High-thermal-conductivity well cementation cement slurry system using solid waste as well as preparation method and application thereof

Abstract

The invention discloses a high-thermal-conductivity well cementation cement slurry system applying solid waste as well as a preparation method and application thereof, and belongs to the technical field of geothermal resource development. The well cementation cement slurry system provided by the invention comprises 40-60 parts of cement; 5-25 parts of a high thermal conductivity material; 30-45 parts of a high-temperature strength stabilizing material; 1-5 parts of a retarder; 1-5 parts of a fluid loss agent; 0.4-2 parts of a dispersant; 3-4 parts of a suspension stabilizer; and 0.05 to 0.2 part of a defoaming agent. The high-thermal-conductivity material is formed by mixing wollastonite fibers with waste side blocks and cathode carbon blocks in treated electrolytic aluminum overhaul slag. The electrolytic aluminum solid waste is used as a heat conduction material, the method for harmlessly treating the electrolytic aluminum solid waste is provided, the method is environmentally friendly, the use cost of silicon carbide and silicon nitride in a well cementation cement system is remarkably reduced, the heat conduction performance of water well cementation mudstone is enhanced, and the high-temperature stability of the cement stone is improved; the corrosion of CO2 is reduced, and the high-temperature strength decline of the set cement is inhibited.

Description

Technical Field

[0001] The present invention belongs to the technical field of geothermal resource development, and particularly relates to a high thermal conductivity cement slurry system using solid waste, its preparation method and application. Background Art

[0002] Under the background of accelerating the transformation of the global energy structure, geothermal energy, as a stable and reliable renewable energy, has received extensive attention. Although geothermal resources have significant advantages such as a wide distribution range and the energy conversion efficiency not being restricted by climate conditions, the commercial development of medium and high-temperature geothermal resources still faces multiple technical bottlenecks. Among them, the cementing project, as the core link to ensure the safe operation of geothermal wells throughout their life cycle, the performance breakthrough of its material system has become a key restrictive factor for the industry's development.

[0003] Cementing is a key process to maintain the safe and efficient production of geothermal wells, and the quality of the cement sheath affects the operation effectiveness of geothermal wells. In the existing technology, the cement sheath of the well faces two technical challenges: on the one hand, the cement sheath of the well is a typical multiphase inhomogeneous brittle material with a low thermal conductivity, which is not conducive to the efficient heat exchange of the heat transfer medium in the injection / production wells; on the other hand, high temperature also causes the performance of the cement sheath of the well to deteriorate, and it cannot effectively seal the formation. Especially when CO2 is selected as the heat transfer medium, the corrosion effect of CO2 on the cement stone will further cause the compressive strength of the cement stone to decrease. Based on the above problems, it is particularly important to develop a new type of cementing cement system with high thermal conductivity, high temperature stability and corrosion resistance to CO2. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a high thermal conductivity cement slurry system using solid waste, which has excellent high temperature strength stability, high thermal conductivity and corrosion resistance.

[0005] The second purpose of the present invention is to provide a preparation method of the cement slurry system.

[0006] The third purpose of the present invention is to provide an application of the cement slurry system.

[0007] To achieve the above purposes, the technical solutions adopted by the present invention are as follows:

[0008] In the first aspect, the present invention discloses a high thermal conductivity cement slurry system using solid waste, which comprises the following raw materials in parts by weight: 40 - 60 parts of cement; 5 - 25 parts of high thermal conductivity material; 30 - 45 parts of high temperature strength stabilizing material; 1 - 5 parts of retarder; 1 - 5 parts of fluid loss reducer; 0.4 - 2 parts of dispersant; 3 - 4 parts of suspension stabilizer; 0.05 - 0.2 parts of defoamer.

[0009] In some embodiments of the present invention, the cement slurry system comprises the following raw materials in parts by weight: 47-60 parts of cement; 5-23 parts of high thermal conductivity material; 30-40 parts of high-temperature strength stabilizing material; 3-4 parts of retarder; 1-3 parts of fluid loss reducer; 0.4-1 part of dispersant; 3-4 parts of suspension stabilizer; 0.05-0.2 part of defoamer.

[0010] In some embodiments of the present invention, the cement is selected from G-grade high sulfate-resistant cement; further preferably, it is the G-grade high sulfate-resistant cement produced by Jiahua Special Cement Co., Ltd.

[0011] In some embodiments of the present invention, the high thermal conductivity material is composed of wollastonite fiber mixed with waste side blocks and cathode carbon blocks in the treated electrolytic aluminum overhaul slag;

[0012] Preferably, the mass ratio of the treated waste side blocks, the treated cathode carbon, and wollastonite fiber is (5-8):(1-3):(0.5-3);

[0013] In the waste side blocks of the present invention, the silicon carbide content is 65-75 wt%, and the silicon nitride content is 15-25%;

[0014] The main component of the cathode carbon block in the present invention is graphite, with a proportion of 65-70 wt%, and the rest are 20-30 wt% of fluoride and aluminum-containing compounds.

[0015] In some embodiments of the present invention, the preparation method of the high thermal conductivity material comprises the following steps:

[0016] S1: Treatment of waste side blocks: Mix and grind the waste side blocks with slaked lime to obtain the treated waste side block powder; preferably, the mass ratio of the waste side blocks to slaked lime is 280-320:1; preferably, grind to a particle size of 150-200 mesh, and further preferably 180 mesh;

[0017] S2: Treatment of cathode carbon blocks: First soak the cathode carbon blocks in a hydrogen peroxide solution, then add slaked lime and continue to soak, filter, dry, and grind after adding slaked lime to obtain the treated cathode carbon block powder;

[0018] Preferably, the concentration of the hydrogen peroxide solution is 1.0-2.0 wt%; its dosage should be sufficient to completely immerse the cathode carbon blocks; the soaking time in the hydrogen peroxide solution is 1-5 h;

[0019] Preferably, the mass ratio of the cathode carbon blocks to the slaked lime used for soaking is 80-120:1; add slaked lime and continue to soak for 1-5 h;

[0020] Preferably, the mass ratio of the cathode carbon blocks to the slaked lime incorporated after filtration and drying is 250-350:1;

[0021] Preferably, in S2, it is ground to a particle size of 200 - 250 mesh, more preferably 230 mesh;

[0022] S3: Mixing: The powders obtained by grinding in S1 and S2 are mixed uniformly with wollastonite fibers to obtain a high - thermal - conductivity material.

[0023] In some embodiments of the present invention, the high - temperature strength - stable material is a mixture of waste aluminosilicate glass powder and industrial quartz sand; wherein the proportion of aluminosilicate glass powder is 10 - 40 wt%, preferably 25 - 40 wt%, the particle size is 150 - 200 mesh, preferably 170 mesh; the proportion of industrial quartz sand is 60 - 90 wt%, preferably 60 - 75%; the particle size of industrial quartz sand is divided into two gradations of 300 - 350 mesh and 700 - 900 mesh, preferably two gradations of 325 mesh and 800 mesh; and their mass ratio is 40 - 62:5 - 25.

[0024] In some embodiments of the present invention, the retarder is at least one of gluconates and sulfonates;

[0025] Preferably, the fluid - loss reducer is of the AMPS - amide - carboxylic acid polymer type;

[0026] Preferably, the dispersant is of the formaldehyde - acetone condensate type;

[0027] Preferably, the suspension stabilizer is at least one of AM - AMPS - NVP polymer type and microsilica;

[0028] Preferably, the defoamer is tributyl phosphate.

[0029] In the second aspect, the present invention discloses a preparation method of the above - mentioned cement slurry system, and the cement slurry system is prepared according to the oil well cement test method of GB / T 19139 - 2012.

[0030] Preferably, the water - cement ratio is 0.44.

[0031] In the third aspect, the present invention discloses the application of the above - mentioned cement slurry system, as an application for well - cementing cement slurry; preferably, as an application for geothermal well well - cementing cement slurry.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention is scientifically designed and ingeniously conceived. It creatively uses electrolytic aluminum solid waste as a thermal - conductivity material, provides a method for harmless treatment of electrolytic aluminum solid waste, is green and environmentally friendly, and significantly reduces the use cost of silicon carbide and silicon nitride in the well - cementing cement system, and enhances the thermal - conductivity performance of water - well - cementing mudstone.

[0034] The electrolytic aluminum solid waste used in the present invention contains some cryolite (Na4AlF6) and fluoride. 3+ It can increase the stability of tobermorite (the high-temperature hydration product of oil well cement and siliceous materials), inhibit the transformation to xonotlite, and improve the high-temperature stability of cement paste; while F - It can react with the hydration product to generate insoluble calcium fluoride to coat the hydration product and fill the pores of cement paste, while reducing the corrosion of CO2, it can also reduce the Ca / Si ratio of cement and inhibit the high-temperature strength decline of cement paste. Experimental results show that the cementing slurry system of the present invention has better corrosion resistance and thermal conductivity than ordinary cementing slurry. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The cement described in the embodiments of the present invention is the G-grade high sulfate-resistant cement produced by Jiahua Special Cement Co., Ltd.

[0037] Example 1

[0038] As a preferred embodiment of the present invention, a high-temperature corrosion-resistant and high-thermal-conductivity cementing slurry system provided in this embodiment includes the following components by mass, specifically as follows:

[0039] Table 1

[0040] Component Parts by mass Cement 52 High thermal conductivity material 16 Strength stabilizer 32 Retarder 3 Fluid loss reducer 3 Dispersant 0.8 Suspension stabilizer 3 Defoamer 0.06 Mixing water 44

[0041] The preparation method of the high thermal conductivity material of this embodiment is as follows:

[0042] S1: Treatment of waste side blocks: Mix the waste side blocks with slaked lime in a mass ratio of 300:1 and grind them to a particle size of 180 mesh to obtain treated waste side block powder;

[0043] S2: Treatment of cathode carbon block: first soak the cathode carbon block in a 1.5wt% hydrogen peroxide solution for 3 hours, then add slaked lime and continue soaking for 3 hours, filter, dry, add slaked lime and grind to a particle size of 230 mesh to obtain a treated cathode carbon block powder; wherein the mass ratio of the cathode carbon block to the slaked lime used for soaking is 100:1, and the mass ratio of the cathode carbon block to the slaked lime added after filtering and drying is 300:1;

[0044] S3: Mixing: The powder obtained by grinding S1 and S2 is evenly mixed with wollastonite fiber to obtain a high thermal conductivity material, wherein the mass ratio of the treated waste side block powder, the treated cathode carbon block powder and the wollastonite fiber is 7:2:1.

[0045] In this embodiment, the strength stabilizer is a mixture of aluminosilicate glass powder and industrial quartz sand, and the mass ratio thereof is aluminosilicate glass powder: 325 mesh industrial quartz sand: 800 mesh industrial quartz sand = 3:4.5:2.5.

[0046] The suspension stabilizer in this embodiment is AM-AMPS-NVP polymer, the retarder is gluconate, the fluid loss reducer is AMPS-amide-carboxylic acid polymer, the dispersant is formaldehyde-acetone condensate, and the foaming agent is tributyl phosphate.

[0047] Example 2

[0048] As a preferred embodiment of the present invention, a high-temperature corrosion-resistant and high-thermal-conductivity cementing slurry system provided in this embodiment includes the following components by mass, specifically as follows:

[0049] Table 2

[0050] Component Parts by mass Cement 47 High thermal conductivity material 10 Strength stabilizer 43 Retarder 3 Fluid loss reducer 3 Dispersant 0.4 Suspension stabilizer 3 Defoamer 0.06 Mixing water 44

[0051] Compared with Example 1, the preparation method of the high thermal conductivity material in this embodiment has a mass ratio of the treated waste side block powder, the treated cathode carbon block powder and the wollastonite fiber of 7:2.5:0.5, and the other conditions are the same.

[0052] In this embodiment, the strength stabilizer is a mixture of aluminosilicate glass powder and industrial quartz sand, and the mass ratio thereof is aluminosilicate glass powder: 325 mesh industrial quartz sand: 800 mesh industrial quartz sand = 3:5.5:1.5.

[0053] The suspension stabilizer in this embodiment is AM-AMPS-NVP polymer, the retarder is gluconate, the fluid loss reducer is AMPS-amide-carboxylic acid polymer, the dispersant is formaldehyde-acetone condensate, and the foaming agent is tributyl phosphate.

[0054] Example 3

[0055] As a preferred embodiment of the present invention, a high-temperature corrosion-resistant and high-thermal-conductivity cementing slurry system provided in this embodiment includes the following components by mass, specifically as follows:

[0056] Table 3

[0057]

[0058]

[0059] Compared with Example 1, the preparation method of the high thermal conductivity material in this embodiment has a mass ratio of the treated waste side block powder, the treated cathode carbon block powder and the wollastonite fiber of 6:2:2, and the other conditions are the same.

[0060] In this embodiment, the strength stabilizer is a mixture of aluminosilicate glass powder and industrial quartz sand, and the mass ratio thereof is aluminosilicate glass powder: 325 mesh industrial quartz sand: 800 mesh industrial quartz sand = 2.5:6.2:1.3.

[0061] The suspension stabilizer in this embodiment is AM-AMPS-NVP polymer, the retarder is gluconate, the fluid loss reducer is AMPS-amide-carboxylic acid polymer, the dispersant is formaldehyde-acetone condensate, and the foaming agent is tributyl phosphate.

[0062] Example 4

[0063] As a preferred embodiment of the present invention, a high-temperature corrosion-resistant and high-thermal-conductivity cementing slurry system provided in this embodiment includes the following components by mass, specifically as follows:

[0064] Table 4

[0065] Component Parts by mass Cement 60 High thermal conductivity material 8 Strength stabilizer 32 Retarder 4 Fluid loss reducer 3 Dispersant 1 Suspension stabilizer 4 Defoamer 0.06 Mixing water 44

[0066] Compared with Example 1, the preparation method of the high thermal conductivity material in this embodiment has a mass ratio of the treated waste side block powder, the treated cathode carbon block powder and the wollastonite fiber of 5.5:2:2.5, and the other conditions are the same.

[0067] In this embodiment, the strength stabilizer is a mixture of aluminosilicate glass powder and industrial quartz sand, and the mass ratio thereof is 4:5.5:0.5 of aluminosilicate glass powder: 325 mesh industrial quartz sand: 800 mesh industrial quartz sand.

[0068] The suspension stabilizer in this embodiment is AM-AMPS-NVP polymer, the retarder is gluconate, the fluid loss reducer is AMPS-amide-carboxylic acid polymer, the dispersant is formaldehyde-acetone condensate, and the foaming agent is tributyl phosphate.

[0069] Example 5

[0070] As a preferred embodiment of the present invention, a high-temperature corrosion-resistant and high-thermal-conductivity cementing slurry system provided in this embodiment includes the following components by mass, specifically as follows:

[0071] Table 5

[0072] Component Parts by mass Cement 55 High thermal conductivity material 5 Strength stabilizer 40 Retarder 3.5 Fluid loss reducer 3 Dispersant 0.8 Suspension stabilizer 3.5 Defoamer 0.06 Mixing water 44

[0073] The preparation method of the high thermal conductivity material in this example, compared with Example 1, the mass ratio of the treated waste side block powder, the treated cathode carbon block powder to wollastonite fiber is 8:1.5:0.5, and the other conditions are the same.

[0074] In this example, the strength stabilizer is a mixture of aluminosilicate glass powder and industrial quartz sand, and its mass ratio is aluminosilicate glass powder: 325-mesh industrial quartz sand: 800-mesh industrial quartz sand 4:4:2.

[0075] The suspension stabilizer in this example is AM-AMPS-NVP polymer type, the retarder is gluconate, the fluid loss reducer is AMPS-amide-carboxylic acid polymer, the dispersant is formaldehyde-acetone condensate type, and the foaming agent is tributyl phosphate.

[0076] Comparative Example 1

[0077] Prepare the cement slurry according to the following mass percentages:

[0078] 65% G-class cement, 35% siliceous material, 4% fluid loss reducer, 3% retarder, 2.5% suspension stabilizer, 0.06% defoaming agent. Prepare the cement slurry according to "GB / T 19139 Test Methods for Oil Well Cements", and the water-cement ratio is 0.44.

[0079] The G-class cement in this comparative example is the G-class high sulfate-resistant cement produced by Jiahua Special Cement Co., Ltd.; the siliceous material is 325-mesh industrial quartz sand; the fluid loss reducer is AMPS-amide-carboxylic acid polymer; the retarder is gluconate, and the foaming agent is tributyl phosphate.

[0080] Test Example 1

[0081] According to "GB / T 19139 Test Methods for Oil Well Cements", conduct engineering performance tests on the cement slurry systems of Examples 1-5 and Comparative Example 1, and the experimental results are shown in Table 6.

[0082] Table 6 Test Results of Engineering Performance of Cement Slurry Systems

[0083]

[0084] As can be seen from Table 6, the water loss of the cement slurries prepared in Examples 1-5 is less than 50 ml / 30 min, the fluidity is in the range of 22-24 cm, meeting the technical requirements of well cementing construction, with a small density difference up and down, good slurry stability, and a controllable thickening time.

[0085] The test results of the hardened cement paste are shown in Table 7. The cement paste is first cured in a high-temperature and high-pressure curing autoclave for 3 days to form, and then transferred to a high-temperature and high-pressure corrosion reaction autoclave for curing. The curing conditions of the high-temperature and high-pressure curing autoclave are 180 °C / 20.7 MPa, and the curing conditions of the high-temperature and high-pressure corrosion curing autoclave are 180 °C, CO2 pressure 5 MPa, and N2 partial pressure 5 MPa.

[0086] Table 7 Test Results of Hardened Cement Paste

[0087]

[0088]

[0089] As can be seen from Table 7, the early compressive strength development of both the examples and the comparative examples is relatively rapid. Only the 3-day compressive strengths of Examples 1 and 3 are slightly lower than that of Comparative Example 1. After being placed in the high-temperature and high-pressure corrosion autoclave for corrosion curing, within a relatively short age, the compressive strengths of both the examples and the comparative examples can develop normally. However, when the corrosion age is extended to 28 days, the strength of Comparative Example 1 has started to decline, while the compressive strength of the examples still maintains a small increase, indicating that the corrosion resistance of the examples is better than that of the comparative examples. From the results of the elastic modulus, due to the addition of wollastonite fibers, the elastic modulus of the examples is significantly smaller than that of the comparative examples. The thermal conductivity of the examples is significantly higher than that of Comparative Example 1, indicating that the high thermal conductivity material described in the present invention can effectively improve the thermal conductivity of the hardened cement paste.

[0090] The above is only the preferred embodiment of the invention, and it does not impose any form of limitation on the invention. According to the technical essence of the invention, any simple modification, equivalent replacement, and improvement made to the above embodiments within the spirit and principle of the invention still fall within the protection scope of the technical solution of the invention.

Claims

1. A high thermal conductivity cement slurry system for well cementing using solid waste, characterized in that, It comprises raw materials in the following parts by weight: 40 - 60 parts of cement; 5 - 25 parts of high thermal conductivity material; 30 - 45 parts of high-temperature strength stabilizing material; 1 - 5 parts of retarder; 1 - 5 parts of fluid loss reducer; 0.4 - 2 parts of dispersant; 3 - 4 parts of suspension stabilizer; 0.05 - 0.2 parts of defoamer.

2. The high thermal conductivity cement slurry system for well cementing using solid waste according to claim 1, wherein 47 - 60 parts of cement; 5 - 23 parts of high thermal conductivity material; 30 - 40 parts of high-temperature strength stabilizing material; 3 - 4 parts of retarder; 1 - 3 parts of fluid loss reducer; 0.4 - 1 parts of dispersant; 3 - 4 parts of suspension stabilizer; 0.05 - 0.2 parts of defoamer.

3. A high thermal conductivity cement slurry system for well cementing using solid waste according to claim 1 or 2, characterized in that, The cement is selected from G-grade high sulfate-resistant cement; further preferably, it is the G-grade high sulfate-resistant cement produced by Jiahua Special Cement Co., Ltd.

4. A high thermal conductivity cement slurry system for well cementing using solid waste according to claim 1 or 2, characterized in that, The high thermal conductivity material is composed of wollastonite fiber mixed with waste side blocks and cathode carbon blocks in the treated electrolytic aluminum overhaul slag; Preferably, the mass ratio of the treated waste side blocks, the treated cathode carbon, and wollastonite fiber is (5 - 8):(1 - 3):(0.5 - 3).

5. A high thermal conductivity cement slurry system for well cementing using solid waste according to claim 4, characterized in that, The preparation method of the high thermal conductivity material comprises the following steps: S1: Treatment of waste side blocks: Mix and grind the waste side blocks with slaked lime to obtain the treated waste side block powder; preferably, the mass ratio of the waste side blocks to slaked lime is 280 - 320:1; preferably, grind to a particle size of 150 - 200 mesh, further preferably 180 mesh; S2: Treatment of cathode carbon blocks: First soak the cathode carbon blocks in a hydrogen peroxide solution, then add slaked lime and continue to soak, filter, dry, and grind after incorporating slaked lime to obtain the treated cathode carbon block powder; Preferably, the concentration of the hydrogen peroxide solution is 1.0 - 2.0 wt%; its amount should be such that the cathode carbon blocks are completely immersed; the soaking time with the hydrogen peroxide solution is 1 - 5 h; Preferably, the mass ratio of the cathode carbon blocks to the slaked lime for soaking is 80 - 120:1; add slaked lime and continue to soak for 1 - 5 h; Preferably, the mass ratio of the cathode carbon blocks to the slaked lime incorporated after filtration and drying is 250 - 350:1; Preferably, in S2, grind to a particle size of 200 - 250 mesh, further preferably 230 mesh; S3: Mixing: Mix the powders obtained by grinding in S1 and S2 with wollastonite fiber evenly to obtain the high thermal conductivity material.

6. The high thermal conductivity cement slurry system for well cementing using solid waste according to claim 1 or 2, characterized in that, The high-temperature strength stabilizing material is a mixture of waste aluminosilicate glass powder and industrial quartz sand; Among them, the proportion of aluminosilicate glass powder is 10 - 40 wt%, preferably 25 - 40 wt%, the particle size is 150 - 200 mesh, preferably 170 mesh; The proportion of industrial quartz sand is 60 - 90 wt%, preferably 60 - 75%; the particle size of industrial quartz sand is divided into two gradations of 300 - 350 mesh and 700 - 900 mesh, preferably two gradations of 325 mesh and 800 mesh; their mass ratio is 40 - 62:5 - 25.

7. A high thermal conductivity cement slurry system for well cementing using solid waste according to claim 1 or 2, characterized in that, The retarder is at least one of gluconates and sulfonates; Preferably, the fluid loss reducer is an AMPS - amide - carboxylic acid polymer; Preferably, the dispersant is a formaldehyde - acetone condensate; Preferably, the suspension stabilizer is at least one of AM - AMPS - NVP polymers and microsilica; Preferably, the defoamer is tributyl phosphate.

8. The preparation method of the cement slurry system according to any one of claims 1-7, characterized in that, The cement slurry system was prepared according to the test method for oil well cement of GB / T 19139-2012.

9. The preparation method of the cement slurry system according to claim 8, characterized in that, The water-cement ratio was 0.

44.

10. Use of the cement slurry system according to any one of claims 1-7, characterized in that, It is used as the cement slurry for well cementing; preferably, it is used as the cement slurry for well cementing in geothermal wells.

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