A broad spectrum set cement slurry and a method of making the same

Abstract

The present application provides a kind of broad-spectrum setting type high-temperature cement slurry and its preparation method.The broad-spectrum setting type high-temperature cement slurry includes: 100 parts of G-grade oil well cement, 30-60 parts of high-temperature reinforcing material, 1-5 parts of suspension stabilizer, 0.5-2 parts of dispersing agent, 0.2-1 part of setting aid, 0.5-4 parts of retarder, 3-6 parts of fluid loss additive, 0.1-1 part of defoaming agent, and 45-70 parts of water, by weight.The broad-spectrum setting type high-temperature cement slurry provided by the present application is suitable for circulating temperature of 110-220℃, effectively solving the problem of abnormal gelation of high-temperature cement slurry at sensitive temperature point;and the cement slurry setting provided by the present application is normal and stable, with excellent comprehensive performance, which can effectively ensure the safety of well cementation operation, and has good application prospect in well cementation of deep well, ultra-deep well, special deep well, high-temperature and high-pressure gas well, unconventional oil and gas well, gas storage well, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield drilling and relates to a cement slurry, in particular to a broad-spectrum regulated-setting high-temperature cement slurry and a preparation method thereof. Background Art

[0002] Deep oil and gas reservoirs are important alternative energy sources for oil and gas. As well depths continue to increase, bottomhole temperatures continue to rise, and the risks of high-temperature cementing in deep wells gradually increase, placing higher demands on cement slurry systems. With the large-scale application of high-temperature cementing in deep and ultra-deep formations, high-temperature cement slurry systems still have certain problems: (1) Abnormal gelation of high-temperature cement slurry is prone to occur in the temperature-sensitive range, resulting in core-encapsulation, abnormal fluctuations such as bulging on the thickening curve, and deterioration of the rheological properties of the cement slurry; (2) The retarder dosage at special high-temperature points is sensitive, and the retarder dosage has a nonlinear relationship with the cement slurry thickening time, making the thickening time difficult to control; (3) The retarder fails to regulate the setting in the temperature-sensitive range, resulting in the "inverted" phenomenon of "slow setting at high temperatures and early setting at low temperatures" in cement slurry. The above problems may increase the risk of cementing construction and make cementing quality unguaranteed, limiting the efficient application of high-temperature cement slurry in deep and ultra-deep wells.

[0003] The following are the main solutions to these problems: First, optimizing the cement slurry formulation based on the properties of existing cement slurry admixtures and additives. However, this involves significant experimental effort, consuming significant human and material resources, and achieving unsatisfactory results. Second, improving the high-temperature adaptability of polymer admixtures by incorporating high-steric hindrance functional groups, hydrophobic side chains, and inorganic salt treatment into the molecular structure of the polymer admixture. Third, improving the system's gelling properties to meet application requirements through the use of specialized reagents such as gelling regulators.

[0004] To address the above issues, CN 107162512A discloses a high-temperature resistant cement slurry system for ultra-deep wells. The water slurry system contains cement, high-temperature fluid loss additive, silica sand, high-temperature retarder, high-temperature stabilizer, and dispersant. This patent solves the performance problems of cement slurry such as rapid hydration, slurry instability, and large water loss at high temperatures by adding a fluid loss additive and retarder resistant to temperatures of 180-230°C to the cement slurry, and ensures that the cement slurry thickening time meets the requirements of safe construction. CN 112479635A discloses a high-temperature resistant and large temperature difference elastic and tough cement system and its preparation method. The cement system contains G-grade oil well cement, retarder, fluid loss additive, elastic material, toughening material, strength stabilizer, expansion agent, early strength agent, weighting agent, interface bonding enhancer, defoaming agent, and water. The cement system provided by this patent solves the problem of large temperature differences between the top and bottom of long cementing sections, which can lead to excessively slow setting or even non-setting of the top cement slurry. It meets cementing requirements for circulating temperatures not exceeding 180°C and temperature differences not exceeding 100°C. CN 107418536A discloses a high-density cementing slurry that is resistant to high temperatures and prevents gas channeling, and its preparation method. The cementing slurry comprises oil well cement, a weighting agent, silica powder, microsilica fume, a suspension stabilizer, a high-temperature fluid loss additive, a high-temperature retarder, a dispersant, an anti-gas channeling agent, a defoamer, and water. The cementing slurry provided by this patent is temperature-resistant from 180°C to 220°C and exhibits excellent flow properties, solving the problem of excessively slow setting of cementing slurries at temperatures above 180°C. While existing technologies, such as those represented by the aforementioned patents, have achieved some success in improving the setting performance of high-temperature cement slurries, they fail to address the issues of abnormal thickening curves under high-temperature conditions, the inverse relationship between thickening time, dosage, and temperature, and have a relatively narrow applicable temperature range.

[0005] Therefore, developing a broad-spectrum high-temperature cement slurry system suitable for high temperatures and a wide temperature range can effectively solve problems such as abnormal gelation of high-temperature cement slurry and "inverted" thickening time at sensitive temperature points. It has important practical significance and application value for ensuring the safety of cementing construction and improving the efficiency of oilfield development. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the present invention aims to provide a broad-spectrum, controlled-setting, high-temperature cement slurry and its preparation method. This slurry exhibits no abnormal gelation under high-temperature conditions, exhibits normal and stable controlled-setting behavior, and exhibits excellent overall performance, including water loss and stability, to meet cementing requirements under various high-temperature conditions.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In the first aspect, the present invention provides a broad-spectrum regulated setting high-temperature cement slurry, which comprises, in parts by weight: 100 parts of G-grade oil well cement, 30-60 parts of high-temperature reinforcing material, 1-5 parts of suspension stabilizer, 0.5-2 parts of dispersant, 0.2-1 parts of regulating setting aid, 0.5-4 parts of retarder, 3-6 parts of fluid loss additive, 0.1-1 parts of defoaming agent, and 45-70 parts of water.

[0009] The broad-spectrum regulated high-temperature cement slurry provided by the present invention has no abnormal gelling phenomenon under high temperature conditions (110-220°C), and the regulated setting is normal and stable. At the same time, the cement slurry has excellent comprehensive performance such as water loss and stability, and can meet the cementing needs under different high-temperature conditions.

[0010] The setting agent of the present invention has a long side chain structure and an adsorptive group, which improves the dispersion state of cement particles in the solution, can effectively control the hydration process of cement slurry, and alleviate the abnormal gelation phenomenon of high-temperature cement slurry caused by polymer admixtures.

[0011] Exemplarily, the weight proportion of the high-temperature reinforcing material of the present invention is 30 to 60 parts, for example, 35 parts, 40 parts, 50 parts or 55 parts, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable; too high a content will affect the fluidity and sedimentation stability of the cement slurry, and too low a content will reduce the content of high-temperature resistant calcium silicate hydration products.

[0012] The weight ratio of the suspension stabilizer is 1 to 5 parts, for example, 2 parts, 3 parts or 4 parts, but is not limited to the values ​​listed, and other values ​​not listed within the numerical range are also applicable;

[0013] The weight ratio of the dispersant is 0.5 to 2 parts, for example, 0.8 parts, 1 part, 1.4 parts or 1.8 parts, but is not limited to the values ​​listed, and other values ​​not listed within the numerical range are also applicable;

[0014] The weight ratio of the setting agent is 0.2 to 1 part, for example, it can be 0.4 part, 0.6 part or 0.8 part, but it is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. If its content is too high, the thickening time of the cement slurry will be excessively prolonged, and if its content is too low, abnormal gelation will occur.

[0015] The weight ratio of the retarder is 0.5 to 4 parts, for example, 1 part, 2 parts or 3 parts, but is not limited to the values ​​listed, and other values ​​not listed within the numerical range are also applicable;

[0016] The weight ratio of the fluid loss additive is 3 to 6 parts, for example, 3.5 parts, 4 parts, 5 parts or 5.5 parts, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0017] The weight portion of the defoaming agent is 0.1 to 1 part, for example, 0.2 part, 0.4 part, 0.6 part or 0.8 part, but is not limited to the values ​​listed, and other values ​​not listed within the numerical range are also applicable;

[0018] The weight percentage of the water is 45 to 70 parts, for example, 50 parts, 60 parts or 65 parts, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] It is worth noting that the G-grade oil well cement (high sulfur resistance type, HSR) described in the present invention is a commercially available product, and its main mineral components include tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite.

[0020] As a preferred technical solution of the present invention, the coagulant adjustment aid includes a terpolymer of a polyether macromonomer, acrylic acid and an ester compound.

[0021] Preferably, the polyether macromonomer includes any one of vinyl polyoxyethylene ether, isobutylene polyoxyethylene ether or isopentanol polyoxyethylene ether, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of vinyl polyoxyethylene ether and isobutylene polyoxyethylene ether, a combination of isobutylene polyoxyethylene ether and isopentanol polyoxyethylene ether, a combination of vinyl polyoxyethylene ether and isopentanol polyoxyethylene ether, or a combination of vinyl polyoxyethylene ether, isobutylene polyoxyethylene ether and isopentanol polyoxyethylene ether.

[0022] Preferably, the weight average molecular weight of the polyether macromonomer is 2000 to 5000, for example, 2500, 3000, 3500, 4000 or 4500, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the ester compound comprises an esterification product of carboxymethyl chitosan and maleic anhydride.

[0024] It is worth noting that the reaction ratio of the carboxymethyl chitosan and maleic anhydride during the esterification process of the present invention is 1:1 to 1:2.

[0025] As a preferred technical solution of the present invention, the retarder includes a combination of at least two of a binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid, sodium salt of ethylenediaminetetramethylenephosphonic acid, potassium salt of hexamethylenediaminetetramethylenephosphonic acid or tetrasodium 2-phosphonobutane-1,2,4-tricarboxylate. Typical but non-limiting combinations include a combination of a binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid and sodium salt of ethylenediaminetetramethylenephosphonic acid, sodium salt of ethylenediaminetetramethylenephosphonic acid, potassium salt of hexamethylenediaminetetramethylenephosphonic acid and tetrasodium 2-phosphonobutane-1,2,4-tricarboxylate. A combination of tetrasodium 2-phosphonobutane-1,2,4-tricarboxylate, a combination of potassium salt of hexamethylenediaminetetramethylenephosphonic acid and tetrasodium 2-phosphonobutane-1,2,4-tricarboxylate, or a combination of a binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid, sodium salt of ethylenediaminetetramethylenephosphonic acid, potassium salt of hexamethylenediaminetetramethylenephosphonic acid and tetrasodium 2-phosphonobutane-1,2,4-tricarboxylate; more preferably, a combination of a binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid and sodium salt of ethylenediaminetetramethylenephosphonic acid.

[0026] The retarder of the present invention improves the high-temperature setting stability and adaptability of polymer retarders by compounding organic and inorganic retarders, ensures normal setting of high-temperature cement slurry, and avoids the "inverted" phenomenon of "retarded setting at high temperature and early setting at low temperature".

[0027] Preferably, the weight average molecular weight of the binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid is 100,000 to 200,000, for example, 120,000, 140,000, 160,000 or 180,000, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the mass ratio of the binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid to ethylenediaminetetramethylenephosphonic acid sodium salt is (0.1-2):(1-10), for example, it can be 0.5:1, 0.5:10, 1:1, 1:5 or 1:10, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] As a preferred technical solution of the present invention, the high-temperature strengthening material includes coarse quartz sand and / or surface acid-treated quartz sand.

[0030] Preferably, the purity of the high temperature enhancement material is not less than 99%, for example, it can be 99.2%, 99.4%, 99.6% or 99.8%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] The surface acid-treated quartz sand of the present invention is quartz sand that has been leached with hydrochloric acid.

[0032] Preferably, the average particle size of the coarse quartz sand is 80 to 600 mesh, for example, it can be 100 mesh, 200 mesh, 300 mesh, 400 mesh or 500 mesh, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable; more preferably, it is 200 mesh.

[0033] Preferably, the average particle size of the surface acid-treated quartz sand is 600 to 3000 mesh, for example, it can be 1000 mesh, 1400 mesh, 1800 mesh, 2200 mesh or 2600 mesh, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable; more preferably, it is 600 mesh.

[0034] As a preferred technical solution of the present invention, the dispersant includes an aldehyde-ketone condensation polymer or a polystyrene sulfonate dispersant.

[0035] Further preferably, the dispersant of the present invention includes dispersant DRS-1S.

[0036] As a preferred technical solution of the present invention, the suspension stabilizer includes a 2-acrylamide-2-methylpropanesulfonic acid polymer stabilizer and / or an ore powder stabilizer.

[0037] Preferably, the suspension stabilizer includes high temperature stabilizer DRK-2S.

[0038] Preferably, the defoamer comprises any one of tributyl phosphate defoamer, silicone defoamer or polyether defoamer, or a combination of at least two thereof. Typical but non-limiting combinations include: a combination of tributyl phosphate defoamer and silicone defoamer, a combination of tributyl phosphate defoamer and polyether defoamer, a combination of silicone defoamer and polyether defoamer, or a combination of tributyl phosphate defoamer, silicone defoamer and polyether defoamer.

[0039] As a preferred technical solution of the present invention, the fluid loss additive includes any one of fluid loss additive DRF-2L, fluid loss additive DRF-1S or fluid loss additive DRF-3L, or a combination of at least two of them. Typical but non-limiting combinations include a combination of fluid loss additive DRF-2L and fluid loss additive DRF-1S, a combination of fluid loss additive DRF-1S and fluid loss additive DRF-3L, a combination of fluid loss additive DRF-2L and fluid loss additive DRF-3L, or a combination of fluid loss additive DRF-2L, fluid loss additive DRF-1S and fluid loss additive DRF-3L.

[0040] As a preferred technical solution of the present invention, the sedimentation stability of the broad-spectrum high-temperature cement slurry is ≤0.03g / cm 3 , for example, it can be 0.025g / cm 3 , 0.02g / cm 3, 0.015g / cm 3 or 0.01g / cm 3 , but not limited to the listed values, other values ​​not listed within the numerical range are also applicable.

[0041] Preferably, the API water loss of the broad-spectrum controlled-setting high-temperature cement slurry is ≤50 mL, but is not limited to 50 mL, 45 mL, 40 mL, 35 mL or 30 mL, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0042] In a second aspect, the present invention provides a method for preparing the broad-spectrum regulated setting high-temperature cement slurry provided in the first aspect, the preparation method comprising the following steps:

[0043] (1) mixing Grade G oil well cement, high temperature reinforcement material, suspension stabilizer, and dispersant according to the formula to obtain a mixed powder;

[0044] (2) uniformly mixing the fluid loss additive, setting aid, retarder, defoamer and water according to the formula to obtain a mixed solution;

[0045] (3) Pour the mixed solution obtained in step (2) into the mixed powder obtained in step (1) under stirring, and stir twice to obtain the broad-spectrum high-temperature cement slurry.

[0046] As a preferred technical solution of the present invention, the rotation speed in the stirring state in step (3) is 3800-4200 r / min, for example, it can be 3900 r / min, 4000 r / min or 4100 r / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0047] Preferably, the rotation speed of the secondary stirring in step (3) is 11500-12500 r / min, for example, it can be 11800 r / min, 12000 r / min, 12200 r / min or 12400 r / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] Preferably, the secondary stirring time in step (3) is 30 to 40 seconds, for example, 32 seconds, 34 seconds, 36 seconds or 38 seconds, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0049] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] (1) The broad-spectrum high-temperature cement slurry provided by the present invention has stable gelling performance in the range of 110-220°C, no "core-wrapping" phenomenon, no "inversion" in thickening time, good slurry fluidity, and sedimentation stability ≤0.03g / cm 3 , API water loss ≤ 50mL;

[0052] (2) The broad-spectrum high-temperature cement slurry provided by the present invention has readily available raw materials, is simple to prepare, is convenient for on-site operation, has good comprehensive performance, can be applied to cementing requirements of different high-temperature wells, and ensures construction safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a thickening curve of the broad-spectrum regulated setting high-temperature cement slurry provided in Example 1 of the present invention at 150°C;

[0054] Figure 2 This is a thickening curve of the cement slurry provided in Comparative Example 1 of the present invention at 150°C. DETAILED DESCRIPTION

[0055] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0056] Example 1

[0057] This embodiment provides a broad-spectrum regulated setting high-temperature cement slurry, which includes, by weight, 100 parts of G-grade oil well cement (high sulfur resistance, HSR), 30 parts of high-temperature reinforcing material, 1 part of suspension stabilizer, 2 parts of dispersant, 1 part of regulating setting aid, 1.5 parts of retarder, 4 parts of fluid loss additive, 1 part of defoaming agent, and 57 parts of water.

[0058] Wherein, the high temperature strengthening material is a mixture of 200 mesh coarse quartz sand and 600 mesh surface acid treated quartz sand in a mass ratio of 1:1;

[0059] The suspension stabilizer is high temperature stabilizer DRK-2S; the dispersant is dispersant DRS-1S;

[0060] The setting agent is a terpolymer of polyether macromonomer, acrylic acid and ester compound;

[0061] The retarder is a composition of a binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid and sodium salt of ethylenediaminetetramethylenephosphonic acid in a mass ratio of 1:1;

[0062] The fluid loss additive is DRF-3L; the defoaming agent is DRX-1L, an organic ester defoaming agent.

[0063] The preparation method of the broad-spectrum controlled-setting high-temperature cement slurry comprises the following steps:

[0064] (1) mixing Grade G oil well cement, high temperature reinforcement material, suspension stabilizer, and dispersant according to the formula to obtain a mixed powder;

[0065] (2) uniformly mixing the fluid loss additive, setting aid, retarder, defoamer and water according to the formula to obtain a mixed solution;

[0066] (3) Pour the mixed solution obtained in step (2) into the mixed powder obtained in step (1) under stirring at 4000 r / min, and stir for a second time at 12000 r / min for 35 seconds to obtain the broad-spectrum high-temperature cement slurry.

[0067] The thickening curve of the cement slurry provided in this embodiment at 150°C is as follows: Figure 1 shown.

[0068] Example 2

[0069] This embodiment provides a broad-spectrum regulated setting high-temperature cement slurry. The broad-spectrum regulated setting high-temperature cement slurry differs from that of embodiment 1 only in that:

[0070] In this embodiment, the weight proportions of the components are modified as follows: 100 parts of G-grade oil well cement, 40 parts of high-temperature reinforcing material, 4 parts of suspension stabilizer, 1 part of dispersant, 0.5 parts of setting aid, 3 parts of retarder, 3 parts of fluid loss additive, 0.1 parts of defoamer, and 54 parts of water.

[0071] The preparation method of the broad-spectrum regulated high-temperature cement slurry is the same as that in Example 1.

[0072] Example 3

[0073] This embodiment provides a broad-spectrum regulated setting high-temperature cement slurry. The broad-spectrum regulated setting high-temperature cement slurry differs from that of embodiment 1 only in that:

[0074] In this embodiment, the weight proportions of the components are modified as follows: 100 parts of G-grade oil well cement, 30 parts of high-temperature reinforcing material, 4 parts of suspension stabilizer, 1 part of dispersant, 0.8 parts of setting aid, 3 parts of retarder, 4 parts of fluid loss additive, 1 part of defoamer, and 50 parts of water.

[0075] The preparation method of the broad-spectrum regulated high-temperature cement slurry is the same as that in Example 1.

[0076] Example 4

[0077] This embodiment provides a broad-spectrum regulated setting high-temperature cement slurry. The broad-spectrum regulated setting high-temperature cement slurry differs from that of embodiment 1 only in that:

[0078] In this embodiment, the weight proportions of the components are modified as follows: 100 parts of G-grade oil well cement, 30 parts of high-temperature reinforcing material, 5 parts of suspension stabilizer, 2 parts of dispersant, 0.8 parts of setting aid, 3 parts of retarder, 5 parts of fluid loss additive, 1 part of defoamer, and 49 parts of water.

[0079] The preparation method of the broad-spectrum regulated high-temperature cement slurry is the same as that in Example 1.

[0080] Example 5

[0081] This embodiment provides a broad-spectrum regulated setting high-temperature cement slurry. The broad-spectrum regulated setting high-temperature cement slurry differs from that of embodiment 1 only in that:

[0082] In this embodiment, the weight proportions of the components are modified as follows: 100 parts of G-grade oil well cement, 50 parts of high-temperature reinforcing material, 5 parts of suspension stabilizer, 1 part of dispersant, 0.2 parts of setting aid, 4 parts of retarder, 6 parts of fluid loss additive, 0.1 parts of defoamer, and 54 parts of water.

[0083] The preparation method of the broad-spectrum regulated high-temperature cement slurry is the same as that in Example 1.

[0084] Example 6

[0085] This embodiment provides a broad-spectrum regulated setting high-temperature cement slurry. The broad-spectrum regulated setting high-temperature cement slurry differs from that of embodiment 1 only in that:

[0086] In this embodiment, the retarder is modified to a binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid in equal parts by weight.

[0087] The preparation method of the broad-spectrum regulated high-temperature cement slurry is the same as that in Example 1.

[0088] Comparative Example 1

[0089] This comparative example provides a cement slurry, which differs from Example 1 only in that:

[0090] In this comparative example, the setting agent was omitted.

[0091] The preparation method of the cement slurry is the same as that in Example 1.

[0092] The thickening curve of the cement slurry provided in this comparative example at 150°C is as follows: Figure 2 shown.

[0093] Comparative Example 2

[0094] This comparative example provides a broad-spectrum regulated setting high-temperature cement slurry. The broad-spectrum regulated setting high-temperature cement slurry differs from Example 1 only in that:

[0095] In this comparative example, the weight portion of the setting aid is modified to 2 parts.

[0096] The preparation method of the cement slurry is the same as that in Example 1.

[0097] Comparative Example 3

[0098] This comparative example provides a broad-spectrum regulated setting high-temperature cement slurry. The broad-spectrum regulated setting high-temperature cement slurry differs from Example 1 only in that:

[0099] In this comparative example, the weight portion of the setting aid was modified to 0.1 part.

[0100] The preparation method of the cement slurry is the same as that in Example 1.

[0101] Performance testing:

[0102] According to GB / T19139-2012 "Test Methods for Oil Well Cement", the thickening performance, API water loss, stability and compressive strength of the cement slurries provided in the above examples and comparative examples were evaluated. The results are shown in Table 1. It is worth noting that the density of the cement slurries provided in the above examples and comparative examples is 1.90 g / cm 3 .

[0103] The main experimental instruments used in the experiment include: (1) 30-60 type corrugated agitator, a product of Shenyang Tiger Petroleum Instrument and Equipment Manufacturing Co., Ltd.; (2) 8240 type high pressure thickener, a product of American Qiandele Industrial Instrument Co., Ltd.; (3) TG-71 type water loss meter, a product of Shenyang Tiger Petroleum Instrument and Equipment Manufacturing Co., Ltd.; (4) YJ-2001 uniform load pressure testing machine, a product of Shenyang Tiger Petroleum Instrument and Equipment Manufacturing Co., Ltd.; (5) 7370D type pressurized curing kettle, a product of Shenyang Tiger Petroleum Instrument and Equipment Manufacturing Co., Ltd.

[0104] Table 1

[0105]

[0106]

[0107] From Table 1 and the accompanying drawings, we can see the following points:

[0108] (1) Analysis of Examples 1-5 shows that the cement slurry provided by the present invention has low API water loss (≤50 mL) and good sedimentation stability (density difference between upper and lower parts is less than 0.03 g / cm3) under the condition of a circulation temperature of 110°C to 220°C. 3), there is no free liquid. At the same temperature, the thickening time increases with the increase of retarder dosage, and the thickening time is adjustable.

[0109] (2) Compared with Comparative Examples 1-3, the cement slurry provided in Examples 1-5 of the present invention has a normal thickening curve at the sensitive temperature point of 150°C, without abnormal gelling phenomena such as "bulging", and the thickening time at the high temperature point (high temperature is 5°C higher than the normal temperature point) is shorter than the thickening time at the normal temperature point, and the thickening time inversion phenomenon does not occur. It can solve the problem of abnormal gelling at the sensitive temperature point of high-temperature cement slurry and meet the requirements for safe cementing construction under cyclic temperature conditions.

[0110] (3) A comprehensive analysis of Example 1 and Example 6 shows that if the retarder is a single organic retarder, the cement slurry is prone to thickening time inversion at sensitive temperature points, making it difficult to ensure the safety of cementing construction.

[0111] (4) Analysis Figure 1 and Figure 2 As can be seen, the cement slurry prepared in Example 1 has a relatively stable consistency curve, with no "bulging" occurring during the heating process. In contrast, the cement slurry prepared in Comparative Example 1 exhibits dramatic temperature fluctuations and a "bulging" consistency curve during the heating process, indicating abnormal gelation. Therefore, compared to Comparative Example 1, Example 1 exhibits stable gelation under high-temperature conditions and does not exhibit abnormal gelation.

[0112] In summary, the broad-spectrum high-temperature cement slurry provided by the present invention is suitable for a circulation temperature of 110°C to 220°C, which effectively solves the problem of abnormal gelation at sensitive temperature points of high-temperature cement slurry; and the cement slurry provided by the present invention has normal and stable setting and excellent comprehensive performance, which can effectively ensure the safety of cementing operations and has good application prospects in cementing deep wells, ultra-deep wells, extra-deep wells, high-temperature and high-pressure gas wells, unconventional oil and gas wells, gas storage wells, etc.

[0113] The applicant declares that the present invention is intended to illustrate the detailed structural features of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed structural features. This does not mean that the present invention must rely on the above-described detailed structural features in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

[0114] The applicant declares that the present invention uses the above-described embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above-described detailed process flow, that is, it does not mean that the present invention must rely on the above-described detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for various raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., are all within the scope of protection and disclosure of the present invention.

Claims

1. A broad-spectrum high-temperature cement slurry, characterized in that: The broad-spectrum controlled-setting high-temperature cement slurry comprises, by weight: 100 parts of G-grade oil well cement, 30-60 parts of high-temperature reinforcing material, 1-5 parts of suspension stabilizer, 0.5-2 parts of dispersant, 0.2-1 parts of controlled-setting aid, 0.5-4 parts of retarder, 3-6 parts of fluid loss additive, 0.1-1 parts of defoamer, and 45-70 parts of water. The setting agent is a terpolymer of polyether macromonomer, acrylic acid and ester compound; The retarder is a combination of a binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid and sodium salt of ethylenediaminetetramethylenephosphonic acid.

2. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The polyether macromonomer includes any one of vinyl polyoxyethylene ether, isobutylene polyoxyethylene ether or isopentanol polyoxyethylene ether, or a combination of at least two of them.

3. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The weight average molecular weight of the polyether macromonomer is 2000-5000.

4. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The ester compound includes an esterification product of carboxymethyl chitosan and maleic anhydride.

5. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The weight average molecular weight of the binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid is 100,000-200,000.

6. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 5, characterized in that: The mass ratio of the binary copolymer of 2-acrylamido-2-methylpropanesulfonic acid and itaconic acid to ethylenediaminetetramethylenephosphonic acid sodium salt is (0.1-2):(1-10).

7. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The high-temperature strengthening material includes coarse quartz sand and / or surface acid-treated quartz sand.

8. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 7, characterized in that: The purity of the high temperature strengthening material is not less than 99%.

9. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 7, characterized in that: The average particle size of the coarse quartz sand is 80-600 meshes.

10. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 9, characterized in that: The average particle size of the coarse quartz sand is 200 meshes.

11. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 7, characterized in that: The average particle size of the surface acid-treated quartz sand is 600-3000 meshes.

12. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 11, characterized in that: The average particle size of the surface acid-treated quartz sand is 600 meshes.

13. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The dispersant includes an aldehyde-ketone condensation polymer or a polystyrene sulfonate dispersant.

14. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The suspension stabilizer includes a 2-acrylamide-2-methylpropanesulfonic acid polymer stabilizer and / or an ore powder stabilizer.

15. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 14, characterized in that: The suspension stabilizer includes high temperature stabilizer DRK-2S.

16. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The defoaming agent is any one of tributyl phosphate defoaming agent, silicone defoaming agent or polyether defoaming agent, or a combination of at least two of them.

17. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The fluid loss additive includes any one of fluid loss additive DRF-2L, fluid loss additive DRF-1S or fluid loss additive DRF-3L, or a combination of at least two of them.

18. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The sedimentation stability of the broad-spectrum high-temperature cement slurry is ≤0.03g / cm 3 .

19. The broad-spectrum controlled-setting high-temperature cement slurry according to claim 1, characterized in that: The API water loss of the broad-spectrum controlled-setting high-temperature cement slurry is ≤50 mL.

20. A method for preparing the broad-spectrum controlled-setting high-temperature cement slurry according to any one of claims 1 to 19, characterized in that: The preparation method comprises the following steps: (1) Mixing Grade G oil well cement, high temperature reinforcement material, suspension stabilizer and dispersant according to the formula to obtain a mixed powder; (2) Mix the fluid loss additive, setting aid, retarder, defoamer and water evenly according to the formula to obtain a mixed solution; (3) Pour the mixed solution obtained in step (2) into the mixed powder obtained in step (1) under stirring, and stir twice to obtain the broad-spectrum high-temperature cement slurry.

21. The preparation method according to claim 20, characterized in that The rotation speed in the stirring state in step (3) is 3800~4200r / min.

22. The preparation method according to claim 20, characterized in that The rotation speed of the secondary stirring in step (3) is 11500~12500r / min.

23. The preparation method according to claim 20, characterized in that The time of the secondary stirring in step (3) is 30 to 40 seconds.

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