Experimental device and test method for curing and laying performance of phase change proppant

Abstract

The invention belongs to the technical field of oil and gas development, and discloses an experimental device and a test method for curing and laying performance of a phase change proppant. The phase change proppant curing paving performance experiment device comprises a device main body, a piston plate and an elastic piece. A cavity for containing a rock core is formed in the device main body, a plurality of visible windows are formed in the periphery of the device main body, and a liquid outlet pipeline is arranged on the device main body; the piston plate is in sliding connection with the device main body; a liquid inlet pipeline is arranged on the piston plate; and the elastic piece is arranged in the crack or the radial hole of the rock core. The experimental device is simple in overall structure and convenient to use, various testing experiments of the liquid phase change proppant can be completed, and the condition of the liquid phase change proppant can be observed in real time through the visible window. The experimental device is used in the experimental test method, accurate experimental results can be obtained, liquid phase change proppant materials suitable for corresponding reservoirs can be screened out according to specific reservoir conditions, and better guidance is provided for site construction.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas development, and in particular to a phase change proppant solidification paving performance experimental device and a testing method. Background Art

[0002] At present, the development of conventional oil and gas has entered the high water content stage. Unconventional oil and gas resources have huge reserves and are the main force to replace conventional oil and gas and ensure my country's energy security. The geological structure of unconventional oil and gas reservoirs is complex, and the geological exploration and development theories and conventional oil and gas development technologies that have been mastered cannot be fully applied to the development of unconventional oil and gas. The development of unconventional oil and gas requires large-scale hydraulic fracturing to open complex cracks in the formation and fill them with proppants to provide channels for the flow of unconventional oil and gas. Traditional solid proppants have a rigid structure and rely on sand-carrying fluid to carry them into the cracks, but they have problems such as easy sedimentation, short migration distance, and difficulty in entering branch cracks. The complex cracks formed by hydraulic fracturing cannot be effectively supported, which affects the effect of hydraulic fracturing and restricts the development of unconventional oil and gas.

[0003] Liquid phase change proppants have become a research hotspot in recent years due to their good migration ability within fractures and the fact that the proppants can be directly carried by the fracturing fluid without the need for a separate sand-carrying fluid, thereby simplifying the construction process.

[0004] However, there are few experimental devices and related experimental methods for testing liquid phase change proppants. Considering the formation filtration and wall roughness, the influence of reservoir temperature and pressure conditions, rock physical properties and other factors on the liquid-solid conversion ability and pressure bearing capacity of liquid phase change proppants is still unclear. New experimental devices and physical simulation experimental methods are needed to evaluate the important parameters of different types of phase change proppants under different reservoir conditions, optimize the formulation of liquid phase change proppants according to the requirements of on-site construction, provide guidance for the design of on-site fracturing schemes, and improve the application scope of liquid phase change proppants technology. Summary of the invention

[0005] The purpose of the present invention is to provide a phase change proppant solidification paving performance experimental device and a testing method, which is conducive to completing the performance research of the phase change proppant through physical simulation experiments.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] On the one hand, a phase change proppant solidification paving performance experimental device is provided, comprising:

[0008] A device body, wherein a cavity for accommodating a core is arranged in the device body, a plurality of visual windows are arranged on the periphery of the device body, and a liquid outlet pipeline is arranged on the device body;

[0009] A piston plate is slidably connected to the device body, and a liquid inlet pipeline is arranged on the piston plate;

[0010] The elastic member is installed in the crack or radial hole of the core.

[0011] Optionally, a window pressurizing member is further included, and the window pressurizing member is installed outside the visible window and can press-fit the visible window.

[0012] Optionally, the window pressure member includes a plurality of parallel and spaced-apart transverse support rods, and a plurality of vertical support rods vertically connected to the transverse support rods.

[0013] Optionally, the visible window is made of sapphire material.

[0014] On the other hand, a method for testing the curing paving performance of a phase change proppant is provided, using the above-mentioned phase change proppant curing paving performance test device, comprising the following steps:

[0015] Step S1, making a core according to the site conditions;

[0016] Step S2, installing the manufactured core into the device body, and placing the elastic member into the crack or radial hole of the core;

[0017] Step S3, pushing the piston plate into the device body;

[0018] Step S4, injecting phase-change proppant from the liquid inlet pipeline, and stopping when the phase-change proppant flows out of the liquid outlet pipeline, and closing the liquid inlet pipeline and the liquid outlet pipeline to make the device body in a sealed state;

[0019] Step S5, performing phase change proppant performance test.

[0020] Optionally, the phase change proppant performance test includes: testing the solidification, sedimentation and accumulation of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions; including the following steps:

[0021] Step S61, using computer control to start the true triaxial pressure chamber and adjust it according to the reservoir temperature and pressure conditions;

[0022] Step S62, placing the phase change proppant under pressure according to the curing time required;

[0023] Step S63, during the static process, the solidification, sedimentation and accumulation of the phase change proppant are recorded in full through the visual window;

[0024] Step S64: Take out the core and crush it to check the solidification and accumulation of the liquid phase-change proppant in the multi-level branch fractures.

[0025] Optionally, the phase change proppant performance test includes: a liquid-solid conversion rate test of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions; comprising the following steps:

[0026] Step S71, using computer control to start the true triaxial pressure chamber and adjust it according to the reservoir temperature and pressure conditions;

[0027] Step S72, placing the phase change proppant under pressure according to the curing time required;

[0028] Step S73, opening the device body to take out the phase change proppant together with the core, the total mass of the injected phase change proppant is M, the core is crushed to take out the solidified spherical phase change proppant, and the mass of the spherical phase change proppant is measured to be M1;

[0029] Step S74, calculating the liquid-to-solid conversion rate M1 / M of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions.

[0030] Optionally, the phase change proppant performance test includes: a pressure bearing capacity test of the phase change proppant under different reservoir temperature and pressure conditions; comprising the following steps:

[0031] Step S81, using computer control to start the true triaxial pressure chamber and adjust it according to the reservoir temperature and pressure conditions;

[0032] Step S82, placing the phase change proppant under pressure according to the curing time required;

[0033] Step S83, after the phase change of the phase change proppant is completed, the true triaxial pressure chamber is started by the computer, and the pressure is increased to 20MPa, 30MPa, and 4MPa respectively, and the pressure is released after maintaining for a period of time;

[0034] Step S84: During the pressurization process, the fractures are recorded through the visual window. After the pressurization is completed, the embedding of the liquid phase-change proppant is observed through the video, and the core is crushed to check the crushing of the phase-change proppant.

[0035] Optionally, the phase change proppant performance test includes: evaluation of the use effect of the phase change proppant under the temperature and pressure conditions of the marine natural gas hydrate reservoir; including the following steps:

[0036] Step S91, before injecting the phase change proppant, inject the prepared tetrahydrofuran aqueous solution from the front end according to the hydrate saturation requirement, and use computer control to start the true triaxial pressure chamber, so that the internal temperature of the device body is maintained at 1°C, and let it stand for 24 hours to ensure that the hydrate is completely generated;

[0037] Step S92, after injecting the phase change proppant, let it stand for a solidification time required by the phase change proppant;

[0038] Step S93: During the static period, the fracture is recorded through the visual window, and after the phase change is completed, the solidification, sedimentation, accumulation and embedding of the liquid phase change proppant are observed through the video.

[0039] Optionally, the cracks in the core include any one of horizontal cracks, vertical cracks and multi-level branch cracks.

[0040] Beneficial effects of the present invention:

[0041] The phase change proppant solidification and paving performance experimental device has a simple overall structure and is easy to use. It can complete a variety of test experiments on liquid phase change proppants and observe the phase change, sedimentation, accumulation, and embedding of liquid phase change proppants through a visual window. Furthermore, formation rock blocks or rock blocks made according to formation physical properties are used to simulate formation conditions, making the experimental results more accurate and more meaningful for reference, which can provide better guidance for on-site construction.

[0042] The above experimental device is used in the experimental test method of phase change proppant curing and laying performance. This method can obtain more accurate experimental results, can screen out liquid phase change proppant materials suitable for the corresponding reservoir according to specific reservoir conditions, and can provide better guidance for on-site construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic structural diagram of the phase change proppant solidification and paving performance experimental device described in an embodiment of the present invention.

[0044] In the figure:

[0045] 1. Device body; 11. Visual window; 2. Piston plate; 21. Liquid inlet pipeline; 3. Elastic part; 4. Window pressure part; 41. Horizontal support rod; 42. Vertical support rod; 100. Core. DETAILED DESCRIPTION

[0046] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar parts or parts having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0047] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, it can be a mechanical connection or an electrical connection, it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the description of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0049] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0050] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0051] like Figure 1 As shown, the present invention provides a phase change proppant solidification paving performance experimental device, including a device body 1, a piston plate 2 and an elastic member 3. A cavity for accommodating a core 100 is provided in the device body 1, and a plurality of visual windows 11 are provided on the periphery of the device body 1. Optionally, the visual windows 11 are made of sapphire material, which has high hardness, high temperature resistance and good chemical stability. The experimenter can observe the phase change, sedimentation, accumulation and embedding of the liquid phase change proppant through the visual window 11. In addition, a liquid outlet pipeline (not shown in the figure) for the phase change proppant to flow out is provided on the device body 1. The piston plate 2 is slidably connected to the device body 1, and a liquid inlet pipeline 21 is arranged on it. The phase change proppant can flow out through the liquid inlet pipeline 21 and the liquid outlet pipeline. The elastic member 3 is installed in the cracks or radial holes of the core 100. Specifically, it is compressed and placed in the cracks or radial holes of the core 100 to ensure that the cores 100 on both sides do not move before the phase change proppant is injected, and to ensure that the cracks in the middle of the core 100 or the simulated radial holes are not closed before the phase change proppant is injected.

[0052] Optionally, the phase change proppant solidification paving performance experimental device further includes a window pressurizing member 4, which is installed outside the visible window 11 and can press the visible window 11. It can be understood that the present application installs the window pressurizing member 4 outside the visible window 11 to prevent the visible window 11 from being broken due to excessive internal pressure of the device body 1 during the experiment.

[0053] Optionally, the window pressure member 4 of this embodiment includes a plurality of parallel and spaced horizontal support rods 41 , and a plurality of vertical support rods 42 vertically connected to the horizontal support rods 41 , and the horizontal support rods 41 and the vertical support rods 42 intersect to form a grid-like pressurized visual window 11 .

[0054] The phase change proppant curing and laying performance experimental device has a simple overall structure and is easy to use. The visual window 11 allows the experimenter to check the experimental status in the device body 1 at any time. The liquid phase change proppant formula can be optimized according to the on-site construction requirements, providing guidance for the on-site fracturing program design and improving the application scope of liquid phase change proppant technology.

[0055] Based on the above phase change proppant curing paving performance experimental device, this embodiment proposes a phase change proppant curing paving performance experimental test method, which is completed using the above phase change proppant curing paving performance experimental device, including the following steps:

[0056] Step S1, manufacturing the core 100 according to the on-site requirements. Optionally, the core 100 has horizontal seams, vertical seams, multi-level branch seams and radial holes, which are selected and manufactured according to actual needs.

[0057] Step S2, installing the manufactured core 100 in the device body 1, and placing the elastic member 3 into the crack or radial hole of the core 100;

[0058] Step S3, pushing the piston plate 2 into the device body 1;

[0059] Step S4, injecting phase-change proppant from the liquid inlet pipeline 21, and stopping when the phase-change proppant flows out of the liquid outlet pipeline, and closing the liquid inlet pipeline 21 and the liquid outlet pipeline to put the device body 1 in a sealed state;

[0060] Step S5, performing phase change proppant performance test.

[0061] Exemplarily, the performance test of the phase change proppant of this embodiment includes at least the following four tests: 1) testing the solidification, sedimentation and accumulation of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions; 2) testing the liquid-solid conversion rate of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions; 3) testing the pressure bearing capacity of the phase change proppant under different reservoir temperature and pressure conditions; 4) evaluating the use effect of the phase change proppant under the temperature and pressure conditions of the marine natural gas hydrate reservoir.

[0062] For example, based on the above steps S1 to S4, in the test of solidification, sedimentation and accumulation of phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions, the following steps are specifically included:

[0063] Step S61: After the phase change proppant is injected and the device body 1 is in a sealed state, a true triaxial pressure chamber is started by computer control. The pressure chamber has a built-in circulating refrigeration device and an electric heating device, which are common devices in the field and can be adjusted according to the temperature and pressure conditions of the reservoir;

[0064] Step S62, placing the phase change proppant under pressure according to the curing time required;

[0065] Step S63, during the static process, the solidification, sedimentation and accumulation of the phase change proppant are recorded in full through the visual window 11;

[0066] Step S64, take out the core 100 and crush it to check the solidification and accumulation of the liquid phase change proppant in the multi-level branch fractures. The liquid phase change proppant material suitable for the corresponding reservoir can be screened according to specific reservoir conditions, and the solidification, sedimentation and accumulation process of the liquid phase change proppant under the reservoir lithology and temperature and pressure conditions can be recorded, so that the position where solidification first occurs in the entire fracture or radial hole can be known, providing guidance for subsequent on-site construction.

[0067] For example, based on the above steps S1 to S4, in the test of liquid-solid conversion rate of phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions, the following steps are specifically included:

[0068] Step S71, using computer control to start the true triaxial pressure chamber and adjust it according to the reservoir temperature and pressure conditions;

[0069] Step S72, placing the phase change proppant under pressure according to the curing time required;

[0070] Step S73, open the device body 1 and take out the phase change proppant together with the core 100, record the total mass of the phase change proppant injected in step S4 as M, crush the core and take out the solidified spherical phase change proppant, and measure the mass of the spherical phase change proppant as M1;

[0071] Step S74, calculating the liquid-to-solid conversion rate M1 / M of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions, to provide guidance for the injection amount of the liquid phase change proppant during on-site construction.

[0072] For example, based on the above steps S1 to S4, when testing the pressure bearing capacity of the phase change proppant under different reservoir temperature and pressure conditions, the following steps are specifically included:

[0073] Step S81, using computer control to start the true triaxial pressure chamber and adjust it according to the reservoir temperature and pressure conditions;

[0074] Step S82, placing the phase change proppant under pressure according to the curing time required;

[0075] Step S83, after the phase change of the phase change proppant is completed, the true triaxial pressure chamber is started by the computer, and the pressure is increased to 20MPa, 30MPa, and 4MPa respectively, and the pressure is released after maintaining for a period of time;

[0076] Step S84, during the pressurization process, the fractures are recorded through the visual window 11, and after the pressurization is completed, the embedding of the liquid phase-change proppant is observed through the video, and the core is broken to check the breaking of the phase-change proppant.

[0077] Exemplarily, based on the above steps S1 to S4, when evaluating the use effect of the phase change proppant under the temperature and pressure conditions of the marine natural gas hydrate reservoir, the following steps are also included:

[0078] Step S91, before injecting the phase-change proppant in step S4, inject the prepared tetrahydrofuran aqueous solution from the liquid inlet pipeline 21 according to the hydrate saturation requirement, and start the true triaxial pressure chamber using computer control to keep the internal temperature of the device body 1 at 1°C, and let it stand for 24 hours to ensure that the hydrate is completely generated;

[0079] Step S92: After the phase-change proppant is injected in step S4, the phase-change proppant is allowed to stand for a solidification time required by the phase-change proppant;

[0080] Step S93, during the static period, the fracture is recorded through the visual window 11, and after the phase change is completed, the solidification, sedimentation, accumulation and embedding of the liquid phase change proppant are observed through the video.

[0081] In summary, this application solution has at least the following technical effects:

[0082] 1) Considering that the applicable conditions of liquid phase-change proppants are different under different reservoir lithology conditions and that filtration will occur in the formation, formation rock blocks or rock blocks made according to formation physical properties are used in the experiment to simulate formation conditions, which can make the experimental results more accurate and provide better guidance for on-site construction.

[0083] 2) Considering that liquid phase-change proppants may be lost under reservoir lithology and formation temperature and pressure conditions, the results may differ greatly from those tested in the laboratory. By simulating the formation, more accurate data can be measured.

[0084] 3) The existing devices are unable to observe the solidification of the liquid phase change proppant under reservoir conditions, and are unable to obtain the solidification, sedimentation, accumulation, and embedding of the liquid phase change proppant under reservoir conditions. The present solution can better observe the phase change, sedimentation, accumulation, and embedding of the liquid phase change proppant through the visual window 11 made of transparent sapphire, and gain a deeper understanding of the situation of the liquid phase change proppant in the reservoir.

[0085] 4) The present invention takes into account the different embedding and crushing conditions of liquid phase change proppants in different reservoirs, simulates different reservoir conditions and records the embedding and crushing processes of liquid phase change proppants in reservoirs, which can provide guidance for the selection of liquid phase change proppants under different reservoir conditions.

[0086] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A phase change proppant curing paving performance experimental device, characterized in that: include: A device body (1), wherein a cavity for accommodating a core (100) is provided in the device body (1), a plurality of visual windows (11) are provided on the periphery of the device body (1), and a liquid outlet pipeline is provided on the device body (1); A piston plate (2) is slidably connected to the device body (1), and a liquid inlet pipeline (21) is provided on the piston plate (2); The elastic member (3) is installed in the crack or radial hole of the core (100).

2. The phase change proppant solidification paving performance experimental device according to claim 1, characterized in that: It also includes a window pressurizing member (4), which is installed outside the visible window (11) and can press-fit the visible window (11).

3. The phase change proppant solidification paving performance experimental device according to claim 2, characterized in that: The window pressure member (4) comprises a plurality of parallel and spaced transverse support rods (41), and a plurality of vertical support rods (42) vertically connected to the transverse support rods (41).

4. The phase change proppant curing paving performance experimental device according to any one of claims 1 to 3, characterized in that: The visible window (11) is made of sapphire material.

5. A phase change proppant curing paving performance experimental test method, characterized in that: The phase change proppant solidification paving performance experimental device according to any one of claims 1 to 4 comprises the following steps: Step S1, producing a core (100) according to on-site requirements; Step S2, installing the manufactured core (100) in the device body (1), and placing the elastic member (3) into the crack or radial hole of the core (100); Step S3, pushing the piston plate (2) into the device body (1); Step S4, injecting phase-change proppant from the liquid inlet pipeline (21), and stopping the injection when the phase-change proppant flows out of the liquid outlet pipeline, and closing the liquid inlet pipeline (21) and the liquid outlet pipeline to put the device body (1) in a sealed state; Step S5, performing phase change proppant performance test.

6. The phase change proppant curing paving performance experimental test method according to claim 5, characterized in that: The phase change proppant performance test includes: testing the solidification, sedimentation and accumulation of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions; including the following steps: Step S61, using computer control to start the true triaxial pressure chamber and adjust it according to the reservoir temperature and pressure conditions; Step S62, placing the phase change proppant under pressure according to the curing time required; Step S63, during the static process, the solidification, sedimentation and accumulation of the phase change proppant are recorded in full through the visual window (11); Step S64: Take out the core (100) and crush it to check the solidification and accumulation of the liquid phase-change proppant in the multi-level branch fractures.

7. The phase change proppant curing paving performance experimental test method according to claim 5, characterized in that: The phase change proppant performance test includes: testing the liquid-solid conversion rate of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions; including the following steps: Step S71, using computer control to start the true triaxial pressure chamber and adjust it according to the reservoir temperature and pressure conditions; Step S72, placing the phase change proppant under pressure according to the curing time required; Step S73, opening the device body (1) and taking out the phase change proppant together with the core (100), the total mass of the injected phase change proppant is M, the core is crushed and the solidified spherical phase change proppant is taken out, and the mass of the spherical phase change proppant is measured to be M1; Step S74, calculating the liquid-to-solid conversion rate M1 / M of the phase change proppant under reservoir rock properties and reservoir temperature and pressure conditions.

8. The phase change proppant curing paving performance experimental test method according to claim 5, characterized in that: The phase change proppant performance test includes: testing the pressure bearing capacity of the phase change proppant under different reservoir temperature and pressure conditions; including the following steps: Step S81, using computer control to start the true triaxial pressure chamber and adjust it according to the reservoir temperature and pressure conditions; Step S82, placing the phase change proppant under pressure according to the curing time required; Step S83, after the phase change of the phase change proppant is completed, the true triaxial pressure chamber is started by the computer, and the pressure is increased to 20MPa, 30MPa, and 4MPa respectively, and the pressure is released after maintaining for a period of time; Step S84: During the pressurization process, the fractures are recorded through the visual window (11). After the pressurization is completed, the embedding of the liquid phase-change proppant is observed through the video, and the core is crushed to check the crushing of the phase-change proppant.

9. The phase change proppant curing paving performance experimental test method according to claim 5, characterized in that: The phase change proppant performance test includes: evaluating the use effect of the phase change proppant under the temperature and pressure conditions of the marine natural gas hydrate reservoir; including the following steps: Step S91, before injecting the phase change proppant, inject the prepared tetrahydrofuran aqueous solution from the front end according to the hydrate saturation requirement, and use computer control to start the true triaxial pressure chamber, so that the internal temperature of the device body (1) is maintained at 1°C, and let it stand for 24 hours to ensure that the hydrate is completely generated; Step S92, after injecting the phase change proppant, let it stand for a solidification time required by the phase change proppant; Step S93: During the static period, the fracture is recorded through the visual window (11), and after the phase change is completed, the solidification, sedimentation, accumulation and embedding of the liquid phase change proppant are observed through the video.

10. The method for testing the curing and laying performance of a phase change proppant according to any one of claims 5 to 9, characterized in that: The cracks in the core (100) include any one of horizontal cracks, vertical cracks and multi-level branch cracks.

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