temperature-strain cross-sensitivity, and a temperature compensation solution needs to be designed.
[0006] In order to accurately measure the strain of the casing, it is necessary to measure the strain of the armored optical cable in a simulated downhole environment, complete the calibration of the strain coefficient and verify the temperature compensation scheme. Therefore, it is particularly necessary to establish a set of casing deformation monitoring simulation experimental equipment and methods based on distributed strain sensing technology. Summary of the invention
[0007] The purpose of the present invention is to provide a casing deformation monitoring simulation device and method based on distributed strain sensing to solve the problems existing in the prior art, and has the advantages of easy operation, high measurement accuracy, safety and reliability.
[0008] In order to achieve the above object, the present invention adopts the following technical solutions: On the one hand, the present invention provides a casing deformation monitoring simulation device based on distributed strain sensing, including a distributed strain monitoring system, a high-temperature and high-pressure casing deformation simulation system, and a pressure control system; The distributed strain monitoring system is used to monitor in real time the strain of casing samples in a high-temperature and high-pressure casing deformation simulation system under different temperature, pressure and deformation conditions; The high-temperature and high-pressure casing deformation simulation system comprises a simulated wellbore, a casing sample placed in the simulated wellbore, and an armored optical cable placed in the casing sample. The high-temperature and high-pressure casing deformation simulation system is used to simulate the underground high-temperature and high-pressure environment and the deformation of the casing sample; The pressure control system is used for supplying and discharging pressurized liquid of the high temperature and high pressure casing deformation simulation system; The distributed strain monitoring system is connected to the armored optical cable in the high-temperature and high-pressure casing deformation simulation system, and the pressure control system is connected to the high-temperature and high-pressure casing deformation simulation system through a fluid pipeline.
[0009] Preferably, the distributed strain monitoring system includes a data processing and display control device and a distributed strain demodulation device; The distributed strain demodulation device is connected to the armored optical cable in the high-temperature and high-pressure casing deformation simulation system through an optical fiber; the data processing and display control device is connected to the distributed strain demodulation device through a data communication cable; The distributed strain demodulation device is used to generate a modulated pulse light signal and input it into the armored optical cable. The scattered light generated by the pulse light carries the strain and temperature information of the armored optical cable and returns to the distributed strain demodulation device, where it is demodulated to obtain the strain and temperature information. The data processing and display control device is used to process and interpret the strain and temperature information, and display the strain distribution of the casing sample in the form of graphics and data.
[0010] Preferably, the distributed strain demodulation device adopts a distributed strain sensing demodulation method based on Brillouin optical time domain reflection or Brillouin optical time domain analysis.
[0011] Preferably, the high temperature and high pressure casing deformation simulation system further comprises a high temperature and high pressure container, a heating device and a casing deformation device; The simulated wellbore is used to simulate the high temperature and high pressure environment downhole and the stress environment to which the casing is subjected; The simulated wellbore has a built-in high-temperature and high-pressure container, in which a casing sample and a casing deformation device in contact with the casing sample are installed, and the casing deformation device is used to apply stress to the casing sample to cause casing deformation; The heating device is installed around the outer surface of the high-temperature and high-pressure container and covers the high-temperature and high-pressure container in the axial direction; the heating device is covered with a heat-insulating layer; A sealing head is provided at the port of the high-temperature and high-pressure container; an optical cable passing hole is provided on the sealing head for the armored optical cable to pass through to the outside of the simulated wellbore; The two ends of the high-temperature and high-pressure container are each provided with a fluid penetration hole for the fluid to enter and exit the pressure control system.
[0012] Preferably, the casing sample further comprises an end protector, a casing support, an outer casing and an inner casing; Both ends of the outer casing and the inner casing are fixed on the casing support; the casing sample is installed inside the simulated wellbore through the casing support; The armored optical cable is fixed on the surface of the inner sleeve, and an end protector is provided at the end of the armored optical cable, and the end protector is used to seal the end of the armored optical cable and protect the end optical fiber; Cement is filled between the outer casing and the inner casing to form a cement layer; The number of the armored optical cables is one or more.
[0013] Preferably, the armored optical cable comprises an outer continuous metal tube, a first inner continuous metal thin tube, a second inner continuous metal thin tube, a strain optical fiber, a temperature compensating optical fiber, an armored steel wire and an outer sheath; A strain optical fiber is placed in the first inner continuous metal tube, and the strain optical fiber is tightly attached to the inside of the first inner continuous metal tube; the first inner continuous metal tube is located at the center of the armored optical cable; a second inner continuous metal tube and an armored steel wire are arranged outside the first inner continuous metal tube, and the first inner continuous metal tube, the second inner continuous metal tube and the armored steel wire are twisted together and then tightly wrapped with an outer continuous metal tube; The temperature compensation optical fiber and the redundant optical fiber are placed in the second inner continuous metal tube; The first inner continuous metal tube, the second inner continuous metal tube and the armored steel wire are twisted together and then tightly wrapped with an outer continuous metal tube; The outer continuous metal tube is covered with an outer sheath.
[0014] Preferably, the strain optical fiber is a high-sensitivity strain optical fiber tightly wrapped with a high-temperature resistant and high-strength composite material; The strain optical fiber is a single-mode optical fiber, the temperature compensation optical fiber is a single-mode optical fiber, and the redundant optical fiber is a single-mode or multi-mode optical fiber.
[0015] Preferably, the second inner continuous metal tube is filled with high temperature resistant optical fiber paste; The first inner continuous metal tube, the second inner continuous metal tube and the outer continuous metal tube are made of stainless steel or alloy metal.
[0016] Preferably, the pressure control system includes a liquid storage device, a liquid collecting device, a fluid pipeline, a high-pressure pump body, a booster pump body and a pressure sensor; The high-pressure pump body is connected to the liquid storage device through a first fluid pipeline, the booster pump body is connected to the liquid storage device through a second fluid pipeline, the second fluid pipeline is connected to the first fluid pipeline, and is connected to a fluid passing hole of the high-temperature and high-pressure casing deformation simulation system through the first fluid pipeline; The first fluid pipeline is also provided with a first high-pressure valve, a first pressure gauge and a first overflow pipe; the second fluid pipeline is provided with a second high-pressure valve; one end of the first overflow pipe is connected to the outlet of the high-pressure pump body, and the other end is connected to the liquid storage device; The liquid collecting device is connected to another fluid passing hole of the high temperature and high pressure casing deformation simulation system through a third fluid pipeline; The third fluid pipeline is installed with a pressure sensor, a second pressure gauge and a third high-pressure valve; A second overflow pipe is installed between the liquid storage device and the liquid collecting device.
[0017] In a second aspect, the present invention provides a casing deformation monitoring simulation method of the above-mentioned casing deformation monitoring simulation device based on distributed strain sensing, comprising: S1: Assemble the casing sample; install the casing deformation device and the casing sample into the high-temperature and high-pressure container of the simulated wellbore, let the armored optical cable pass through the optical cable through the cable through hole, connect the pressure control system with the high-temperature and high-pressure container, inject working liquid into the high-temperature and high-pressure container, and install the sealing head; connect the optical fiber in the armored optical cable to the distributed strain demodulation device through the optical fiber jumper, and assemble the casing deformation monitoring simulation device based on distributed strain sensing; S2: Turn on the distributed strain monitoring system, and after the readings are stable, test and record the strain and temperature information of the armored optical cable; S3: starting the heating device of the high-temperature and high-pressure casing deformation simulation system and the high-pressure pump body and the booster pump body of the pressure control system, so that the inside of the simulated wellbore reaches the temperature and pressure requirements required for the test; S4: starting the casing deformation device in the simulated wellbore to record the strain and temperature information of the casing sample under different deformation conditions; S5: Using the data processing and display control device in the distributed strain monitoring system, combined with formula Δ V B = C ε Δ ε + C T Δ T Temperature compensation is performed, and then the strain and temperature data are further processed and interpreted to obtain the strain and deformation distribution of the casing sample; where Δ V B is the change in Brillouin frequency shift, C ε and C T is the strain and temperature sensitivity coefficient, Δ ε and Δ T is the strain and temperature change; S6: changing the temperature, pressure and deformation degree in the high temperature and high pressure casing deformation simulation system to obtain the casing sample deformation distribution under different working conditions.
[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. The casing deformation monitoring simulation device based on distributed strain sensing provided by the present invention can be used to simulate the deformation of the casing in an actual downhole environment, as well as the deformation of the casing under different temperatures and pressures, to achieve the calibration of the strain coefficients of armored optical cables and casings of different specifications, and to improve the measurement accuracy of casing deformation monitoring based on distributed strain sensing; 2. The device provided by the present invention can reflect the casing deformation in the actual scene and perform continuous and real-time monitoring by making the simulation conditions consistent with the actual situation and providing verification of the temperature compensation scheme; 3. The present invention is easy to use, low in cost, high in measurement accuracy, safe and reliable, and has good applicability. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 A schematic diagram of the structure of a casing deformation monitoring simulation device based on distributed strain sensing provided by the present invention; Figure 2 It is a structural schematic diagram of the casing sample in the present invention; Figure 3 Schematic diagram of the internal structure of the armored optical cable in the present invention; In the figure: 1. Distributed strain monitoring system, 2. High temperature and high pressure casing deformation simulation system, 3. Pressure control system, 101. Data processing and display control device, 102. Distributed strain demodulation device, 201. Simulated wellbore, 202. Casing sample, 211. High temperature and high pressure container, 212. Heating device, 213. Insulation layer, 214. Optical cable through hole, 215. Sealing head, 216. First fluid through hole, 217. Casing deformation device, 218. Second fluid through hole; 221. Armored optical cable, 222. End protector, 223. First casing bracket, 224. Outer casing, 225. Inner casing, 226. Cement layer, 227. Second casing bracket, 2211. Outer casing Continuous metal tube, 2212, first inner continuous metal capillary, 2213, strain optical fiber, 2214, second inner continuous metal capillary, 2215, temperature compensation optical fiber, 2216, redundant optical fiber, 2217, armored steel wire, 2218, outer sheath; 301, liquid storage device, 302, liquid collecting device, 303, first fluid pipeline, 304, first pressure gauge, 305, first high-pressure valve, 306, high-pressure pump body, 307, first overflow pipe, 308, second fluid pipeline, 309, second high-pressure valve, 310, booster pump body, 311, third fluid pipeline, 312, pressure sensor, 313, second pressure gauge, 314, third high-pressure valve, 315, second overflow pipe. DETAILED DESCRIPTION
[0020] The specific implementation of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are illustrative and intended to be used to explain the present invention, but should not be construed as limiting the present invention.
[0021] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "installation" and the like should be understood in a broad sense, for example, it can be a fixed connection, a direct connection, or a 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.
[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.
[0023] The specific embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.
[0024] During the exploration and development of oil fields, the downhole casing is subjected to complex stress conditions and harsh service environment, which may lead to deformation and damage. Casing damage directly affects the safety and reliability of oil and gas production, resulting in waste of resources and property losses. Therefore, it is of great significance to monitor the deformation of the casing. The common casing damage monitoring technology process is time-consuming and complicated to operate, and the sensor probe needs to be lowered into the well along the casing, making it impossible to perform real-time online monitoring. Compared with traditional monitoring methods, distributed fiber optic sensing monitoring has the characteristics of small sensor size, high measurement point density, controllable spacing, corrosion resistance, and no electromagnetic interference.
[0025] However, there are still some problems in the actual use of distributed strain sensing technology: the armored oil well optical cable used to withstand the harsh environment of high temperature and high pressure underground is significantly different from the traditional strain optical cable in terms of structure, and its strain coefficient is also different from that of the traditional strain optical cable. The high temperature and high pressure environment underground and the coupling between the optical cable and the casing will also affect the strain measurement. In addition, the distributed strain sensing technology based on Brillouin scattering also has the problem of temperature-strain cross-sensitivity, and a temperature compensation solution needs to be designed.
[0026] At present, there is no strain measurement simulation experiment device and method for armored strain optical cable to simulate the downhole environment. Therefore, the present invention proposes a casing deformation monitoring simulation experiment device and method based on distributed strain sensing to calibrate the strain coefficient and verify the temperature compensation scheme of the armored strain optical cable to simulate the downhole environment.
[0027] like Figure 1 As shown, a casing deformation monitoring simulation device based on distributed strain sensing includes a distributed strain monitoring system 1, a high-temperature and high-pressure casing deformation simulation system 2 and a pressure control system 3.
[0028] Specifically, The distributed strain monitoring system 1 is used to monitor in real time the strain of the casing sample 202 in the high temperature and high pressure casing deformation simulation system 2 under different simulation conditions; The high temperature and high pressure casing deformation simulation system 2 is used to simulate the underground high temperature and high pressure environment and the deformation of the casing; The pressure control system 3 is used for the liquid supply and discharge of the high-temperature and high-pressure casing deformation simulation system 2 .
[0029] In the present invention, the distributed strain monitoring system 1 is connected to the armored optical cable 221 of the high-temperature and high-pressure casing deformation simulation system 2, and the pressure control system 3 is connected to the first fluid through hole 216 and the second fluid through hole 218 of the high-temperature and high-pressure casing deformation simulation system 2 through the first fluid pipeline 303 and the third fluid pipeline 311.
[0030] In the present invention, the distributed strain monitoring system 1 includes a data processing and display control device 101 and a distributed strain demodulation device 102. The distributed strain demodulation device 2 is connected to the armored optical cable 221 passing through the optical cable through hole 214 through an optical fiber, and the data processing and display control device 101 is connected to the distributed strain demodulation device 102 through a data communication cable. The distributed strain demodulation device 102 generates a modulated pulse light signal and inputs it into the armored optical cable 221. The scattered light generated by the pulse light carries the environmental information such as the strain and temperature of the armored optical cable 221 and returns to the distributed strain demodulation device 102 again, and the information such as strain and temperature is obtained by demodulation. The temperature and strain data are transmitted to the data processing and display control device 101 for further data processing and interpretation, and the strain distribution of the casing sample is displayed in the form of graphics and data.
[0031] In the present invention, the distributed strain demodulation device 102 adopts a distributed strain sensing technology based on Brillouin Optical Time Domain Reflectometry (BOTDR) or Brillouin Optical Time Domain Analysis (BOTDA). The sensing principle is that there is a linear relationship between the frequency shift change of Brillouin scattered light and the temperature and strain change of the medium: Δ V B = C ε Δ ε + C T Δ T ; Where: Δ V B is the change in Brillouin frequency shift, Cε and C T is the strain and temperature sensitivity coefficient, Δ ε and Δ T are the strain and temperature changes.
[0032] In the present invention, the high-temperature and high-pressure casing deformation simulation system 2 includes a simulated wellbore 201, a casing sample 202, a high-temperature and high-pressure container 211, a heating device 212, an insulation layer 213, an optical cable through hole 214, a sealing head 215, a first fluid through hole 216, a second fluid through hole 218 and a casing deformation device 217.
[0033] The simulated wellbore 201 is used to simulate the high temperature and high pressure environment underground and the stress environment to which the casing is subjected.
[0034] The simulated wellbore 201 has a built-in high-temperature and high-pressure container 211, and a casing sample 202 and a casing deformation device 217 in contact with the casing sample 202 are arranged inside the high-temperature and high-pressure container 211, and an armored optical cable 221 is arranged inside the casing sample 202. The casing deformation device 217 is used to apply stress to the casing sample 202 to cause casing deformation. It should be noted that the high-temperature and high-pressure container 211 is a cylindrical container with a large diameter, which can be set on the ground or in a factory building. The container is customized with a material that can withstand high temperature and high pressure, and usually steel is used.
[0035] The heating device 212 is installed around the outer surface of the high temperature and high pressure container 211, covers the high temperature and high pressure container 211 along the axial direction, and is covered with a heat preservation layer 213. The heating device 212 cooperates with the heat preservation layer 213 to realize the high temperature environment control of the simulated casing.
[0036] The sealing head 215 is connected to the high-temperature and high-pressure container 211 to play a sealing role; the sealing head is provided with an optical cable passing hole 214 for the armored optical cable 221 in the casing sample 202 to pass through to the outside of the simulated wellbore 201.
[0037] A first fluid through hole 216 and a second fluid through hole 218 are respectively provided at both ends of the high temperature and high pressure container 211 for the fluid of the pressure control system 3 to enter and exit, thereby realizing the high pressure environment control of the simulated casing.
[0038] In the present invention, the pressure control system 3 includes a liquid storage device 301, a liquid collecting device 302, a first fluid pipeline 303, a second fluid pipeline 308, a third fluid pipeline 311, a first pressure gauge 304, a second pressure gauge 313, a first high-pressure valve 305, a second high-pressure valve 309, a third high-pressure valve 314, a high-pressure pump body 306, a first overflow pipe 307, a second overflow pipe 315, a boosting pump body 310 and a pressure sensor 312. One end of the first fluid pipeline 303 is connected to the liquid storage device 301, and the other end of the first fluid pipeline 303 is connected to the high-temperature and high-pressure casing deformation simulation system 2 through the first fluid penetration hole 216. One end of the second fluid pipeline 308 is connected to the liquid storage device 301, and the other end of the second fluid pipeline 308 is connected to the first fluid pipeline 303. One end of the third fluid pipeline 311 is connected to the simulated wellbore 201 through the second fluid penetration hole 218, and the other end of the third fluid pipeline 311 is connected to the liquid collecting device 302. High-pressure valves and pressure pumps are provided on the three fluid pipelines to achieve flow balance and temperature control of the fluid in the high-temperature and high-pressure casing deformation simulation system 2.
[0039] The liquid storage device 301 is connected to the high-pressure pump body 306 and the booster pump body 310 through the first fluid pipeline 303 and the second fluid pipeline 308, respectively. The first overflow pipe 307, the first high-pressure valve 305 and the first pressure gauge 304 are installed in sequence on the first fluid pipeline 303 behind the high-pressure pump body 306 according to the liquid flow direction, and the second high-pressure valve 309 is installed on the second fluid pipeline 308 behind the booster pump body 310. The first fluid pipeline 303 and the second fluid pipeline 308 are connected, and then connected to the first fluid passing hole 216 of the simulated wellbore 201 in the high-temperature and high-pressure casing deformation simulation system 2.
[0040] The liquid collecting device 302 is connected to the second fluid crossing hole 218 at the other end of the simulated wellbore 201 in the high-temperature and high-pressure casing deformation simulation system 2 through the third fluid pipeline 311. A pressure sensor 312, a second pressure gauge 313 and a third high-pressure valve 314 are installed on the third fluid pipeline 311 in sequence according to the liquid flow direction.
[0041] A second overflow pipe 315 is installed between the liquid storage device 301 and the liquid collecting device 302. Fluid is injected into the simulated wellbore 201 through the high-pressure pump body 306 and the booster pump body 310 to establish a high-pressure test environment, and the third high-pressure valve 314 on the liquid collecting device 302 is opened to discharge the fluid in the simulated wellbore 201 to achieve pressure relief.
[0042] like Figure 2 As shown, in one embodiment, the casing sample 202 includes an armored optical cable 221 , an end protector 222 , a first casing support 223 , a second casing support 227 , an outer casing 224 , an inner casing 225 and a cement layer 226 .
[0043] The two ends of the outer casing 224 and the inner casing 225 are respectively connected to the first casing support 223 and the second casing support 227, which can be tightened by welding or threading. The first casing support 223 and the second casing support 227 play the role of supporting the casing sample 202, and a space for the casing deformation device 217 to pass through should be reserved on the first casing support 223. The casing sample 202 is installed inside the simulated wellbore 201 through the first casing support 223 and the second casing support 227.
[0044] The armored optical cable 221 is fixed on the surface of the inner sleeve 225, and can be fixed by a metal clamp or other means. An end protector 222 is provided at the end of the armored optical cable 221 to seal the end of the armored optical cable 221 and protect the end optical fiber. Cement is filled between the outer sleeve 224 and the inner sleeve 225 to form a cement layer 226.
[0045] like Figure 3 As shown, in one embodiment, the armored optical cable 221 includes an outer continuous metal tube 2211, a first inner continuous metal tube 2212, a second inner continuous metal tube 2214, a strain optical fiber 2213, a temperature compensation optical fiber 2215, a redundant optical fiber 2216, an armored steel wire 2217 and an outer sheath 2218.
[0046] A special high-sensitivity strain optical fiber 2213 tightly wrapped with a high-temperature resistant and high-strength composite material is placed in the first inner continuous metal tube 2212. The strain optical fiber 2213 is a single-mode optical fiber and fits tightly inside the first inner continuous metal tube 2212. It should be noted that the first inner continuous metal tube 2212 with the strain optical fiber 2213 placed should be located at the center of the armored optical cable 221 so that the strain optical fiber is evenly stressed.
[0047] The first inner continuous metal tube 2212 is provided with a second inner continuous metal tube 2214 and an armored steel wire 2217. The first inner continuous metal tube 2212, the second inner continuous metal tube 2214 and the armored steel wire 2217 are twisted together and then tightly wrapped with the outer continuous metal tube 2211. There can be multiple armored steel wires 2217, which are used to increase the strength of the sensor optical cable and improve its pressure resistance and tensile strength.
[0048] The temperature compensation optical fiber 2215 and the redundant optical fiber 2216 are placed in the second inner continuous metal tube 2214.
[0049] Furthermore, the temperature compensation optical fiber 2215 is a single-mode optical fiber, and the redundant optical fiber 2216 is a single-mode or multi-mode optical fiber. The second inner continuous metal tube 2214 is filled with high temperature resistant optical fiber paste, so that the internal optical fiber can slide freely without being affected by the strain of the optical cable.
[0050] In the present invention, the armored optical cable 221 includes a tightly wrapped special high-sensitivity strain optical fiber 2213 and a strain-insensitive temperature compensation optical fiber 2215 filled with optical fiber paste. The two optical fibers are connected at the end of the armored optical cable 221 and protected by an end protector 222. According to the Brillouin sensing principle, the temperature compensation optical fiber is insensitive to strain, so the measured Brillouin frequency shift change is only related to temperature. The strain optical fiber is sensitive to both strain and temperature. The strain optical fiber and the temperature compensation optical fiber are located in the same armored optical cable. The temperatures to which the two are subjected can be approximately considered to be the same. Therefore, the Brillouin frequency shift change of the temperature compensation optical fiber is deducted from the Brillouin frequency shift change measured by the strain optical fiber to obtain the strain change that is not affected by temperature.
[0051] Furthermore, the first inner continuous metal tube 2212, the second inner continuous metal tube 2214 and the outer continuous metal tube 2211 are made of stainless steel or alloy metal.
[0052] Furthermore, the outer continuous metal tube 2211 is covered with an outer sheath 2218 to protect the armored optical cable and facilitate fixed installation.
[0053] The casing deformation monitoring simulation experiment method based on distributed strain sensing using the above simulation experiment device includes the following steps: Step 1: Assemble the casing sample 202 in the high-temperature and high-pressure casing deformation simulation system 2 according to the above-mentioned simulation experimental device. At the end of the armored optical cable 221, the strain optical fiber 2213 and the temperature compensation optical fiber 2215 are fused and the end protector 222 is installed. One or more armored optical cables 221 are installed on the surface of the inner casing 225 by metal clamps or other fixing methods. The outer casing 224 and the inner casing 225 with the armored optical cable 221 installed are installed on the first casing bracket 223 and the second casing bracket 227, and then cement slurry is poured between the inner and outer casings. After the cement slurry solidifies to form a cement layer 226, the assembly of the casing sample 202 is completed; Step 2: Install the casing deformation device 217 and the casing sample 202 into the high temperature and high pressure container 211 of the simulated wellbore 201, and pass the armored optical cable 221 through the optical cable through hole 214 on the sealing head 215. Connect the pressure control system 3 with the simulated wellbore 201, inject the working liquid into the high temperature and high pressure container 211, and install the sealing head 215; Step 3: Connect the optical fiber in the armored optical cable 221 to the distributed strain demodulation device 102 in the distributed strain monitoring system 1 through an optical fiber jumper, start the distributed strain monitoring system 102, and after the system readings are stable, test and record the strain and temperature information of the armored optical cable; Step 4: Start the heating device 212 of the high-temperature and high-pressure casing deformation simulation system 2 and the high-pressure pump body 306 and the booster pump body 310 of the pressure control system 3 to make the inside of the simulated wellbore 201 reach the temperature and pressure requirements required for the test; Step 5: Start the casing deformation device 217 in the simulated wellbore 201 to record the strain and temperature information of the casing sample 202 under different deformation conditions; Step 6: Using the data processing and display control device 101 in the distributed strain monitoring system 1, combined with the formula Δ V B = C ε Δ ε + C T Δ T Temperature compensation is performed, and then the strain and temperature data are further processed and interpreted to obtain the strain and deformation distribution of the casing sample 202.
[0054] Step 7: Change the temperature, pressure and deformation degree in the high-temperature and high-pressure casing deformation simulation system 2 to obtain the deformation distribution of the casing sample 202 under different working conditions.
[0055] It should be noted that the present invention uses a simulated casing sample including an inner and outer casing and a cement layer structure, which is consistent with the actual casing structure. By using a casing deformation simulation system that simulates downhole high temperature and high pressure, the high temperature and high pressure conditions that are the same as the actual situation are simulated, so that the test results are consistent with the actual situation, and the deformation of the actual casing can be reflected. At the same time, the present invention can quantitatively change the casing deformation, so the calibration of the strain coefficient and the verification of the temperature compensation scheme can be completed.
[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A casing deformation monitoring simulation device based on distributed strain sensing, characterized in that: Including distributed strain monitoring system, high temperature and high pressure casing deformation simulation system and pressure control system; The distributed strain monitoring system is used to monitor in real time the strain of casing samples in a high-temperature and high-pressure casing deformation simulation system under different temperature, pressure and deformation conditions; The high-temperature and high-pressure casing deformation simulation system comprises a simulated wellbore, a casing sample placed in the simulated wellbore, and an armored optical cable placed in the casing sample. The high-temperature and high-pressure casing deformation simulation system is used to simulate the underground high-temperature and high-pressure environment and the deformation of the casing sample; The pressure control system is used for supplying and discharging pressurized liquid of the high temperature and high pressure casing deformation simulation system; The distributed strain monitoring system is connected to the armored optical cable in the high-temperature and high-pressure casing deformation simulation system, and the pressure control system is connected to the high-temperature and high-pressure casing deformation simulation system through a fluid pipeline.
2. The casing deformation monitoring simulation device based on distributed strain sensing according to claim 1 is characterized in that: The distributed strain monitoring system includes a data processing and display control device and a distributed strain demodulation device; The distributed strain demodulation device is connected to the armored optical cable in the high-temperature and high-pressure casing deformation simulation system through an optical fiber; the data processing and display control device is connected to the distributed strain demodulation device through a data communication cable; The distributed strain demodulation device is used to generate a modulated pulse light signal and input it into the armored optical cable. The scattered light generated by the pulse light carries the strain and temperature information of the armored optical cable and returns to the distributed strain demodulation device, where it is demodulated to obtain the strain and temperature information. The data processing and display control device is used to process and interpret the strain and temperature information, and display the strain distribution of the casing sample in the form of graphics and data.
3. The casing deformation monitoring simulation device based on distributed strain sensing according to claim 2 is characterized in that: The distributed strain demodulation device adopts a distributed strain sensing demodulation method based on Brillouin optical time domain reflection or Brillouin optical time domain analysis.
4. The casing deformation monitoring simulation device based on distributed strain sensing according to claim 2 is characterized in that: The high temperature and high pressure casing deformation simulation system also includes a high temperature and high pressure container, a heating device and a casing deformation device; The simulated wellbore is used to simulate the high temperature and high pressure environment downhole and the stress environment to which the casing is subjected; The simulated wellbore has a built-in high-temperature and high-pressure container, in which a casing sample and a casing deformation device in contact with the casing sample are installed, and the casing deformation device is used to apply stress to the casing sample to cause casing deformation; The heating device is installed around the outer surface of the high-temperature and high-pressure container and covers the high-temperature and high-pressure container in the axial direction; the heating device is covered with a heat-insulating layer; A sealing head is provided at the port of the high-temperature and high-pressure container; an optical cable passing hole is provided on the sealing head for the armored optical cable to pass through to the outside of the simulated wellbore; The two ends of the high-temperature and high-pressure container are each provided with a fluid penetration hole for the fluid to enter and exit the pressure control system.
5. The casing deformation monitoring simulation device based on distributed strain sensing according to claim 4 is characterized in that: The casing sample also includes an end protector, a casing support, an outer casing and an inner casing; Both ends of the outer casing and the inner casing are fixed on the casing support; the casing sample is installed inside the simulated wellbore through the casing support; The armored optical cable is fixed on the surface of the inner sleeve, and an end protector is provided at the end of the armored optical cable, and the end protector is used to seal the end of the armored optical cable and protect the end optical fiber; Cement is filled between the outer casing and the inner casing to form a cement layer; The number of the armored optical cables is one or more.
6. The casing deformation monitoring simulation device based on distributed strain sensing according to claim 5 is characterized in that: The armored optical cable comprises an outer continuous metal tube, a first inner continuous metal thin tube, a second inner continuous metal thin tube, a strain optical fiber, a temperature compensation optical fiber, an armored steel wire and an outer sheath; A strain optical fiber is placed in the first inner continuous metal tube, and the strain optical fiber is tightly attached to the inside of the first inner continuous metal tube; the first inner continuous metal tube is located at the center of the armored optical cable; a second inner continuous metal tube and an armored steel wire are arranged outside the first inner continuous metal tube, and the first inner continuous metal tube, the second inner continuous metal tube and the armored steel wire are twisted together and then tightly wrapped with an outer continuous metal tube; The temperature compensation optical fiber and the redundant optical fiber are placed in the second inner continuous metal tube; The outer continuous metal tube is covered with an outer sheath.
7. The casing deformation monitoring simulation device based on distributed strain sensing according to claim 6 is characterized in that: The strain optical fiber is a high-sensitivity strain optical fiber tightly wrapped with a high-temperature-resistant and high-strength composite material; The strain optical fiber is a single-mode optical fiber, the temperature compensation optical fiber is a single-mode optical fiber, and the redundant optical fiber is a single-mode or multi-mode optical fiber.
8. The casing deformation monitoring simulation device based on distributed strain sensing according to claim 6 is characterized in that: The interior of the second inner continuous metal tube is filled with high temperature resistant optical fiber paste; The first inner continuous metal tube, the second inner continuous metal tube and the outer continuous metal tube are made of stainless steel or alloy metal.
9. The casing deformation monitoring simulation device based on distributed strain sensing according to claim 1 is characterized in that: The pressure control system includes a liquid storage device, a liquid collecting device, a fluid pipeline, a high-pressure pump body, a booster pump body and a pressure sensor; The high-pressure pump body is connected to the liquid storage device through a first fluid pipeline, the booster pump body is connected to the liquid storage device through a second fluid pipeline, the second fluid pipeline is connected to the first fluid pipeline, and is connected to a fluid passing hole of the high-temperature and high-pressure casing deformation simulation system through the first fluid pipeline; The first fluid pipeline is also provided with a first high-pressure valve, a first pressure gauge and a first overflow pipe; the second fluid pipeline is provided with a second high-pressure valve; one end of the first overflow pipe is connected to the outlet of the high-pressure pump body, and the other end is connected to the liquid storage device; The liquid collecting device is connected to another fluid passing hole of the high temperature and high pressure casing deformation simulation system through a third fluid pipeline; The third fluid pipeline is installed with a pressure sensor, a second pressure gauge and a third high-pressure valve; A second overflow pipe is installed between the liquid storage device and the liquid collecting device.
10. The casing deformation monitoring simulation method of the casing deformation monitoring simulation device based on distributed strain sensing according to any one of claims 4 to 9, characterized in that: include: S1: Assembling the casing sample; The casing deformation device and the casing sample are installed in the high-temperature and high-pressure container of the simulated wellbore, the armored optical cable is passed through the optical cable through-hole, the pressure control system is connected to the high-temperature and high-pressure container, the working liquid is injected into the high-temperature and high-pressure container, and the sealing head is installed; the optical fiber in the armored optical cable is connected to the distributed strain demodulation device through an optical fiber jumper, and the casing deformation monitoring simulation device based on distributed strain sensing is assembled; S2: Turn on the distributed strain monitoring system, and after the readings are stable, test and record the strain and temperature information of the armored optical cable; S3: starting the heating device of the high-temperature and high-pressure casing deformation simulation system and the high-pressure pump body and the booster pump body of the pressure control system, so that the inside of the simulated wellbore reaches the temperature and pressure requirements required for the test; S4: starting the casing deformation device in the simulated wellbore to record the strain and temperature information of the casing sample under different deformation conditions; S5: Using the data processing and display control device in the distributed strain monitoring system, combined with formula Δ V B = C ε Δ ε + C T Δ T Temperature compensation is performed, and then the strain and temperature data are further processed and interpreted to obtain the strain and deformation distribution of the casing sample; where Δ V B is the change in Brillouin frequency shift, C ε and C T is the strain and temperature sensitivity coefficient, Δ ε and Δ T is the strain and temperature change; S6: changing the temperature, pressure and deformation degree in the high temperature and high pressure casing deformation simulation system to obtain the casing sample deformation distribution under different working conditions.