A high-temperature resistant, high-density cement slurry

Abstract

This application discloses a high-temperature resistant, high-density cement slurry, comprising the following components in parts by weight: 100 parts oil well cement, 32-38 parts silica fume, 70-150 parts weighting agent, 4-6 parts microsilica, 4-5 parts suspending agent, 4-5 parts fluid loss reducer, 2-4 parts retarder, 0.1-0.5 parts defoamer, and 61-69 parts water. The high-temperature resistant, high-density cement slurry provided by this application maintains good stability at 180℃, exhibits no free fluid and low fluid loss, and its thickening curve at high temperatures is stable and free of core encapsulation, meeting the requirements of cementing operations and showing promising application prospects.

Description

Technical Field

[0001] This application relates to the field of cementing slurry, and more particularly to a high-temperature resistant, high-density cementing slurry. Background Technology

[0002] To meet the growing industrial demand, the development of downhole oil and gas resources is gradually moving towards deep and ultra-deep wells. As a crucial aspect of exploration and development, cementing quality directly impacts the exploration results of oil drilling. Under complex working conditions and geological conditions at the bottom of the well, a cement slurry system with excellent comprehensive performance is a key factor for successful high-temperature and high-pressure cementing.

[0003] Poor settling stability of cement slurry leads to uneven cement sheath development and varying compressive strength, negatively impacting the sealing performance of the cement sheath and severely affecting cementing quality. Under high-temperature conditions at the bottom of the well, high-density cement slurry, containing high-density weighting agents, generally causes solid particles to settle, resulting in poor settling stability, especially at high temperatures. Therefore, maintaining the settling stability of high-density cement slurry at high temperatures is crucial. Summary of the Invention

[0004] This application provides a high-temperature resistant, high-density cement slurry that can solve the problem of poor settling stability of high-density cement slurry at high temperatures.

[0005] The following technical solution was adopted in this application:

[0006] This application provides a high-temperature resistant, high-density cement slurry, comprising the following components in parts by weight: 100 parts oil well cement, 32-38 parts silica fume, 70-150 parts weighting agent, 4-6 parts microsilica, 4-5 parts suspending agent, 4-5 parts fluid loss reducing agent, 2-4 parts retarder, 0.1-0.5 parts defoamer, and 61-69 parts water.

[0007] Furthermore, the high-temperature resistant, high-density cement slurry comprises the following components in parts by weight: 100 parts oil well cement, 35 parts silica fume, 70-150 parts weighting agent, 5 parts microsilica, 4-5 parts suspending agent, 4-5 parts fluid loss reducing agent, 2-4 parts retarder, 0.2 parts defoamer, and 61-69 parts water.

[0008] Furthermore, the polymer monomers of the suspending agent contain the following components in parts by weight: 10 parts sodium allyl sulfonate, 5 parts acrylic acid, 20 parts N,N-dimethylacrylamide, 20 parts N-tert-butylacrylamide, and 40 parts dimethyldiallylammonium chloride.

[0009] Further, the preparation method of the suspending agent includes the following steps: Add 10 parts of sodium allyl sulfonate, 5 parts of acrylic acid, 20 parts of N,N-dimethylacrylamide, 20 parts of N-tert-butylacrylamide, and 40 parts of dimethyldiallyl ammonium chloride to 300 parts of deionized water, and stir until a mixed solution is formed. Adjust the pH of the solution to 7 with NaOH under ice bath conditions, turn on the heater, and raise the temperature to 60°C under nitrogen protection. Add 0.25 parts of ammonium persulfate to initiate the reaction, and stop the reaction after stirring at a constant temperature for 4 hours. Cool to room temperature to obtain the suspending agent.

[0010] Furthermore, the purity of the silicon powder is not less than 98%, and the mesh size is greater than or equal to 100 mesh.

[0011] Furthermore, the weighting agent includes at least one of manganese ore powder and iron ore powder.

[0012] Furthermore, the particle size of the microsilicon is less than 1 μm.

[0013] Furthermore, water loss reducing agents include AMPS multi-polymer water loss reducing agents.

[0014] Furthermore, retarders include organic acid salt retarders.

[0015] Furthermore, the defoamer includes at least one of organic ester defoamers and organosilicon defoamers.

[0016] Compared with the prior art, this application has the following beneficial effects:

[0017] The high-temperature resistant, high-density cement slurry provided in this application maintains good stability at 180℃, with no free fluid and low water loss. At the same time, its thickening curve at high temperatures is stable and without core encapsulation, which can meet the requirements of cementing construction and has good application prospects. Attached Figure Description

[0018] Figure 1 The infrared spectrum of the suspending agent prepared in Example 1 of this application;

[0019] Figure 2 This is a thermal analysis curve of the suspending agent prepared in Example 1 of this application;

[0020] Figure 3 The thickening curve of the cement slurry prepared in Example 2 of this application is shown at 180°C and 115MPa.

[0021] Figure 4 The thickening curve of the cement slurry prepared in Comparative Example 2 of this application is shown at 180°C and 115 MPa. Detailed Implementation

[0022] The technical methods in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] An embodiment of this application provides a high-temperature resistant, high-density cementing slurry, comprising the following components in parts by weight: 100 parts oil well cement, 32-38 parts silica fume, 70-150 parts weighting agent, 4-6 parts microsilica, 4-5 parts suspending agent, 4-5 parts fluid loss reducing agent, 2-4 parts retarder, 0.1-0.5 parts defoamer, and 61-69 parts water. Optionally, the high-temperature resistant, high-density cementing slurry comprises the following components in parts by weight: 100 parts oil well cement, 35 parts silica fume, 70-150 parts weighting agent, 5 parts microsilica, 4-5 parts suspending agent, 4-5 parts fluid loss reducing agent, 2-4 parts retarder, 0.2 parts defoamer, and 61-69 parts water.

[0024] Oil well cement can be Grade G oil well cement that conforms to the People's Republic of China National Standard GB / T 10238-2015 "Oil Well Cement".

[0025] The amount of silicon powder used can be 32 parts, 35 parts, 38 parts, etc. The purity of the silicon powder can be no less than 98%. The mesh size of the silicon powder can be greater than or equal to 100 mesh.

[0026] The amount of weighting agent can be 70 parts, 100 parts, 150 parts, etc. The weighting agent may include at least one of manganese ore powder and iron ore powder. The weighting agent can be manganese ore powder, iron ore powder, or a mixture of manganese ore powder and iron ore powder. Optionally, the manganese ore powder has a density of 5.0 g / cm³. 3 Manganese ore powder.

[0027] The amount of microsilicon used can be 4 parts, 5 parts, 6 parts, etc. The particle size of the microsilicon can be less than 1 μm.

[0028] The amount of suspending agent can be 4 parts, 4.5 parts, 5 parts, etc. The polymer monomers of the suspending agent can contain the following components in parts by weight: 10 parts of sodium allyl sulfonate, 5 parts of acrylic acid, 20 parts of N,N-dimethylacrylamide, 20 parts of N-tert-butylacrylamide, and 40 parts of dimethyldiallylammonium chloride.

[0029] The preparation method of the suspending agent may include the following steps: Add 10 parts of sodium allyl sulfonate, 5 parts of acrylic acid, 20 parts of N,N-dimethylacrylamide, 20 parts of N-tert-butylacrylamide, and 40 parts of dimethyldiallyl ammonium chloride to 300 parts of deionized water, and stir until a mixed solution is formed; adjust the pH of the solution to 7 with NaOH under ice bath conditions, turn on the heater, raise the temperature to 60°C under nitrogen protection, add 0.25 parts of ammonium persulfate to initiate the reaction, stir at a constant temperature for 4 hours, then stop the reaction and cool to room temperature to obtain the suspending agent. The suspending agent is a liquid product.

[0030] The aforementioned suspending agent is an amphoteric polymer suspending agent containing both anionic and cationic groups. By adjusting the charge balance, it exerts a charge effect in the cement slurry, preventing the sedimentation of solid particles.

[0031] The dosage of the water loss reducing agent can be 4 parts, 4.5 parts, 5 parts, etc. The water loss reducing agent may include AMPS multi-polymer water loss reducing agents. Optionally, the water loss reducing agent is BXF-200L(AF).

[0032] The dosage of the retarder can be 2 parts, 3 parts, 4 parts, etc. The retarder may include organic acid salt retarder. Optionally, the retarder is retarder BCR-300L.

[0033] The amount of defoamer used can be 0.1 parts, 0.2 parts, 0.5 parts, etc. The defoamer can include at least one of organic ester defoamers and organosilicon defoamers. Optionally, the defoamer is defoamer G603.

[0034] The amount of water used can be 61 parts, 65 parts, 69 parts, etc. The water is fresh water.

[0035] The above-mentioned high-temperature resistant, high-density cement slurry was prepared in accordance with the People's Republic of China National Standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0036] The high-temperature resistant, high-density cement slurry of this application can maintain the settling stability of high-density cement slurry at 180℃, improve cementing quality, and ensure cementing construction safety.

[0037] The following detailed description is provided with reference to specific embodiments:

[0038] The materials used in the embodiments and comparative examples of this application are as follows:

[0039] Grade G oil well cement is a product manufactured by Jiahua Special Cement Co., Ltd.; silica fume and microsilica fume are products manufactured by Tianjin Yuyang Ultrafine Mineral Powder Processing Co., Ltd.; iron ore powder has a density of 6.0 g / cm³. 3 Products manufactured by Emeishan City Tuoyang Oilfield Engineering Technology Co., Ltd.; Commercially available suspending agent X is a commercially available product; manganese ore powder has a density of 5.0 g / cm³.3 The manganese ore powder; the water loss reducing agent BXF-200L(AF), the retarder BCR-300L and the defoamer G603 are products manufactured by Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0040] The suspending agent in this embodiment is prepared by the following method:

[0041] Add 10 parts sodium allyl sulfonate, 5 parts acrylic acid, 20 parts N,N-dimethylacrylamide, and 20 parts N to 300 parts of deionized water. - Tert-butylacrylamide and 40 parts of dimethyldiallylammonium chloride were stirred to form a homogeneous solution. The pH of the solution was adjusted to 7 with NaOH under ice bath conditions. Heating was then initiated at 60°C under nitrogen protection. 0.25 parts of ammonium persulfate were added to initiate the reaction. The reaction was stopped after stirring at a constant temperature for 4 hours and then cooled to room temperature to obtain the liquid suspension product.

[0042] Example 1

[0043] This embodiment provides a density of 2.10 g / cm³. 3 High-temperature resistant, high-density cement slurry for cementing wells.

[0044] The cement slurry of this embodiment comprises the following components in parts by weight: 100 parts Jiahua G-grade oil well cement, 35 parts silica fume, 70 parts iron ore powder, 5 parts microsilica, 4.5 parts suspending agent, 5 parts water loss reducing agent BXF-200L(AF), 4 parts retarder BCR-300L, 0.2 parts defoamer G603, and 67 parts fresh water.

[0045] The cement slurry in this embodiment was prepared in accordance with the People's Republic of China National Standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0046] Example 2

[0047] This embodiment provides a density of 2.30 g / cm³. 3 High-temperature resistant, high-density cement slurry for cementing wells.

[0048] The cement slurry of this embodiment comprises the following components in parts by weight: 100 parts Jiahua G-grade oil well cement, 35 parts silica fume, 120 parts iron ore powder, 5 parts microsilica, 5 parts suspending agent, 5 parts water loss reducing agent BXF-200L(AF), 4 parts retarder BCR-300L, 0.2 parts defoamer G603, and 69 parts fresh water.

[0049] The cement slurry in this embodiment was prepared in accordance with the People's Republic of China National Standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0050] Example 3

[0051] This embodiment provides a density of 2.50 g / cm³. 3 High-temperature resistant, high-density cement slurry for cementing wells.

[0052] The cement slurry of this embodiment comprises the following components in parts by weight: 100 parts Jiahua G-grade oil well cement, 35 parts silica fume, 140 parts iron ore powder, 10 parts manganese ore powder, 5 parts microsilica, 5 parts suspending agent, 5 parts water loss reducing agent BXF-200L(AF), 4 parts retarder BCR-300L, 0.2 parts defoamer G603, and 61 parts fresh water.

[0053] The cement slurry in this embodiment was prepared in accordance with the People's Republic of China National Standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0054] Comparative Example 1

[0055] This comparative example provides a density of 2.10 g / cm³. 3 High-density cement slurry.

[0056] The cement slurry of this comparative example comprises the following components in parts by weight: 100 parts Jiahua G-grade oil well cement, 35 parts silica fume, 70 parts iron ore powder, 5 parts microsilica, 4.5 parts commercially available suspending agent X, 5 parts water loss reducing agent BXF-200L(AF), 4 parts retarder BCR-300L, 0.2 parts defoamer G603, and 67 parts fresh water.

[0057] The cement slurry in this comparative example was prepared in accordance with the People's Republic of China National Standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0058] Comparative Example 2

[0059] This comparative example provides a density of 2.30 g / cm³. 3 High-density cement slurry.

[0060] The cement slurry of this comparative example comprises the following components in parts by weight: 100 parts Jiahua G-grade oil well cement, 35 parts silica fume, 120 parts iron ore powder, 5 parts microsilica, 5 parts commercially available suspending agent X, 5 parts water loss reducing agent BXF-200L(AF), 4 parts retarder BCR-300L, 0.2 parts defoamer G603, and 69 parts fresh water.

[0061] The cement slurry in this comparative example was prepared in accordance with the People's Republic of China National Standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0062] Comparative Example 3

[0063] This comparative example provides a density of 2.50 g / cm³. 3High-density cement slurry.

[0064] The cement slurry of this comparative example comprises the following components in parts by weight: 100 parts Jiahua G-grade oil well cement, 35 parts silica fume, 140 parts iron ore powder, 10 parts manganese ore powder, 5 parts microsilica, 5 parts commercially available suspending agent X, 5 parts water loss reducing agent BXF-200L(AF), 4 parts retarder BCR-300L, 0.2 parts defoamer G603, and 61 parts fresh water.

[0065] The cement slurry in this comparative example was prepared in accordance with the People's Republic of China National Standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0066] Comparative Example 4

[0067] This comparative example provides a density of 2.30 g / cm³. 3 High-density cement slurry.

[0068] The cement slurry of this comparative example comprises the following components in parts by weight: 100 parts Jiahua G-grade oil well cement, 35 parts silica fume, 120 parts iron ore powder, 5 parts microsilica, 5 parts water loss reducer BXF-200L(AF), 4 parts retarder BCR-300L, 0.2 parts defoamer G603, and 74 parts fresh water.

[0069] The cement slurry in this comparative example was prepared in accordance with the People's Republic of China National Standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0070] Experimental Example 1

[0071] (1) The infrared spectrum of the suspension prepared in Example 1 was tested using an IR-Tracer 100 Fourier transform infrared spectrometer, and the thermal stability of the suspension prepared in Example 1 was tested using a Swiss-Mettler-TGA / DSC3+ synchronous thermal analyzer.

[0072] Figure 1 The image shows the infrared spectrum of the suspending agent prepared in Example 1. Figure 1 As can be seen from the test results, 3435.4cm -1 The peak at 1620.1 cm⁻¹ represents the NH stretching vibration of the amide group. -1 The peak at 2941.6 cm⁻¹ represents the stretching vibration of the carbonyl group. -1 The peak at 1405.2 cm⁻¹ represents the CH stretching vibration of the methyl group. -1 The peak at 608.3 cm⁻¹ represents the stretching vibration of the sulfonic acid group SO. -1 The stretching vibration peak of CS is 1101.6 cm⁻¹. -1 The peak at 3000-3100 cm⁻¹ is the characteristic absorption peak of CN in the quaternary ammonium group of cationic monomer A. -1and 1600~1640cm -1 No characteristic absorption peaks of carbon-carbon double bonds were observed. The above analysis indicates that all monomers participated in the polymerization reaction, and the suspending agent was consistent with the expected product.

[0073] Figure 2 This is a thermal analysis curve of the suspending agent prepared in Example 1. TG represents thermogravimetric analysis, and DTG represents the rate of weight loss per unit time. Figure 2 As can be seen, the thermal decomposition of suspending agent molecules mainly consists of three stages:

[0074] The thermal decomposition of suspension molecules mainly consists of three stages. The first stage is thermal degradation within the temperature range of 201–262℃, with a mass loss of 12.2%. The main reason for this weight loss is the imidization reaction of adjacent amide groups in the suspension molecules at high temperatures, generating imide groups and losing some water molecules. The second stage is thermal degradation within the temperature range of 262–360℃, with a mass loss of 30.8%. The main reason for this weight loss is the extensive decomposition and breakage of side chain groups such as amide and sulfonic acid groups in the suspension molecules. The third stage is thermal degradation within the temperature range of 360–500℃, with a mass loss of 33.8%. The main reason for this weight loss is the initial breakage of the main chain in the suspension molecules. Above 500℃, the thermogravimetric curve tends to stabilize, leaving only a small amount of carbonaceous residue. In summary, the suspension begins to decompose at 262℃, exhibiting high temperature resistance, which can meet the cementing requirements of most deep wells.

[0075] (2) The comprehensive performance of the cement slurry prepared in the examples and comparative examples was investigated. The comprehensive performance test results of the cement slurry at 180℃ are shown in Table 1.

[0076] Table 1. Comprehensive performance test of cement paste at 180℃

[0077]

[0078] According to the experimental data in Table 1, the cement slurry without suspending agent (Comparative Example 4) showed severe settling at high temperatures, with a density difference of up to 0.650 g / cm³. 3 After adding a suspending agent, the stability of the cement slurry in this embodiment is far superior to that of the comparative cement slurry. The density difference between the upper and lower parts of the cement slurry prepared in the embodiment is less than 0.035 g / cm³. 3 The fluidity and water loss of the cement slurry meet the performance requirements under high-temperature environments and construction requirements.

[0079] (3) Figure 3 This is a thickening curve of the cement slurry prepared in Example 2 at 180°C and 115 MPa. Figure 4This is a thickening curve of the cement slurry prepared in Comparative Example 2 at 180℃ and 115MPa. The comparison of the experimental results shows that the initial consistency of the cement slurry prepared in Comparative Example 2 is significantly affected, resulting in a higher initial consistency that decreases sharply with increasing temperature. In contrast, the initial consistency of the cement slurry prepared in Example 2 is less affected, its consistency curve is more stable, there is no core-forming phenomenon, and the decrease in consistency with increasing temperature is smaller, maintaining the stability of the cement slurry at high temperatures. The high-density cement slurry prepared in Example 2 does not significantly thicken at low temperatures and exhibits good settling stability at high temperatures.

[0080] In summary, the high-temperature resistant, high-density cement slurry prepared in this application has low consistency and good fluidity at room temperature; it can maintain good settling stability at high temperature (180℃), with no free liquid and low water loss. At the same time, the thickening curve at high temperature is stable and without core encapsulation, which can meet the requirements of cementing construction and has good application prospects.

[0081] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made without departing from the spirit and scope of this application. The scope of protection claimed by this application is defined by the appended claims, specification, and their equivalents.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A high-temperature resistant, high-density cement slurry, characterized in that, The components include the following parts by weight: 100 parts oil well cement, 32-38 parts silica fume, 70-150 parts weighting agent, 4-6 parts microsilica, 4-5 parts suspending agent, 4-5 parts water loss reducing agent, 2-4 parts retarder, 0.1-0.5 parts defoamer, and 61-69 parts water; The suspending agent comprises the following components in parts by weight: 10 parts sodium allyl sulfonate, 5 parts acrylic acid, 20 parts N,N-dimethylacrylamide, 20 parts N-tert-butylacrylamide, and 40 parts dimethyldiallylammonium chloride. The preparation method of the suspension includes the following steps: adding 10 parts of sodium allyl sulfonate, 5 parts of acrylic acid, 20 parts of N,N-dimethylacrylamide, 20 parts of N-tert-butylacrylamide, and 40 parts of dimethyldiallyl ammonium chloride to 300 parts of deionized water, and stirring evenly to form a mixed solution; adjusting the pH of the solution to 7 with NaOH under ice bath conditions, turning on the heater, raising the temperature to 60°C under nitrogen protection, adding 0.25 parts of ammonium persulfate to initiate the reaction, stirring at a constant temperature for 4 hours to stop the reaction, and cooling to room temperature to obtain the suspension.

2. The high-temperature resistant, high-density cement slurry as described in claim 1, characterized in that, The components include the following parts by weight: 100 parts oil well cement, 35 parts silica fume, 70-150 parts weighting agent, 5 parts microsilica, 4-5 parts suspending agent, 4-5 parts water loss reducing agent, 2-4 parts retarder, 0.2 parts defoamer, and 61-69 parts water.

3. The high-temperature resistant, high-density cement slurry as described in claim 1, characterized in that, The purity of the silicon powder is not less than 98%, and the mesh size is greater than or equal to 100 mesh.

4. The high-temperature resistant, high-density cement slurry as described in claim 1, characterized in that, The weighting agent includes at least one of manganese ore powder and iron ore powder.

5. The high-temperature resistant, high-density cement slurry as described in claim 1, characterized in that, The particle size of the microsilicon is less than 1 μm.

6. The high-temperature resistant, high-density cement slurry as described in claim 1, characterized in that, The water loss reducing agent includes AMPS multi-polymer water loss reducing agent.

7. The high-temperature resistant, high-density cement slurry as described in claim 1, characterized in that, The retarder includes organic acid salt retarder.

8. The high-temperature resistant, high-density cement slurry as described in claim 1, characterized in that, The defoamer includes at least one of organic ester defoamers and organosilicon defoamers.

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