Composite suspension stabilizer for well cementation and preparation method thereof

Abstract

The invention relates to a composite suspension stabilizer for well cementation and a preparation method thereof, the suspension stabilizer comprises the following components: biological rubber powder, water, a hydration promoter and a solvent, the hydration promoter is used for promoting the affinity of the biological rubber powder to water; the solvent serves as an initial swelling medium of the biological rubber powder prior to water and is used for promoting uniform dispersion of the biological rubber powder in a system and enabling the biological rubber powder to be swelled to a semi-swelled state at the same time, and a space is reserved for a subsequent swelling reaction of the biological rubber powder and water; the suspension stabilizer can be completely hydrated and dispersed in water within 1-2 minutes to play a suspension role while ensuring various properties, the suspension stability of a prepad fluid system is improved, the formed prepad fluid has the characteristics of low viscosity and high shear, drilling fluid and cement paste can be effectively separated, a stratum can be stably pressed, the construction safety and the well cementation quality in the well cementation process are ensured, and the well cementation efficiency is improved. And the fluidity is good, pouring is convenient, and the prepad fluid processing convenience and production efficiency can be greatly improved.

Description

Technical Field

[0001] This disclosure relates to the field of cementing pre-fill fluid additives in drilling engineering, specifically to composite cementing suspension stabilizers and their preparation methods. Background Technology

[0002] Currently, most suspension stabilizers for cementing pre-flush fluids are composed of bio-adhesive powder, polymers, and clay. This composition can support the weighting material and effectively improve the isolation properties of the pre-flush fluid. For example, CN104962260A discloses "a suspension stabilizer for cementing high-temperature isolation fluid and its preparation method and application". The aforementioned suspension stabilizer for cementing high-temperature isolation fluid includes clay substances, warm sizing gum, xanthan gum, inorganic salts, and polymers.

[0003] Currently, the main research focuses on how to improve the high-temperature resistance of pre-fluids using suspension stabilizers. The developed suspension stabilizers have achieved a temperature resistance exceeding 220℃. However, during the experiment, it was found that the hydration time of most suspension stabilizers is at least 3 hours, and they generally have the problems of extremely slow hydration and dispersion speed and long onset time. This situation will greatly reduce the processing efficiency of the pre-fluid. Summary of the Invention

[0004] In view of this, this disclosure provides a composite cementing suspension stabilizer that solves the problem of slow hydration and dispersion speed and long onset time of current suspension stabilizers, which greatly reduces the processing efficiency of pre-flush fluid.

[0005] To achieve the aforementioned objectives, in a first aspect, the composite cementing suspension stabilizer disclosed herein comprises the following components:

[0006] The invention comprises bio-adhesive powder, water, a hydration accelerator, and a solvent. The hydration accelerator is used to promote the affinity of the bio-adhesive powder for water. The solvent is preferred over water as the initial swelling medium for the bio-adhesive powder, which promotes the uniform dispersion of the bio-adhesive powder in the system and allows the bio-adhesive powder to swell to a semi-swelled state, reserving space for the subsequent swelling reaction between the bio-adhesive powder and water.

[0007] Preferably, the contents of each component, by weight percentage, are as follows:

[0008] Bio-adhesive powder 2%-6%, hydration accelerator 7%-15%, solvent 16%-25%, deionized water 55%-70%.

[0009] Preferably, the bio-adhesive powder is one or more of xanthan gum, viniferin, and zeaxanthin.

[0010] Preferably, the composition and content of the bio-adhesive powder are as follows: xanthan gum is 10%-30%, viniferin is 20%-30%, and zeatin is 40%-60%.

[0011] Preferably, the hydration accelerator is one or more of fatty alcohol polyoxyethylene ether, coconut oil diethanolamine, alkylphenol polyoxyethylene ether, and polyoxyethylene sorbitan monooleate.

[0012] Preferably, the composition and content of the hydration accelerator are as follows:

[0013] The fatty alcohol polyoxyethylene ether is 30%-60%, the coconut oil diethanolamine is 10%-20%, the alkylphenol polyoxyethylene ether is 20%-30%, and the polyoxyethylene sorbitan monooleate is 10%-20%.

[0014] Preferably, the solvent is one or more of DMF, ethanol, isopropanol and ethylene glycol monobutyl ether.

[0015] Preferably, the composition and content of the solvent, by mass percentage, are as follows:

[0016] The DMF is 10%-20%, the ethanol is 10%-20%, the isopropanol is 20%-30%, and the ethylene glycol monobutyl ether is 50%-60%.

[0017] Secondly, the method for preparing the composite cementing suspension stabilizer described in any one of the first aspects includes:

[0018] The bio-adhesive powder is completely dispersed in the solvent to form the first solution;

[0019] The hydration accelerator is completely dispersed in water to form a second solution;

[0020] After the first solution and the second solution are stirred evenly, they are stirred for 0.5-1.5 hours at a temperature of 40-60℃ to obtain the composite cementing suspension stabilizer.

[0021] Preferably, an antifoaming agent is added when the hydration accelerator is dispersed in water.

[0022] The present invention has the following beneficial effects:

[0023] This invention provides a low-viscosity, high-shear composite suspension stabilizer with rapid dissolution and action. It can be quickly hydrated and dispersed, and the resulting base fluid can effectively support the weighted particles. While ensuring that the performance of various components does not decline, its greatest feature is that it can be completely hydrated and dispersed in water within 1-2 minutes, exerting a suspension effect and improving the suspension stability of the pre-flush system. The resulting pre-flush has the characteristics of "low viscosity and high shear," which can effectively separate drilling fluid and cement slurry and stabilize the formation, ensuring construction safety and cementing quality during the cementing process. In addition, it has good fluidity and is easy to pour, which can greatly improve the processing convenience and production efficiency of the pre-flush. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to illustrate the technical solutions of this disclosure.

[0025] Figure 1 This is an example of the viscosity change trend of the mixed liquid after the suspending agent is added to water in an embodiment of this disclosure;

[0026] Figure 2 This is the thickening curve of pure low-density cement slurry at 110°C according to an embodiment of this disclosure;

[0027] Figure 3 The thickening curve of the low-density cement slurry + pre-fermented liquid mixture at 110°C is shown in the embodiment of this disclosure. Detailed Implementation

[0028] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. Although various aspects of embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise. The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0029] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details.

[0030] To address the problems described in the background section, this disclosure provides a composite cementing suspension stabilizer, the core of which is:

[0031] The suspension stabilizer mainly consists of bio-adhesive powder and water. A hydration accelerator is then used to significantly improve the affinity efficiency between the bio-adhesive powder and water, greatly enhancing the affinity of the bio-adhesive powder for water. A solvent is used instead of water as the initial swelling medium for the bio-adhesive powder, aiming to promote the uniform dispersion of the bio-adhesive powder in the system and maintain it in a semi-swollen state, thus reserving space for the subsequent full reaction between the bio-adhesive powder and water.

[0032] The roles of each component in composite cementing suspension stabilizers are detailed below:

[0033] Bio-adhesive powder, as the "core of efficacy" in the system, lays the foundation for its "rapid onset of action" due to its molecular structure characteristics. On the one hand, high-quality bio-adhesive powder has a high specific surface area and abundant active sites, which can quickly adsorb surrounding medium molecules in the early stage of hydration, significantly shortening the "water absorption-dispersion" start-up cycle and avoiding the "hydration lag" caused by the lack of active sites in traditional adhesive powder. On the other hand, its high flexibility and interweaving ability of molecular chains can quickly form a microscopic "elastic scaffold" after hydration and dispersion. Compared with ordinary adhesive powder, which takes several hours to build a stable scaffold, this component can wrap suspended particles in a short time through surface tension and intermolecular forces, initially counteracting gravity settling and achieving a rapid onset of action of "dispersion is the initial stable suspension". It can play a basic stabilizing role without waiting for the system to become completely viscous.

[0034] Solvents are the key to solving the problem of slow hydration and dispersion, directly circumventing the core drawback of using water as the initial swelling medium. In traditional processes, the large surface tension difference between water and adhesive powder causes the adhesive powder particles to quickly form a "water film adhesion layer" after absorbing water instantly. This leads to the particles adsorbing and clumping together, preventing the internal adhesive powder from contacting water. This not only prolongs the swelling time to more than 4 hours, but also renders the insufficiently hydrated adhesive powder ineffective. In contrast, specialized solvents have a high surface tension matching that of the adhesive powder particles. During the initial swelling stage, they can quickly penetrate into the gaps between the adhesive powder particles, preventing particle adhesion and allowing the adhesive powder to be evenly dispersed in the form of "single particles or small aggregates." The swelling time can be shortened to within a few minutes. More importantly, the solvent regulates the adhesive powder to a "semi-swollen state," avoiding molecular chain entanglement caused by excessive swelling and keeping the adhesive powder particles in a "awaiting hydration and activation" state, preparing them for subsequent reactions with water. This fundamentally breaks through the bottleneck of slow dispersion and prolonged effectiveness caused by "clumping together."

[0035] Hydration accelerators, acting as "bridge accelerators," significantly increase the reaction rate between adhesive powder and water, further compressing the "dispersion-onset" interval. In traditional systems, adhesive powder molecules contain certain hydrophobic regions, exhibiting weak affinity for water molecules. Prolonged stirring is required for full hydration, and uneven hydration, characterized by "fully hydrated areas and unhydrated areas," leads to dispersed onset times. In contrast, the "amphiphilic structure" of hydration accelerators allows rapid penetration to the surface of semi-swollen adhesive powder particles. Their hydrophilic groups quickly capture deionized water molecules through hydrogen bonding and polar adsorption, while their lipophilic groups tightly bind to the hydrophobic regions of the adhesive powder, effectively creating a "highly efficient transport channel" between them. Water molecules that would normally diffuse slowly can now rapidly enter the interior of the adhesive powder particles through this channel, shortening the time from "semi-swollen" to "fully swollen" by more than 50%. This ensures uniform hydration of each adhesive powder particle, avoiding "delayed onset" caused by localized unhydrated areas, achieving an effect of "onset upon completion of hydration."

[0036] Deionized water accelerates the onset of action while ensuring that the effect is not compromised after "rapid dispersion," avoiding "temporary effectiveness followed by subsequent failure" caused by uneven hydration. Deionized water contains no impurity ions and can quickly penetrate along the natural pores of the polymer powder molecular chains. Compared to ordinary water containing impurities, it binds to the active groups of the polymer powder at a faster rate, quickly "opening up" and uniformly stretching the coiled and contracted polymer powder molecular chains. When the molecular chains stretch to a critical state, the active groups of adjacent chain segments can quickly cross-link through hydrogen bonds and van der Waals forces, forming a dense three-dimensional network structure. This structure formation time is 30% shorter than that of ordinary water systems, and the structure is more uniform. It not only quickly locks in suspended particles, preventing stratification and sedimentation, but also allows the system viscosity to quickly reach a stable value without the need for prolonged subsequent stirring and adjustment, truly achieving the synergistic goal of "fast hydration and dispersion, short onset time, and stable effect."

[0037] Based on the above-mentioned core technology, this disclosure provides a composite cementing suspension stabilizer that can achieve the purpose of this invention, the components of which and the weight percentage of each component are as follows:

[0038] The bio-gum powder comprises 2%-6%, hydration accelerator 7%-15%, solvent 16%-25%, and deionized water 55%-70%; the bio-gum powder is one or more of xanthan gum, vinifera gum, and zeaxanthin.

[0039] Preferably, the composition and content of the bio-gum powder, by mass percentage, are as follows: xanthan gum 10%-30%, vinyl gum 20%-30%, and eugenol gum 40%-60%.

[0040] Preferably, the hydration accelerator is one or more of fatty alcohol polyoxyethylene ether, coconut oil diethanolamine, alkylphenol polyoxyethylene ether, and polyoxyethylene sorbitan monooleate.

[0041] Preferably, the composition and content of the hydration accelerator, by mass percentage, are: 30%-60% fatty alcohol polyoxyethylene ether, 10%-20% coconut oil diethanolamine, 20%-30% alkylphenol polyoxyethylene ether, and 10%-20% polyoxyethylene sorbitan monooleate.

[0042] Preferably, the solvent is one or more of N,N-dimethylformamide (DMF), ethanol, isopropanol, and ethylene glycol monobutyl ether.

[0043] Preferably, the composition and content of the solvent, by mass percentage, are: 10%-20% DMF, 10%-20% ethanol, 20%-30% isopropanol, and 50%-60% ethylene glycol monobutyl ether.

[0044] The following provides a method for preparing the composite cementing suspension stabilizer, including the following steps:

[0045] S1. Stir the mixture of bio-adhesive powder and solvent to completely disperse the bio-adhesive powder in the solvent, forming solution A;

[0046] S2. Thoroughly stir the mixture of hydration accelerator and deionized water to form solution B; preferably, an antifoaming agent is also added during stirring.

[0047] S3. After mixing solution A and solution B evenly, stir for 0.5-1.5 hours at a temperature of 40-60℃ to obtain the finished product.

[0048] Preferably, in step S1, the stirring speed is 300-500 rpm and the stirring time is 10-15 min; in step S2, the stirring speed is 1000 rpm and the stirring time is 10 min; and in step S3, the stirring speed is 200-300 rpm.

[0049] The following are preferred embodiments of this disclosure.

[0050] Example 1

[0051] Example 1 describes the preparation of a composite cementing suspension stabilizer.

[0052] (1) Add 1.8 g xanthan gum, 1.8 g warming gum, 2.4 g tinning gum, 2 g DMF, 2 g ethanol, 4 g isopropanol and 12 g ethylene glycol monobutyl ether to beaker 1 in sequence. Stir the mixture at 400 rpm for 10 min to completely disperse the warming gum and tinning gum in the mixed solvent.

[0053] (2) Weigh 5 g of fatty alcohol polyoxyethylene ether, 2 g of coconut oil diethanolamine, 2 g of alkylphenol polyoxyethylene ether, 1 g of polyoxyethylene sorbitan monooleate and 0.5 g of defoamer into beaker 2, then add 62 g of deionized water and stir the mixture at 1000 rpm for 10 min to form a solution.

[0054] (3) While stirring, add the solution in beaker 2 into beaker 1, and stir the material in beaker 1 at 200 rpm for 1 h at 50°C before discharging to obtain the finished composite cementing suspension stabilizer.

[0055] Example 2

[0056] Example 1 describes the preparation of a composite cementing suspension stabilizer.

[0057] (1) Add 1 g xanthan gum, 1 g warming gum, 2 g tinning gum, 2.2 g DMF, 4.4 g ethanol, 4.4 g isopropanol and 11 g ethylene glycol monobutyl ether to beaker 1 in sequence. Stir the mixture at 400 rpm for 10 min to completely disperse the warming gum and tinning gum in the mixed solvent.

[0058] (2) Weigh 6 g of fatty alcohol polyoxyethylene ether, 3 g of coconut oil diethanolamine, 3 g of alkylphenol polyoxyethylene ether, 3 g of polyoxyethylene sorbitan monooleate and 0.5 g of defoamer into beaker 2, then add 59 g of deionized water and stir the mixture at 1000 rpm for 10 min to form a solution.

[0059] (3) While stirring, add the solution in beaker 2 into beaker 1, and stir the material in beaker 1 at 200 rpm for 1 h at 50°C before discharging to obtain the finished composite cementing suspension stabilizer.

[0060] Application Example 1

[0061] This application example 1 describes the preparation of cementing pre-fill fluid.

[0062] Weigh 100 parts by weight of deionized water, add 5 parts of the suspension stabilizer prepared in Example 1 to the deionized water at 500 rpm, stir for 3 min, and then add 28-140 parts of a solution with a density of 4.20 g / cm³ to the mixture according to the required density of the pretreatment solution. 3 Barite powder is stirred for another 10 minutes to obtain cementing pre-filled fluids for water-based drilling fluids of different densities.

[0063] Application Example 2

[0064] This application example 2 describes the preparation of cementing pre-fill fluid.

[0065] Weigh 100 parts by weight of deionized water. Add 4 parts of the suspension stabilizer prepared in Example 1 and 6 parts of the well cementing pre-flushing agent (each part of the flushing agent consists of 20% fatty alcohol polyoxyethylene ether + 8% coconut oil diethanolamine + 8% sodium dodecylbenzene sulfonate + 24% alkylphenol polyoxyethylene ether + 20% petroleum ether + 5% sodium citrate + 15g sodium silicate) to the mixture after stirring for 5 minutes. Then, according to the required pre-flushing agent density, add 28-140 parts of a solution with a density of 4.20 g / cm³ to the mixture. 3 Barite powder, continue stirring for 15 minutes to obtain cementing pre-fill fluids for oil-based drilling fluids of different densities.

[0066] Application Example 3

[0067] This application example 2 describes the preparation of cementing pre-fill fluid.

[0068] Weigh 100 parts of deionized water by weight, add 6.5 parts of the suspension stabilizer prepared in Example 2 to the deionized water at 500 rpm, stir for 3 min, and then add 28-140 parts of barite powder with a density of 4.20 g / cm3 to the mixture according to the density requirements of the pre-flush fluid. Continue stirring for 10 min to obtain cementing pre-flush fluids for water-based drilling fluids of different densities.

[0069] Application Example 4

[0070] Weigh 100 parts of deionized water by weight, add 5.5 parts of the suspension stabilizer prepared in Example 2 and 6 parts of the cementing pre-flush agent to the deionized water at 500 rpm, stir for 5 min, add 28-140 parts of barite powder with a density of 4.20 g / cm3 to the mixture according to the density requirements of the pre-flush, and continue stirring for 15 min to obtain cementing pre-flush for oil-based drilling fluids of different densities.

[0071] The following section evaluates the performance of the products in each embodiment and application example.

[0072] 1. Evaluation of the hydration time of composite cementing suspension stabilizer (hereinafter referred to as suspension agent) upon water entry.

[0073] The hydration time of the suspending agent in water was evaluated using the mixed fluid viscosity change method. The samples selected for the experiment were the suspending agent samples prepared in Examples 1 and 2. The specific evaluation method was as follows: the suspending agent and the on-site application water at a set temperature (25 ℃) were weighed according to the standard ratio. The suspending agent was slowly added to the water while stirring with a magnetic stirrer (fixed speed, 200-300 rpm), and a stopwatch was started simultaneously. The temperature of the mixture was maintained stable throughout the process using a constant temperature water bath (accuracy ±0.5 ℃). A rotational viscometer with a suitable rotor was used. Due to the short hydration time of the suspending agent, the viscosity (mPa·s) was measured every 30-6 seconds from the start of timing, and the data was recorded simultaneously. When the viscosity difference of 5 consecutive measurements was ≤2 mPa·s, the viscosity was considered to have reached a stable state. The time displayed on the stopwatch at this point was the hydration time (min) of the suspending agent. The experimental results are as follows: Figure 1 As shown.

[0074] 2. Evaluation of the suspension stability of cementing pre-fill fluid.

[0075] The pretreatment solution used in Application Examples 1-4 had a density of 1.20-1.80 g / cm³. 3For the pretreatment solution, the room temperature stability test method in this experiment was mainly based on the graduated cylinder method. The prepared pretreatment solution was poured into a 500 ml graduated cylinder, sealed, and allowed to stand at 23 ℃ for 24 h. The density difference between the upper and lower parts of the pretreatment solution was then measured. For the high-temperature stability test, the pretreatment solution was placed in a curing vessel and cured at 180 ℃ for 4 h. After cooling, the density difference between the upper and lower parts of the pretreatment solution was measured. The experimental results are shown in Tables 1 and 2.

[0076] Table 1. Stability Evaluation of Pre-fluid for Water-Based Drilling Fluids

[0077]

[0078] Table 2. Stability Evaluation of Pre-fluids for Oil-Based Drilling Fluids

[0079]

[0080] 3. Evaluation of the rheological compatibility (thickening compatibility) of the pre-flush fluid with drilling fluid and cement slurry.

[0081] Rheological compatibility test method: The pretreatment solution was the one with a density of 1.50 g / cm³, as used in Application Examples 1 and 3. 3 The density of the water-based drilling fluid pre-fluid formed in Application Examples 2 and 4 is 1.65 g / cm³. 3 Pre-fluid for oil-based drilling fluid. Referring to API specification GB / T19139-2003, the pre-fluid was mixed with cement slurry and drilling fluid in a specific volume ratio indoors. After thorough mixing, the mixture was cured for a period of time at 50 ℃ using an atmospheric pressure thickener. The rheological data of the mixed fluid were measured using a six-speed rotational viscometer to evaluate the compatibility of the pre-fluid with the cement slurry and the field drilling fluid.

[0082] Thickening compatibility test method: The pre-test solution was the one with a density of 1.60 g / cm³, as formed in Application Examples 2 and 4. 3 The oil-based drilling fluid used as a pre-fluid was tested, and the cement slurry was a fluid loss reducing agent system with a density of 1.60 g / cm³. 3 Indoors, 1.60 g / cm 3 Low-density cement slurry and a mixture of cement slurry and pre-mixed liquid at a volume ratio of 75:25 were prepared and subjected to high-temperature and high-pressure thickening experiments after thorough mixing. The thickening time for the low-density cement slurry and the mixture to reach a consistency of 100 BC was recorded. The thickening compatibility between the pre-mixed liquid and the cement slurry was evaluated by comparing the time difference between the two.

[0083] The compatibility test data of the pre-flush fluid for water-based drilling fluid with water-based drilling fluid and cement slurry are shown in Table 3; the compatibility test data of the pre-flush fluid for oil-based drilling fluid with oil-based drilling fluid and cement slurry are shown in Table 4.

[0084] The thickening curve of low-density cement paste at 100℃ is shown below. Figure 2 The thickening curve of low-density cement slurry mixed with pre-fermented liquid (75:25) at 100℃ is shown in the figure. Figure 3 .

[0085] Table 3. Compatibility test data of 1.50 g / cm³ water-based drilling fluid pre-flush fluid with water-based drilling fluid and cement slurry.

[0086]

[0087] Table 4 1.65 g / cm 3 Compatibility test data of oil-based drilling fluid pre-flush fluid with oil-based drilling fluid and cement slurry.

[0088]

[0089] The test data from the above embodiments and application examples show that the hydration time evaluation results of the suspension stabilizer of the present invention indicate that the hydration time of the two suspension stabilizers prepared in Examples 1 and 2 is extremely short (≤2 min), achieving the predetermined goal of "rapid dissolution and rapid effect," indicating that the additives and preparation process used in this suspension are scientifically sound. The stability evaluation results of the pre-treatment solution show that the density difference between the different densities of the pre-treatment solutions formed in Application Examples 1 to 4 at 23 ℃ × 24 h / 180 ℃ × 4 h is < 0.02 g / cm³. 3 The suspension stability is good. The rheological compatibility evaluation results show that as the proportion of pre-flush added increases, the rheological data of the mixture between the pre-flush, drilling fluid, and cement slurry gradually decreases, indicating that the pre-flushes of different densities formed in Application Examples 1 to 4 have good compatibility with the drilling fluid and cement slurry. The thickening compatibility evaluation results show that the thickening time of the cement slurry mixed with the pre-flush is extended by about 1 hour compared to pure cement slurry, proving that the experimental pre-flush has no contamination, thickening, or coagulation-promoting effects on the cement slurry. These experiments demonstrate that the suspending agent has excellent suspension-aiding and anti-contamination properties, ensuring the safety of on-site cementing operations.

[0090] This invention relates to a composite cementing suspension stabilizer. The various additives exhibit strong compatibility, and the suspension system maintains a uniform and stable appearance even after prolonged storage (>60 days), with no solid precipitation or degradation of active ingredients. At an addition rate of 5%, it effectively supports the pre-flush fluid, with a density difference of ≤0.02 g / cm³ at 180°C. 3 Meanwhile, the suspension stabilizer has excellent fluidity and rapid dissolution and effect after dissolving in water. At room temperature, its funnel viscosity is only 43s. When added to water at a dosage of 5% and stirred for about 2 minutes, the suspending agent can be completely dissolved in water, thereby playing a suspending role and greatly improving the short-time processing efficiency of cementing pre-filling fluid, ensuring the actual needs of on-site production.

[0091] In summary, the composite cementing suspension stabilizer provided by this invention, when added to water, can rapidly hydrate and disperse. The resulting base fluid can effectively support weighted particles and improve the suspension stability of the pre-flush system. The resulting pre-flush has "low viscosity and high shear" characteristics, which can effectively separate drilling fluid and cement slurry and stabilize the formation, ensuring construction safety and cementing quality during the cementing process.

[0092] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A composite cementing suspension stabilizer, characterized in that, Its components include: The invention comprises bio-adhesive powder, water, a hydration accelerator, and a solvent. The hydration accelerator is used to promote the affinity of the bio-adhesive powder for water. The solvent is preferred over water as the initial swelling medium for the bio-adhesive powder, which promotes the uniform dispersion of the bio-adhesive powder in the system and allows the bio-adhesive powder to swell to a semi-swelled state, reserving space for the subsequent swelling reaction between the bio-adhesive powder and water.

2. The composite cementing suspension stabilizer according to claim 1, characterized in that, The content of each component by weight percentage is as follows: Bio-adhesive powder 2%-6%, hydration accelerator 7%-15%, solvent 16%-25%, deionized water 55%-70%.

3. The composite cementing suspension stabilizer according to claim 1 or 2, characterized in that: The bio-adhesive powder is one or more of xanthan gum, viniferin, and zeaxanthin.

4. The composite cementing suspension stabilizer according to claim 3, characterized in that, The composition and content of the bio-gum powder by mass percentage are as follows: xanthan gum 10%-30%, vinyl gum 20%-30%, and eugenol gum 40%-60%.

5. The composite cementing suspension stabilizer according to claim 3, characterized in that: The hydration accelerator is one or more of fatty alcohol polyoxyethylene ether, coconut oil diethanolamine, alkylphenol polyoxyethylene ether, and polyoxyethylene sorbitan monooleate.

6. The composite cementing suspension stabilizer according to claim 5, characterized in that, The composition and content of the hydration accelerator, by mass percentage, are as follows: The fatty alcohol polyoxyethylene ether is 30%-60%, the coconut oil diethanolamine is 10%-20%, the alkylphenol polyoxyethylene ether is 20%-30%, and the polyoxyethylene sorbitan monooleate is 10%-20%.

7. The composite cementing suspension stabilizer according to claim 5, characterized in that: The solvent is one or more of DMF, ethanol, isopropanol and ethylene glycol monobutyl ether.

8. The composite cementing suspension stabilizer according to claim 7, characterized in that, The composition and content of the solvent, by mass percentage, are as follows: The DMF is 10%-20%, the ethanol is 10%-20%, the isopropanol is 20%-30%, and the ethylene glycol monobutyl ether is 50%-60%.

9. The method for preparing the composite cementing suspension stabilizer according to any one of claims 1-8, characterized in that, include: The bio-adhesive powder is completely dispersed in the solvent to form the first solution; The hydration accelerator is completely dispersed in water to form a second solution; After the first solution and the second solution are stirred evenly, they are stirred for 0.5-1.5 hours at a temperature of 40-60℃ to obtain the composite cementing suspension stabilizer.

10. The preparation method of the composite cementing suspension stabilizer according to claim 9, characterized in that: An antifoaming agent is added when dispersing the hydration accelerator in water.

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