Sand box physical simulation device for simulating petroleum migration under different geological conditions

Abstract

The invention discloses a sand box physical simulation device for simulating petroleum migration under different geological conditions, and relates to the technical field of physical simulation. The device comprises a sand box, an experimental sand body is arranged in the sand box, the sand box comprises a top plate, a bottom plate and four side plates, the top plate and the bottom plate are each provided with a limiting groove, the limiting grooves comprise two sets of transversely-arranged first sliding grooves and two sets of longitudinally-arranged second sliding grooves, intersection points are arranged between the first sliding grooves and the second sliding grooves adjacent to the first sliding grooves, and the intersection points are perpendicular to the first sliding grooves and the second sliding grooves. The first sliding groove and the second sliding groove are each provided with at least two sub-sliding grooves. The side plates are telescopic plates, the two ends, close to the top plate and the bottom plate, of each side plate are each provided with a set of universal wheels, and the universal wheels are arranged in the limiting grooves and can slide along the limiting grooves. And pressurizing driving devices are arranged on at least two side plates. The device can simulate the crude oil migration path in the extrusion or tensile evolution process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of physical simulation technology, in particular to a sand box physical simulation device for simulating oil migration under different geological conditions. BACKGROUND

[0002] A large number of fractures are generated in sedimentary basins due to tectonic activity and fluid overpressure. These natural fractures are important factors affecting oil and gas exploration and development. Fractures in conventional oil and gas cap rocks and shale oil and gas top and bottom plates affect the preservation conditions of oil and control the enrichment layer and scale of oil. The development of fractures in reservoirs determines the porosity and permeability of the reservoirs, which has an important influence on productivity. Many oil and gas reservoirs with well-developed fractures are classified as fractured oil and gas reservoirs. In addition, when selecting the site of a gas storage and storing CO2, fractures are particularly important as possible paths for pollutants to diffuse from the reservoir to the outside.

[0003] At present, scholars at home and abroad have conducted a lot of research on the development law, connectivity and prediction method of natural fractures using field outcrops, core data, logging data and seismic data. Various sand box simulation devices for simulating fracture development have been designed, and different fracture connectivity evaluation methods have been proposed. However, these devices have very simple functions and are only used for simple simulation in sand boxes under fixed boundary conditions, and cannot simulate the migration path of oil in fractured formations under the background of real extrusion or tension tectonic evolution. Therefore, it is urgent to carry out physical simulation of the migration path of oil in fractured formations under different pressure conditions and different tectonic backgrounds. At present, there is no sand box device that can achieve such simulation at home and abroad. Based on the need for geological problems such as oil and gas exploration, physical simulation of the migration path of oil in fractured formations under different pressure conditions and different tectonic backgrounds is becoming more and more urgent. SUMMARY

[0004] To solve at least one of the above problems, the present application provides a sand box physical simulation device for simulating oil migration under different geological conditions.

[0005] The technical scheme of the present application is as follows: a sand box physical simulation device for simulating oil migration under different geological conditions, comprising a sand box, an experimental sand body is arranged in the sand box, the sand box comprises a top plate, a bottom plate and four side plates, a limiting groove is arranged on the top plate and the bottom plate, the limiting groove comprises two groups of first sliding grooves arranged transversely and two groups of second sliding grooves arranged longitudinally, an intersection is arranged between adjacent first sliding grooves and second sliding grooves, and at least two sub-sliding grooves are arranged in the first sliding grooves and the second sliding grooves; the side plates are telescopic plates, a group of universal wheels is arranged at both ends of each side plate close to the top plate and the bottom plate, the universal wheels are arranged in the limiting groove and can slide along the limiting groove; a pressurizing driving device is arranged on at least two side plates.

[0006] In one embodiment of the present invention, when the caster slides in the first or second slide groove, all the casters on the side plate slide in the same direction.

[0007] In one embodiment of the present invention, the limiting groove further includes two sets of obliquely arranged third sliding grooves, the two ends of the third sliding grooves passing through two opposite intersection points; the third sliding grooves are provided with two sub-sliding grooves.

[0008] Furthermore, multiple detachable sand-blocking strips that match the sub-slide groove are provided. These detachable sand-blocking strips can be embedded in the sub-slide groove to prevent sand from entering the interior of the sub-slide groove.

[0009] Furthermore, when the omnidirectional wheel slides in the third groove, the sliding direction of the omnidirectional wheel is towards the center of the base plate or away from the center of the base plate.

[0010] In one embodiment of the present invention, two adjacent side plates are fixed together by a snap fastener, a fixing rod is provided between the top plate and the bottom plate, and sealing strips are provided between two adjacent side plates, between the top plate and the side plates, and between the bottom plate and the side plates.

[0011] In one embodiment of the present invention, the side plate includes fixed plates at both ends and a movable plate between the fixed plates. An elastic element is provided between the movable plate and the fixed plate. At least two extended protective plates are provided at one end of the fixed plate facing the movable plate. The extended protective plates and the fixed plates form a semi-closed cavity. One end of the movable part and the elastic element are both located inside the semi-closed cavity.

[0012] Furthermore, the pressure-driving device is a hydraulic drive device, which applies pressure to the fixed plate.

[0013] One embodiment of the present invention is that the bottom plate is provided with a plurality of oil injection ports, at least one of the oil injection ports is connected in sequence to an oil injection pump and an oil storage tank, any side plate is provided with a pressurization drive device, and the top plate is provided with a plurality of sensors, the sensors being used to detect whether there is oil in the sand body.

[0014] One embodiment of the present invention is that a crack strain sensing system is also provided inside the experimental sand body. The crack strain sensing system consists of a strain sensor and an acoustic emission probe, which is used to capture the strain changes of the crack in real time.

[0015] Beneficial effects: This invention provides a sandbox physical simulation device that can simulate the migration path of crude oil in fractured strata under different geological conditions according to actual geological conditions.

[0016] The present application can realize simulation of oil migration path in fractured formation under different geological conditions by adjusting the driving device and the overpressure loading system. The simulation of oil migration path under stable geological conditions with constant stress conditions can be completed in one test condition, and the simulation of oil migration path in the process of extrusion or stretching evolution can be realized by controlling the movement of the telescopic side plate during the test. At the same time, the simulation under fixed fluid pressure condition can be carried out, and the simulation of oil migration path in the process of pressure evolution can be realized by adjusting the pressure during the test. At the same time, before the test starts, different density, different occurrence, different opening and length of the fractures can be inserted into the formation to reflect the characteristics of the real fractured formation. The strain change of the fracture is monitored in real time by the fracture strain sensing system to provide data for the later analysis of the oil migration path. The simulation device can greatly improve the diversity and contrast of the simulation, so that the experimental data is more abundant, and has the characteristics of economy, model diversification and multifunction. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the device of the present embodiment; Figure 2 It is a perspective structural schematic diagram of the sand box of the present embodiment; Figure 3 It is a structural schematic diagram of the first sliding groove and the second sliding groove on the bottom plate being continuous sliding grooves; Figure 4 It is a structural schematic diagram of the first sliding groove and the second sliding groove on the bottom plate being non-continuous sliding grooves; Figure 5 It is a structural schematic diagram of the first sliding groove, the second sliding groove and the third sliding groove being provided on the bottom plate; Figure 6 It is a structural schematic diagram of the side plate; Figure 7 It is a sectional view of the side plate.

[0018] In the figure, 1 is a sand box, 2 is an oil storage tank, 3 is a control computer, 4 is a buckle, 5 is a placing table, 6 is an oil injection hole, and 7 is a pressure driving device; 101 is a side plate, 102 is a top plate, 103 is a bottom plate, and 104 is a fixed rod; 1011 is a fixed plate, 1012 is a universal wheel, 1013 is a movable plate, 1014 is an elastic member, and 1015 is an extension protection plate; 1031 is a first sliding groove, 1032 is a second sliding groove, 1033 is a sub sliding groove, and 1034 is a third sliding groove. DETAILED DESCRIPTION

[0019] The specific embodiments of the present application will be described below in conjunction with examples and drawings. Obviously, the described examples are only part of the embodiments of the present application, not all.

[0020] As Figures 1-4 shown, a sand box physical simulation device for simulating oil migration under different geological conditions, comprising a sand box 1, the sand box 1 is provided with experimental sand body, the sand box 1 includes top plate 102, bottom plate 103 and four side plates 101, the top plate 102 and the bottom plate 103 are provided with limiting slot, the limiting slot includes two groups of first sliding groove 1031 arranged transversely, two groups of second sliding groove 1032 arranged longitudinally, the adjacent first sliding groove 1031 and second sliding groove 1032 are provided with intersection, and the first sliding groove 1031 and the second sliding groove 1032 are provided with at least two sub-slots 1033; the side plate 101 is a telescopic plate, and the two ends of the side plate 101 close to the top plate 102 and the bottom plate 103 are provided with a group of universal wheels 1012, the universal wheels 1012 are arranged in the limiting slot and can slide along the limiting slot; at least two side plates 101 are provided with pressure driving device 7.

[0021] Specifically, as Figures 1-7 shown, the main improvement point of the embodiment is the sand box 1. The conventional sand box 1 part is only a sealed, non-adjustable box structure, which can be filled with corresponding sand body in use and compacted, and cannot be adjusted in each direction during use. In some existing technologies, four movable side plates are designed, and the four movable side plates can be individually pressurized, combined with the top plate and the bottom plate, so that the stress adjustment in multiple directions can be realized, and further conforms to the actual reservoir conditions. However, in the actual reservoir, there are external forces such as extrusion or stretching when the crude oil migrates, which will have a great influence on the migration of the crude oil, resulting in relatively poor accuracy of the simulation results of the existing device.

[0022] In the embodiment, in order to solve the above problems, a plurality of limiting slots, telescopic side plates 101 and universal wheels 1012 on the side plates 101 are provided to solve the problem.

[0023] For the top plate 102, the bottom plate 103 and the side plate 101, those skilled in the art know that they constitute a complete sand box 1, and for the sand box 1, the inside needs to be sealed to ensure that the oil, water and other fluids flow under a relatively closed condition during the simulation process, and as far as possible to simulate their flow rule in the reservoir. In the embodiment, the same is true: the top plate 102, the bottom plate 103 and the four side plates 104 constitute a complete sand box 1.

[0024] In order to simulate the extrusion force or tensile force suffered by the crude oil during migration, in the embodiment, the four side plates 101 are set as telescopic plates which can be elongated or compressed in the horizontal direction when subjected to external force; in order to make the side plates better simulate extrusion and stretching, in the embodiment, a limiting slot is arranged on the top plate 102 and the bottom plate 103, wherein the limiting slot comprises two groups of first sliding grooves 1031 arranged transversely and two groups of second sliding grooves 1032 arranged longitudinally, and an intersection is arranged between adjacent first sliding grooves 1031 and second sliding grooves 1032. At the same time, the inventor sets a group of universal wheels 1012 on both ends of the side plate 101 close to the top plate 102 and the bottom plate 103, which can be embedded in the first sliding grooves 1031 and the second sliding grooves 1032 and slide, in order to facilitate the application of corresponding force to the side plate 101, a pressing driving device 7 is further arranged on at least two side plates 101, for example, the pressing driving device 7 can be arranged on two side plates 101, three side plates 101 or four side plates 101, when the pressing driving device 7 is arranged on four side plates 101, the force can be applied to the sand body in the sand box 1 from four directions. Of course, those skilled in the art know that the universal wheel 1012 of the embodiment needs to have a locking mechanism, which can be locked when it is not needed to move.

[0025] Through the above setting, as shown in Figure 3 FIG. 7 is a structural schematic view of the bottom plate 103, the first sliding groove 1031 comprises A1 and A2 arranged on the left and right sides, the second sliding groove 1032 comprises B1 and B2 arranged on the upper and lower sides, the first sliding groove 1031 and the second sliding groove 1032 are continuous sliding grooves, wherein A1, A2, B1 and B2 each comprise four groups of sub-sliding grooves 1033, and the four side plates are arranged on A1, A2, B1 and B2 respectively, and the universal wheel 1012 on the side plate 101 is clamped in the sub-sliding groove 1033; when it is needed to compress or stretch the entire sand box 1 along the extension direction of the first sliding groove 1031, the universal wheels 1012 close to A1 on the four side plates 101 are arranged in the sub-sliding grooves 1033 of A1, and the universal wheels 1012 close to A2 on the four side plates 101 are arranged in the sub-sliding grooves 1033 of A2, in this case, when pressure is applied to the side plate 101 arranged on B2 (the same pressure is applied to the side plate 101 arranged on B1 or it is fixed), under the action of the pressure, the side plate 101 arranged on B2 will move to B1, and the side plates 101 arranged on A1 and A2 will contract. The remaining pressing modes have the same working principle.

[0026] In this embodiment, similar to other physical simulation experimental devices, additional components are provided, such as an oil storage tank 2 connected to the sand box 1, and an oil injection pump (not shown in the figure) is also provided between the oil storage tank 2 and the sand box 1. In some cases, to achieve real-time control and monitoring, a control computer 3 is also provided. This control computer 3 is electrically connected to the oil injection pump and other electrical components for real-time monitoring of the simulation. These are all conventional operations in the art, and their specific structures will not be described in detail here.

[0027] Meanwhile, in this embodiment, since sand is provided inside the sand box 1, its side plates 101 cannot be compressed indefinitely; considering the movement of crude oil, the side plates 101 cannot be stretched indefinitely either. Taking into account practical considerations, the inventors have ensured that the maximum compression and maximum stretching length of the side plates 101 does not exceed 30% of their original length, and typically does not exceed 20%. Under such circumstances, neither the first chute 1031 nor the second chute 1032 needs to be configured as a complete chute. Figure 4 As shown, the set chute is a discontinuous chute, which can retain only a part of the chute near the intersection point, and the rest can be set as a flat plate.

[0028] In some implementations, such as Figure 5 As shown, the limiting groove also includes two sets of obliquely arranged third sliding grooves 1034, with the two ends of the third sliding grooves 1034 passing through two opposite intersection points. The third sliding grooves 1034 can be configured with two sub-sliding grooves or one sub-sliding groove 1033; when one sub-sliding groove 1033 is provided, it needs to be able to simultaneously accommodate two universal wheels 1012 arranged in parallel and sliding.

[0029] In this case, in addition to conducting experiments in a single direction or relative to two directions, this device can also conduct experiments under common force in four directions: C1 and C2 are two obliquely arranged sliding grooves. During the experiment, the universal wheels on the side plates are respectively placed in C1 and C2. When pressure is applied to all side plates (or only pressure is applied to two adjacent side plates while the other two side plates remain stationary), all side plates begin to contract towards the center of the sand body.

[0030] In actual use, those skilled in the art will know that, in order to achieve the above functions, the top plate 102 is also provided with the same first slide groove 1031, second slide groove 1032 and third slide groove 1034 as the bottom plate 103.

[0031] In this embodiment, in order to avoid the sand entering the inside of the sub chute 1033 during the experiment, a plurality of detachable sand blocking strips (not shown in the figure) matching the sub chute 1033 are arranged, which can be embedded in the sub chute 1033 to prevent the sand from entering the inside of the sub chute 1033.

[0032] In this embodiment, in order to avoid the sand leaking from the gap between the side plates 101, the adjacent two side plates 101 are fixed by the buckles 4, the top plate 102 and the bottom plate 103 are provided with the fixing rods 104, and the sealing strips are arranged between the adjacent two side plates 101, between the top plate 102 and the side plate 101, and between the bottom plate 103 and the side plate 101. Such arrangement not only ensures the firmness of the connection of the side plates 101, but also ensures that the sand or fluid cannot leak from the gap between the side plates. Of course, the skilled in the art can replace the fixing buckle 4 with a flange or the like.

[0033] In this embodiment, as shown in Figure 6 , Figure 7 The side plate 101 includes the fixed plates 1011 arranged at both ends and the movable plates 1013 arranged between the fixed plates 1011, the elastic members 1014 are arranged between the movable plates 1013 and the fixed plates 1011, at least two extension protection plates 1015 are arranged at one end of the fixed plate 1011 towards the movable plate 1013, the extension protection plate 1015 and the fixed plate 1011 surround a semi-closed chamber, and one end of the movable plate 1013 and the elastic member 1014 are arranged inside the semi-closed chamber. Similar to the conventional design in the art, the movable plate 1013, the fixed plate 1011 and the extension protection plate 1015 are all made of rigid material and have good compression resistance; the elastic member 1014 can be a tension spring, a spring sheet or the like, which is a conventional means in the art.

[0034] In this embodiment, referring to Figures 3-5The bottom plate 103 is provided with a plurality of oil injection openings 6, at least one of which is connected with an oil injection pump and an oil storage tank 2 in sequence, and each side plate 101 is provided with a pressurizing driving device, and the top plate is provided with a plurality of sensors for detecting whether oil exists in the sand body; the sensors meeting the foregoing requirements can be oil leakage sensing ropes, oil leakage detection sensors, oil leakage detection alarms and the like, which are common detection devices in the field. By providing a plurality of oil injection openings 6, the migration of crude oil during multi-angle oil injection can be simulated, so that the simulation result is more abundant and it is easier to provide data for actual production; the sensors on the top plate 102 are mainly used for detecting when and where the crude oil in the sand box 1 reaches the top, and the test can be stopped when one of the sensors detects the crude oil, or the test can be stopped when all the sensors detect the crude oil, and the specific setting can be made according to the requirements in the field.

[0035] In some embodiments, a crack strain sensing system is further arranged inside the experimental sand body, which is composed of a strain sensor and an acoustic emission probe, and is used for capturing the strain change of the crack in real time. The crack strain sensing system is laid in advance before the sand body is pressurized, and in the actual production process, the system can sense the strain change and acoustic emission phenomenon of the crack in real time, so as to analyze the relationship between the crack and the migration of oil and gas.

[0036] For the pressurizing driving device 7 of the present embodiment, its main function is to apply a certain pressure or tension to the side plate 101. In the prior art, many devices can meet this requirement, such as linear motors, combinations of motors and lead screws, hydraulic driving devices and the like, which can all be applied to the present embodiment. In the present embodiment, a hydraulic driving device is selected to pressurize it, and the output end of the hydraulic driving device is arranged on the two fixed plates of the side plate. Those skilled in the art can understand that for the hydraulic driving device, one end is fixed to apply the corresponding pressure.

[0037] Since the sand box 1 has a large volume, in the present embodiment, a placing table 5 is further arranged to facilitate placing the sand box.

[0038] In order to facilitate those skilled in the art to understand the scheme of the present embodiment, a use method of the scheme of the present embodiment is given below, and those skilled in the art should understand that the use method given by the present embodiment is not a limitation on the device.

[0039] Simulation Test Design: Based on the simulation requirements, the material and thickness ratio of the formation are determined. Different lithologies can be simulated using quartz sand, clay, and silica gel with varying particle sizes and friction coefficients. To focus on fracture simulation, epoxy resin can be used to bind the quartz sand, thereby reducing its permeability and preventing crude oil migration along the pores during injection. Furthermore, the test parameters for the drive device and overpressure loading system need to be set according to the actual geological conditions of the simulated area. The drive device requires setting the number of moving sideplates, their trajectory, and their speed. The overpressure loading system requires setting the injection pressure, injection volume, and injection rate.

[0040] Preparation for the simulation test: First, select the style and quantity of detachable sliding sand-proof movable baffle strips according to the side plate movement scheme design in the simulation test, and install them at the corresponding sliding positions on the top and bottom plates. Second, according to the determined stratum thickness ratio, alternately lay epoxy resin-bonded quartz sand and non-permeable strata throughout the sand box to simulate real strata. During the material laying process, simulated cracks are inserted into different material strata. The simulated cracks consist of a pair of plastic sheets or other similar materials with good ductility and resistance to breakage. The plastic sheets have a certain opening in the middle, which can be filled with quartz sand or silica gel with different degrees of bonding. Multiple sets of crack systems with different densities, lengths, openings, and orientations can be set. An integrated fiber optic strain sensor and acoustic emission probe are attached to each crack. To simulate real geological conditions, the laid model needs to be moistened with water. Third, use fixing rods and fixing clips to fix the sand box to ensure its stability during the simulation process. The fourth step is to connect the high-pressure resistant sealing hose of the overpressure loading system to the oil injection port of the bottom plate, fill the oil storage tank with simulated crude oil, and use kerosene with tracer to simulate formation crude oil.

[0041] Simulation test: Simulated crude oil is pressurized using an overpressure loading system and delivered to a high-pressure resistant hose. Once the high-precision pressure gauge at the injection port reaches the predetermined pressure and stabilizes, one or multiple injection ports are opened according to simulation requirements. The number, location, and injection pressure of the injection ports can be adjusted during the simulation as it progresses. During injection, a drive device moves the oil on all four sides to simulate compression or tension within the basin. Simultaneously, real-time data from the crack sensing system is monitored to track stress changes at the cracks. The test stops when the intelligent control system detects an oil spill alarm via a high-sensitivity sensor on the roof.

[0042] The simulation process is ended: the overpressure loading system is closed, the physical simulation test box is opened, the sand body model is shaped using a shaping liquid, the sand body model after shaping is scanned as a whole, the integrated optical fiber strain sensor and the acoustic emission probe are removed after scanning, the sand body model is sliced, observed and photographed, finally the tracer is used to calibrate the crude oil migration path, the fracture strain data are combined to analyze the crude oil migration path in the fractured formation under specific geological conditions.

[0043] The above merely describes preferred embodiments of the present application and is not intended to limit the present application in any form. Although the present application has been disclosed with reference to the preferred embodiments, the present application is not intended to be limited thereto. Any person skilled in the art can make some changes or modifications to the above disclosed technical contents to obtain equivalent embodiments with equivalent changes, as long as the changes or modifications do not depart from the technical solution of the present application. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still falls within the scope of the technical solution of the present application.

Claims

1. A sandbox physical simulation device for simulating oil migration in different geological conditions, characterized in that, The sand box is internally provided with an experimental sand body, and the sand box comprises a top plate, a bottom plate and four side plates, the top plate and the bottom plate are both provided with a limiting groove, the limiting groove comprises two groups of first sliding grooves arranged transversely, two groups of second sliding grooves arranged longitudinally, adjacent first sliding grooves and second sliding grooves are provided with intersection points, and the first sliding grooves and the second sliding grooves are both provided with at least two sub-sliding grooves; the side plates are telescopic plates, and each of the two ends of the side plate close to the top plate and the bottom plate is provided with a group of universal wheels, the universal wheels are arranged in the limiting groove and can slide along the limiting groove; at least two side plates are provided with a pressure driving device.

2. The apparatus of claim 1, wherein, When the universal wheels slide in the first sliding groove or the second sliding groove, the sliding directions of all the universal wheels on the side plate are consistent.

3. The apparatus of claim 1, wherein, The limiting groove further comprises two groups of third sliding grooves arranged obliquely, and the two ends of the third sliding grooves pass through the opposite intersection points.

4. The apparatus of claim 3, wherein, A plurality of detachable sand blocking strips matched with the sub-sliding grooves are further arranged, and the detachable sand blocking strips can be embedded in the sub-sliding grooves to prevent the sand body from entering the inside of the sub-sliding grooves.

5. The apparatus of claim 3, wherein, When the universal wheels slide in the third sliding groove, the sliding direction of the universal wheels is towards or away from the center of the bottom plate.

6. The apparatus of claim 1, wherein, The adjacent two side plates are fixed through buckles, the top plate and the bottom plate are provided with a fixing rod, and a sealing strip is arranged between the adjacent two side plates, between the top plate and the side plate, and between the bottom plate and the side plate.

7. The apparatus of claim 1, wherein, The side plate comprises a fixed plate arranged at two ends and a movable plate arranged between the fixed plates, an elastic member is arranged between the movable plate and the fixed plate, at least two extension protection plates are arranged at one end of the fixed plate towards the movable plate, the extension protection plates and the fixed plate surround a semi-closed chamber, and one end of the movable plate and the elastic member are arranged in the semi-closed chamber.

8. The apparatus of claim 7, wherein, The pressure driving device is a hydraulic driving device, and the hydraulic driving device pressurizes the fixed plate.

9. The apparatus of claim 1, wherein, A plurality of oil injection ports are arranged on the bottom plate, at least one oil injection port is sequentially connected with an oil injection pump and an oil storage tank, a pressure driving device is arranged on any side plate, a plurality of sensors are arranged on the top plate, and the sensors are used for detecting whether there is oil in the sand body.

10. The apparatus of claim 1, wherein, A crack strain sensing system is further arranged in the experimental sand body, the crack strain sensing system is composed of a strain sensor and an acoustic emission probe, and is used for capturing the strain change of the crack in real time.

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