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CN-121974604-A - Barite weighting cement paste

CN121974604ACN 121974604 ACN121974604 ACN 121974604ACN-121974604-A

Abstract

The invention relates to barite weighting cement paste. The heavy spar cement slurry comprises, by mass, 1.5-2.5 parts of dispersing agent PC-F41L, 1.2-1.5 parts of retarder PC-H40L, 5-6 parts of fluid loss agent PC-G80L, 0.8-1.2 parts of defoamer, 40-45 parts of heavy spar weighting agent, 40-42 parts of water, 30-40 parts of silicon powder and 100 parts of cement, wherein the heavy spar weighting agent is obtained by dispersing heavy spar in water, and the particle size distribution of the heavy spar in the heavy spar weighting agent satisfies D50.3 μm or less and D90.8 μm or less. On the premise that the density of the barite weighting cement slurry is greater than 1.80 g/cm 3 , the density distribution is uniform, the sedimentation stability is excellent, the rheological property is good, and the barite weighting cement slurry is suitable for well cementation operations of deep wells and the like with larger stratum pressure.

Inventors

  • LI XIN
  • ZHU JIANGLIN
  • OUYANG JIANXIN
  • LI ZHOU
  • LING WEIZHONG

Assignees

  • 南方海洋科学与工程广东省实验室(湛江)

Dates

Publication Date
20260505
Application Date
20251203

Claims (10)

  1. 1. The barite weighting cement slurry is characterized by comprising, by mass, 1.5-2.5 parts of a dispersing agent PC-F41L, 1.2-1.5 parts of a retarder PC-H40L, 5-6 parts of a fluid loss agent PC-G80L, 0.8-1.2 parts of a defoaming agent, 40-45 parts of a barite weighting agent, 40-42 parts of water, 30-40 parts of silicon powder and 100 parts of cement; The barite weighting agent is obtained by dispersing barite in water, and the grain size distribution of the barite in the barite weighting agent meets D50 less than or equal to 0.3 mu m and D90 less than or equal to 0.8 mu m.
  2. 2. The barite weighting cement slurry according to claim 1, wherein the weight ratio of barite to water in the barite weighting agent is (60-70): 30-40.
  3. 3. The barite weighted cement slurry of claim 1, wherein the dispersing temperature is 25-35 ℃.
  4. 4. The barite weighted cement slurry of claim 1, wherein a dispersant is also added during the dispersing.
  5. 5. The barite weighted cement slurry of claim 4, wherein said dispersant is sodium hexametaphosphate.
  6. 6. The barite weighting cement slurry of claim 1, wherein an aqueous anti-blocking agent is also added during said dispersing.
  7. 7. The barite weighting cement slurry of claim 6, wherein said aqueous detackifier is aqueous detackifier J2301.
  8. 8. The method for preparing the barite weighted cement paste according to any one of claims 1 to 7, which is characterized by comprising the following steps: s1, adding a dispersing agent PC-F41L, a retarder PC-H40L, a fluid loss agent PC-G80L, a defoaming agent and a barite weighting agent into water, and uniformly mixing to obtain homogenate; and S2, adding cement and silica powder into the homogenate obtained in the step S1, and uniformly mixing to obtain the barite weighted cement paste.
  9. 9. Use of the barite weighted cement paste according to any one of claims 1 to 7 in well cementing.
  10. 10. The use according to claim 9, wherein the well cementing is directed to a straight well of 4500-6000 m.

Description

Barite weighting cement paste Technical Field The invention belongs to the technical field of drilling. And more particularly to a barite weighted cement slurry. Background In deep wells (4500-6000 m vertical wells), formation pressure may reach over 70 MPa, where cement slurry with a density greater than 1.80 g/cm3 is needed to provide sufficient hydrostatic column pressure to isolate the high pressure formation. The micro manganese weighting agent is a drilling cement slurry weighting agent widely applied in well cementation engineering, can obviously improve the density of cement slurry to balance formation pressure, effectively prevent blowout accidents, has the functions of cooling a drill bit and lubricating a drill rod, and is important to guaranteeing drilling efficiency. However, the micro manganese weighting agent is greatly limited by mineral distribution and refining technology, so that the cost is high, the micro manganese weighting agent is difficult to naturally degrade in the environment, and manganese contained in the micro manganese weighting agent can enter a human body through a respiratory tract, so that the risk of causing chronic manganese poisoning exists. Based on the above, the barite weighting agent with lower cost and higher environmental protection property and safety is one of the first choice for replacing the micro manganese weighting agent. However, when the barite is adopted as the weighting agent to weight the cement slurry until the density is more than 1.80 g/cm 3, the cement slurry is easy to subside in the cement slurry, so that the density of the cement slurry is unevenly distributed, the viscosity of the cement slurry is also greatly increased, the rheological property is obviously deteriorated, the difficulty of pumping is greatly increased, and the construction efficiency in the well cementation engineering is seriously affected. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide the barite weighting cement slurry, which is prepared by compounding the barite weighting agent prepared by barite with specific particle size with specific retarder, fluid loss agent, dispersing agent and other components, and the obtained barite weighting cement slurry has uniform density distribution and excellent sedimentation stability, has good rheological property, can reduce pumping resistance during construction, ensures well cementation efficiency and is suitable for well cementation operations of deep wells and the like with larger stratum pressure on the premise that the density is more than 1.80 g/cm 3. A first object of the present invention is to provide a barite weighted cement slurry. The second object of the invention is to provide a preparation method of the barite weighting cement paste. A third object of the invention is to provide the use of the barite weighted cement slurry in well cementing. The above object of the present invention is achieved by the following technical scheme: The invention provides barite weighting cement slurry, which comprises, by mass, 1.5-2.5 parts of a dispersing agent PC-F41L, 1.2-1.5 parts of a retarder PC-H40L, 5-6 parts of a fluid loss agent PC-G80L, 0.8-1.2 parts of a defoaming agent, 40-45 parts of a barite weighting agent, 40-42 parts of water, 30-40 parts of silicon powder and 100 parts of cement; The barite weighting agent is obtained by dispersing barite in water, and the grain size distribution of the barite in the barite weighting agent meets D50 less than or equal to 0.3 mu m and D90 less than or equal to 0.8 mu m. The term "D50≤0.3. Mu.m" means that the number of barite particles having a particle diameter of 0.3. Mu.m is 50%, and the term "D90≤0.8. Mu.m" means that the number of barite particles having a particle diameter of 0.8. Mu.m is 90%. Optionally, the barite weighting cement slurry comprises the following components, by mass, 1.5 parts of a dispersing agent PC-F41L, 1.2 parts of a retarder PC-H40L, 5 parts of a fluid loss agent PC-G80L, 0.8 part of a defoaming agent, 40 parts of a barite weighting agent, 40.3 parts of water, 35 parts of silicon powder and 100 parts of cement. The heavy spar weighting cement slurry comprises, by mass, 1.3 parts of dispersing agent PC-F41L 2 parts, retarder PC-H40L 1.3 parts, fluid loss agent PC-G80L 5.5 parts, defoamer 1 part, heavy spar weighting agent 43 parts, water 40.3 parts, silicon powder 35 parts and cement 100 parts. Still alternatively, the barite weighting cement slurry comprises the following components, by mass, 2.5 parts of a dispersing agent PC-F41L, 1.5 parts of a retarder PC-H40L, 80L 6 parts of a fluid loss agent PC-G, 1.2 parts of a defoaming agent, 45 parts of a barite weighting agent, 40.3 parts of water, 35 parts of silicon powder and 100 parts of cement. Preferably, in the barite weighting agent, the mass ratio of barite to water is (60-70): 30-40. Further, in the barite weighting agent, the mass ratio of barite to water i