CN207637392U - A fracture-cavity artificial core - Google Patents

Abstract

A kind of fracture hole type artificial core of the utility model, mainly by crack, solution cavity, gap, matrix.The crack, solution cavity, gap are made of organic glass, and the matrix is made of carbonate rock powder and curing agent with by a certain percentage, its cementing strength is made to reach requirement of experiment.The crack, solution cavity, gap inner wall are after processing, keep its uneven full of slight crack, the fully practical crack of simulation and solution cavity inner wall, using length, the different crack of thickness and solution cavity volume organic glass hollow ball not of uniform size, carry out random combine, the strong anisotropism for embodying actual reservoir, makes its experiment effect be more nearly true reservoir.With matrix slight fluid communication can occur for crack, solution cavity, gap as a result, realize the treble medium flowing of seam_cavern type.The utility model is convenient to use, time saving and energy saving, and energy actual response reservoir, the utility model material, principle are simple, cheap.

Description

A fracture-cavity artificial core

technical field

The utility model relates to a fracture-cavity carbonate rock core model and a manufacturing method, which are mainly used for evaluating technical fields such as oil and gas field development, gas drive, well logging and the like.

Background technique

Carbonate reservoirs occupy a very important position in the world's oil and gas resources, and more than 30% of the carbonate reservoirs are fracture-cavity reservoirs. The reservoirs of this type of reservoir have experienced multiple structural movements, and are greatly affected by weathering, denudation and leaching. Therefore, the reservoirs of this type of reservoir have poor continuity, strong heterogeneity, and developed fractures, caves, and faults.

The Tahe Oilfield in the Tarim Basin is a typical fractured-vuggy carbonate reservoir, and the reservoir space is formed by pore, cave, cavity and fracture formed by previous tectonic movement, karst, metamorphism and weathering leaching and other geological processes. Among them, large caves are the most important storage space, and fractures are not only effective storage spaces, but also the main seepage channels. The existing experimental methods are limited by the size of the sample and the poor representativeness of the sample, so they cannot truly simulate the connectivity of fractures and holes. Due to the high cost of manual coring and the extremely limited amount of coring, laboratory research on fractured-vuggy carbonate rocks requires the preparation of artificial cores that are more in line with the actual reservoir conditions.

Therefore, the present invention provides a fractured-cavity carbonate rock artificial core that meets the requirements of mechanical strength and conforms to the characteristics of real fracture-cavity system and its preparation method, so as to overcome the defects of the prior art.

Contents of the invention

The purpose of the utility model is to provide a new type of artificial rock core technology in order to overcome the deficiency of the existing fracture-cavity artificial rock core preparation technology in the market.

The technical scheme adopted in the utility model is:

The utility model discloses a novel fracture-cavity rock core preparation method, mainly comprising cracks, karst caves, voids and matrix. The cracks, caves, and voids are all made of plexiglass that can withstand a certain pressure, and the matrix is made of carbonate rock powder with a particle size and a curing agent in a certain proportion, so that the bonding strength meets the experimental requirements. The matrix is convenient and easy to obtain, and the permeability after compaction is very small, almost negligible, and can completely model the matrix of an actual fractured-cavity carbonate reservoir. After the inner walls of the cracks, caves, and voids are processed, they will be uneven and filled with cracks, fully simulating the actual cracks and inner walls of the caves, and using plexiglass hollow balls with different lengths, thicknesses, and volumes of cracks and caves to randomly combine , reflecting the strong heterogeneity of the actual reservoir, making the experimental results closer to the real reservoir. The cracks, caves, and voids have openings on the surface, some of which can be randomly connected with the cracks and voids, and the other part is in contact with the matrix, so that the cracks, caves, and voids can exchange slightly with the matrix. Realize the triple medium flow of the fracture-cavity system. Because the cracks and caves have openings on the surface, the inner surface should be treated with rosin. The rosin is black rosin with a softening point of 60°C, or red rosin with a softening point of 70°C. In the above-mentioned manufacturing method, steel plates are used to make the mold; there are 4 side plates and 1 base plate, and the 4 side plates are spliced into a cube box shape and hollow by detachable connection with screws (for easy demoulding). First clean the inside of the mold, brush the inner surface with high-temperature grease, and paste tin foil. A briquetting block is arranged on the mould; the briquetting block matches the size of the mould.

The brush of the utility model has the advantages of convenient and fast use, saving time and effort, and can truly reflect the reservoir. The utility model has simple material and principle and low manufacturing cost.

Description of drawings

Fig. 1 is a schematic diagram of a section structure of a novel fracture-cavity artificial rock core of the present invention.

Figure 2 is a cross-sectional view of the slit.

Figure 3 is a cross-sectional view of the cave.

In the figure: 1. Large karst cave, 2. Small karst cave, 3. Void, 4. Crack, 5. Matrix, 6. Worm hole, 7. Inner wall of karst cave, 8. Crack in inner wall,

9. The inner wall of the crack.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 1 , a novel method for preparing a fracture-cavity artificial rock core of the present invention is mainly composed of a large karst cave 1 , a small karst cave 2 , pores 3 , cracks 4 , and a matrix 5 . A method for preparing a fracture-cavity carbonate rock artificial core, comprising the following steps:

A fracture-cavity artificial rock core, the cracks, caves, and pores are made of plexiglass, a high-temperature and high-pressure-resistant, anti-corrosion material, and the inner wall is treated with a corrosive plexiglass liquid to produce uneven and random cracks, Clean the residual corrosive liquid with clean water, because there are wormholes on the surface of the cracks, caves, and pores, the selected matrix is sand particles with a small particle size. The inner surface of caves and pores is coated with a layer of rosin film, and the molten rosin is poured in, and then cooled. The matrix used is carbonate rock powder with a particle size of less than 13 μm, which is widely and conveniently obtained. The matrix is mixed with selected carbonate rock powder and curing agent in a certain proportion to make it reach the strength required by the experiment. Randomly match caves of different sizes and cracks of different lengths. Due to the existence of wormholes, the cracks can be directly connected to the surface of the cave, and then put the combined hollow spheres and cracks into the cube model, and then Put the matched matrix into the cube model, and press the front and back with a pressure of 3-5MPa for 10-20min. After the pressure is released, put the whole cube model in an oven at 100°C to make it fully cemented. When it is about 90°C, the rosin It will melt, so in this process, the rosin can be cleaned with absolute alcohol The model is conducive to the study of physical property differences and fluid flow laws of real reservoirs; the invention can realize unlimited replication of carbonate rocks in the same fracture-cavity system, and can be used for tests of reservoir reconstruction measures such as acid fracturing to realize the comparison of stimulation effects with quantitative evaluation.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within.

Claims (4)

1. a kind of fracture hole type artificial core, mainly by cavern (1), small solution cavity (2), hole (3), crack (4), matrix (5) group At, it is characterised in that：Solution cavity, crack, hole random distribution embody the strong anisotropism of actual reservoir, realize seam_cavern type Treble medium flowing.

2. a kind of fracture hole type artificial core according to claim 1, it is characterised in that：Crack, solution cavity, internal pore surface are recessed Convex injustice has irregular slight crack.

3. a kind of fracture hole type artificial core according to claim 1, it is characterised in that：Matrix permeability and carbonate rock storage Layer matrix permeability is close.

4. a kind of fracture hole type artificial core according to claim 1, it is characterised in that：Matrix permeability can be with grain size Change and changes.