CN115974454A - Middle-deep heat exchange hole well cementation material and preparation method thereof - Google Patents

Abstract

The invention discloses a well cementation material of a middle-deep heat exchange hole, which comprises the following components in percentage by mass: 70-80% of fine sand, 15-25% of graphite powder, 4% of acrylate and 1% of polyacrylamide; the preparation method comprises the following steps: step 1: uniformly mixing graphite powder, fine sand and acrylic ester according to a certain mass ratio to obtain a mixture; step 2: and then adding polyacrylamide into the mixture obtained in the step 1 to obtain the well cementing material. The invention can greatly improve the heat conductivity of the heat exchange hole annulus by adopting the novel well cementation material, the heat conductivity of the traditional cement sheath is 0.7-1 w/(m.k), the heat conductivity of the novel well cementation material can reach more than 2.5 w/(m.k), the heat exchange capacity of a single well is greatly improved, and the invention has extremely high economic benefit.

Description

A medium-deep layer heat exchange hole cementing material and its preparation method

technical field

The invention relates to the technical field of geothermal heating, in particular to a medium-deep layer heat exchange hole cementing material and a preparation method.

Background technique

Geothermal energy is renewable heat energy from the interior of the earth. It originates from the decay of magma and radioactive substances in the interior of the earth. The heat conducts heat through the formation, and is continuously transferred from the lower high-temperature rock layer to the upper low-temperature rock layer. The reserves are huge and renewable. At present, geothermal energy can be divided into two types from the utilization form, hydrothermal geothermal (water source) and dry hot rock (ground source).

Hydrothermal geothermal (water source), using water as the medium, utilizes the heat of high-temperature groundwater, and then refills the geothermal tail water into the ground. Due to this utilization form, the groundwater flows faster, so the heat extraction radius of a single well is large. The heating power is also great.

However, for middle and deep buried pipes, since groundwater is not used, heat extraction can only be conducted through high-temperature rocks to the casing annulus cement sheath, then to the casing, and then to the heat exchange fluid in the wellbore. Thermal efficiency is low.

Contents of the invention

1. Technical problems to be solved

The purpose of the present invention is to solve the problems in the prior art for medium-deep buried pipes. Since groundwater is not used, heat extraction can only be conducted to the casing annulus cement sheath through high-temperature rocks, then to the casing, and then to the casing. In order to solve the problem of heat exchange fluid in the wellbore, a medium-deep layer heat exchange hole cementing material and its preparation method are proposed.

2. Technical solution

In order to achieve the above object, the present invention adopts the following technical solutions:

A medium-deep layer heat exchange hole cementing material, the cementing material comprises the following components in mass ratio: 70-80% of fine sand, 15-25% of graphite powder, 4% of acrylate and 1% of polyacrylamide.

Preferably, the cementing material comprises the following components by mass ratio: fine sand 80%, graphite powder 15%, acrylate 4% and polyacrylamide 1%.

Preferably, the cementing material comprises the following components by mass ratio: fine sand 70%, graphite powder 25%, acrylate 4% and polyacrylamide 1%.

Preferably, the cementing material includes the following components by mass ratio: fine sand 75%, graphite powder 20%, acrylate 4% and polyacrylamide 1%.

The present invention also proposes a method for preparing a medium-deep layer heat exchange hole cementing material, comprising the following steps:

Step 1: uniformly mix graphite powder, fine sand and acrylate in a certain mass ratio to obtain a mixture;

Step 2: Then add polyacrylamide into the mixture in step 1 to obtain the cementing material.

Preferably, the fine sand has a density of 1.9-2.3 g/cm ³ and a specification of 100 mesh.

The present invention also proposes medium-deep layer heat exchange hole cementing, including surface casing and artificial well bottom, the outside of the surface casing is covered with surface cement cementing, and the inside of the surface casing is filled with the cementing Material.

The present invention also proposes a construction method for medium-deep heat exchange hole cementing, comprising the following steps:

S1: After the cementing material is evenly mixed on the surface, it is injected from the outside of the surface casing. At the same time, the air compressor is used to wash out the drilling fluid in the surface casing, and the reverse circulation process of external injection and internal suction ensures that the cementing material is smoothly lowered into the bottom of the hole;

S2: After the cementing is completed, the drill pipe is run into the surface casing, and the cement slurry is injected to form an artificial well bottom.

3. Beneficial effect

Compared with the prior art, the present invention has the advantages of:

In the present invention, by adopting the new cementing material, the thermal conductivity of the annulus of the heat exchange hole can be greatly improved. The thermal conductivity of the traditional cement sheath is 0.7-1w/(m k), and the thermal conductivity of the new cementing material can reach 2.5w/( m·k) or above, which greatly improves the heat exchange capacity of a single well and has extremely high economic benefits.

Description of drawings

Fig. 1 is a structural schematic diagram of a middle-deep layer heat exchange hole cementing proposed by the present invention.

In the picture: 1 surface casing, 2 artificial well bottom, 3 surface cementing.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention.

Example 1:

The invention relates to a well cementing material for medium-deep heat exchange holes. The well cementing material comprises the following components in mass ratio: 70-80% of fine sand, 15-25% of graphite powder, 4% of acrylate and 1% of polyacrylamide.

In the present invention, the preparation method of the medium-deep layer heat exchange hole cementing material comprises the following steps:

Step 1: uniformly mix graphite powder, fine sand and acrylate in a certain mass ratio to obtain a mixture, the density of the fine sand is 1.9-2.3g/cm ³ , and the specification is 100 mesh;

Step 2: Then polyacrylamide is added to the mixture in step 1 to obtain a cementing material.

In the present invention, by adopting the new cementing material, the thermal conductivity of the annulus of the heat exchange hole can be greatly improved. The thermal conductivity of the traditional cement sheath is 0.7-1w/(m k), and the thermal conductivity of the new cementing material can reach 2.5w/( m·k) or above, which greatly improves the heat exchange capacity of a single well and has extremely high economic benefits.

Example 2:

It has the implementation content of the above-mentioned embodiments, wherein, for the specific implementation of the above-mentioned embodiments, please refer to the above-mentioned description, and the embodiments here will not be repeated in detail; and in the embodiments of the present application, the difference from the above-mentioned embodiments is that :

A well cementing material for medium-deep heat exchange holes. The cementing material comprises the following components in mass ratio: 80% fine sand, 15% graphite powder, 4% acrylate and 1% polyacrylamide.

Example 3:

It has the implementation content of the above-mentioned embodiments, wherein, for the specific implementation of the above-mentioned embodiments, please refer to the above-mentioned description, and the embodiments here will not be repeated in detail; and in the embodiments of the present application, the difference from the above-mentioned embodiments is that :

A well cementing material for medium-deep heat exchange holes. The cementing material comprises the following components in mass ratio: 70% of fine sand, 25% of graphite powder, 4% of acrylate and 1% of polyacrylamide.

Example 4:

It has the implementation content of the above-mentioned embodiments, wherein, for the specific implementation of the above-mentioned embodiments, please refer to the above-mentioned description, and the embodiments here will not be repeated in detail; and in the embodiments of the present application, the difference from the above-mentioned embodiments is that :

A well cementing material for medium-deep heat exchange holes. The cementing material comprises the following components in mass ratio: 75% of fine sand, 20% of graphite powder, 4% of acrylate and 1% of polyacrylamide.

Example 5:

It has the implementation content of the above-mentioned embodiments, wherein, for the specific implementation of the above-mentioned embodiments, please refer to the above-mentioned description, and the embodiments here will not be repeated in detail; and in the embodiments of the present application, the difference from the above-mentioned embodiments is that :

Referring to Fig. 1, the heat exchange hole cementing in the medium-deep layer includes the surface casing and the artificial well bottom. The outside of the surface casing is covered with surface cement for well cementing, and the inside of the surface casing is filled with cementing materials.

The construction method of heat exchange hole cementing in middle and deep layers includes the following steps:

S1: After the cementing material is evenly mixed on the surface, it is injected from the outside of the surface casing. At the same time, the air compressor is used to wash out the drilling fluid in the surface casing, and the reverse circulation process of external injection and internal suction ensures that the cementing material is smoothly lowered into the bottom of the hole;

S2: After the cementing is completed, the drill pipe is run into the surface casing, and the cement slurry is injected to form an artificial well bottom.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (8)

1. A medium-deep heat exchange hole cementing material, characterized in that, the cementing material comprises the following components in mass ratio: fine sand 70-80%, graphite powder 15-25%, acrylate 4% and poly Acrylamide 1%. 2. The medium-deep layer heat exchange hole cementing material according to claim 1, characterized in that the cementing material comprises the following components in mass ratio: fine sand 80%, graphite powder 15%, acrylate 4 % and polyacrylamide 1%. 3. A medium-deep layer heat exchange hole cementing material according to claim 1, characterized in that the cementing material comprises the following components in mass ratio: fine sand 70%, graphite powder 25%, acrylate 4 % and polyacrylamide 1%. 4. A medium-deep layer heat exchange hole cementing material according to claim 1, characterized in that the cementing material comprises the following components in mass ratio: fine sand 75%, graphite powder 20%, acrylate 4 % and polyacrylamide 1%. 5. A method for preparing a medium-deep layer heat exchange hole cementing material according to any one of claims 1-4, characterized in that it comprises the following steps: Step 1: uniformly mix graphite powder, fine sand and acrylate in a certain mass ratio to obtain a mixture; Step 2: Then add polyacrylamide into the mixture in step 1 to obtain the cementing material. 6 . The method for preparing a medium-deep layer heat exchange hole cementing material according to claim 5 , wherein the fine sand has a density of 1.9-2.3 g/cm ³ and a specification of 100 mesh. 7. A medium-deep heat exchange hole cementing application of any one of claims 1-4, characterized in that it comprises a surface casing (1) and an artificial well bottom (2), the surface casing The outside of (1) is covered with surface cement cementing (3), and the inside of the surface casing (1) is filled with the cementing material. 8. The construction method of medium-deep heat exchange hole cementing according to claim 7, characterized in that, comprising the following steps: S1: After the cementing material is mixed evenly on the surface, it is injected from the surface casing (1), and at the same time, an air compressor is used to wash out the drilling fluid in the surface casing (1), and the reverse circulation process of external injection and internal suction ensures that the cementing material smoothly into the bottom of the hole; S2: After the well cementing is completed, the drill pipe is lowered into the surface casing (1), and the cement slurry is injected to form an artificial well bottom.

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