Additive for oil well cement, and cement composition and cement slurry both including said additive for oil well cement
AssigneeDenka Company Limited
InventorHiroshi Tamai
Life of this patent
Estimating the term…
Abstract
Provided is a PVA-containing additive for oil well cement superior in fluid loss-reducing property. Specifically, provided is an additive for oil well cement, the additive containing polyvinyl alcohol having a saponification value of 75 to 85 mol % and a viscosity-average polymerization degree of 2,800 to 4,500. Also provided are a cement composition containing the additive for oil well cement in an amount of 0.01 to 30% bwoc and a cement slurry containing the additive for oil well cement in an amount of 0.01 to 30% bwoc.
Claims5
An additive for oil well cement comprising polyvinyl alcohol particles containing a polyvinyl alcohol having a saponification value of 75 to 85 mol % and a viscosity-average polymerization degree of 2,800 to 4,500,
- wherein the polyvinyl alcohol particles comprise particles having a particle diameter in a range greater than 0 μm and not more than 75 μm in an amount of a range greater than 0 and not more than 25 mass % in 100 mass % of the particles, particles having a particle diameter of 500 μm or more in an amount of a range equal to or greater than 0 and not more than 10 mass % in 100 mass % of the particles, and particles having a particle diameter in a range greater than 75 μm to less than 500 μm in an amount of balance in 100 mass % of the particles.
A cement composition containing an additive for oil well cement in an amount of 0.01 to 30% bwoc,
- wherein the additive comprises polyvinyl alcohol particles containing polyvinyl alcohol having a saponification value of 75 to 85 mol % and a viscosity-average polymerization degree of 2,800 to 4,500, and
- wherein the polyvinyl alcohol particles comprise particles having a particle diameter in a range greater than 0 and not more than 75 μm in an amount of a range greater than 0 and not more than 25 mass % in 100 mass % of the particles, particles having a particle diameter of 500 μm or more in an amount of a range equal to or greater than 0 and not more than 10 mass % in 100 mass % of the particles, and particles having a particle diameter in a range greater than 75 μm to less than 500 μm in an amount of balance in 100 mass % of the particles.
A cement slurry containing an additive for oil well cement in an amount of 0.01 to 30% bwoc,
- wherein the additive comprises polyvinyl alcohol particles containing polyvinyl alcohol having a saponification value of 75 to 85 mol % and a viscosity-average polymerization degree of 2,800 to 4,500, and
- wherein the polyvinyl alcohol particles comprise particles having a particle diameter in a range greater than 0 and not more than 75 μm in an amount of a range greater than 0 and not more than 25 mass % in 100 mass % of the particles, particles having a particle diameter of 500 μm or more in an amount of a range equal to or greater than 0 and not more than 10 mass % in 100 mass % of the particles, and particles having a particle diameter in a range greater than 75 μm to less than 500 μm in an amount of balance in 100 mass % of the particles.
Dependencies are inferred from the claim text.