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CN-119060699-B - Drilling fluid treating agent with interface enhancement and mud cake lubrication functions and preparation method and application thereof

CN119060699BCN 119060699 BCN119060699 BCN 119060699BCN-119060699-B

Abstract

The invention belongs to the technical field of drilling fluid treatment agents, and discloses a drilling fluid treatment agent with interface enhancement and mud cake lubrication functions, and a preparation method and application thereof, wherein the drilling fluid treatment agent consists of 75-99% of fly ash, 0.5-15% of sodium silicate nonahydrate, 0.5-10% of modified sodium lignin sulfonate and 0.2-10% of polypropylene fiber by mass percent. The addition amount of the cement paste additive in the drilling fluid is 0.5-1.5%, the cementing strength of the two interfaces of well cementation can be improved by 30-50 times, the lubricity of mud cakes is improved by 90-97%, and the effects of enhancing the interfaces and reducing the friction resistance of the well wall are obvious. The drilling fluid is added into the drilling fluid according to a certain proportion at the middle and later stages of the horizontal well drilling to the horizontal section, so that the operation is simple and the field application is easy.

Inventors

  • HE JUN
  • Miao Bingzhang
  • SHI HAIMIN
  • YU YANG
  • ZHAO YUNFEI
  • ZHANG QING
  • HAN YUSHU
  • JIA JUQUAN
  • Jia Sigang
  • LI CHUANJUN

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260512
Application Date
20230531

Claims (7)

  1. 1. The drilling fluid treating agent with the interface enhancement and mud cake lubrication functions is solid micro powder, and is characterized by comprising, by mass, 97% of fly ash, 1% of sodium silicate nonahydrate, 1% of modified sodium lignin sulfonate, 1% of polypropylene fiber or 97% of fly ash, 0.5% of sodium silicate nonahydrate, 1.5% of modified sodium lignin sulfonate, 1.5% of polypropylene fiber and 7-9% of modified sodium lignin sulfonate.
  2. 2. The drilling fluid treating agent with both interface enhancement and mud cake lubrication functions according to claim 1, wherein the particle size of the fly ash particles is 100-500 mesh.
  3. 3. The drilling fluid treating agent with both interface enhancement and mud cake lubrication functions according to claim 1, wherein the particle size of the fly ash particles is 120-400 mesh.
  4. 4. The drilling fluid treatment agent with both interface enhancement and mud cake lubrication functions according to claim 1, wherein the polypropylene fiber has a length of 1.5-200nm.
  5. 5. The drilling fluid treatment agent with both interface enhancement and mud cake lubrication functions according to claim 1, wherein the polypropylene fiber has a length of 60-150nm.
  6. 6. The preparation method of the drilling fluid treating agent with the functions of interface enhancement and mud cake lubrication is characterized in that according to the formula of the drilling fluid treating agent according to any one of claims 1-5, fly ash, sodium silicate nonahydrate, modified sodium lignin sulfonate and polypropylene fibers are stirred and mixed uniformly in a mixer according to the respective content ratio requirements, and no sequence exists in the mixing preparation process.
  7. 7. The application of the drilling fluid treating agent with the functions of interface enhancement and mud cake lubrication is characterized in that the drilling fluid treating agent according to any one of claims 1-5 is added into the drilling fluid from the middle and later period of horizontal drilling, and the addition amount of the drilling fluid treating agent is 0.5% -1.5% of the drilling fluid in percentage by mass.

Description

Drilling fluid treating agent with interface enhancement and mud cake lubrication functions and preparation method and application thereof Technical Field The invention belongs to the technical field of drilling fluid treatment agents, and relates to a drilling fluid treatment agent with interface enhancement and mud cake lubrication functions, and a preparation method and application thereof. Background As conventional oil and gas resource development enters the middle and later stages, development of unconventional tight reservoir energy becomes an important point gradually. For these reservoirs, horizontal well fracturing is most commonly used for production. Due to the characteristics of the horizontal well structure, the pipe column is in large-area contact with the lower well wall under the action of gravity, so that the displacement resistance of the lower part of an annulus is increased, the thickness of a virtual mud cake on the well wall is increased by residual drilling fluid which cannot be displaced effectively, on one hand, the friction of the horizontal section is increased, the torque is increased, the abrasion of a drilling tool is serious, the drilling safety and the extension limit of the horizontal well are seriously influenced, on the other hand, the compatibility of a thicker mud cake on the well wall and cement paste is poor, the affinity of the mud cake and cement paste is only physical acting force, so that the mud cake cannot be well cemented with a cement ring, the cementing strength of an interface is reduced, the cementing quality is reduced, the annulus is further caused to be invalid, the fluid is generated, dangerous accidents are caused, and the later fracturing transformation effect is also influenced. In conclusion, the low friction resistance of the tubular column and the low bonding strength of the two interfaces are main reasons for restricting the technical development of the horizontal well. Currently, in order to solve the friction problem of a horizontal well string, the oilfield site is usually solved by adding a lubricant into the drilling fluid, and the common lubricants comprise asphalt and oil-based liquid phase lubricants. The lubricant has a remarkable lubricating effect in the initial mining stage of the horizontal section, and can generally lead the viscosity coefficient of the mud cake to be lower than 0.2. However, as the solid content in drilling fluid increases in the middle and later stages of drilling, the action effect of asphalt and oil-based liquid phase lubricant is not obvious, and excessive oil-based liquid phase lubricant causes the deficiency of a well wall mud cake, so that the phenomenon of sticking the drilling is easily caused. Aiming at the problem of poor cementing strength of the two interfaces, high-efficiency drilling fluid flushing fluid is generally adopted to improve the cleaning efficiency, reduce the residue of drilling fluid on the lower well wall and reduce the thickness of mud cakes, or improve the density difference of the drilling fluid and cement slurry, thereby improving the displacement efficiency. The method can not realize complete removal of the well wall drilling fluid mud cake and complete replacement of cement paste, and the dissolubility of the two properties leads to poor affinity between the well wall and the cement sheath, which inevitably leads to reduction of the cementing strength of the two interfaces. In summary, in the oil field, asphalt or oil-based liquid phase lubricant is added into drilling fluid to improve the lubricity of mud cakes, and after the completion, the interface cementing strength is improved by a method of cleaning the well wall mud cakes when flushing fluid is discharged, and the two are sequential in process and are not performed simultaneously. Disclosure of Invention In order to make up for the defects of the prior art, the invention aims to provide a water-based drilling fluid treating agent with the functions of interface enhancement and mud cake lubrication. The treating agent has simple use method, can be directly added into drilling fluid, increases cementing interface cementing strength, improves the lubricity of mud cakes, and simultaneously realizes the purposes of well solidification cementing of the well wall mud cakes and cement paste and reducing the friction resistance of the well wall, thereby being beneficial to improving the interface cementing strength and improving the drilling speed. The technical scheme adopted for solving the technical problems is as follows: The water-based drilling fluid treating agent with the interface enhancement and mud cake lubrication functions is solid micro powder, and consists of 75-99% of fly ash, 0.5-15% of sodium silicate nonahydrate, 0.5-10% of modified sodium lignin sulfonate and 0.2-10% of polypropylene fiber by mass percent. In the scheme, the particle size of the fly ash particles is 100-500 meshes, preferably 120-400 meshes. Mo