Fractured core and method for fabricating the fractured core

Abstract

The present invention discloses a fractured core and a method for manufacturing the fractured core. The method for manufacturing the fractured core includes: filling a first diagenetic mixture into a core mold and pressing to form a base layer; placing a first fracture-making plate having a first fracture-making groove in the core mold; filling a fracture filler into the first fracture-making groove; removing the first fracture-making plate; filling a second diagenetic mixture into the core mold, pressing and curing to form a core block; demolding the core block from the core mold; injecting water into the core block to discharge the fracture filler from the core block and form a first fracture groove. When pressing the core block, the second diagenetic mixture and the base layer cooperate to extrude the fracture filler, so that the fracture filler develops irregularly under pressure, improving the surface roughness of the inner wall of the first fracture groove, greatly reducing the difference between the first fracture groove and the fractures in natural cores, and thus improving the simulation degree of the first fracture groove.

Description

Technical Field

[0001] The present invention belongs to the technical field of artificial cores, and particularly relates to a fractured core and a method for manufacturing the fractured core. Background Art

[0002] In oil and gas reservoirs, fractures are an important storage and seepage space, which can be used to store fluids, communicate the matrix with the wellbore, and improve the seepage capacity of the reservoir. However, during the development of oil and gas reservoirs, the existence of fractures often exacerbates the heterogeneity of oil and gas reservoirs, increases the development difficulty of oil and gas reservoirs, and the impact on the ultimate recovery rate cannot be ignored. Therefore, the development simulation experiment of fractured oil and gas reservoirs has always been the focus and difficulty in oil and gas field development engineering.

[0003] When conducting the development simulation experiment of fractured oil and gas reservoirs, it is necessary to sample natural fractured cores in the underground reservoir for the experiment. However, limited by the natural structure of the underground reservoir, whether it is downhole coring or outcrop sampling, the obtained cores are mostly fragmented and residual samples, which cannot be used for simulation experiments.

[0004] Therefore, artificial fractured cores are usually used for experiments. However, the inner wall surface of the fractures in artificial fractured cores is smooth and flat, and the fracture shape is regular, which does not conform to the characteristics of the inner wall surface of natural fractures being rough and irregular. Moreover, the fractures are arranged evenly, and the fracture strike, dip angle, and aperture are relatively single. The fractures in artificial cores are quite different from those in natural cores, resulting in a low fracture simulation degree in artificial cores, being unable to reflect the actual characteristics of natural cores, and further reducing the accuracy of experimental results. Summary of the Invention

[0005] Aiming at the above defects or deficiencies, the present invention provides a fractured core and a method for manufacturing the fractured core, aiming to solve the technical problem of low fracture simulation degree in artificial cores.

[0006] To achieve the above object, the present invention provides a method for manufacturing a fractured core, wherein the method for manufacturing the fractured core includes the following steps:

[0007] Fill a core mold with a first diagenetic mixture and press to form a base layer;

[0008] Place a first fracture-forming plate with a first fracture-forming groove in the core mold;

[0009] Fill the first fracture-forming groove with a fracture filler;

[0010] Take out the first fracture-forming plate from the core mold;

[0011] Fill the core mold with a second diagenetic mixture, press and cure to form a core block;

[0012] Demold the core block from the core mold;

[0013] Water is injected into the core block so that the fracture filler is discharged from the core block and a first fracture groove is formed.

[0014] In the embodiment of the present invention, before the step of placing the first slot-making plate with the first slot-making groove in the core mold, it includes:

[0015] The third diagenetic mixture is filled into the core mold on the base layer and pressed to form the middle layer;

[0016] The second slot-making plate with the second slot-making groove is placed on the middle layer;

[0017] The first slot-making mold is inserted into the middle layer through the second slot-making groove so that a second fracture groove is formed on the middle layer; wherein, the first slot-making mold matches the shape of the second slot-making groove;

[0018] The first slot-making mold and the second slot-making plate are sequentially taken out of the core mold;

[0019] The fracture filler is filled into the second fracture groove.

[0020] In the embodiment of the present invention, after the step of filling the fracture filler into the second fracture groove, it includes:

[0021] The third slot-making plate with the third slot-making groove is placed on the middle layer; wherein, the shape of the third slot-making groove is different from that of the second slot-making groove and is arranged staggeredly;

[0022] The second slot-making mold is inserted into the middle layer through the third slot-making groove so that a third fracture groove is formed on the middle layer; wherein, the second slot-making mold matches the shape of the third slot-making groove;

[0023] The second slot-making mold and the third slot-making plate are sequentially taken out of the core mold;

[0024] The fracture filler is filled into the third fracture groove.

[0025] In the embodiment of the present invention, the second slot-making groove is inclined, and the third slot-making groove is in an X shape.

[0026] In the embodiment of the present invention, the first slot-making mold includes a first slot-making part and a first grip part. The first slot-making part matches the shape of the second slot-making groove, and the first grip part is connected to the first slot-making part and is bent upward from the upper end of the first slot-making part;

[0027] The second slot-making mold includes a second slot-making part and a second grip part. The second slot-making part matches the shape of the third slot-making groove, and the second grip part is connected to the second slot-making part and extends vertically.

[0028] In the embodiment of the present invention, the step of injecting water into the core block so that the fracture filler is discharged from the core block and a first fracture groove is formed includes:

[0029] Use a core drill to drill multiple core columns from within the core block;

[0030] Use a gripper to grip the core column;

[0031] Inject water into the core column so that the fracture filler is discharged from the core column and a first fracture groove is formed.

[0032] In the embodiment of the present invention, before the step of filling the core mold with the first diagenetic mixture and pressing to form the base layer, it includes:

[0033] Coat the inner side wall of the core mold with a release agent.

[0034] In the embodiment of the present invention, the core mold includes a bottom plate, a first side plate and a second side plate. The bottom plate is provided with a first installation groove and a second installation groove that are perpendicular to each other and communicate with each other, and the end of the first installation groove extends out of the second installation groove. The bottom of the first side plate is inserted into the first installation groove, and the first side plate is provided with a third installation groove extending vertically at a position opposite to the second installation groove. The bottom of the second side plate is inserted into the second installation groove, and the side of the second side plate is inserted into the third installation groove.

[0035] In the embodiment of the present invention, the fracture filler is starch and / or glycerol.

[0036] To achieve the above object, the present invention also provides a fractured core, wherein the fractured core is formed according to the manufacturing method of the fractured core described above.

[0037] Through the above technical solutions, the manufacturing method of the fractured core provided by the embodiment of the present invention has the following beneficial effects:

[0038] In the technical solution of the present invention, when pressing the core block, the second diagenetic mixture and the base layer cooperate to extrude the fracture filler, so that the fracture filler develops irregularly under pressure, improving the surface roughness of the inner wall of the first fracture groove, greatly reducing the difference between the first fracture groove and the fractures in the natural core, and thus improving the simulation degree of the first fracture groove; moreover, the fracture filler has flexibility and plasticity, is soluble in water at normal temperature, and the hardness of the fracture filler is less than the hardness of the second diagenetic mixture, so that the fracture filler can be completely discharged outside the core block by flushing with water without affecting the physical and chemical properties of the core block, improving the reliability of the experimental results; in addition, the number and arrangement mode of the first fracture grooves on the first fracture plate can be flexibly set according to actual experimental needs, making the shape of the first fracture grooves formed irregular, uneven and diverse, further highly restoring the fracture characteristics in the natural core.

[0039] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation part. Description of the Drawings

[0040] The drawings are used to provide an understanding of the present invention and form a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0041] Figure 1 is a schematic flow chart of the method for manufacturing a fractured core according to the first embodiment of the present invention;

[0042] Figure 2 is a schematic flow chart of the method for manufacturing a fractured core according to the second embodiment of the present invention;

[0043] Figure 3 is a schematic flow chart of the method for manufacturing a fractured core according to the third embodiment of the present invention;

[0044] Figure 4 is a schematic flow chart of step S70 in the method for manufacturing a fractured core according to the first embodiment of the present invention;

[0045] Figure 5 is a schematic structural diagram of a first slotting plate according to an embodiment of the present invention;

[0046] Figure 6 is a schematic structural diagram of a second slotting plate and a first slotting mold according to an embodiment of the present invention;

[0047] Figure 7 is a schematic structural diagram of a first slotting mold according to an embodiment of the present invention;

[0048] Figure 8 is a schematic structural diagram of a third slotting plate according to an embodiment of the present invention;

[0049] Figure 9 is a schematic structural diagram of a second slotting mold according to an embodiment of the present invention;

[0050] Figure 10 is a schematic structural diagram of a core mold according to an embodiment of the present invention;

[0051] Figure 11 is a schematic structural diagram of a core block according to an embodiment of the present invention;

[0052] Figure 12 is a schematic structural diagram of a core column according to an embodiment of the present invention.

[0053] Description of the Reference Numerals

[0054] 10 Core mold 40 First slotting mold

[0055] 11 Cover plate 41 First slotting part

[0056] 12 Base plate 42 First grip part

[0057] 121 First installation groove 50 Third seam - creating plate

[0058] 122 Second installation groove 51 Third seam - creating groove

[0059] 13 First side plate 60 Second seam - making die

[0060] 131 Third installation groove 61 Second seam - making part

[0061] 14 Second side plate 62 Second grip part

[0062] 20 First seam - creating plate 200 Core block

[0063] 21 First seam - creating groove 201 First crack groove

[0064] 30 Second seam - creating plate 202 Core column

[0065] 31 Second seam - creating groove Detailed implementation manners

[0066] The following describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present invention, and are not used to limit the present invention.

[0067] The following describes the method for manufacturing a cracked core of the present invention with reference to the drawings.

[0068] The present invention provides a method for manufacturing a cracked core. Referring to Figure 1 , which is a schematic flow chart of the first embodiment of the method for manufacturing a cracked core of the present invention. Among them, the method for manufacturing a cracked core includes the following steps:

[0069] Step S10: Fill the core mold 10 with a first diagenetic mixture and press it to form a base layer;

[0070] Specifically, provide a core mold 10 for manufacturing a cracked core, put the first diagenetic mixture into the core mold 10, place the cover plate 11 on the first diagenetic mixture, and apply a certain pressure to the cover plate 11 to press the first diagenetic mixture into a base layer.

[0071] Step S20: Place a first seam - creating plate 20 with a first seam - creating groove 21 in the core mold 10;

[0072] Specifically, a first slot-forming plate 20 for making the first crack slot 201 is provided. A plurality of first slot-forming grooves 21 are formed in the first slot-forming plate 20. The orientation, size, and opening degree of each first slot-forming groove 21 can be flexibly set according to actual experimental requirements, and any two first slot-forming grooves 21 can be arranged in parallel, offset, or crosswise.

[0073] Step S30: Fill the first slot-forming groove 21 with a crack filler.

[0074] Specifically, select one or more first slot-forming grooves 21 according to actual experimental requirements, and fill the one or more slot-forming grooves with a crack filler, so that the crack filler is laid on the base layer along the extension direction and shape of each first slot-forming groove 21.

[0075] Step S40: Take out the first slot-forming plate 20 from the core mold 10.

[0076] Step S50: Fill the core mold 10 with a second diagenetic mixture, press and cure it to form a core block 200.

[0077] Specifically, put the second diagenetic mixture into the core mold 10 so that the second diagenetic mixture is located on the upper side of the base layer, and the crack filler is located between the second diagenetic mixture and the base layer; place the cover plate 11 on the second diagenetic mixture, and apply the same pressure to the cover plate 11 as when pressing the base layer, so that the second diagenetic mixture and the base layer cooperate to squeeze the crack filler, and press and cure the second diagenetic mixture, the crack filler, and the base layer into a core block 200.

[0078] Step S60: Demold the core block 200 from the core mold 10.

[0079] Specifically, take out the compression-molded core block 200 from the core mold 10.

[0080] Step S70: Inject water into the core block 200 so that the crack filler is discharged from the core block 200 to form the first crack slot 201.

[0081] Specifically, after fixing the core block 200, inject water into the core block 200 to wash the crack filler in the core block 200. The crack filler is soluble in water at normal temperature, and the dissolution rate is fast and the dissolution is complete, so that the dissolved crack filler can be discharged out of the core block 200 with the water flow. When the water discharged from the water discharge end of the core block 200 is transparent and there is no particle residue, it can be determined that the first crack slot 201 is formed at the position where the crack filler was originally filled in the core block 200, and thus the production of the cracked core is completed.

[0082] In the first embodiment of the present invention, as Figure 5As shown, when pressing the core block 200, the second diagenetic mixture is combined with the base layer to extrude the fracture filler, so that the fracture filler develops irregularly under pressure, improving the surface roughness of the inner wall of the first fracture groove 201, greatly reducing the difference between the first fracture groove 201 and the fractures in the natural core, and thus improving the simulation degree of the first fracture groove 201; moreover, the fracture filler is flexible and plastic, dissolves in water at room temperature, and the hardness of the fracture filler is less than that of the second diagenetic mixture, so that the fracture filler can be completely discharged outside the core block 200 by flushing with water without affecting the physical and chemical properties of the core block 200, improving the reliability of the experimental results; in addition, the sizes, orientations, opening degrees of the first fracture grooves 21 on the first slotting plate 20, and the number and arrangement modes of the multiple first fracture grooves 21 can all be flexibly set according to actual experimental requirements, and the fracture filler can be flexibly selected to be filled into one or more of the first fracture grooves 21 according to actual experimental requirements, making the formed first fracture groove 201 irregular in shape and uneven in arrangement, and the sizes, orientations and opening degrees of the first fracture groove 201 are diversified, further highly restoring the fracture characteristics in the natural core.

[0083] Referring to Figure 2 , which is a schematic flow chart of the second embodiment of the method for manufacturing a fractured core according to the present invention. Based on the above first embodiment, before step S20, it includes:

[0084] Step S11, filling a third diagenetic mixture into the core mold 10 on the base layer and pressing to form a middle layer;

[0085] Specifically, the third diagenetic mixture is placed into the core mold 10 so that the third diagenetic mixture is located on the upper side of the base layer, the cover plate 11 is placed on the third diagenetic mixture, and a pressure less than that when pressing the base layer is applied to the cover plate 11 to press the third diagenetic mixture into a middle layer; moreover, the first diagenetic mixture, the second diagenetic mixture and the third diagenetic mixture are made of the same material, which all include the materials required for the core and inorganic binders, etc.

[0086] Step S12, placing a second slotting plate 30 with second fracture grooves 31 on the middle layer;

[0087] Specifically, a second slotting plate 30 for manufacturing the second fracture groove is provided, and a plurality of second fracture grooves 31 are formed on the second slotting plate 30.

[0088] Step S13, inserting the first slotting mold 40 through the second fracture groove 31 into the middle layer to form a second fracture groove on the middle layer; wherein, the first slotting mold 40 matches the shape of the second fracture groove 31;

[0089] Specifically, a first slot-making mold 40 that matches the shape and size of the second slot 31 is provided. Hold the first slot-making mold 40 and insert the first slot-making mold 40 along the second slot 31 so that the first slot-making mold 40 extends into the middle layer along the extension direction of the second slot 31, and then a second crack slot is formed in the middle layer under the extrusion of the first slot-making mold 40. Moreover, the depth, quantity, and arrangement position of the second crack slot can be flexibly set according to actual experimental requirements.

[0090] Step S14: Take out the first slot-making mold 40 and the second slot-making plate 30 from the core mold 10 in sequence.

[0091] Specifically, when taking out the first slot-making mold 40, apply a certain pressure to the second slot-making plate 30. Hold the first slot-making mold 40 and take out the first slot-making mold 40 along the second slot 31. By applying pressure to the second slot-making plate 30, the structure of the second crack slot can be prevented from being damaged during the process of taking out the first slot-making mold 40.

[0092] Step S15: Fill the second crack slot with crack filler.

[0093] In the second embodiment of the present invention, insert the first slot-making mold 40 into the middle layer along the extension direction of the second slot 31 so that a second crack slot matching the shape of the first slot-making mold 40 is formed in the middle layer. Then place the first slot-making plate 20 on the middle layer, fill the crack filler in the first slot 21, and finally fill the second diagenetic mixture onto the middle layer, press and solidify to form the core block 200. Flush the core block 200 with water so that the crack filler dissolves and is discharged out of the core block 200 with the water flow. Furthermore, a first crack slot 201 is formed on the middle layer in the core block 200, and the second crack slot in the middle layer is in a hollow state. The shapes, sizes, and arrangement modes of the first crack slot 201 and the second crack slot are diverse, which better restores the characteristics of the cracks in the natural fractured core and is beneficial to improving the accuracy of the development simulation experiment of the fractured oil and gas reservoir.

[0094] Refer to Figure 3 , which is a schematic flow chart of the third embodiment of the method for manufacturing the fractured core of the present invention. Based on the above second embodiment, after step S15, it includes:

[0095] Step S16: Place a third slot-making plate 50 with a third slot 51 on the middle layer; wherein, the shape of the third slot 51 is different from that of the second slot 31 and is arranged staggeredly.

[0096] Specifically, a third slot-making plate 50 for manufacturing the third crack slot is provided. A plurality of third slots 51 are formed on the third slot-making plate 50. The third slots 51 and the second slots 31 are of two different shapes respectively, so that the formed third crack slots are different in shape from the second crack slots.

[0097] Step S17: Insert the second seam-making mold 60 through the third seam-making groove 51 into the middle layer, so as to form a third crack groove on the middle layer; wherein, the second seam-making mold 60 matches the shape of the third seam-making groove 51.

[0098] Specifically, provide a second seam-making mold 60 that matches the shape and size of the third seam-making groove 51, hold the second seam-making mold 60, and insert the second seam-making mold 60 along the third seam-making groove 51, so that the second seam-making mold 60 extends into the middle layer along the extending direction of the third seam-making groove 51, and then a third crack groove is formed in the middle layer under the extrusion of the second seam-making mold 60; moreover, the depth, quantity and arrangement position of the third crack groove can be flexibly set according to actual experimental requirements.

[0099] Step S18: Take out the second seam-making mold 60 and the third seam-making plate 50 from the core mold 10 in sequence.

[0100] Specifically, when taking out the second seam-making mold 60, apply a certain pressure to the third seam-making plate 50, hold the second seam-making mold 60, and take out the second seam-making mold 60 along the third seam-making groove 51. By applying pressure to the third seam-making plate 50, the structure of the third crack groove can be prevented from being damaged during the process of taking out the second seam-making mold 60.

[0101] Step S19: Fill the third crack groove with crack filler.

[0102] In the second embodiment of the present invention, as Figures 5 to 11 shown, first, a second crack groove is formed in the middle layer, then the second seam-making mold 60 is inserted into the middle layer along the extending direction of the third seam-making groove 51, so as to form a third crack groove in the middle layer that matches the shape of the second seam-making mold 60. Then, place the first seam-making plate 20 on the middle layer and selectively fill the first seam-making groove 21 with crack filler. Finally, fill the second diagenetic mixture on the middle layer to press and cure to form a core block 200. Inject water into the core block 200 for flushing, so that the crack filler on the middle layer is discharged to form a first crack groove 201, and the crack filler in the second crack groove and the third crack groove is discharged to complete the production of the cracked core. Since the crack filler is a flexible plastic material that is easily soluble in water at room temperature and its hardness is much smaller than that of the second diagenetic mixture, the crack filler is prone to slight deformation in the core block 200 when being pressed and cured into the core block 200, making the first crack groove 201, the second crack groove and the third crack groove develop irregularly, and the inner wall surface is rough and uneven, realizing the fine simulation of complex cracks; the method for manufacturing the cracked core in the embodiment of the present invention can take into account both the irregular development of cracks and the artificial controllability of crack design. It is not only convenient to manufacture, has a simple process flow, but also has high compatibility and repeatability, improving the simulation degree of cracks in the cracked core.

[0103] In the embodiment of the present invention, the second slotting groove 31 is inclined, and the third slotting groove 51 is in an X shape. As Figures 6 to 9 shown, the second slotting plate 30 is provided with a second slotting groove 31, and the second slotting groove 31 is inclined from top to bottom, so that the first slotting die 40 can be inserted into the middle layer along the inclined direction of the second slotting groove 31 to form an inclined second crack groove in the middle layer. The inclination angle of the second slotting groove 31 can be flexibly set according to actual experimental requirements, improving the diversity of the second crack groove; the third slotting plate 50 is provided with a third slotting groove 51, and the third slotting groove 51 is in an X shape, so that the second slotting die 60 can be inserted into the middle layer along the third slotting groove 51 downward to form an X-shaped third crack groove in the middle layer. The intersection angle of the third slotting groove 51 can be flexibly set according to actual experimental requirements, improving the diversity of the third crack groove; in the method for manufacturing a cracked core according to the embodiment of the present invention, by using the second slotting groove 31 and the third slotting groove 51 with different shapes to individually manufacture the second crack groove and the third crack groove in the middle layer, and the number, size, orientation and inclination angle of the second crack groove and the third crack groove are all flexibly controllable, realizing the fine simulation of cracks and realizing the batch reproducible and non-damaging manufacturing of cracked cores.

[0104] In the embodiment of the present invention, the first slotting die 40 includes a first slotting part 41 and a first grip part 42. The first slotting part 41 matches the shape of the second slotting groove 31, and the first grip part 42 is connected to the first slotting part 41 and is bent upward from the upper end of the first slotting part 41; the second slotting die 60 includes a second slotting part 61 and a second grip part 62. The second slotting part 61 matches the shape of the third slotting groove 51, and the second grip part 62 is connected to the second slotting part 61 and extends vertically.

[0105] As Figures 6 to 9As shown, the first seam-making part 41 is in a plate shape so that the first seam-making part 41 can be inserted into the middle layer along the inclined direction of the second seam-making groove 31, and then an inclined second crack groove is made in the middle layer. And a first grip part 42 is connected to the first seam-making part 41. By holding the first grip part 42, the first seam-making part 41 can be driven to be inserted into the middle layer along the second seam-making groove 31 or taken out from the second seam-making groove 31, which is convenient and fast to use. The second seam-making part 61 includes two intersecting plates, so that the second seam-making part 61 is in an X shape, which is convenient for the second seam-making part 61 to be inserted downward into the middle layer along the third seam-making groove 51, and then a third crack groove in an X shape is made in the middle layer. And a second grip part 62 is connected to the second seam-making part 61. By holding the second grip part 62, the second seam-making part 61 can be driven to be inserted into the middle layer along the third seam-making groove 51 or taken out from the third seam-making groove 51, which is convenient and fast to use. Moreover, both the first seam-making part 41 and the second seam-making part 61 can be made of steel. The steel has a relatively high hardness, which is convenient for the first seam-making part 41 to extrude the third diagenetic mixture in the middle layer to form the second crack groove, and is also convenient for the second seam-making part 61 to extrude the third diagenetic mixture in the middle layer to form the third crack groove.

[0106] Referring to Figure 4 , which is a detailed process schematic diagram of step S70 in the first embodiment of the method for manufacturing a fractured core of the present invention. Based on the above first embodiment, step S70 includes:

[0107] Step S71, using a core drill to drill a plurality of core columns 202 from the core block 200;

[0108] Specifically, as Figure 11 shown, using a core drill equipped with a hollow drill bit to drill core columns 202 from the core block 200. The core columns 202 are columnar, which is convenient for carrying out simulation experiments on the development of fractured oil and gas reservoirs.

[0109] Step S72, using a gripper to grip the core column 202;

[0110] Specifically, providing a gripper for gripping the core column 202 to fix the gripper, which is convenient for injecting water into the core column 202.

[0111] Step S73, injecting water into the core column 202 so that the fracture filler is discharged from the core column 202 and a first crack groove 201 is formed;

[0112] Specifically, as Figure 12As shown in the figure, after fixing the core column 202, water is injected into the core column 202 to wash the crack filler in the core column 202. The crack filler is soluble in water under normal temperature conditions, with a fast dissolution rate and complete dissolution, so that the dissolved crack filler can be discharged out of the core column 202 along with the water flow. When the water discharged from the water discharge end of the core column 202 is transparent and there is no particle residue, it can be determined that the first crack groove 201 is formed at the position where the crack filler was originally filled in the core column 202, thus completing the production of the cracked core. And because the crack filler has extremely strong water solubility and will not adhere to the inner wall of the first crack groove 201, the crack simulation degree is further improved.

[0113] In the embodiment of the present invention, before step S10, it includes:

[0114] Coating a release agent on the inner side wall of the core mold 10;

[0115] Specifically, when making the cracked core, first provide the core mold 10 for making the cracked core, and coat a release agent on the inner side wall of the core mold 10. The release agent can adopt a silicone release agent or a methyl silicone oil release agent and other release agents that are beneficial to the demolding of the core block 200. Then put the first diagenetic mixture into the core mold 10 and press it into a base layer. Then put the third diagenetic mixture into the core mold 10 and press it into a middle layer with a pressure less than that when pressing the base layer. Make the second crack groove and the third crack groove in the middle layer according to the actual experimental requirements and fill the crack filler in the second crack groove and the second crack groove. Fill the crack filler on the middle layer according to the shape of the first crack groove 21. Finally, put the second diagenetic mixture into the core mold 10 with the same pressure as when pressing the base layer, and press and cure the second diagenetic mixture, the base layer, the middle layer and the crack filler into the core block 200; demold the core block 200 from the core mold 10. Because the inner side wall of the core mold 10 is coated with a release agent, the demolding of the core block 200 is convenient and fast, which not only improves the demolding efficiency of the core block 200, but also effectively avoids damage to the core block 200 during demolding and maintains the demolding integrity of the core block 200; inject water into the core block 200 to wash it, so that the crack filler in the second crack groove and the third crack groove is discharged, so that the second crack groove and the third crack groove are in a hollow state, and the crack filler on the middle layer is discharged, so that the first crack groove 201 is formed on the upper side of the middle layer. The forms of the first crack groove 201, the second crack groove and the third crack groove are diversified, and the crack simulation degree of the cracked core is improved.

[0116] In the embodiment of the present invention, before step S70, it includes:

[0117] Step S61, performing vacuum saturation water treatment on the core block 200;

[0118] Specifically, there is gas inside the core block 200 after it is manufactured and formed. By means of vacuum pumping, the gas inside the core block 200 is discharged, and the core block 200 is subjected to saturated water treatment to simulate the groundwater environment, so that the core block 200 has a higher degree of simulation.

[0119] In the embodiment of the present invention, after step S73, it includes:

[0120] Step S74, drying the core column 202;

[0121] Specifically, water is injected into the core column 202 to wash the crack filler, so that the crack filler dissolves in water and is discharged out of the core column 202 with the water flow. When the water discharged from the water discharge end of the core column 202 is transparent and free of particles, it can be determined that the first crack groove 201, the second crack groove and the third crack groove inside the core column 202 are washed clean and there is no attached residue on the inner wall. Then the core column 202 is heated and dried, and the production of the cracked core is completed. The production of the cracked core is convenient and fast, and the production simulation degree is high.

[0122] In the embodiment of the present invention, the core mold 10 includes a bottom plate 12, a first side plate 13 and a second side plate 14. The bottom plate 12 is provided with a first installation groove 121 and a second installation groove 122 that are perpendicular to each other and communicate with each other, and the end of the first installation groove 121 extends out of the second installation groove 122. The bottom of the first side plate 13 is inserted into the first installation groove 121, and the first side plate 13 is provided with a third installation groove 131 extending vertically at a position opposite to the second installation 122. The bottom of the second side plate 14 is inserted into the second installation groove 122, and the side of the second side plate 14 is inserted into the third installation groove 131.

[0123] Such as Figure 10As shown in the figure, in the length direction of the bottom plate 12, first mounting grooves 121 are provided at both ends of the bottom plate 12; in the width direction of the bottom plate 12, second mounting grooves 122 are provided on both sides of the bottom plate 12, and the second mounting grooves 122 are perpendicular to the first mounting grooves 121; a first side plate 13 is inserted into each first mounting groove 121, and two third mounting grooves 131 are provided on the opposite sides of the two first side plates 13, and the two third mounting grooves 131 on each first side plate 13 are respectively arranged at both ends of the first side plate 13 in the width direction of the bottom plate 12; a second side plate 14 is inserted into each second mounting groove 122, and both ends of each second side plate 14 are respectively inserted into the two third mounting grooves 131; when demolding the core block 200, first remove the two second side plates 14, and then remove the two first side plates 13 to complete the demolding of the core block 200. The demolding is convenient and fast, improving the demolding integrity of the core block 200; moreover, the two first side plates 13 can be connected by fasteners such as stud bolts and nuts, which not only increases the structural strength, improves the connection reliability, but also is convenient for disassembly to improve the demolding efficiency; in addition, the bottom plate 12, the first side plate 13 and the second side plate 14 can all be made of Hartz alloy, which can not only be reused, but also has good corrosion resistance and thermal stability, and will not affect the physical and chemical properties of the core block 200.

[0124] In the embodiment of the present invention, the crack filler is starch and / or glycerol, that is, the crack filler can be starch, glycerol or a mixture of starch and glycerol, so that the crack filler has extremely strong water solubility and will not damage the physical and chemical properties of the core block 200; moreover, the crack filler can make cracks with extremely thin thickness, the minimum single-layer thickness of the crack filler can reach 20 μm, and the crack filler can make cracks of different sizes by cutting, stacking, etc., which not only improves the crack diversity, but also can make fine cracks, thereby further improving the crack simulation degree.

[0125] In addition, the present invention also provides a cracked core, wherein the cracked core is formed according to the manufacturing method of the cracked core described above. Since the manufacturing of the cracked core adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0126] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0127] In the present invention, unless otherwise clearly specified or limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention may be understood according to specific circumstances.

[0128] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0129] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for fabricating a cracked core, characterized in that, The method for manufacturing the cracked core includes the following steps: Fill a first diagenetic mixture into the core mold (10) and press to form a base layer; Place a first slot-making plate (20) with a first slot-making groove (21) in the core mold (10); Fill the crack filler into the first slot-making groove (21); Take out the first slot-making plate (20) from the core mold (10); Fill a second diagenetic mixture into the core mold (10), press and cure to form a core block (200), wherein the hardness of the crack filler is less than that of the second diagenetic mixture; Demold the core block (200) from the core mold (10); Inject water into the core block (200) to discharge the crack filler from the core block (200) and form a first crack groove (201).

2. The method for fabricating a cracked core according to claim 1, wherein Before the step of placing the first slot-making plate (20) with a first slot-making groove (21) in the core mold (10), it includes: Fill a third diagenetic mixture into the core mold (10) on the base layer and press to form a middle layer; Place a second slot-making plate (30) with a second slot-making groove (31) on the middle layer; Insert a first slot-making mold (40) through the second slot-making groove (31) into the middle layer to form a second crack groove on the middle layer; wherein the first slot-making mold (40) matches the shape of the second slot-making groove (31); Take out the first slot-making mold (40) and the second slot-making plate (30) from the core mold (10) in sequence; Fill the crack filler into the second crack groove.

3. The method for fabricating a cracked core according to claim 2, wherein, After the step of filling the crack filler into the second crack groove, it includes: Place a third slot-making plate (50) with a third slot-making groove (51) on the middle layer; wherein the shape of the third slot-making groove (51) is different from that of the second slot-making groove (31) and is staggeredly arranged; Insert a second slot-making mold (60) through the third slot-making groove (51) into the middle layer to form a third crack groove on the middle layer; wherein the second slot-making mold (60) matches the shape of the third slot-making groove (51); Take out the second slot-making mold (60) and the third slot-making plate (50) from the core mold (10) in sequence; Fill the crack filler into the third crack groove.

4. The method for fabricating a cracked core according to claim 3, wherein The second slot-making groove (31) is inclined, and the third slot-making groove (51) is in an X shape.

5. The method for fabricating a cracked core according to claim 4, wherein The first slot-making mold (40) includes a first slot-making part (41) and a first grip part (42), the first slot-making part (41) matches the shape of the second slot-making groove (31), and the first grip part (42) is connected to the first slot-making part (41) and is bent upward from the upper end of the first slot-making part (41); The second slot-making mold (60) includes a second slot-making part (61) and a second grip part (62), the second slot-making part (61) matches the shape of the third slot-making groove (51), and the second grip part (62) is connected to the second slot-making part (61) and extends vertically.

6. The method for manufacturing a cracked core according to any one of claims 1 to 5, characterized in that, The step of injecting water into the core block (200) to discharge the crack filler from the core block (200) and form a first crack groove (201) includes: Drilling a plurality of core columns (202) from the core block (200) using a core drill; Clamping the core column (202) using a clamp; Injecting water into the core column (202) to discharge the crack filler from the core column (202) and form the first crack groove (201).

7. The method for manufacturing a cracked core according to any one of claims 1 to 5, characterized in that, Before the step of filling the core mold (10) with a first diagenetic mixture and pressing to form a base layer: Coating a release agent on the inner side wall of the core mold (10).

8. The method for fabricating a cracked core according to any one of claims 1 to 5, characterized in that, The core mold (10) includes a bottom plate (12), a first side plate (13) and a second side plate (14). A first installation groove (121) and a second installation groove (122) which are perpendicular to each other and communicate are formed on the bottom plate (12), and the end of the first installation groove (121) extends out of the second installation groove (122). The bottom of the first side plate (13) is inserted into the first installation groove (121), and a third installation groove (131) extending vertically is formed at a position of the first side plate (13) opposite to the second installation groove (122). The bottom of the second side plate (14) is inserted into the second installation groove (122), and the side of the second side plate (14) is inserted into the third installation groove (131).

9. The method for fabricating a cracked core according to any one of claims 1 to 5, characterized in that, The crack filler is starch and / or glycerin.

10. A fractured core, characterized in that, The cracked core is formed by the method for manufacturing a cracked core according to any one of claims 1 to 9.

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