Low-shear low-friction cement slurry system and method for preparing same

Abstract

The application discloses a low-shear low-mobility-resistance cement slurry system and a preparation method thereof. The cement slurry system comprises oil well G-grade cement, macroscopic physical friction-reducing agent, microscopic chemical composite friction-reducing agent, fluid loss additive, reinforcing agent, retarder and defoaming agent. In one aspect, the physical ball lubrication of the macroscopic physical friction-reducing agent improves the flow mobility of the cement slurry system under low shear, and reduces the flow friction pressure loss. In another aspect, the polymer viscoelastic lubrication drag reduction principle of the microscopic chemical composite friction-reducing agent reduces the flow micro internal friction under low shear, and the conjugated steric hindrance effect of the molecular structure of the substance is combined to adjust the dispersion capacity of the system, prevent local bunching, reduce the adhesion between flow micro units, and reduce the flow friction pressure loss. Through the synergistic effect of the above two aspects, the expansion fluid with a flow index greater than 1 under low shear is finally formed, the flow friction pressure loss of the cement slurry under low shear can be effectively reduced, and the efficient development of oil and gas horizontal wells is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas well cementing technology, in particular to a low shear low friction cement slurry system and a preparation method thereof. BACKGROUND

[0002] With the continuous breakthrough of large well cluster horizontal well drilling technology, the length of horizontal open hole section is extended from 1500m to more than 5000m, the vertical ratio is as high as 2.5, and in order to improve the drilling rate of oil layers, the well trajectory is adjusted nearly 70 times, the wellbore presents a wavy distribution, the cement slurry flow friction pressure consumption is large, the loss is serious (the loss ratio is more than 70%), the cement slurry return height and cementing quality are seriously affected, and the cementing quality is reduced. At present, the existing cementing technology measures only design and research on reducing the construction discharge and improving the conventional rheological properties of cement slurry, and basically fail to effectively combine the actual construction conditions to research and design the low shear low friction performance.

[0003] The invention patent with publication number CN111875315A discloses "a ultra-low density cement slurry system for slim hole cementing and its preparation method and application", the cement slurry prepared by the prior art has a flow index less than 1, belongs to pseudoplastic fluid, and the friction performance is the performance of cement slurry under turbulent flow state at high annular return speed, without design and analysis of the friction performance of the swelling fluid under low shear at low return speed.

[0004] For example, the invention patent with publication number CN113060993A discloses "a drag reduction material for fine pressure control cementing and drag reduction cement slurry", the cement slurry prepared by the prior art has a flow index less than 1, also belongs to pseudoplastic fluid, and the friction performance is designed and analyzed by rheological performance under 3-300 full range shear, without detailed consideration of the design and analysis of rheological performance under low shear and friction performance of the swelling fluid under low shear at low return speed. SUMMARY

[0005] In order to solve the problems and deficiencies in the prior art, the present application provides a low shear low friction cement slurry system and a preparation method thereof, which reduces the friction of the cement slurry under low shear from the macro and micro perspectives, and reduces the friction of the cement slurry under low shear by combining physical friction reduction and chemical friction reduction.

[0006] In order to achieve the above-mentioned application purposes, the technical scheme of the present application is as follows:

[0007] A low shear low friction cement slurry system, the raw materials of the cement slurry system include the following components in mass fraction:

[0008] 100 parts of oil well G-grade cement;

[0009] 5-10 parts of macroscopic physical friction reducer;

[0010] Microcosmic chemical composite friction reducer 10-20 parts;

[0011] Fluid loss additive 1.0-3.0 parts;

[0012] Reinforcing agent 2-5 parts;

[0013] Retarder 0.1-0.5 parts;

[0014] Defoamer 0.05-0.1 parts;

[0015] Water 40-44 parts.

[0016] In the present application, when the above cement slurry system is configured, water is clean water.

[0017] Further, in the present application, the macroscopic physical friction reducer is mainly composed of 60 parts of pressure-resistant vitrified microbeads and 40 parts of spherical fused silica sand, wherein the density of the pressure-resistant vitrified microbeads ranges from 2.25 to 2.35 g / cm3, the particle size ranges from 180 to 280 mesh, the sphericity is greater than 95%, and the ball breakage rate needs to be less than 1% when the static pressure strength is 50 MPa, which guarantees the stability of the performance after entering the well and the sphericity is not damaged; the density of the spherical fused silica sand ranges from 2.3 to 2.45 g / cm3, the particle size ranges from 110 to 150 mesh, the sphericity is greater than 92%, and the ball breakage rate needs to be less than 1.5% when the static pressure strength is 50 MPa, which guarantees the stability of the performance after entering the well and the sphericity is not damaged. 3

[0018] Further, in the present application, the microcosmic chemical composite friction reducer is composed of 60 parts of polymer microsphere emulsion, 35 parts of lubricant and 5 parts of modified aldehyde ketone polycondensation dispersant; wherein the polymer microsphere emulsion is a quaternary copolymer microsphere synthesized by using styrene, methyl methacrylate, acrylic acid and 3-sulfonic acid propyl methacrylate potassium salt by means of soap-free emulsion polymerization method, with a molecular weight of 400-600 thousand and a particle size of 180-200 nm. The lubricant is an organic negative ion compound obtained by a series of reactions of polyhydric alcohol amine, fatty acid, non-ionic surfactant and nano-level micro-fine material, and the reactions include esterification, amidation, emulsification, complexation reaction (the complexation reaction needs to be carried out at a high temperature of 150-180 degrees Celsius), etc. The above reactions can refer to the common knowledge in the field and will not be described in detail here. The non-ionic surfactant is usually a non-ionic surfactant composed of polyethylene glycol group, i.e. polyoxyethylene group. The nano-level micro-fine material is usually nano-level molybdenum metal compound micro-fine material (any one or combination of molybdenum carbide, molybdenum nitride and molybdenum oxide). The modified aldehyde ketone polycondensation dispersant is a gelatin grafted sulfonated polycondensate synthesized by sulfonation grafting reaction of animal gelatin with formaldehyde, acetone and sodium pyrosulfite.​

[0019] Further, in the present application, the fluid loss additive is a kind of AMPS ternary copolymer, which is mainly modified by AMPS, low molecular amide and polyhydroxy carboxylic acid ternary copolymer.

[0020] Further, the reinforcing agent is composed of polyether modified polysiloxane, fluorosilicate, potassium chloride, sodium silicate, sodium sulfate and the like.

[0021] Further, in the present application, the retarder is acid hydrolysis modified starch, which can be G407R1 produced by Xi'an Chuanjin Petroleum Technology Co., Ltd.

[0022] Further, in the present application, the defoaming agent is polyether silicone oil tributyl phosphate.

[0023] A preparation method of a low shear low friction resistance cement slurry system, the method is used for the above-mentioned cement slurry system, mainly includes the following steps:

[0024] Step S1. According to the mass fraction of each liquid phase component of the low shear low friction resistance cement slurry system, the micro-chemical composite friction reducer, the defoaming agent and the water are weighed to form a mixed solution and placed in a constant speed stirrer, and stirred at a speed of 2000±200r / min for about 50s;

[0025] Step S2. According to the mass fraction of each solid phase component of the low shear low friction resistance cement slurry system, the oil well G-grade cement, the macro-physical friction reducer, the fluid loss additive, the reinforcing agent and the retarder are weighed and mixed uniformly to form a solid mixture;

[0026] Step S3. The solid mixture obtained in step S2 is added to the mixed solution obtained in step S1 at a speed of 4000±200r / min within 15s, and then continues to stir for about 35s to obtain a low shear low friction resistance cement slurry system.

[0027] The beneficial effects of the present application are as follows:

[0028] 1. The cement slurry system of the present application, on the one hand, improves the flow mobility of the cement slurry system under low shear through the physical ball lubrication effect of macro vitrified spherical friction reducer, and reduces the flow friction pressure loss; on the other hand, through the polymer viscoelastic lubrication drag reduction principle of the polymer microsphere emulsion and high-efficiency lubricant in the microcosmic chemical composite friction reducer, the dispersion capacity of the system is adjusted to prevent local bunching, the adhesion between the flow micro-units is reduced, and the flow friction pressure loss is reduced. Through the synergistic effect of the above two aspects, an expansive fluid with a flow index greater than 1 under low shear is finally formed, which can effectively reduce the flow friction pressure loss of the cement slurry under low shear, solve the problems of large flow friction pressure loss and serious leakage of cementing in long horizontal wells in Changqing Oilfield, and ensure efficient development of oil and gas horizontal wells.

[0029] 2. In the low-shear low-friction cement slurry system of the present application, the macroscopic physical friction reducer used is spherical particles with two different particle size ranges, wide particle size distribution and high sphericity, which can play a rolling friction reduction role under low shear, and has high static pressure strength, can maintain high integrity after being pressurized in the well, and has good migration and rolling effect. BRIEF DESCRIPTION OF DRAWINGS

[0030] The foregoing and the following detailed description of the present application will become more apparent when read in conjunction with the following drawings, in which:

[0031] Figure 1 is a shear stress-shear rate relationship diagram of cement slurry A in Example 1 of the present application in linear coordinates;

[0032] Figure 2 is a shear stress-shear rate relationship diagram of cement slurry B in Example 2 of the present application in linear coordinates.

[0033] Figure 3 is a shear stress-shear rate relationship diagram of cement slurry C in Example 3 of the present application in linear coordinates;

[0034] Figure 4 is a shear stress-shear rate relationship diagram of cement slurry D in Example 4 of the present application in linear coordinates.

[0035] Figure 5 is a shear stress-shear rate relationship diagram of cement slurry E in Example 5 of the present application in linear coordinates. DETAILED DESCRIPTION

[0036] With the continuous breakthrough of the horizontal well group drilling technology in large well cluster, the length of horizontal open hole section is extended from 1500m to more than 5000m, the water vertical ratio is up to 2.5, and in order to improve the oil layer drilling rate, the well trajectory is adjusted up to nearly 70 times, the well bore presents a wavy distribution, the cement slurry flow resistance pressure consumption is large, the loss is serious (the loss ratio is more than 70%), the cement slurry return height and the cementing quality are seriously affected, and the cementing quality is reduced. At present, the existing cementing technology measures only design and research on reducing the construction discharge and improving the conventional rheological property of the cement slurry, and the low shear low friction property research and the cement slurry system design research are not effectively combined with the actual construction.

[0037] Based on this, the embodiment of the present application provides a low shear low friction cement slurry system and a preparation method thereof. The low shear low friction cement slurry system mainly uses macroscopic physical friction reducing agent and microscopic chemical composite friction reducing agent, applies the physical ball lubrication, the polymer viscoelastic lubrication drag reduction principle and the conjugated steric hindrance effect of the molecular structure, develops a low friction cement slurry system suitable for low shear cementing and a corresponding preparation method, can effectively reduce the flow resistance pressure consumption under low shear, can meet the long open hole low pressure easy leakage well small discharge low return speed cementing demand (such wells are subjected to small shear in the annulus during the construction process, for example, the long horizontal well of shale oil and gas in Changqing Oilfield), reduces the construction friction pressure consumption, guarantees the construction safety and supports the efficient development of oil and gas horizontal wells.

[0038] In order to enable the skilled person in the art to better understand the technical solutions in the present application, the following will further illustrate the technical solutions for achieving the purpose of the present application through several specific embodiments. It should be noted that the technical solutions claimed by the present application include but are not limited to the following embodiments. Based on the embodiments in the present application, all other embodiments obtained by the skilled person in the art without creative labor shall belong to the scope of protection of the present application.

[0039] Embodiment 1

[0040] 10 parts of microscopic chemical composite friction reducing agent, 0.05 parts of defoaming agent and 44 parts of water are weighed to form a mixed solution and placed in a constant speed stirrer for stirring at a speed of 2000±200r / min for 50s;

[0041] 100 parts of oil well G-grade cement, 5 parts of macroscopic physical friction reducing agent, 2 parts of fluid loss reducer, 3 parts of reinforcing agent and 0.2 parts of retarder are weighed and mixed uniformly to form a solid phase mixture;

[0042] The solid phase mixture is added into the mixed solution in the constant speed stirrer under the speed of 4000±200r / min within 15s, and then the stirring is continued for 35s to obtain the low shear low friction cement slurry A, and the density is 1.85g / cm 3 .

[0043] Example 2

[0044] Take 15 parts of micro-chemical composite friction reducer, 0.08 parts of defoaming agent and 42 parts of clean water to form a mixed solution and place it in a constant speed stirrer to stir at a speed of 2000±200 r / min for 50 s;

[0045] Take 100 parts of oil well G-grade cement, 8 parts of macro-physical friction reducer, 1.5 parts of fluid loss reducer, 4 parts of strength enhancer and 0.25 parts of retarder to mix uniformly as a solid phase mixture;

[0046] Under the speed of 4000±200 r / min, the solid phase mixture is added to the mixed solution in the constant speed stirrer within 15 s, and then continue to stir for 35 s to obtain the low shear low friction resistance cement slurry B with a density of 1.85 g / cm 3 .

[0047] Example 3

[0048] The main difference between this embodiment and Example 1 is that no micro-chemical composite friction reducer and macro-physical friction reducer are added when preparing the cement slurry, which is as follows:

[0049] Take 0.05 parts of defoaming agent and 50 parts of clean water to form a mixed solution and place it in a constant speed stirrer to stir at a speed of 2000±200 r / min for 50 s;

[0050] Take 100 parts of oil well G-grade cement, 2 parts of fluid loss reducer, 3 parts of strength enhancer and 0.2 parts of retarder to mix uniformly as a solid phase mixture;

[0051] Under the speed of 4000±200 r / min, the solid phase mixture is added to the mixed solution in the constant speed stirrer within 15 s, and then continue to stir for 35 s to obtain the conventional cement slurry C with a density of 1.85 g / cm 3 .

[0052] Example 4

[0053] The main difference between this embodiment and Example 1 is that no micro-chemical composite friction reducer is added when preparing the cement slurry, which is as follows:

[0054] Take 0.05 parts of defoaming agent and 52 parts of clean water to form a mixed solution and place it in a constant speed stirrer to stir at a speed of 2000±200 r / min for 50 s;

[0055] Take 100 parts of oil well G-grade cement, 5 parts of macro-physical friction reducer, 2 parts of fluid loss reducer, 3 parts of strength enhancer and 0.2 parts of retarder to mix uniformly as a solid phase mixture;

[0056] The solid mixture is added into the mixed solution in the constant speed stirrer at a speed of 4000±200 r / min within 15 s, and then the stirring is continued for 35 s to obtain the cement slurry D with a density of 1.85 g / cm 3 .

[0057] Example 5

[0058] The main difference between this example and Example 1 is that no macro-physical friction reducer is added in the preparation of the cement slurry, which is as follows:

[0059] 10 parts of the micro-chemical composite friction reducer, 0.05 parts of the defoaming agent and 43 parts of the clean water are weighed to form a mixed solution and placed in a constant speed stirrer to stir at a speed of 2000±200 r / min for 50 s;

[0060] 100 parts of the oil well G-grade cement, 2 parts of the fluid loss reducer, 3 parts of the strength enhancer and 0.2 parts of the retarder are weighed and uniformly mixed to form a solid mixture;

[0061] The solid mixture is added into the mixed solution in the constant speed stirrer at a speed of 4000±200 r / min within 15 s, and then the stirring is continued for 35 s to obtain the cement slurry E with a density of 1.85 g / cm 3 .

[0062] Example 6

[0063] The low-shear low-friction cement slurries A and B prepared in Examples 1-5 and the conventional cement slurries C, D and E are respectively placed in a pressurized thickener for curing, first heated and pressurized to 80℃ / 40MPa for 40 min, and then taken out after constant temperature and pressure for 20 min, and the rheological properties are measured by a 12-speed rotary viscometer as shown in Table 1. The annular cement slurry friction performance of the open hole section is evaluated by taking the shale oil long horizontal well depth structure and construction technology in Changqing Oilfield as an example. The drilling bit of the Changqing Oilfield shale oil long horizontal well is 215.9 mm, the open hole diameter expansion rate is 5-10%, the 139.7 mm casing is cemented, the displacement injection is 300-1000 L / min, and the shear rate is calculated according to the formula (1):

[0064]

[0065] In the formula, γ is the shear rate, s -1 ; v is the upward velocity of the cement slurry in the annulus, m / s; D e is the borehole diameter, mm; D i is the casing outer diameter, mm; the calculation results are as shown in Table 2, and the shear rate range is 6.95-30.81 s -1 . The data in Table 1 at 1-30 r / min are taken to draw a graph on the linear coordinate for regression analysis, and the analysis results are as shown in Table 3, and the graph is shown in Figure 1. Figures 1-5The cement slurries all tend to be power-law fluids under low shear, and the flow behavior indexes n of the cement slurries A and B are both greater than 1, which means that the cement slurries A and B are dilatant fluids; the flow behavior indexes n of the cement slurries C, D and E are all less than 1, which means that the cement slurries C, D and E are pseudoplastic fluids. Taking the borehole diameter expansion rate of 7.5%, the injection displacement of 600 L / min and the flow section length of 1500 m, the friction performance is calculated and compared, and the flow friction pressure loss is calculated according to formula (2):

[0066]

[0067] In the formula, P is the flow friction pressure loss, MPa; f is the Fann friction coefficient; p is the cement slurry density, g / cm3; and L is the flow section length, m. The calculation and analysis results are shown in Table 4. The flow friction pressure loss of the blank sample (the cement slurry C) is 0.89 MPa; the flow friction pressure loss of the cement slurry A is 0.50 MPa, which is reduced by 43.8% compared with the blank sample; the flow friction pressure loss of the cement slurry B is 0.38 MPa, which is reduced by 57.3% compared with the blank sample; the flow friction pressure loss of the cement slurry D is 0.85 MPa, and the flow friction pressure loss of the cement slurry E is 0.78 MPa, which are both slightly reduced compared with the blank sample (the cement slurry C), but the flow friction pressure losses of the cement slurries D and E are both obviously higher than those of the cement slurries A and B.

[0068] In summary, the experimental data show that the flow friction pressure loss of the cement slurry can be reduced by adding a certain amount of friction reducer in the conventional cement slurry system; and further, by comparing Example 1, Example 2, Example 4 and Example 5, it can be seen that the flow friction pressure loss can be reduced by using a single macroscopic physical friction reducer or a single microscopic chemical friction reducer, but the reduction is very limited, while the cement slurry system of the present application uses both macroscopic physical friction reducers and microscopic chemical friction reducers, and the flow friction pressure loss of the cement slurry under low shear can be significantly reduced under the synergistic effect of the two kinds of friction reducers. Therefore, the low shear and low friction cement slurry system prepared by the present application has good friction reduction effect, and can ensure the efficient development of oil and gas horizontal wells.

[0069]

[0070] Table 2 Shear rate of annular cement slurry during construction

[0071]

[0072] Table 3 Regression analysis results of rheological properties of cement slurry under low shear

[0073]

[0074] Table 4 Analysis results of friction performance of cement slurry under low shear

[0075]

[0076] Example 7

[0077] The low-shear low-mobility cement slurries A and B formed in Examples 1-5 and the conventional cement slurries C, D and E were subjected to comprehensive performance tests according to the method for testing oil well cement in GBT 19139-2012, and the results are shown in Table 5. The API water separation of the cement slurries A and B is 0 mL, the API fluid loss is less than 50 mL, the fluidity range is 23-25 cm, the initial thickening is < 30 Bc, and the 24h compressive strength is > 14 Mpa, which meets the performance requirements of the oil well cement slurry in the industry standard SY-T6544-2017 and the performance requirements of the cement slurry into the well. The performance indicators of the cement slurries C, D and E also meet the industry standards and can meet the performance requirements of the cement slurry into the well, but the fluidity of the three is significantly lower than that of the cement slurries A and B, the initial thickening is higher than that of the cement slurries A and B, and the flow resistance of the cement slurry system is greater. Therefore, the cement slurry system prepared by the present application has good comprehensive engineering performance and can better meet the requirements of the field cementing construction.

[0078] Table 5 Comprehensive performance of low-shear low-mobility cement slurry

[0079]

[0080] It should be noted that in the above examples, the stirrer is selected as the constant speed stirrer of CHANDLER3260 model of CHANDLER company in the United States, the densimeter is selected as the digital liquid density meter of YMS1-5 model produced by Qingdao Haitongda Special Instrument Factory, the weighing balance is selected as YP-20002 produced by Shanghai Guangzheng Medical Instrument Co., Ltd. and AR223CN electronic balance produced by Ohaus Instrument (Changzhou) Co., Ltd., the rotary viscometer is selected as ZNN-D12 digital viscometer produced by Qingdao Senxin Machine Electrical Equipment Co., Ltd., the pressure thickening instrument is selected as OWC-9380Q high temperature and high pressure thickening instrument of Shenyang Aerospace University Institute of Applied Technology, the curing box is selected as OWC-118 double temperature strength curing box of Shenyang Aerospace University Institute of Applied Technology, the pressure testing machine is selected as OWC-2002 oil well cement pressure testing machine of Shenyang Aerospace University Institute of Applied Technology, and the water loss instrument is selected as OWC-9510 high temperature and high pressure water loss instrument of Shenyang Aerospace University Institute of Applied Technology.

[0081] The above is only a preferred embodiment of the present application, and does not hinder the present application in any form. Any simple modification or equivalent change made according to the technical essence of the present application to the above embodiment falls within the protection scope of the present application.

Claims

1. A low-shear, low-friction cement slurry system, characterized in that, By weight, the raw materials of this cement slurry system include the following components: 100 parts of Grade G cement for oil wells; 5-10 parts of macroscopic physical friction reducer; 10-20 parts of microscopic chemical composite friction reducer; 1.0~3.0 parts of water loss reducer; 2-5 parts of reinforcing agent; 0.1 to 0.5 parts of retarder; Defoamer 0.05~0.1 parts; 40-44 parts water; The macroscopic physical friction reducer consists of 60 parts of pressure-resistant vitrified microspheres and 40 parts of spherical fused silica sand, wherein the density of the pressure-resistant vitrified microspheres ranges from 2.25 to 2.35 g / cm³. 3 The particle size ranges from 180 to 280 mesh, with a sphericity greater than 95%, and the spherical breakage rate is less than 1% when the static compressive strength is 50 MPa; the density of the spherical molten silica sand ranges from 2.3 to 2.45 g / cm³. 3 The particle size ranges from 110 to 150 mesh, the sphericity is greater than 92%, and the breakage rate of the spheres is less than 1.5% when the static compressive strength is 50 MPa. The microscopic chemical composite friction reducer consists of 60 parts polymer microsphere emulsion, 35 parts lubricant, and 5 parts modified aldehyde-ketone condensation dispersant. The polymer microsphere emulsion is a quaternary copolymer microsphere synthesized by soap-free emulsion polymerization of styrene, methyl methacrylate, acrylic acid, and potassium 3-sulfonate propyl methacrylate, with a molecular weight of 400,000 to 600,000 and a particle size of 180-200 nm. The high-efficiency lubricant is an organic anionic compound obtained by a series of reactions between polyol amines, fatty acids, nonionic surfactants, and nano-scale fine materials. The modified aldehyde-ketone condensation dispersant is a gelatin graft sulfonated condensate synthesized by sulfonation grafting reaction of animal gelatin with formaldehyde, acetone, and sodium metabisulfite.

2. The low-shear, low-friction cement slurry system according to claim 1, characterized in that, The water loss reducing agent is an AMPS-based terpolymer, which is modified by terpolymerization of AMPS, low molecular weight amide, and polyhydroxycarboxylic acid.

3. The low-shear, low-friction cement slurry system according to claim 1, characterized in that, The reinforcing agents include polyether-modified polysiloxane, fluorosilicate, and potassium chloride.

4. The low-shear, low-friction cement slurry system according to claim 1, characterized in that, The retarder is acid-hydrolyzed modified starch.

5. The low-shear, low-friction cement slurry system according to claim 1, characterized in that, The defoamer is polyether silicone oil tributyl phosphate.

6. The low-shear, low-friction cement slurry system according to claim 1, characterized in that, The amount of the macroscopic physical friction reducer is 8 parts.

7. The low-shear, low-friction cement slurry system according to claim 1, characterized in that, The microscopic chemical composite friction reducer is present in 15 parts.

8. A method for preparing a low-shear, low-friction cement slurry system, the method being used to prepare the cement slurry system according to any one of claims 1-7, characterized in that, include: Step S1. Weigh out the micro-chemical composite friction reducer, defoamer and water according to the mass fraction of each liquid phase component of the low-shear low-friction cement slurry system to form a mixed solution and place it in a constant speed stirrer and stir at a speed of 2000±200r / min. Step S2. Weigh out the oil well grade G cement, macroscopic physical friction reducer, fluid loss reducer, reinforcing agent and retarder according to the mass fraction of each solid component in the low shear low friction cement slurry system, and mix them evenly to form a solid mixture. Step S3. Add the solid mixture obtained in step S2 to the mixed solution obtained in step S1 at a rotation speed of 4000±200 r / min, and then continue stirring to obtain a low-shear, low-friction cement slurry system.

9. The method for preparing a low-shear, low-friction cement slurry system according to claim 8, characterized in that, In step S1, the stirring time is 50 seconds.

10. The method for preparing a low-shear, low-friction cement slurry system according to claim 8, characterized in that, In step S3, the solid mixture obtained in step S2 is added to the mixed solution obtained in step S1 within 15s at a rotation speed of 4000±200r / min, and then stirring is continued for 35s to obtain a low-shear, low-friction cement slurry system.

Images