METHOD AND DEVICE FOR PREPARING ARTIFICIAL CORE FOR PETROLEUM GEOLOGICAL EXPLORATION

Abstract

The present disclosure provides a method and device for preparing an artificial core for petroleum geological exploration. The method includes: step 1, establishing a relation curve between a median grain diameter of quartz sand and a permeability, determining a type and a usage amount of epoxy resin, and preparing a cementing agent according to a principle that the epoxy resin has a direct ratio with a specific surface; step 2, based on a method of controlling a core permeability, preparing benchmark sand with quartz sand of different grain sizes in a certain ratio, fabricating a low-permeability core by adjusting a ratio of the benchmark sand to fine sand, and fabricating a high-permeability core by adjusting a ratio of the benchmark sand to coarse sand; step 3, separately and proportionally weighing quartz sand of different grain diameters and putting them into a magnetic tray, manually mixing and agitating for later use.

Claims

1. A method for preparing an artificial core for petroleum geological exploration, comprising the following steps: step 1, establishing a relation curve between a median grain diameter of quartz sand and a permeability, determining a type and a usage amount of epoxy resin, and preparing a cementing agent according to a principle that the epoxy resin has a direct ratio with a specific surface; step 2, based on a method of controlling a core permeability, preparing benchmark sand with quartz sand of different grain sizes in a certain ratio, fabricating a low-permeability core by adjusting a ratio of the benchmark sand to fine sand, and fabricating a high-permeability core by adjusting a ratio of the benchmark sand to coarse sand; step 3, separately and proportionally weighing quartz sand of different grain diameters and putting them into a magnetic tray, and manually mixing and agitating for later use, wherein since agitating frequency, times and uniformity degree for per capita have a great influence on porosity and permeability values of an artificial core during stirring, and a quartz sand mixing agitator is employed to avoid man-made nonuniform agitation; step 4, adding a clay mineral, wherein a clay mineral in a natural rock core plays an important role on a structure and physical properties of the rock core; according to a principle of physical simulation similarity criterion, a certain amount of clay mineral is added to an artificial core; and a special method of adding the clay mineral is used to avoid the clay mineral from being covered with the epoxy resin; and step 5, preparing an artificial core: preparing a slightly oil-wet core by diluting silicone oil which is 10% by weight of a sand mold with 20 times petroleum ether, evenly agitating the diluted silicone oil with 40 to 70-mesh quartz sand, 70 to 140-mesh quartz sand and 140 to 200-mesh quartz sand, volatilizing at room temperature for 20 h, then putting the mixed quartz sand into an electrothermal blowing dry box, warming according to temperature programming of 60 C., 80 C., 100 C. and 120 C., each for 2 h and at intervals of 1 h, keeping a constant temperature at 120 C. for 2 h and then turning off the dry box for natural cooling to the room temperature, wherein the warming process guarantees that an oil film on the surface of sand grains does not burst during rapid warming; and preparing neutral and water-wet cores with untreated quartz sand and epoxy resin, 20% dibutyl phthalate as a flexibilizer and 7% ethanediamine as a curing agent, wherein the prepared artificial cores have neutral and slightly oil-wet properties.

2. The method for preparing an artificial core for petroleum geological exploration according to claim 1, wherein during sand filling, sand is added each time in an appropriate amount and at an appropriate thickness to avoid local compaction, and the sand added each time needs to be carded and flattened.

3. The method for preparing an artificial core for petroleum geological exploration according to claim 1, wherein a specific operation method in step 4 comprises: (1) fully agitating the quartz sand with the epoxy resin in a certain proportion and putting a resulting mixture into a prepared evacuator; (2) saturating the mixture with a water-based clay suspension of a known composition such that the sand mold is in full contact with or adsorbs the clay in the water; then removing the water-based clay suspension, repeating the above process for a plurality of times, and finally drying the water-based clay suspension and weighing the residual clay to obtain an amount of the adsorbed clay; and (3) putting suction-filtered sand mold into a mold, and pressurizing and drying.

4. The method for preparing an artificial core for petroleum geological exploration according to claim 1, wherein a drum, an agitating impeller and a main box of the agitator in step 3 are all controlled to rotate in different directions such that the quartz sand is agitated therein in a three-dimensional rotational manner, avoiding nonuniform manual agitation of the quartz sand and guaranteeing that porosities, permeability values, pore structures and rock grain size distributions at all points of the artificial core are respectively consistent.

5. A device for preparing an artificial core for petroleum geological exploration, applied to the method for preparing an artificial core for petroleum geological exploration according to claim 1.

6. The device for preparing an artificial core for petroleum geological exploration according to claim 5, wherein during sand filling, sand is added each time in an appropriate amount and at an appropriate thickness to avoid local compaction, and the sand added each time needs to be carded and flattened.

7. The device for preparing an artificial core for petroleum geological exploration according to claim 5, wherein a specific operation method in step 4 comprises: (1) fully agitating the quartz sand with the epoxy resin in a certain proportion and putting a resulting mixture into a prepared evacuator; (2) saturating the mixture with a water-based clay suspension of a known composition such that the sand mold is in full contact with or adsorbs the clay in the water; then removing the water-based clay suspension, repeating the above process for a plurality of times, and finally drying the water-based clay suspension and weighing the residual clay to obtain an amount of the adsorbed clay; and (3) putting suction-filtered sand mold into a mold, and pressurizing and drying.

8. The device for preparing an artificial core for petroleum geological exploration according to claim 5, wherein a drum, an agitating impeller and a main box of the agitator in step 3 are all controlled to rotate in different directions such that the quartz sand is agitated therein in a three-dimensional rotational manner, avoiding nonuniform manual agitation of the quartz sand and guaranteeing that porosities, permeability values, pore structures and rock grain size distributions at all points of the artificial core are respectively consistent.

9. The device for preparing an artificial core for petroleum geological exploration according to claim 5, comprising a screening assembly, an agitating assembly, an evacuating assembly and a drying assembly.

10. The device for preparing an artificial core for petroleum geological exploration according to claim 6, comprising a screening assembly, an agitating assembly, an evacuating assembly and a drying assembly.

11. The device for preparing an artificial core for petroleum geological exploration according to claim 7, comprising a screening assembly, an agitating assembly, an evacuating assembly and a drying assembly.

12. The device for preparing an artificial core for petroleum geological exploration according to claim 8, comprising a screening assembly, an agitating assembly, an evacuating assembly and a drying assembly.

13. The device for preparing an artificial core for petroleum geological exploration according to claim 5, wherein the agitating assembly is an agitator; and a drum, an agitating impeller and a main box of the agitator are all controlled to rotate in different directions such that quartz sand is agitated therein in a three-dimensional rotational manner.

14. The device for preparing an artificial core for petroleum geological exploration according to claim 6, wherein the agitating assembly is an agitator; and a drum, an agitating impeller and a main box of the agitator are all controlled to rotate in different directions such that quartz sand is agitated therein in a three-dimensional rotational manner.

15. The device for preparing an artificial core for petroleum geological exploration according to claim 7, wherein the agitating assembly is an agitator; and a drum, an agitating impeller and a main box of the agitator are all controlled to rotate in different directions such that quartz sand is agitated therein in a three-dimensional rotational manner.

16. The device for preparing an artificial core for petroleum geological exploration according to claim 8, wherein the agitating assembly is an agitator; and a drum, an agitating impeller and a main box of the agitator are all controlled to rotate in different directions such that quartz sand is agitated therein in a three-dimensional rotational manner.

17. The device for preparing an artificial core for petroleum geological exploration according to claim 5, wherein the screening assembly comprises a 20 to 80-mesh sieve mesh and a vibration motor; the evacuating assembly comprises a vacuum pump and a suction filtration pump; and the drying assembly comprises an electrothermal blowing dry box, a constant temperature box and a cooling box.

18. The device for preparing an artificial core for petroleum geological exploration according to claim 6, wherein the screening assembly comprises a 20 to 80-mesh sieve mesh and a vibration motor; the evacuating assembly comprises a vacuum pump and a suction filtration pump; and the drying assembly comprises an electrothermal blowing dry box, a constant temperature box and a cooling box.

19. The device for preparing an artificial core for petroleum geological exploration according to claim 7, wherein the screening assembly comprises a 20 to 80-mesh sieve mesh and a vibration motor; the evacuating assembly comprises a vacuum pump and a suction filtration pump; and the drying assembly comprises an electrothermal blowing dry box, a constant temperature box and a cooling box.

20. The device for preparing an artificial core for petroleum geological exploration according to claim 8, wherein the screening assembly comprises a 20 to 80-mesh sieve mesh and a vibration motor; the evacuating assembly comprises a vacuum pump and a suction filtration pump; and the drying assembly comprises an electrothermal blowing dry box, a constant temperature box and a cooling box.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To describe the technical solutions in the embodiments of the present disclosure more clearly, the present disclosure will be described in detail below in conjunction with the accompanying drawings and the specific embodiments. Apparently, the drawings in the following description show merely some embodiments of the present disclosure, and other drawings may be derived from these drawings by those of ordinary skill in the art without creative efforts. In the drawings:

[0028] FIG. 1 is a flowchart of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To make the foregoing objective, features, and advantages of the present disclosure clearer and more comprehensible, a specific embodiment of the present disclosure is described in detail below with reference to the accompanying drawings.

[0030] Many specific details are set forth in the following descriptions to facilitate full understanding of the present disclosure, but the present disclosure may also be implemented in other ways that are different from those described herein. Similar derivatives may be made by those skilled in the art without departing from the connotation of the present disclosure, and therefore, the present disclosure is not limited by the specific embodiment disclosed below.

[0031] Secondly, the present disclosure is described in detail in combination with the figure. When the embodiment of the present disclosure is described in detail, for the convenience of description, a sectional view of a structure of a device will not be locally enlarged according to a general scale, and the figure shows merely an example and may not limit the protection scope of the present disclosure. In addition, dimensions in a three-dimensional (3D) space including a length, width and depth should be provided in actual manufacture.

[0032] In order to make the objective, technical solutions and advantages of the present disclosure clearer, the embodiment of the present disclosure will be further described in detail in combination with the accompanying drawings.

EXAMPLE 1

[0033] Provided are a method and device for preparing an artificial core for petroleum geological exploration. The method includes the following steps: [0034] step 1, establish a relation curve between a median grain diameter of quartz sand and a permeability, determine a type and a usage amount of epoxy resin, and prepare a cementing agent according to a principle that the epoxy resin has a direct ratio with a specific surface; [0035] step 2, based on a method of controlling a core permeability, prepare benchmark sand with quartz sand of different grain sizes in a certain ratio, fabricate a low-permeability core by adjusting a ratio of the benchmark sand to fine sand, and fabricate a high-permeability core by adjusting a ratio of the benchmark sand to coarse sand; [0036] step 3, separately and proportionally weigh quartz sand of different grain diameters and putting them into a magnetic tray, and manually mix and agitate for later use, where since agitating frequency, times and uniformity degree for per capita have a great influence on porosity and permeability values of an artificial core during stirring, and a quartz sand mixing agitator is employed to avoid man-made nonuniform agitation; [0037] step 4, add a clay mineral, where a clay mineral in a natural rock core plays an important role on a structure and physical properties of the rock core; according to a principle of physical simulation similarity criterion, a certain amount of clay mineral is added to an artificial core; and a special method of adding the clay mineral is used to avoid the clay mineral from being covered with the epoxy resin; and [0038] step 5, prepare an artificial core: prepare a slightly oil-wet core by diluting silicone oil which is 10% by weight of a sand mold with 20 times petroleum ether, evenly agitating the diluted silicone oil with 40 to 70-mesh quartz sand, 70 to 140-mesh quartz sand and 140 to 200-mesh quartz sand, volatilizing at room temperature for 20 h, then putting the mixed quartz sand into an electrothermal blowing dry box, warming according to temperature programming of 60 C., 80 C., 100 C. and 120 C., each for 2 h and at intervals of 1 h, keeping a constant temperature at 120 C. for 2 h and then turning off the dry box for natural cooling to the room temperature, where this warming process guarantees that an oil film on the surface of sand grains does not burst during rapid warming; and prepare neutral and water-wet cores with untreated quartz sand and epoxy resin, 20% dibutyl phthalate as a flexibilizer and 7% ethanediamine as a curing agent, where the prepared artificial cores have neutral and slightly oil-wet properties.

[0039] Specifically, the following must be noted during sand filling: sand should be added each time in an appropriate amount and at an appropriate thickness to avoid local compaction, and the sand added each time needs to be carded and flattened.

[0040] Specifically, a specific operation method in step 4 includes: [0041] (1) fully agitate the quartz sand with the epoxy resin in a certain proportion and put a resulting mixture into a prepared evacuator; (2) saturate the mixture with a water-based clay suspension of a known composition such that the sand mold is in full contact with or adsorbs the clay in the water; then remove the water-based clay suspension, repeat the above process for a plurality of times, and finally dry the water-based clay suspension and weigh the residual clay to obtain an amount of the adsorbed clay; and (3) put suction-filtered sand mold into a mold, and perform pressurizing and drying.

[0042] Specifically, a drum, an agitating impeller and a main box of the agitator in step 3 are all controlled to rotate in different directions such that the quartz sand is agitated therein in a three-dimensional rotational manner, avoiding nonuniform manual agitation of the quartz sand and guaranteeing that porosities, permeability values, pore structures and rock grain size distributions at all points of the artificial core are respectively consistent.

[0043] Specifically, the device includes a screening assembly, an agitating assembly, an evacuating assembly and a drying assembly, where the agitating assembly is an agitator; and a drum, an agitating impeller and a main box of the agitator are all controlled to rotate in different directions such that quartz sand is agitated therein in a three-dimensional rotational manner; the screening assembly includes a 20 to 80-mesh sieve mesh and a vibration motor; the evacuating assembly includes a vacuum pump and a suction filtration pump; and the drying assembly includes an electrothermal blowing dry box, a constant temperature box and a cooling box.

[0044] Working Principle: during the use of the present disclosure, the quartz sand is agitated within the agitator in a three-dimensional rotational manner, avoiding nonuniform manual agitation of the quartz sand and guaranteeing that porosities, permeability values, pore structures and rock grain size distributions at all points of the artificial core are respectively consistent. Cores different in permeability are closer to each other in pore structure and thus are more scientific and practical. A cementing agent is prepared by using the formula described above. No matter how the sand mold changes, an optimum content of the cementing agent can be guaranteed such that the artificial core has consistent hardness, consistent uniformity degree and consistent oil displacement effect after bearing a high temperature and a high pressure.

[0045] Although the present disclosure has been described above with reference to the embodiment, various improvements can be made thereto and components therein can be replaced with equivalents without departing from the scope of the present disclosure. In particular, as long as there is no structural conflict, various features in the embodiment disclosed in the present disclosure can be combined with each other in any manner. These combinations are not exhaustively described in this description only for the sake of omitting space and saving resources. The present disclosure is not limited to the specific embodiment disclosed herein, but shall include all technical solutions falling within the scope of the claims.