Oil and gas well cementing cement high-temperature stabilizer and preparation method thereof

Abstract

The invention discloses an oil-gas well cementing cement high-temperature stabilizer and a preparation method thereof, and relates to the technical field of mortar high-temperature-resistant components. The invention relates to a high-temperature stabilizer for well cementation cement of an oil and gas well, which comprises the following components in parts by mass: 40 to 45 parts of modified aluminosilicate, 5 to 7 parts of water reducing agent, 25 to 30 parts of barite, 10 to 13 parts of silica fume, 7 to 9 parts of anhydrite and 3 to 5 parts of aluminum phosphate. The oil and gas well cementing cement high-temperature stabilizer provided by the invention can effectively solve the problems of oil and gas well cementing cement sheath strength decline, toughness reduction, casing damage and shaft integrity failure under the high-temperature condition of a heavy oil thermal production well, so that the service life of the thermal production well is prolonged, the frequency of well repair operation is reduced, and remarkable economic benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature resistant mortar components, in particular to a high-temperature stabilizer for oil and gas well cementing cement and a preparation method thereof. Background Art

[0002] Currently, heavy oil production is primarily based on thermal recovery, where steam temperatures typically reach 300°C or even above 350°C. Heavy oil reservoir cementing slurries primarily utilize conventional G-grade silicate-sanded cement slurry systems. Under high-temperature thermal recovery conditions, the wellbore cement sheath is repeatedly subjected to the high temperatures generated by steam over multiple cycles. This exposure degrades the compressive strength and toughness of the cement sheath, compromising the stability and homogeneity of the cement stone. This can lead to a series of wellbore integrity failures, including casing deformation or fracture, casing thread seal failure, micro-annular gaps at the cement sheath interface, and cement sheath cracking. These failures can also cause oil, gas, and water channeling, significantly shortening the production life of heavy oil thermal recovery wells and reducing production efficiency. Summary of the Invention

[0003] The object of the present invention is to provide a high-temperature stabilizer for oil and gas well cementing cement and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A high-temperature stabilizer for oil and gas well cementing cement comprises modified aluminosilicate, a water reducer, barite, silica fume, anhydrite and aluminum phosphate.

[0006] This high-temperature stabilizer reacts modified aluminosilicate with silica fume and aluminum phosphate to form a high-temperature resistant mineral phase, creating a stable high-temperature skeleton structure. Barite acts as a high-density filler to enhance compressive strength and, together with anhydrite, regulates volume stability. Aluminum phosphate forms a ceramic phase at high temperatures, strengthening the cementitious properties. The water reducer optimizes the rheology and density of the slurry and reduces porosity defects. This composite system, through the synergistic effect of multiple components, imparts higher compressive strength and toughness to the cement paste even in long-term thermal recovery environments at 350°C. These strength and toughness remain stable over time, without degradation.

[0007] Beneficial effects of this technical solution:

[0008] High-temperature stabilizers enable the cement sheath to protect the casing for a long time, effectively solving problems such as wellbore integrity failure, oil, gas and water channeling, extending the service life of oil and gas wells, reducing the frequency of workover operations, and improving mining efficiency.

[0009] Furthermore, the mass fractions of each component are: modified aluminate 40-45 parts, water reducer 5-7 parts, barite 25-30 parts, silica fume 10-13 parts, anhydrite 7-9 parts, aluminum phosphate 3-5 parts

[0010] Furthermore, the modified aluminosilicate is prepared by mixing bauxite and quartz in a ratio of 5:3 and then melting and sintering at a high temperature above 800°C.

[0011] Furthermore, the modified aluminosilicate is in the form of 80-120 mesh particles.

[0012] Furthermore, the aluminum phosphate is aluminum phosphate powder obtained by reacting phosphoric acid with aluminum hydroxide and then concentrating and drying.

[0013] A method for preparing a high-temperature stabilizer for oil and gas well cementing cement comprises the following steps:

[0014] Step 1: Use dust removal device to remove dust from the zero-gravity mixer;

[0015] Step 2: Add modified aluminum silicate, water reducer, barite and silica fume into the mixer and mix for at least 30 minutes;

[0016] Step 3: Continue to add anhydrite and aluminum phosphate and mix and stir for at least 1 hour.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a high-temperature stabilizer for oil and gas well cementing, which can effectively address the problems of cement sheath strength degradation, reduced toughness, casing damage, and wellbore integrity failure in heavy oil thermal recovery wells under high temperature (300-350°C) conditions. This high-temperature stabilizer, through synergistic action with key components such as modified aluminosilicate and aluminum phosphate, enables the cement stone to maintain excellent mechanical properties and structural integrity even in a long-term thermal recovery environment at 350°C. Applications have shown that the present invention enables the cement sheath to provide long-term protection for the casing, effectively addressing problems such as wellbore integrity failure and oil, gas, and water crosstalk, extending the service life of oil and gas wells, reducing the frequency of well repair operations, and improving production efficiency. At the same time, its excellent construction performance ensures full compatibility with existing cementing processes, eliminating the need for additional adjustments to the operating process. DETAILED DESCRIPTION

[0019] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0020] Example 1

[0021] A high-temperature stabilizer for oil and gas well cementing cement:

[0022] The high-temperature stabilizer for oil and gas well cementing cement is composed of the following raw materials in parts by mass: 42 parts of modified aluminate, 6 parts of water reducer, 28 parts of barite, 12 parts of silica fume, 8 parts of anhydrite, and 4 parts of aluminum phosphate.

[0023] Preparation method:

[0024] Bauxite and quartz were mixed in a ratio of 5:3, melted and sintered at 850°C, and crushed into 100-mesh particles to obtain modified aluminosilicate;

[0025] After the gravity-free mixer has been dusted, modified aluminosilicate, polycarboxylate water reducer, barite, and silica fume are added in sequence and mixed for 30 minutes;

[0026] Anhydrite and aluminum phosphate were added and mixing was continued for 60 minutes to obtain a uniform powder product.

[0027] Example 2

[0028] A high-temperature stabilizer for oil and gas well cementing cement:

[0029] The high-temperature stabilizer for oil and gas well cementing cement is composed of the following raw materials in parts by mass: 40 parts of modified aluminate, 7 parts of water reducer, 30 parts of barite, 10 parts of silica fume, 9 parts of anhydrite, and 5 parts of aluminum phosphate.

[0030] Preparation method:

[0031] Bauxite and quartz were mixed in a ratio of 5:3, melted and sintered at 850°C, and crushed into 80-mesh particles to prepare modified aluminosilicate;

[0032] After the gravity-free mixer has been dusted, modified aluminosilicate, polycarboxylate water reducer, barite, and silica fume are added in sequence and mixed for 30 minutes;

[0033] Anhydrite and aluminum phosphate were added and mixing was continued for 60 minutes to obtain a uniform powder product.

[0034] Example 3

[0035] A high-temperature stabilizer for oil and gas well cementing cement:

[0036] The high-temperature stabilizer for oil and gas well cementing cement is composed of the following raw materials in parts by mass: 45 parts of modified aluminate, 5 parts of water reducer, 25 parts of barite, 13 parts of silica fume, 7 parts of anhydrite, and 3 parts of aluminum phosphate.

[0037] Preparation method:

[0038] Bauxite and quartz were mixed in a ratio of 5:3, melted and sintered at 850°C, and crushed into 120-mesh particles to prepare modified aluminosilicate;

[0039] After the gravity-free mixer has been dusted, modified aluminosilicate, polycarboxylate water reducer, barite, and silica fume are added in sequence and mixed for 30 minutes;

[0040] Anhydrite and aluminum phosphate were added and mixing was continued for 60 minutes to obtain a uniform powder product.

[0041] Example 4

[0042] A high-temperature stabilizer for oil and gas well cementing cement:

[0043] The high-temperature stabilizer for oil and gas well cementing cement is composed of the following raw materials in parts by mass: 42 parts of modified aluminate, 6.5 parts of water reducer, 27 parts of barite, 11 parts of silica fume, 8.5 parts of anhydrite, and 4.5 parts of aluminum phosphate.

[0044] Preparation method:

[0045] Bauxite and quartz were mixed in a ratio of 5:3, melted and sintered at 850°C, and crushed into 90-mesh particles to prepare modified aluminosilicate;

[0046] After the gravity-free mixer has been dusted, modified aluminosilicate, polycarboxylate water reducer, barite, and silica fume are added in sequence and mixed for 30 minutes;

[0047] Anhydrite and aluminum phosphate were added and mixing was continued for 60 minutes to obtain a uniform powder product.

[0048] Example 5

[0049] A high-temperature stabilizer for oil and gas well cementing cement:

[0050] The high-temperature stabilizer for oil and gas well cementing cement is composed of the following raw materials in parts by mass: 44 parts of modified aluminate, 5.5 parts of water reducer, 29 parts of barite, 12.5 parts of silica fume, 7.5 parts of anhydrite, and 3.5 parts of aluminum phosphate.

[0051] Preparation method:

[0052] Bauxite and quartz were mixed in a ratio of 5:3, melted and sintered at 850°C, and crushed into 85-mesh particles to prepare modified aluminosilicate;

[0053] After the gravity-free mixer has been dusted, modified aluminosilicate, polycarboxylate water reducer, barite, and silica fume are added in sequence and mixed for 30 minutes;

[0054] Anhydrite and aluminum phosphate were added and mixing was continued for 60 minutes to obtain a uniform powder product.

[0055] Effect Examples

[0056] A high-temperature stabilizer for oil and gas well cementing cement in Example 1-5 was used to prepare a high-temperature resistant cement slurry for use in oil and gas wellbore cementing cement rings for thermal oil production. The specific implementation was: 12 parts by mass of G-grade oil well cement (solid) + 35 parts by mass of silica fume (solid) + 6 parts by mass of high-temperature strength stabilizer (solid) + 4 parts by mass of anti-high-temperature brittle cracking agent (solid) + 2 parts by mass of early strength agent (liquid) + 1.0 part by mass of drag reducer (liquid) + 4 parts by mass of fluid loss reducer (liquid) + defoamer + 46 parts by mass of water.

[0057] Conventional sand-added cement slurry used in traditional thermal oil production oil and gas wellbore cementing cement ring: 12 parts by mass of G-grade oil well cement (solid) + 35 parts by mass of silica fume (solid) + 2 parts by mass of early strength agent (liquid) + 1.0 parts by mass of drag reducer (liquid) + 4 parts by mass of fluid loss additive (liquid) + defoamer + 46 parts by mass of water.

[0058] Performance tests were conducted on high-temperature resistant cement slurry to which one of the high-temperature stabilizers for oil and gas well cementing cement in Examples 1-5 was added and on conventional sand-added cement slurry. The results are shown in Table 1.

[0059] Table 1 Comparison of cement slurry performance experimental data

[0060]

[0061]

[0062] The experimental data in Table 1 demonstrate that the compressive performance of high-temperature resistant cement slurries containing the present invention's high-temperature stabilizer for oil and gas well cementing outperforms conventional sand-added cement slurries at both low and high temperatures, with the difference in compressive performance increasing significantly with increasing temperature. Comparison of the experimental data in Table 1 demonstrates that, compared to conventional G-grade Portland cement-added sand slurries, the cement slurry containing the present invention's high-temperature stabilizer exhibits superior high-temperature stability, meeting the high-temperature requirements of late-stage heavy oil thermal recovery wells.

[0063] Before the introduction of the high-temperature stabilizer for oil and gas well cementing cement of the present invention, the casing loss rate of heavy oil thermal recovery wells in the blocks of Keqian 10 and Block 9 of Xinjiang Oilfield was basically 3-5%, and the casing loss rate of Xinjiang Baizhong 7 well block reached 26.3%; after the introduction of the high-temperature stabilizer material, the casing loss rate of blocks of Keqian 10 and Block 9 dropped to about 1%, and the casing loss rate of Xinjiang Baizhong 7 well block dropped to 3%; before the introduction of the high-temperature stabilizer for oil and gas well cementing cement of the present invention, the casing loss rate of heavy oil thermal recovery wells in the first 8 rounds of thermal The casing damage rate was as high as 36.8%, and the casing damage rate in the first 12 rounds reached 45%. After the introduction of the high-temperature stabilizer for oil and gas well cementing cement of the present invention, about 20 wells were tested on site. In the early stage, 10 wells have achieved more than 8 rounds of steam injection production, and in the later stage, about 10 wells have also carried out 3-5 rounds of steam injection production. No casing damage, casing deformation or cement sheath breakage problems occurred, indicating that the high-temperature stabilizer cement slurry system has a strength that does not decline at 350°C, and the cement sheath can continuously protect the casing, extend the service life of the injection and production wells, and improve efficiency.

Claims

1. A high temperature stabilizer for oil and gas well cementing cement, characterized in that: Contains: modified aluminum silicate, water reducer, barite, silica fume, anhydrite, aluminum phosphate.

2. The high-temperature stabilizer for oil and gas well cementing according to claim 1, characterized in that: Mass proportions of each component: modified aluminate 40-45 parts, water reducer 5-7 parts, barite 25-30 parts, silica fume 10-13 parts, anhydrite 7-9 parts, aluminum phosphate 3-5 parts 3. The high-temperature stabilizer for oil and gas well cementing according to claim 1, characterized in that: The modified aluminosilicate is prepared by mixing bauxite and quartz in a ratio of 5:3 and then melting and sintering at a high temperature above 800°C.

4. The high-temperature stabilizer for oil and gas well cementing according to claim 1, characterized in that: The modified aluminosilicate is in the form of 80-120 mesh particles.

5. The high-temperature stabilizer for oil and gas well cementing according to claim 1, characterized in that: The aluminum phosphate is aluminum phosphate powder obtained by reacting phosphoric acid with aluminum hydroxide and then concentrating and drying.

6. A method for preparing a high-temperature stabilizer for oil and gas well cementing cement, suitable for the high-temperature stabilizer for oil and gas well cementing cement according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: Use dust removal device to remove dust from the zero-gravity mixer; Step 2: Add modified aluminum silicate, water reducer, barite and silica fume into the mixer and mix for at least 30 minutes; Step 3: Continue to add anhydrite and aluminum phosphate and mix and stir for at least 1 hour.

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