A temperature-resistant composite modified material for well cementing and a preparation method thereof

Abstract

The application discloses a temperature-resistant composite modifying material for well cementing and a preparation method thereof. The modifying material comprises, in percentage by weight, 30-40% of strength modifier type I, 55-60% of strength modifier type II and 5-10% of toughness modifier. The temperature-resistant composite modifying material for well cementing can effectively improve the high-temperature compressive strength and toughness of cement stone, can guarantee the non-decline of the compressive strength of the cement stone under a high-temperature environment, and uses a large amount of solid waste as a main raw material, and has the characteristics of green environmental protection, low cost and excellent performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas field development cementing materials, and particularly relates to a temperature-resistant composite modified material for cementing cement and a preparation method thereof. BACKGROUND

[0002] With the continuous deepening of oil and gas exploration and development, the exploration of resources in the million-meter deep layer has become an important direction for further exploration in the current oil industry, and the deep earth field is a major strategic replacement new field for future oil and gas exploration and development in China. The high-temperature downhole environment in deep wells and ultra-deep wells may cause the strength of the cement stone to decrease, and it is difficult to ensure that the oil and gas well can be effectively isolated after the first cementing is successful. The commonly used method is to add about 30-40% of quartz sand to alleviate the decline in strength. However, the addition of quartz sand will significantly increase the elastic modulus of the cement stone. Moreover, with the increase of temperature, the sand-added cement system will still have a decline in strength. Therefore, it is of great significance to develop a new type of high-temperature-resistant and tough cement system.

[0003] Application No. 201910669046.5 discloses an ultra-high-temperature elastic and tough agent for oil well cementing and its composition. The ultra-high-temperature elastic and tough agent includes the following components blended in a weight ratio: 60% to 90% polytetrafluoroethylene powder, 5% to 20% basalt fiber, and 5% to 20% nano-aluminum oxide fiber.

[0004] Application No. 201910040381.9 discloses an anti-high-temperature toughness material and a preparation method thereof. The application provides an anti-high-temperature toughness material for cementing cement slurry, which includes the following components in weight parts: latex powder 10 to 20 parts; modified rubber powder 10 to 40 parts; polyimide resin 20 to 50 parts; amino silane coupling agent 5 to 10 parts; and modified nanotube 15 to 60 parts. In the modified nanotube, the nanotube is a carbon nanotube and / or a boron nitride nanotube.

[0005] Application No. 201910694360.9 discloses a cementing composition, a composite cementitious material, and a cementing fluid. The cementing composition includes a silico-alumina admixture, a calcium-silica admixture, a reinforcing material, and a toughening material. The composite cementitious material includes cement and the above-mentioned cementing composition.

[0006] Application No. 201610937961.4 discloses a high-temperature oil well cement stone elastic material and a preparation method thereof. The elastic material is prepared from raw materials including the following components: 100 parts by weight of hydrogenated styrene-butadiene block copolymer powder, 20 to 30 parts by weight of silica fume, and 0 to 10 parts by weight of alkyl phenol ether ammonium sulfate salt. The preparation method includes: adding the raw materials in the above-mentioned amounts into a PCS particle composite system to obtain the high-temperature oil well cement stone elastic material.

[0007] In the prior art, although breakthroughs have been made in the compressive strength and toughness of the cement stone, the high temperature and ultra-high temperature cementing requirements faced by deep wells / ultra-deep wells cannot be met, and the present application provides a temperature-resistant composite modifying material for oil and gas well cementing, which can effectively prevent the strength degradation of the cement stone and improve the toughness of the cement stone. SUMMARY

[0008] In order to overcome the defects and deficiencies in the prior art, the present application provides a temperature-resistant composite modifying material for well cementing and a preparation method thereof, which can effectively prevent the strength degradation of the cement stone and improve the toughness of the cement stone.

[0009] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0010] On the one hand, a temperature-resistant composite modifying material for well cementing is provided, which comprises the following raw materials in percentage by weight:

[0011] Strength modifier I: 30-40wt%;

[0012] Strength modifier II: 55-60wt%;

[0013] Toughness modifier: 5-10wt%.

[0014] Further, the strength modifier I is a mixture of waste glass powder, tungsten tailings powder and fused quartz sand in a mass ratio of (1-2):(1-2):1.

[0015] Further, the SiO2 content of the waste glass powder is ≥75wt%, and the powder particle size is 800 mesh; the SiO2 content of the tungsten tailings powder is ≥70wt%, the Al2O3 content is ≥10wt%, and the powder particle size is 325 mesh; the SiO2 content of the fused quartz sand is ≥99wt%, and the powder particle size is 325 mesh.

[0016] Further, the strength modifier II is a mixture of strength stabilizing material A, strength stabilizing material B and crystal form inducing material in a mass ratio of 7:1:2, and the preparation method is as follows:

[0017] S11, after mixing the strength stabilizing material A and the crystal form inducing material, placing them in a sealed stirring tank, using anhydrous ethanol as the solvent, liquid-solid ratio is 5:1, stirring at room temperature for 48h, forming slurry A;

[0018] S12, solid-liquid separation and drying of the slurry A to obtain powder A;

[0019] S13, uniformly mixing the powder A and the strength stabilizing material B to obtain the strength modifier II.

[0020] Further, the strength stabilizing material A is formed by mixing waste siliceous shale, biomass slag and coal gasification slag according to a mass ratio of 2:1:1;

[0021] Preferably, the SiO2 content of the waste siliceous shale is greater than or equal to 85wt%, and the waste siliceous shale is crushed and ground to form a powder with a particle size of 600 mesh.

[0022] Preferably, the SiO2 content of the biomass slag is greater than or equal to 65wt%, and the Al2O3 content is greater than or equal to 15wt%, and the biomass slag is dried and ground to form a powder with a particle size of 600 mesh.

[0023] Preferably, the SiO2 content of the coal gasification slag is greater than or equal to 55wt%, the Al2O3 content is greater than or equal to 20wt%, and the carbon content is greater than or equal to 10wt%, and the particle size is 375 mesh.

[0024] The strength stabilizing material B is formed by mixing nano-clay, waste magnesium brick powder and forsterite powder according to a mass ratio of 1:1:2.

[0025] Preferably, the SiO2 content of the nano-clay is greater than or equal to 47wt%, and the Al2O3 content is greater than or equal to 40wt%.

[0026] Preferably, the MgO content of the waste magnesium brick powder is greater than or equal to 90wt%, and the powder particle size is 325 mesh.

[0027] Preferably, the SiO2 content of the forsterite powder is greater than or equal to 40wt%, and the MgO content is greater than or equal to 50wt%, and the powder particle size is less than 600 mesh.

[0028] The crystal form inducing material is waste inorganic thermal insulation material, preferably waste thermal insulation brick or waste thermal insulation board.

[0029] More preferably, the composition of the waste thermal insulation brick or waste thermal insulation board includes xonotlite, tobermorite and silicon dioxide, and the waste thermal insulation brick or waste thermal insulation board is crushed to form a powder with a particle size of less than 10μm.

[0030] The strength stabilizing material B and the strength stabilizing material A of the present application jointly reduce the calcium-silicon ratio of the cement system, and can form Mg(OH)2 during the high-temperature hydration of the cement, so that the cement stone has a certain expansion property; in addition, the filling and heterogeneous nucleation effect of the nano-clay can refine the pore structure, and in the synergistic effect of the forsterite powder with excellent temperature resistance, the permeability of the cement stone is greatly reduced, the density and interfacial cementation capacity of the cement stone are strengthened, and the anti-channeling capacity and mechanical properties of the cement stone are improved.

[0031] The crystal form inducing material of the present application can induce cement hydration products to crystallize rapidly at high temperature to form more tobermorite and tobermorite, thereby improving the high temperature resistance of the cement stone and avoiding the decline of the strength of the cement stone.

[0032] Further, the toughness modifier is a mixture of kyanite powder, expanded graphite and phenyl silicone rubber powder in a mass ratio of 10:1:1, which is uniformly mixed and then modified by plasma.

[0033] Further, the purity of the kyanite powder is greater than 99wt%, and the particle size of the powder is 325 mesh.

[0034] Further, the particle size of the expanded graphite is 80 mesh.

[0035] Further, the purity of the phenyl silicone rubber powder is greater than 99wt%, and the particle size of the powder is 325 mesh.

[0036] In another aspect, a preparation method of a temperature-resistant composite modifier for cement is provided, which comprises uniformly mixing strength modifier I, strength modifier II and toughness modifier in a certain proportion to obtain the temperature-resistant composite modifier for cement.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] 1. The temperature-resistant composite modifier for cement provided by the present application can effectively improve the high temperature compressive strength and toughness of the cement stone, and can ensure that the compressive strength of the cement stone does not decline under high temperature environment. The present application uses a large amount of solid waste as the main raw material, and has the characteristics of green environmental protection, low cost and excellent performance.

[0039] 2. The main components of the waste glass powder, fused quartz sand and tungsten tailing powder used in the strength modifier I are crystalline or amorphous silicon dioxide, and the main component of the strength modifier II also contains active silicon dioxide and aluminum oxide. Under the joint action of the two, on the one hand, the calcium-silicon ratio of the cement system is reduced; on the other hand, the hydration rate is controlled by different crystal forms of silicon dioxide, thereby regulating the generation of high temperature hydration products, and active aluminum ions are introduced under the dissociation of the strength modifier II to promote the generation of temperature-resistant silicate minerals, further improving the strength and temperature resistance of the system.

[0040] 3. The strength modifier type II of the present invention incorporates a crystal-form-inducing material within the pores and on the surface of the strength-stabilizing material A. This not only significantly accelerates the formation of xonotlite and tobermorite, but also induces the formation of aluminosilicate minerals and aluminum-substituted products, further enhancing the high-temperature resistance of the cement paste. Furthermore, it imparts a certain degree of expansibility to the cement paste, strengthening its interfacial bonding. The small amount of carbon powder present in the strength-stabilizing material A, in synergy with the strength-stabilizing material B, refines the pore structure, reduces the permeability of the cement paste, and increases its density. Furthermore, it synergizes with the toughness modifier to provide crystallization sites for the hydration products and promotes hydration.

[0041] 4. The toughness modifier of the present invention has excellent high-temperature resistance. It combines inorganic fibrous materials (sillimanite powder), rubber elastic particles (phenyl silicone rubber powder) and flexible particles (expanded graphite) and through surface modification, not only increases the specific surface area and roughness of the toughness modifier, but also increases the polar groups on the surface of the toughness modifier. This enhances the compatibility of the toughness modifier with cement stone, and the cement hydration products can adhere to the surface of the toughness modifier, resulting in enhanced interfacial bonding strength in the interface transition zone, thereby improving the mechanical properties of the cement stone. Under the synergy and action modification of each component, not only the elastic toughness and impact resistance of the cement stone are enhanced, but also the compressive strength of the cement stone is improved. In addition, the strength modifier type II mesomorphous inducing material has certain inorganic fibers, which can work together with the toughness modifier to further improve the elastic toughness and impact resistance of the cement stone. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] The cement slurries in the following examples were prepared according to GB / T19139 standard, wherein the G-grade oil well cement was provided by Jiahua Special Cement Co., Ltd.

[0044] Example 1

[0045] As a preferred embodiment of the present invention, a heat-resistant composite modified material for cementing cement in this embodiment has a specific composition as shown in Table 1 below:

[0046] Table 1

[0047] Raw material Weight ratio (%) Strength modifier Type I 30 Strength modifier Type II 60 Toughness modifier 10

[0048] The strength modifier type I of the embodiment is made by mixing waste glass powder, tungsten tailing powder and fused quartz sand in a mass ratio of 1:1:1.

[0049] The strength modifier type II of the embodiment is made by mixing strength stabilizing material A, strength stabilizing material B and crystal form inducing material in a mass ratio of 7:1:2.

[0050] The toughness modifier of the embodiment is made by mixing sintered silicon carbide powder, expanded graphite and phenyl silicone rubber powder in a mass ratio of 10:1:1 and then modifying by plasma.

[0051] The temperature-resistant composite modifier material 1# for cementing cement is obtained by mixing the raw materials in the proportions in Table 1.

[0052] Embodiment 2

[0053] As a preferred embodiment of the application, the temperature-resistant composite modifier material for cementing cement of the embodiment has the specific composition shown in Table 2.

[0054] Table 2

[0055] Raw material Weight ratio (%) Strength modifier Type I 35 Strength modifier Type II 57 Toughness modifier 8

[0056] The strength modifier type I of the embodiment is made by mixing waste glass powder, tungsten tailing powder and fused quartz sand in a mass ratio of 1:1:1.

[0057] The strength modifier type II of the embodiment is made by mixing strength stabilizing material A, strength stabilizing material B and crystal form inducing material in a mass ratio of 7:1:2.

[0058] The toughness modifier of the embodiment is made by mixing sintered silicon carbide powder, expanded graphite and phenyl silicone rubber powder in a mass ratio of 10:1:1 and then modifying by plasma.

[0059] The temperature-resistant composite modifier material 2# for cementing cement is obtained by mixing the raw materials in the proportions in Table 2.

[0060] Embodiment 3

[0061] As a preferred embodiment of the application, the temperature-resistant composite modifier material for cementing cement of the embodiment has the specific composition shown in Table 3.

[0062] Table 3

[0063] Raw material Weight ratio (%) Strength modifier Type I 40 Strength modifier Type II 55 Toughness modifier 5

[0064] The strength modifier type I of the embodiment is made by mixing waste glass powder, tungsten tailing powder and fused quartz sand in a mass ratio of 1:1:1.

[0065] The strength modifier type II of the embodiment is a mixture of the strength stabilizing material A, the strength stabilizing material B and the crystal form inducing material in a mass ratio of 7:1:2.

[0066] The toughness modifier of the embodiment is a mixture of the sillimanite powder, the expanded graphite and the phenyl silicone rubber powder in a mass ratio of 10:1:1, which is uniformly mixed and then modified by plasma.

[0067] The temperature-resistant composite modifying material 3# for well cementing is obtained by mixing the raw materials in the proportions in Table 3 above.

[0068] Embodiment 4

[0069] As a preferred embodiment of the present application, the temperature-resistant composite modifying material for well cementing of the embodiment has the specific composition shown in Table 4 below.

[0070] Table 4

[0071] Raw material Weight ratio (%) Strength modifier Type I 40 Strength modifier Type II 55 Toughness modifier 5

[0072] The strength modifier type I of the embodiment is a mixture of the waste glass powder, the tungsten tailings powder and the fused quartz sand in a mass ratio of 1:2:1.

[0073] The strength modifier type II of the embodiment is a mixture of the strength stabilizing material A, the strength stabilizing material B and the crystal form inducing material in a mass ratio of 7:1:2.

[0074] The toughness modifier of the embodiment is a mixture of the sillimanite powder, the expanded graphite and the phenyl silicone rubber powder in a mass ratio of 10:1:1, which is uniformly mixed and then modified by plasma.

[0075] The temperature-resistant composite modifying material 4# for well cementing is obtained by mixing the raw materials in the proportions in Table 4 above.

[0076] Embodiment 5

[0077] As a preferred embodiment of the present application, the temperature-resistant composite modifying material for well cementing of the embodiment has the specific composition shown in Table 5 below.

[0078] Table 5

[0079] Raw material Weight ratio (%) Strength modifier Type I 40 Strength modifier Type II 55 Toughness modifier Raw material Weight ratio (%) Strength modifier Type I Strength modifier Type II Toughness modifier 5

[0080] The strength modifier type I of the embodiment is a mixture of the waste glass powder, the tungsten tailings powder and the fused quartz sand in a mass ratio of 2:2:1.

[0081] The strength modifier type II of the embodiment is a mixture of the strength stabilizing material A, the strength stabilizing material B and the crystal form inducing material in a mass ratio of 7:1:2.

[0082] The toughness modifier of the embodiment is made by mixing silicon stone powder, expanded graphite and phenyl silicone rubber powder in a mass ratio of 10:1:1 and then modifying by plasma.

[0083] The raw materials were weighed according to the proportions in Table 5 above and mixed to obtain a temperature-resistant composite modifier 5# for cementing cement.

[0084] Comparative Example 1

[0085] The comparative example is a control group, which is a conventional high-temperature cementing cement. The specific components include G-grade oil well cement 65wt% and quartz sand 35wt%.

[0086] Comparative Example 2

[0087] The comparative example is the same as Example 1, except that the strength modifier I does not contain fused quartz sand, to obtain a material 1 for cementing cement.

[0088] Comparative Example 3

[0089] The comparative example is the same as Example 1, except that the strength modifier II does not contain a crystal form inducing material, to obtain a material 2 for cementing cement.

[0090] Comparative Example 4

[0091] The comparative example is the same as Example 1, except that the toughness modifier does not contain phenyl silicone rubber powder, to obtain a material 3 for cementing cement.

[0092] Test Example

[0093] The cement slurry was prepared according to the GB / T 19139 standard, with a water-cement ratio of 0.44. The materials of Examples 1-5 and Comparative Examples 2-4 were mixed at a dosage of 35wt%, and the G-grade oil well cement was mixed at a dosage of 65wt% to form the cement slurry. The conventional high-temperature cementing cement of Comparative Example 1 was used as a comparative cement slurry. Each cement slurry was poured into a copper mold and then placed in a high-temperature curing oven for curing. The curing temperature was 260℃, and the curing period was 2d, 7d and 28d. The compressive strength change was detected, and the permeability of the cement stone was tested. The test results are shown in Table 6. The cement stone after curing was cored, and then the triaxial mechanical property test was performed. The cement stone mechanical test standard was based on GB / T 50266-2013 “Engineering Rock Mass Test Method Standard”. The experimental equipment was RTR-1000 type triaxial rock mechanics tester, and the test results are shown in Table 7.

[0094] Table 6

[0095]

[0096]

[0097] From the data in Table 6, it can be seen that, compared with Comparative Example 1, the cement stone formed in Examples 1-5 has a compressive strength greater than 36 MPa after curing for a certain age, the late strength does not decline, and the permeability is less than 0.3 mD. It is shown that the present application can effectively improve the density and high-temperature compressive strength of the cement stone and effectively inhibit the decline of the strength of the cement stone. In addition, the compressive strength and permeability of Example 1 are better than those of Comparative Examples 2-4, which shows that the components in the present application have a synergistic effect.

[0098] Table 7

[0099]

[0100] From the data in Table 7, it can be seen that, compared with Comparative Example 1, the present application can effectively reduce the elastic modulus of the cement stone in a high-temperature environment, improve the high-temperature toughness of the cement stone, and ensure the engineering requirements of the cement stone in a high-temperature environment. In addition, compared with Comparative Examples 2-4, the components in the present application have a synergistic effect, and the absence of any one cannot achieve the desired effect of the present application.

[0101] In summary, the present application can improve the density and strength of the cement stone, effectively inhibit the decline of the strength of the cement stone, reduce the elastic modulus of the cement stone in a high-temperature environment, improve the high-temperature toughness of the cement stone, and the components have a synergistic effect. The absence of any one cannot achieve the desired effect of the present application.

[0102] Finally, it should be noted that: the above examples are only the preferred embodiments of the present application to illustrate the technical solutions of the present application, but not limit it, of course, nor limit the patent scope of the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application; that is, any modification or polishing that has no substantial significance in the main design idea and spirit of the present application, and the technical problems solved are still consistent with the present application, and should be included in the protection scope of the present application; in addition, the technical solutions of the present application are directly or indirectly applied to other related technical fields, which are also included in the patent protection scope of the present application.

Claims

1. A heat-resistant composite modified material for cementing, characterized in that: The present invention comprises the following raw materials in percentage by weight: Strength modifier type I: 30~40wt%; Strength modifier type II: 55~60wt%; Toughness modifier: 5~10wt%; The strength modifier type I is prepared by mixing waste glass powder, tungsten tailings powder and fused quartz sand in a mass ratio of (1-2):(1-2):1; The strength modifier type II is a mixture of strength stabilizing material A, strength stabilizing material B and crystal form inducing material in a mass ratio of 7:1:2; The strength stabilizing material A is made by mixing waste siliceous shale, biomass slag and coal gasification slag in a mass ratio of 2:1:1; The strength stabilizing material B is a mixture of nano clay, waste magnesia brick powder and forsterite powder in a mass ratio of 1:1:2; The crystal form inducing material is a waste inorganic thermal insulation material.

2. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The SiO2 content of the waste glass powder is ≥75wt%, and the powder particle size is 800 mesh; the SiO2 content of the tungsten tailings powder is ≥70wt%, the Al2O3 content is ≥10wt%, and the powder particle size is 325 mesh; the SiO2 content of the fused quartz sand is ≥99wt%, and the powder particle size is 325 mesh.

3. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The preparation method of the strength modifier type II is as follows: S11, mixing the strength stabilizing material A and the crystal form inducing material and placing them in a sealed stirring tank, using anhydrous ethanol as a solvent with a liquid-to-solid ratio of 5:1, and stirring at room temperature for 48 hours to form slurry A; S12, performing solid-liquid separation and drying on slurry A to obtain powder A; S13. Evenly mix the powder A and the strength stabilizing material B to obtain a strength modifier type II.

4. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The SiO2 content of the waste siliceous shale is ≥85wt%, and the waste siliceous shale is crushed and ground to form powder with a particle size of 600 mesh.

5. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The SiO2 content of the biomass slag is ≥65wt%, and the Al2O3 content is ≥15wt%. The biomass slag is dried and ground to form a powder with a particle size of 600 mesh.

6. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The coal gasification slag has a SiO2 content of ≥55wt%, an Al2O3 content of ≥20wt%, a carbon content of ≥10wt%, and a particle size of 375 meshes.

7. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The SiO2 content of the nanoclay is ≥47wt%, and the Al2O3 content is ≥40wt%.

8. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The MgO content of the waste magnesia brick powder is ≥90wt%, and the powder particle size is 325 mesh.

9. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The SiO2 content of the forsterite powder is ≥40wt%, the MgO content is ≥50wt%, and the powder particle size is <600 mesh.

10. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The waste inorganic thermal insulation material is thermal insulation brick waste or thermal insulation board waste.

11. The heat-resistant composite modified material for cementing according to claim 10, characterized in that: The components of the insulation brick waste and insulation board waste include xonotlite, tobermorite and silicon dioxide; the insulation brick waste or insulation board waste is crushed into powder with a particle size of less than 10 μm.

12. The heat-resistant composite modified material for cementing according to claim 1, characterized in that: The toughness modifier is prepared by uniformly mixing sillimanite powder, expanded graphite, and phenyl silicone rubber powder in a mass ratio of 10:1:1 and then subjecting the mixture to plasma modification.

13. The heat-resistant composite modified material for cementing according to claim 12, characterized in that: The purity of the sillimanite powder is greater than 99 wt %, and the powder particle size is 325 mesh.

14. The heat-resistant composite modified material for cementing according to claim 12, characterized in that: The particle size of the expanded graphite is 80 meshes.

15. The heat-resistant composite modified material for cementing according to claim 12, characterized in that: The purity of the phenyl silicone rubber powder is greater than 99wt%, and the powder particle size is 325 mesh.

16. The method for preparing a heat-resistant composite modified material for cementing cement according to any one of claims 1 to 15, characterized in that: The strength modifier type I, the strength modifier type II and the toughness modifier are uniformly mixed in proportion to obtain the heat-resistant composite modified material for cementing cement.

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