A system and method for testing energy consumption near the wellbore of a water injection well

Abstract

The present invention belongs to the technical field of oil extraction, and specifically relates to an energy consumption experimental system and method for the near-wellbore zone of a water injection well. The energy consumption experimental system for the near-wellbore zone of a water injection well constructed by the present invention can reproduce the characteristics of perforation completion and reservoir contamination zone, truly simulate the radial flow process of water drive, obtain the law of pressure change, and provide support for evaluating the main control factors affecting water injection energy consumption. The embedded distributed optical fiber pressure and strain sensing technology used in the present invention can not only measure the pressure transmitted by the reservoir liquid, but also measure the pressure transmitted due to the compression or expansion of the rock skeleton, realize the real-time monitoring of energy changes in the reservoir under different water injection methods, and provide a new means for studying water injection strategies and energy consumption evaluation.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production, and in particular relates to an energy consumption test system and method for a near-wellbore zone of a water injection well. Background Art

[0002] Water injection is an important means to maintain formation energy and improve recovery, and it is also an important energy consumption link in the process of oilfield development. At present, the energy consumption of water injection system is mainly studied from the perspective of process, while the analysis from the perspective of oil reservoir is rarely involved, and the impact of energy consumption near the wellbore area is not clearly understood.

[0003] For the study of energy consumption in the near-wellbore zone, on the one hand, the pressure distribution in the near-wellbore zone of the water injection well is studied from the perspective of the pressure drop funnel in the near-wellbore zone inverted by well test parameters. This method uses the skin coefficient interpreted by the well test as an additional total pressure drop for inversion calculation. The skin coefficient is actually the comprehensive effect of reservoir damage caused by drilling, rock heterogeneity, multiphase flow, velocity-related pressure drop, and non-uniform flow patterns around the well. This method cannot effectively reveal the complex pressure distribution along the radial direction of the near-wellbore zone. On the other hand, people often use standard core or flat plate model displacement experiments to obtain water drive pressure drop information, but the scale of standard core or flat plate models is small, and it is difficult to reproduce the main features that affect energy consumption, such as perforation technology and reservoir contamination zone in the near-wellbore zone. Therefore, a new experimental method is needed to reveal the energy loss problem caused by complex flow in the near-wellbore zone, and reveal the main controlling factors affecting energy consumption in the near-wellbore zone, so as to provide a basis for subsequent decision-making on measures.

[0004] Chinese patent document CN110704794A (CN201911085803.0) discloses a method for calculating the boundary of turbulent and laminar flow partitions in the near-wellbore zone of an oil reservoir, including: calculating the velocity of any point in an iso-yield one-source-one-sink oil reservoir; calculating the pressure of any point in an iso-yield one-source-one-sink oil reservoir; obtaining the first-order derivative of velocity with respect to distance - acceleration, and the point where the curvature of the near-wellbore zone changes fastest is a possible critical point; obtaining the second-order derivative of velocity with respect to distance - acceleration change rate, and the point where the curvature of the near-wellbore zone changes fastest is a possible critical point; obtaining the first-order derivative of pressure with respect to distance r, and the point where the curvature of the near-wellbore zone changes fastest is a possible critical point; obtaining the second-order derivative of pressure with respect to distance r, and the point where the curvature of the near-wellbore zone changes fastest is a possible critical point; according to the determined critical points, taking the maximum value is the final determined critical point. This method can provide a basis for indoor research and field construction, and guide oilfield development decisions.

[0005] Chinese patent document CN112228002A (202010940586.5) discloses a plugging device for the near-wellbore area of ​​a perforated oil layer, including a tubing coupling, an upper joint, a test joint, a connecting outer tube, a plugging agent pressure test tube, an oil casing annulus test tube, a straightening coupling, a plugging agent storage tube, a constant pressure breaking rod, a plugging agent thrust piston, a conversion joint, a sealing sleeve, an outer distributor, an inner distributor pressure cap, a check valve pressure pad, a check valve valve core, a spring, an inner distributor, a rubber cartridge guide upper joint, an annulus test guide tube, a rubber cartridge, a plugging agent injection guide tube, a lower plugging agent guide tube, a center tube, a rubber cartridge guide lower joint, a lower distributor, a distribution plunger, a sleeve, a threaded female sleeve and a lower joint. The advantages of the invention are: during plugging, the casing annulus and the plugging agent pressure are fully monitored and the pressure is accurately adjusted, the plugging agent can accurately block the perforation at a fixed point without penetrating and diffusing into the formation, and it can be ensured that when the perforation section needs to be opened, it can be reopened by perforation so that the oil layer corresponding to the perforation section can be utilized again.

[0006] Chinese patent document CN117072123A (202311271566.3) discloses a partial pressure water injection device and a partial pressure water injection method for the wellhead of an oilfield water injection well. Through the combined use of multiple through-pipe packers, the area downhole is isolated into different injection layers. With the help of regulating valves and flow meters, the amount of water in each injection layer can be reasonably allocated, and partial pressure water injection can be achieved at different levels to improve the water injection effect and mining efficiency. Secondly, by adjusting the flow rate of each water injection pipe, the water injection process can be flexibly controlled to meet the needs of different bottom hole pressures and formations. In addition, the use of a flow meter can monitor the water injection situation in real time, providing a basis for regulation and management. The invented partial pressure water injection device and method can optimize oilfield water injection operations, improve mining efficiency, and reduce energy consumption costs.

[0007] The above existing technologies are unable to reveal the energy loss problem caused by the complex flow in the near-wellbore area and the main controlling factors affecting the energy consumption in the near-wellbore area. Summary of the invention

[0008] The purpose of the present invention is to provide a near-wellbore zone energy consumption experimental system and method for water injection wells. Based on the established near-wellbore zone energy consumption experimental system for water injection wells, the present invention reproduces the perforation process and reservoir pollution characteristics, and can obtain the near-wellbore zone pressure response characteristics under different completion methods, different pollution levels, and different reservoir rock particle shapes and particle sizes, thereby providing a basis for analyzing the near-wellbore zone energy consumption of water injection wells.

[0009] The technical problem to be solved by the present invention is achieved by adopting the following technical scheme: an energy consumption experimental system for the near-wellbore zone of a water injection well, comprising a reservoir simulation system, an injection system and a pressure and strain measurement system;

[0010] The reservoir simulation system comprises a high-pressure sealed container, a core model and a wellbore, wherein the core model is arranged in the high-pressure sealed container, and the upper and lower end surfaces are sealed, and a drainage channel is arranged between the side wall of the core model and the inner wall of the high-pressure sealed container;

[0011] The core model includes a reservoir contaminated zone, a reservoir uncontaminated zone and a perforation compaction zone model, wherein the reservoir uncontaminated zone is sleeved outside the reservoir contaminated zone, the wellbore is vertically arranged in the reservoir contaminated zone, and the upper and lower ends are sealed, the wellbore sidewall is provided with an injection hole, the perforation compaction zone model is horizontally arranged in a high-pressure sealed container and connected to the outer wall of the wellbore, and the perforation compaction zone model includes a perforation hole communicating with the injection hole and a perforation compaction zone located around the perforation hole;

[0012] The permeabilities of the perforation compaction zone, the reservoir contamination zone and the reservoir uncontaminated zone increase in sequence;

[0013] The pressure and strain measurement system comprises an optical cable and a distributed optical fiber strain sensor demodulator, wherein the optical cables are vertically arranged in a high-pressure sealed container at intervals, and both ends of the optical cable extend out of the high-pressure sealed container, and the optical cables are connected end to end and connected to a distributed optical fiber strain sensor demodulator arranged outside the high-pressure sealed container;

[0014] The injection system includes an outflow pipeline, a water storage tank, an inflow pipeline, a water injection pump, a flow meter, an outlet pressure sensor and an inlet pressure sensor, wherein the water storage tank, the water injection pump and the inflow pipeline are connected in sequence, the outflow pipeline is connected to a drainage channel, the inflow pipeline is connected to an upper inlet of a wellbore, an outlet pressure sensor is arranged on the outflow pipeline, and an inlet pressure sensor and a flow meter are arranged on the inflow pipeline. The present invention seals the core model in a high-pressure sealed container and the upper and lower ends of the wellbore, and sets a drainage channel between the side wall of the core model and the inner wall of the high-pressure sealed container. In the sealed high-pressure sealed container, water is injected into the wellbore by pressurizing, thereby ensuring that the injected water diffuses radially along the core model to simulate the actual water injection process.

[0015] Preferably, the perforation compaction zone model is located in the reservoir contamination zone, and the radial length of the perforation hole along the wellbore is smaller than the radial width of the reservoir contamination zone along the wellbore, so as to simulate the core model under the perforation completion without penetrating the contamination zone.

[0016] Preferably, the perforation compaction zone model of the present invention is located within the reservoir contamination zone and the reservoir uncontaminated zone, and the radial length of the perforation hole along the wellbore is greater than the radial width of the reservoir contamination zone along the wellbore, so as to simulate the core model of perforation completion penetrating the contaminated zone.

[0017] Preferably, the two adjacent optical cables are connected by an optical fiber connecting line, and the optical fiber connecting line is used to connect the two optical cables together to ensure signal transmission.

[0018] Preferably, the present invention further comprises a lower sealing rubber pad and an upper sealing rubber pad;

[0019] The lower sealing rubber pad is arranged at the bottom of the high pressure sealing container;

[0020] The upper sealing rubber pad is arranged on the top of the high-pressure sealing container;

[0021] The upper and lower ends of the reservoir contaminated zone, the reservoir uncontaminated zone and the wellbore are respectively sealed with the lower sealing pad and the upper sealing pad, and the lower and upper sealing pads are used to seal the reservoir contaminated zone, the reservoir uncontaminated zone and the wellbore at the same time, which is convenient for layout.

[0022] Preferably, the reservoir contaminated zone, reservoir uncontaminated zone and perforation compaction zone models are all formed by mixing and compacting water, cement and quartz sand. Water, cement and quartz sand of different particle sizes are mixed and compacted according to a set ratio to simulate reservoir contaminated zone, reservoir uncontaminated zone and perforation compaction zone models with different permeabilities.

[0023] Preferably, the outflow pipeline is connected to a water storage tank. The outflow pipeline is connected to the water storage tank to realize the circulation of water injection and enable repeated experiments with different flow rates.

[0024] Preferably, the outlet pressure sensor and the inlet pressure sensor are located at the same height. The outlet pressure sensor and the inlet pressure sensor are arranged in parallel to overcome the gravity pressure difference and ensure that the two pressure sensors use the same reference position when measuring.

[0025] The present invention also discloses a method for testing energy consumption in the vicinity of a water injection well, using the above-mentioned system for testing energy consumption in the vicinity of a water injection well, comprising the following steps:

[0026] S1. Build an energy consumption experimental system near the injection well;

[0027] S2. Start the distributed optical fiber strain sensor demodulator, and locate the measuring point by knocking on the optical cables at the upper and lower ends of the high-pressure sealed container respectively. Part of the optical cable is inside the model, and part is outside the model. The experiment only needs the signal measured in the part inside the model, and all the optical cables are connected together by fusion splicing. Therefore, it is necessary to calibrate the optical cable inside the model, and only take the signal on this part of the optical cable when taking data later. Apply an external force to the optical cable by knocking, and strain will be generated on the optical cable, so that the interface between the internal and external optical cables can be determined.

[0028] S3, start the water injection pump, adjust it to the preset flow rate, start the water injection process, record the pressure values ​​on the outlet pressure sensor and the inlet pressure sensor, and at the same time, the distributed optical fiber strain sensor demodulator collects the pressure and strain values ​​of each point in the core model in real time; the outlet pressure sensor and the inlet pressure sensor mainly record the pressure difference acting on the entire model. Different pressure differences will produce different strains in the model, which is used to study the influence of different pressure differences on strain;

[0029] S4. After completing a water injection volume, the pressure and strain data collected by the distributed optical fiber strain sensor demodulator are exported, and the pressure or strain distribution in the near-wellbore zone in the radial direction of the core model is plotted to obtain the energy consumption distribution law in the near-wellbore zone of the water injection well;

[0030] S5. Change the flow rate, repeat steps S3 and S4, and obtain the energy consumption distribution law of the near-wellbore area of ​​the water injection well under different flow rates.

[0031] Preferably, the present invention adjusts any parameter of the perforation density, perforation diameter, perforation depth, or porosity or permeability of the perforation compaction zone, the porosity or permeability of the reservoir contaminated zone, or the porosity or permeability of the reservoir uncontaminated zone in the energy consumption experimental system of the near-wellbore zone of the water injection well in step S1, and repeats steps S2-S5. By adjusting any parameter of the perforation density, perforation diameter, perforation depth, or porosity or permeability of the perforation compaction zone, the porosity or permeability of the reservoir contaminated zone, or the porosity or permeability of the reservoir uncontaminated zone in the energy consumption experimental system of the near-wellbore zone of the water injection well, the pressure response characteristics of the near-wellbore zone under different completion methods (i.e., different perforation densities, perforation diameters, perforation depths), different degrees of contamination, and different reservoir rock particle shapes and particle sizes can be simulated.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: the energy consumption experimental system for the near-wellbore zone of the water injection well constructed by the present invention can reproduce the characteristics of the perforation completion and the reservoir contamination zone, truly simulate the radial flow process of water drive, obtain the law of pressure change, and provide support for evaluating the main control factors affecting water injection energy consumption. The embedded distributed optical fiber pressure and strain sensing technology used in the present invention can not only measure the pressure transmitted by the reservoir liquid, but also measure the pressure transmitted by the compression or expansion of the rock skeleton, realize the real-time monitoring of energy changes in the reservoir under different water injection methods, and provide a new means for studying water injection strategies and energy consumption evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the energy consumption experimental system of the near-wellbore zone of the water injection well according to the present invention;

[0034] Figure 2 For the present invention Figure 1The cross-sectional view of the energy consumption experimental system in the near-wellbore area of ​​the water injection well along C-C' is shown;

[0035] Figure 3 It is a schematic diagram of the pressure change in the radial direction of the near-wellbore zone where the perforation completion does not penetrate the contaminated zone measured by the optical cable in Example 1 of the present invention;

[0036] Figure 4 It is a schematic diagram of the pressure change in the radial direction of the near-wellbore zone when the perforation completion penetrates the contaminated zone measured by the optical cable in Example 2 of the present invention;

[0037] In the figure, 1 high pressure sealed container, 2 core model, 3 wellbore, 31 injection hole, 4 drainage channel;

[0038] 21 reservoir contaminated zone, 22 reservoir uncontaminated zone, 23 perforation compaction zone model, 231 perforation holes, 232 perforation compaction zone;

[0039] 5 optical cables, 51 optical fiber connecting lines, 6 distributed optical fiber strain sensor demodulators;

[0040] 7 outflow pipeline, 8 water storage tank, 9 inflow pipeline, 10 water injection pump, 11 flow meter, 12 outlet pressure sensor, 13 inlet pressure sensor;

[0041] 100 lower sealing gasket, 200 upper sealing gasket. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings.

[0043] like Figure 1 and Figure 2 As shown, an energy consumption experimental system for the near-wellbore area of ​​a water injection well includes a reservoir simulation system, an injection system, and a pressure and strain measurement system.

[0044] The reservoir simulation system includes a high-pressure sealed container 1, a core model 2 and a wellbore 3. The core model 2 is arranged in the high-pressure sealed container 1, and the upper and lower end faces are sealed. An annular drainage channel 4 is arranged between the side wall of the core model 2 and the inner wall of the high-pressure sealed container 1. The core model 2 is used to simulate the reservoir structure.

[0045] The core model 2 includes a reservoir contaminated zone 21, a reservoir uncontaminated zone 22 and a perforation compaction zone model 23. The reservoir uncontaminated zone 22 is sleeved on the outside of the reservoir contaminated zone 21. The wellbore 3 is vertically arranged in the reservoir contaminated zone 21, and the upper and lower ends are sealed, that is, the reservoir uncontaminated zone 22 and the reservoir contaminated zone 21 are sequentially sleeved on the outside of the wellbore 3 from the inside to the outside along the radial direction of the wellbore 3. The side wall of the wellbore 3 is radially provided with an injection hole 31. The perforation compaction zone model 23 is horizontally arranged in the high-pressure sealed container 1 along the radial direction of the wellbore 3 and connected to the outer wall of the wellbore 3. The perforation compaction zone model 23 includes a perforation hole 231 communicating with the injection hole 31 and a perforation compaction zone 232 located around the perforation hole 231.

[0046] The permeabilities of the perforation compaction zone 232, the reservoir contamination zone 21 and the reservoir uncontaminated zone 22 increase in sequence.

[0047] The high pressure sealed container 1, the reservoir contaminated zone 21 and the reservoir uncontaminated zone 22 are cylindrical in shape, which is convenient for applying pressure and can also simulate a circular formation.

[0048] Specifically, the wellbore 3 is made of a hollow steel pipe. According to the required perforation density and perforation aperture, a hole 31 is drilled on the wall of the hollow steel pipe with a drill to simulate the holes on the casing body; the wellbore 3 is closely matched with the reservoir contamination zone 21. The reservoir contamination zone 21 is a hollow cylinder, in which the diameter of the hollow hole is equal to the outer diameter of the wellbore 3. The reservoir contamination zone 21 is made of water, cement and quartz sand of a certain particle size mixed and compacted in a certain proportion according to the permeability or porosity requirements required by the experiment.

[0049] The reservoir contamination zone 21 is arranged with perforation holes 231 from top to bottom according to the position of the injection hole 31. The arrangement number, position and orientation of the perforation holes 231 are consistent with the arrangement number, position and orientation of the injection holes 31 on the wellbore 3. The hole diameter at the inlet end of the perforation hole 231 is equal to the diameter of the injection hole 31 on the wellbore 3.

[0050] The perforation hole 231 is cylindrical or truncated cone shaped.

[0051] The perforation holes 231 are surrounded by a perforation compaction zone 232 , and the outside of the perforation compaction zone 232 is closely connected to the reservoir contamination zone 21 .

[0052] The perforation compaction zone model 23 is made by mixing and compacting water, cement and quartz sand of a certain particle size in a certain proportion according to the permeability or porosity requirements of the perforation compaction zone 232, and its permeability or porosity is smaller than that of the reservoir contamination zone 21.

[0053] The perforation compaction zone model 23 needs to be prefabricated in advance according to the shape and size of the determined perforation holes 231 before the reservoir contamination zone 21 is manufactured.

[0054] The reservoir uncontaminated zone 22 is a hollow cylinder, wherein the diameter of the hollow holes is equal to the outer diameter of the reservoir contaminated zone 21 .

[0055] The uncontaminated zone 22 of the reservoir is made by mixing and compacting water, cement and quartz sand of a certain particle size in a certain proportion according to the permeability or porosity requirements of the experiment, and its permeability or porosity is greater than that of the contaminated zone 21 of the reservoir.

[0056] The high-pressure sealed container 1 is a hollow cylindrical structure, consisting of three parts: a cylinder, an upper cover and a lower cover. The upper cover, the lower cover and the cylinder are tightly connected and sealed by bolts; the upper cover and the lower cover are symmetrically provided with lead-out ports for the optical cable 5; the inner diameter of the high-pressure sealed container 1 is larger than the outer diameter of the uncontaminated zone 22 of the reservoir to form a drainage channel 4 to ensure that the injected water flows radially out from all sides in the formation.

[0057] The pressure and strain measurement system includes an optical cable 5 and a distributed optical fiber strain sensor demodulator 6. The specific model of the distributed optical fiber strain sensor demodulator 6 is a PA-OFDR distributed optical fiber strain sensor demodulator. The optical cables 5 are vertically arranged in a high-pressure sealed container 1 at intervals. The optical cables 5 are arranged along the extension direction of the perforation holes 231. The two ends of the optical cables 5 extend out of the high-pressure sealed container 1. The optical cables 5 are connected end to end and connected to the distributed optical fiber strain sensor demodulator 6 arranged outside the high-pressure sealed container 1. The pressure and strain measurement system is coupled with the reservoir simulation system through the optical cable 5 to measure the pressure and strain changes during the water injection process. The optical cable 5 is a distributed optical fiber. The distance between the optical cables 5 can be 1 cm, 2 cm, 5 cm, or several cm. It is ensured that the number of optical cables arranged vertically in the model is not less than 10, which is mainly determined according to the model size and the data points required by the user.

[0058] In this embodiment, the reservoir contamination zone 21 is manufactured by stacking layer by layer. During the manufacturing process, the prefabricated perforation compaction zone model 23 is arranged therein according to the set perforation density and perforation orientation. In addition, during the manufacturing process, the optical cable 5 needs to be vertically pre-buried in the model according to the set data collection interval, and the upper and lower ends of the optical cable 5 must exceed the upper and lower end faces of the reservoir contamination zone 21.

[0059] The reservoir uncontaminated zone 22 is manufactured by stacking layer by layer. During the manufacturing process, the optical cable 5 needs to be vertically pre-buried in the model according to the set data collection interval. The upper and lower ends of the optical cable 5 must exceed the upper and lower end surfaces of the reservoir uncontaminated zone 22.

[0060] The energy consumption experimental system for the near-wellbore zone of a water injection well further comprises a lower sealing rubber pad 100 and an upper sealing rubber pad 200 .

[0061] The lower sealing rubber pad 100 is arranged at the bottom of the high-pressure sealed container 1 .

[0062] The upper sealing rubber gasket 200 is arranged on the top of the high-pressure sealed container 1 .

[0063] The reservoir contaminated zone 21, the reservoir uncontaminated zone 22 and the upper and lower ends of the wellbore 3 are sealed and connected to the lower sealing rubber pad 100 and the upper sealing rubber pad 200 respectively.

[0064] Specifically, the lower sealing pad 100 and the upper sealing pad 200 are circular, and their outer diameters are consistent with the inner diameter of the high-pressure sealed container 1. The lower sealing pad 100 and the upper sealing pad 200 are reserved with lead-out ports for the optical cable 5, and their reserved positions are consistent with the reserved positions of the upper cover and the lower cover of the high-pressure sealed container 1 and with the arrangement positions of the optical cable 5 in the reservoir uncontaminated zone 22 and the reservoir contaminated zone 21.

[0065] When assembling the reservoir simulation system, first, place the lower cover of the high-pressure sealed container 1 on the experimental platform, and then place the lower sealing pad 100 thereon, and make the optical cable 5 outlet of the lower sealing pad 100 correspond to the optical cable 1 outlet on the lower cover of the high-pressure sealed container 1; secondly, place the manufactured reservoir contaminated zone 21 on the lower sealing pad 100, and pass the reserved optical cable 5 that exceeds the lower end surface of the reservoir contaminated zone 21 through the lower sealing pad 100 and the lower cover of the high-pressure sealed container 1 in sequence; then, align the hollow part of the reservoir uncontaminated zone 22 with the outside of the reservoir contaminated zone 21 and lower it to sit on the lower sealing pad 100. Similarly, pass the reserved optical cable 5 that exceeds the lower end surface of the reservoir uncontaminated zone 22 through the lower sealing pad 100 and the lower cover of the high-pressure sealed container 1 in sequence; then, place the wellbore 3 into the reservoir The hollow hole of the contaminated zone 21 is inserted into the wellbore 3, and the injection hole 31 on the wall of the wellbore 3 is aligned with the perforation hole 231 in the contaminated zone 21 of the reservoir; then, the cylinder of the high-pressure sealed container 1 is lowered and seated on the lower cover of the high-pressure sealed container 1, surrounding the uncontaminated zone 22 of the reservoir, and forming a drainage channel 4 between the outer diameter of the uncontaminated zone 22 of the reservoir and the cylinder of the high-pressure sealed container 1; then, an upper sealing pad 200 is placed on the upper end face of the model, and the optical cable 5 is led out through the lead-out port; then, the upper cover of the high-pressure sealed container 1 is placed on the upper sealing pad 200, and the optical cable 5 is led out through the lead-out port on the upper cover of the high-pressure sealed container 1; finally, the upper and lower cover bolts of the high-pressure sealed container 1 are tightened, and the lead-out ports of the optical cable 5 on the upper and lower covers are sealed with ferrules to complete the assembly of the entire reservoir model.

[0066] The optical cable 5 led out through the upper and lower covers of the high-pressure sealed container 1 is sequentially fused into a collection optical fiber using an optical fiber connecting line 51, and then connected to a distributed optical fiber strain sensor demodulator 6. The distributed optical fiber strain sensor demodulator 6 can collect the pressure and strain changes at various positions of the reservoir during the water injection process in real time.

[0067] The injection system includes an outflow pipeline 7, a water storage tank 8, an inflow pipeline 9, an injection pump 10, a flow meter 11, an outlet pressure sensor 12 and an inlet pressure sensor 13. The outflow pipeline 7, the water storage tank 8, the injection pump 10 and the inflow pipeline 9 are connected in sequence. The outflow pipeline 7 is connected to the drainage channel 4, and the inflow pipeline 9 is connected to the upper inlet of the wellbore 3 to form a closed-loop flow process. The outflow pipeline 7 is provided with an outlet pressure sensor 12, and the inflow pipeline 9 is provided with an inlet pressure sensor 13 and a flow meter 11.

[0068] Specifically, the water storage tank 8 is connected to the water injection pump 10 through the inflow pipeline 9, a flow meter 11 is installed on the inflow pipeline 9 at the outlet of the water injection pump 10, an inlet pressure sensor 13 is installed on the inflow pipeline 9 close to the inlet of the wellbore 3, and the inflow pipeline 9 is connected to the inlet of the wellbore 3; the outflow pipeline 7 is connected to the bottom of the high-pressure sealed container 1, and an outlet pressure sensor 12 is installed on the outflow pipeline 7 at a position level with the inlet pressure sensor 13, and the outflow pipeline 7 is connected to the water storage tank 8.

[0069] During the water injection process, the water in the water storage tank 8 is introduced into the water injection pump 10 through the inflow pipeline 9, is pressurized by the water injection pump 10, and is measured by the flow meter 11, and then flows into the wellbore 3 through the inflow pipeline 9. At the same time, the pressure is measured by the inlet pressure sensor 13 before entering the wellbore 3; thereafter, the injected water flows through the perforation holes 231, the perforation compaction zone 232, the reservoir contaminated zone 21, and the reservoir uncontaminated zone 22 in sequence, and finally flows back to the water storage tank 8 through the outlet pipeline 7, and the pressure is measured by the outlet pressure sensor 12; in addition, the distributed optical fiber strain sensor demodulator 6 collects the pressure and strain changes at various positions of the reservoir during the water injection process in real time.

[0070] In this embodiment, the perforation compaction zone model 23 is located in the reservoir contamination zone 21, and the radial length of the perforation hole 231 along the wellbore 3 is smaller than the radial width of the reservoir contamination zone 21 along the wellbore 3, and is used to simulate the core model 2 of the perforation completion without penetrating the contamination zone.

[0071] In this embodiment, the energy consumption test system for the near-well zone of a water injection well is used to perform the energy consumption test method for the near-well zone of a water injection well, simulating the water injection process when the perforation completion does not penetrate the contaminated zone. Figure 1 Taking the experimental system shown in FIG. 1 as an example, the method of the simulation experimental system involved in the present invention and its implementation steps are described in detail. The steps are as follows:

[0072] S1. Build an energy consumption experimental system near the injection well.

[0073] Specifically, according to the construction of the energy consumption experimental system for the near-wellbore area of ​​the water injection well of this embodiment, injection water is added into the water storage tank 8.

[0074] S2, start the distributed optical fiber strain sensor demodulator 6, and locate the measuring point by knocking the optical cable 5 at the optical cable outlets on the upper cover and the lower cover of the high-pressure sealed container 1 respectively.

[0075] S3, start the water injection pump 10, adjust it to the preset flow rate, start the water injection process, record the pressure values ​​on the outlet pressure sensor 12 and the inlet pressure sensor 13, and at the same time, the distributed optical fiber strain sensor demodulator 6 collects the pressure and strain values ​​of each point in the core model 2, i.e., the reservoir, in real time.

[0076] S4, after completing a water injection volume, the pressure and strain data collected by the distributed optical fiber strain sensor demodulator 6 are exported, and the pressure or strain distribution in the radial direction near the wellbore in the core model 2 is plotted, such as Figure 3 As shown in Figure 2, the energy consumption distribution law of the near-well area of ​​the injection well is obtained. Figure 3 The “model boundary” in the figure refers to the outer wall of the “uncontaminated reservoir zone”.

[0077] S5. Change the flow rate, repeat steps S3 and S4, and obtain the energy consumption distribution law of the near-wellbore area of ​​the water injection well under different flow rates.

[0078] Adjust any parameter of the perforation density, perforation aperture, perforation depth or porosity or permeability of the perforation compaction zone 232, the porosity or permeability of the reservoir contaminated zone 21 or the porosity or permeability of the reservoir uncontaminated zone 22 in the energy consumption experimental system of the near-wellbore zone of the water injection well in step S1, repeat steps S2-S5, and simulate different core models 2.

[0079] The present invention has the following advantages:

[0080] (1) The experimental device of the present invention uses embedded distributed optical fiber pressure and strain sensing technology to measure the pressure transmitted by the liquid inside the reservoir near the wellbore during water injection and the pressure transmitted due to the compression or expansion of the rock skeleton.

[0081] (2) The present invention proposes an experimental model preparation method based on distributed optical fiber sensing technology and an energy consumption experimental method for the near-wellbore area of ​​an injection well.

[0082] The present invention is applicable to water flooding development, polymer flooding development, chemical flooding development and CCUS.

[0083] Example 2

[0084] The difference from Example 1 is that the perforation compaction zone model 23 is located in the reservoir contaminated zone 21 and the reservoir uncontaminated zone 22, and the radial length of the perforation hole 231 along the wellbore 3 is greater than or equal to the radial width of the reservoir contaminated zone 21 along the wellbore 3, which is used to simulate the core model 2 of the perforation completion penetrating the contaminated zone.

[0085] The energy consumption experimental method of the near-wellbore zone of the water injection well in this implementation simulates the water injection process of perforating and completing the well to penetrate the contaminated zone, and adopts the same steps as implementation 1, except that the length of the perforation hole 231 in step S1 along the radial direction of the wellbore 3 exceeds the length of the reservoir contamination zone 21 model in the radial direction.

[0086] After completing a water injection volume, the pressure and strain data collected by the distributed optical fiber strain sensor demodulator 6 are exported to draw the core model 2, that is, the pressure or strain distribution in the near-wellbore area in the radial direction of the reservoir, such as Figure 4 As shown, the energy consumption distribution law of the area near the wellbore of the water injection well is obtained; the flow rate is changed, and steps S3 and S4 are repeated to obtain the energy consumption distribution law of the area near the wellbore of the water injection well under different flow rates.

Claims

1. An energy consumption experimental system for the near-well zone of a water injection well, characterized in that: Including reservoir simulation system, injection system and pressure and strain measurement system; The reservoir simulation system comprises a high-pressure sealed container (1), a core model (2) and a wellbore (3); the core model (2) is arranged in the high-pressure sealed container (1), and the upper and lower end surfaces are sealed; a drainage channel (4) is arranged between the side wall of the core model (2) and the inner wall of the high-pressure sealed container (1); The water injection well near-well zone energy consumption experimental system further comprises a lower sealing rubber pad (100) and an upper sealing rubber pad (200); The lower sealing rubber pad (100) is arranged at the bottom of the high-pressure sealed container (1); The upper sealing rubber pad (200) is arranged on the top of the high-pressure sealed container (1); The core model (2) comprises a reservoir contaminated zone (21), a reservoir uncontaminated zone (22) and a perforation compaction zone model (23); the reservoir uncontaminated zone (22) is sleeved on the outside of the reservoir contaminated zone (21); the wellbore (3) is vertically arranged in the reservoir contaminated zone (21) and sealed at both ends; an injection hole (31) is arranged on the side wall of the wellbore (3); the perforation compaction zone model (23) is horizontally arranged in the high-pressure sealed container (1) and connected to the outer wall of the wellbore (3); the perforation compaction zone model (23) comprises a perforation hole (231) communicating with the injection hole (31) and a perforation compaction zone (232) located around the perforation hole (231); The reservoir contaminated zone (21), the reservoir uncontaminated zone (22) and the upper and lower ends of the wellbore (3) are respectively sealed and connected to a lower sealing rubber pad (100) and an upper sealing rubber pad (200); The permeabilities of the perforation compaction zone (232), the reservoir contamination zone (21), and the reservoir uncontaminated zone (22) increase in sequence; The pressure and strain measurement system comprises an optical cable (5) and a distributed optical fiber strain sensor demodulator (6), wherein the optical cables (5) are arranged vertically in a high-pressure sealed container (1) at intervals from each other, and both ends of the optical cable (5) are arranged to extend out of the high-pressure sealed container (1), and the optical cable (5) is connected end to end and connected to the distributed optical fiber strain sensor demodulator (6) arranged outside the high-pressure sealed container (1); Two adjacent optical cables (5) are connected using an optical fiber connecting line (51); The injection system comprises an outflow pipeline (7), a water storage tank (8), an inflow pipeline (9), an injection pump (10), a flow meter (11), an outlet pressure sensor (12) and an inlet pressure sensor (13); the water storage tank (8), the injection pump (10) and the inflow pipeline (9) are connected in sequence; the outflow pipeline (7) is connected to the drainage channel (4); the inflow pipeline (9) is connected to the upper inlet of the wellbore (3); the outflow pipeline (7) is provided with an outlet pressure sensor (12); and the inflow pipeline (9) is provided with an inlet pressure sensor (13) and a flow meter (11).

2. The energy consumption experimental system for the near-wellbore area of ​​a water injection well according to claim 1 is characterized by: The perforation compaction zone model (23) is located within the reservoir contamination zone (21), and the length of the perforation hole (231) along the radial direction of the wellbore (3) is smaller than the width of the reservoir contamination zone (21) along the radial direction of the wellbore (3).

3. The energy consumption experimental system for the near-wellbore area of ​​a water injection well according to claim 1 is characterized in that: The perforation compaction zone model (23) is located within the reservoir contamination zone (21) and the reservoir uncontaminated zone (22), and the length of the perforation hole (231) along the radial direction of the wellbore (3) is greater than the width of the reservoir contamination zone (21) along the radial direction of the wellbore (3).

4. The energy consumption experimental system for the near-wellbore area of ​​a water injection well according to claim 1 is characterized in that: The reservoir contaminated zone (21), the reservoir uncontaminated zone (22) and the perforation compaction zone model (23) are all made by mixing and compacting water, cement and quartz sand.

5. The energy consumption experimental system for the near-wellbore area of ​​a water injection well according to claim 1 is characterized by: The outflow pipeline (7) is connected to the water storage tank (8).

6. The energy consumption experimental system for the near-wellbore area of ​​a water injection well according to claim 1 is characterized by: The outlet pressure sensor (12) and the inlet pressure sensor (13) are located at the same height.

7. A method for testing energy consumption near the wellbore of a water injection well, using the system for testing energy consumption near the wellbore of a water injection well as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Build an energy consumption experimental system near the injection well; S2, starting the distributed optical fiber strain sensor demodulator (6), and positioning the measuring point by knocking on the optical cables (5) at the optical cable outlets at the upper and lower ends of the high-pressure sealed container (1) in sequence; S3, starting the water injection pump (10), adjusting it to a preset flow rate, starting the water injection process, recording the pressure values ​​on the outlet pressure sensor (12) and the inlet pressure sensor (13), and at the same time, the distributed optical fiber strain sensor demodulator (6) collects the pressure and strain values ​​of each point in the core model (2) in real time; S4. After completing a water injection volume, the pressure and strain data collected by the distributed optical fiber strain sensor demodulator (6) are exported, and the pressure or strain distribution in the near-wellbore zone in the radial direction of the core model (2) is plotted to obtain the energy consumption distribution law in the near-wellbore zone of the water injection well; S5. Change the flow rate, repeat steps S3 and S4, and obtain the energy consumption distribution law of the near-wellbore area of ​​the water injection well under different flow rates.

8. The energy consumption test method for the near-wellbore zone of a water injection well according to claim 7 is characterized by: The perforation density, perforation diameter, perforation depth, porosity or permeability of the perforation holes (231) or the perforation compaction zone (232) in the energy consumption experimental system for the near-wellbore zone of the water injection well in step S1, the porosity or permeability of the reservoir contaminated zone (21), or the porosity or permeability of the reservoir uncontaminated zone (22) are adjusted, and steps S2-S5 are repeated.

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