CN-122010450-A - Oil well cement paste stability regulator and preparation method thereof

Abstract

The invention relates to a stabilizing regulator for oil well cement and a preparation method thereof, wherein the stabilizing regulator consists of gel particles and an inhibitor, the gel particles are used for absorbing excessive moisture in cement paste after enlarging the water-cement ratio and reducing the density, the inhibitor is used for inhibiting the gel particles from absorbing moisture at the early stage of cement paste hydration and starting to absorb the excessive moisture in the cement paste after hydration for a period of time, the stabilizing regulator can absorb the excessive moisture in the cement paste after enlarging the water-cement ratio, avoid the generation of free liquid, ensure the stability of the cement paste, ensure the cementing quality of cement rings and have important practical significance for cementing construction safety and improving the cementing quality, and in addition, the stabilizing regulator does not contain harmful substances and changes the preparation mode of the cement paste, has wide dry mixing convenience and applicability, is more convenient for cementing construction and has important economic value and social significance for improving the cementing of oil gas wells such as an adjusting well.

Inventors

• XIANG YUANLONG
• WANG XUGUANG
• WANG HUAN
• ZHENG QINGYOU
• YANG XU
• SONG YANTAO
• ZHAI XIANGYU
• WEI YIXUN
• LI NA
• XU YUNLONG
• ZHANG ZHENHUA
• YANG XIUTIAN
• HOU LIWEI

Assignees

• 大庆钻探工程有限公司
• 中国石油天然气集团有限公司

Dates

Publication Date

20260512

Application Date

20251124

Claims (12)

1. 1. The oil well cement paste stability regulator is characterized by comprising gel particles and an inhibitor, wherein the inhibitor is used for inhibiting the gel particles from absorbing water in the early stage of cement paste hydration, and the gel particles are used for starting to absorb excessive water in the cement paste after the early stage of hydration.
2. 2. The oil well cement slurry stability modifier of claim 1, wherein: The gel particles are polyacrylamide gel particles, and the inhibitor is formate.
3. 3. The oil well cement slurry stability modifier of claim 1, wherein: the formate is sodium formate, potassium formate or calcium formate.
4. 4. A method of preparing an oil well cement slurry stability modifier as claimed in any one of claims 1 to 3, comprising: And (3) neutralizing the acrylic acid monomer, then carrying out polymerization reaction on the acrylic acid monomer and a cross-linking agent to obtain a polyacrylamide colloid, and granulating, drying and crushing the polyacrylamide colloid to obtain the stability regulator.
5. 5. The method for preparing the oil well cement slurry stability modifier according to claim 4, wherein: And adding an enhancer in the polymerization reaction of the acrylic acid monomer, wherein the enhancer is methylene succinic acid.
6. 6. The method of preparing an oil well cement slurry stability modifier of claim 5, wherein the raw material components of the polymerization reaction comprise, in weight percent: 10% -30% of acrylic acid monomer, 10% -30% of alkaline solution, 5% -10% of cross-linking agent, 10% -30% of water, 2% -10% of reinforcing agent and 0.05% -0.2% of initiator.
7. 7. The method for preparing the oil well cement slurry stability modifier according to claim 6, wherein: The cross-linking agent is N, N-methylene bisacrylamide.
8. 8. The method for preparing the oil well cement slurry stability modifier according to claim 6, wherein: The initiator is a mixture of sodium bisulphite and persulfate or a mixture of sodium bisulphite and peroxide.
9. 9. The method for preparing the oil well cement slurry stability modifier according to claim 8, wherein: the persulfate is potassium persulfate or ammonium persulfate, and the peroxide is hydrogen peroxide.
10. 10. A method of preparing an oil well cement slurry stability modifier as claimed in any one of claims 6 to 9, wherein the method of polymerising acrylic monomer with cross-linking agent comprises: adding an acrylic acid monomer into a reaction kettle, and neutralizing with an alkaline solution to obtain a solution A; adding a cross-linking agent, an enhancer and water into the solution A to obtain a solution B; and (3) deoxidizing the solution B, adding an initiator, and polymerizing at 30-80 ℃.
11. 11. The method of preparing an oil well cement slurry stability modifier of claim 10, wherein: The polymerization time was set at the start of the reaction at the beginning of the temperature rise and at the end of the reaction at the end of the temperature no longer rise.
12. 12. The method for preparing an oil well cement slurry stability modifier according to claim 11, wherein: The polymerization time is 3-6 hours.

Description

Oil well cement paste stability regulator and preparation method thereof Technical Field The present disclosure relates to the technical field of oil well cement additives for drilling and completing in the process of oil field development, and in particular to an oil well cement slurry stability regulator and a preparation method thereof. Background In the well drilling and completion construction process of oilfield development, as the annulus size of the upper casing shoe and the well section above is increased, the annulus return speed is reduced after the well cementing cement slurry reaches the well casing shoe and the well section above is reduced, the displacement efficiency is poor, the casing shoe and the well section above are seriously mixed with clear water spacer fluid, and the well cementing quality is influenced. The reason is that after the cement paste is mixed with the clean water, the water cement ratio becomes high, the cement paste density becomes low, the water content in the cement paste is relatively high, a series of problems can be caused, such as uneven distribution of cement particles in the paste, sedimentation and layering phenomena are easy to occur, and the overall performance of the paste is reduced. Meanwhile, the hydration reaction speed and the progress of cement can be influenced due to excessive water, so that the problems of insufficient strength development, prolonged hardening time, large volume shrinkage of cement stone and the like can be caused, and the existence of the problems can finally influence the well cementation quality. In order to solve these problems, ensuring the stability of cement paste after blending is an important and key point of research. At present, materials which can be used as cement paste stabilizers at home and abroad are divided into inorganic materials and organic polymer materials. The stabilizer of inorganic material mainly includes superfine material, clay material, thixotropic material, etc. The superfine material has small particle size and large specific surface area, and has thixotropic thickening effect when being added into cement paste, so that the superfine material has certain suspension capacity. The clay substance generally has higher heat resistance, is more completely hydrated at high temperature, has a thickening effect and can form a grid structure, so that the clay substance has better suspending capability. However, the inorganic material stabilizer has the problems of larger initial consistency, difficult ash discharging and the like, and is unfavorable for on-site ash mixing and pumping, so that the adding amount is strictly controlled during use, and the use of the inorganic material stabilizer as a stabilizer is limited to a certain extent. The organic polymer material mainly comprises natural polymer, modified polymer and synthetic polymer. The natural polymer and its modifier may be used as cement slurry stabilizer mainly including vegetable gum, cellulose, etc. Meanwhile, the synthetic polymer material is fast in development in the well cementation additive, has stable performance and easy control, can carry out corresponding molecular structural design according to the performance required by the product, and then selects proper polymerization monomers to prepare the required product. The synthesized high molecular material has higher relative molecular mass, can effectively increase the viscosity of a system, and can also form a certain net structure, thereby having better suspending capability. The additive can solve the stability problem of cement paste to a certain extent, and the main action mechanisms are that the cement paste viscosity is improved, the suspension capacity is improved and the like, but the additive can not absorb excessive water in cement paste after the water-cement ratio is enlarged and the density is reduced, and the water can influence the hydration reaction of cement and the volume of cement paste, and further influence the cement sheath cementation quality. Disclosure of Invention In view of the above, the present disclosure provides an oil well cement paste stability regulator, which solves the problem that the cement sheath cementing quality is affected due to the fact that the existing cement paste stabilizer cannot absorb excessive water in cement paste after expanding the cement paste ratio and reducing the density. In order to achieve the above object, according to a first aspect, the oil well cement slurry stability regulator of the present disclosure comprises gel particles and an inhibitor, wherein the inhibitor is used for inhibiting absorption of water by the gel particles in the early stage of hydration of the cement slurry, and the gel particles are used for starting to absorb excessive water in the cement slurry after the early stage of hydration. Preferably, the gel particles are polyacrylamide gel particles and the inhibitor is formate salt. Preferably, the format