Cement slurry compositions for cementing oil wells, adapted to control free water and corresponding cementing process
AssigneeEtudes et Fabrication Dowell Schlumberger
InventorCamille Defosse
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Abstract
The invention relates to an additive adapted to suppress free water in conditions of "over-dispersion" of the cement when cementing an oil well. This additive is selected from cerain metal soluble salts such as Mg, Ni, etc. This additive modifies neither the other properties of the slurry (in particular setting time) nor the action of other additives (in particular of retarders).
Claims15
In a cement slurry composition useful for cementing oil wells and comprising cement, water and dispersant, a column of which composition would otherwise form a free water layer, the improvement which comprises the inclusion therein of an agent adapted to control free water, said free water controlling agent being about 100 micromoles to 5 millimoles per 100 grams of cement of a soluble salt of magnesisum, tin, lead, bismuth or a transition metal or a combination thereof.
A composition adapted to control free water in a cement slurry composition useful for oil well cementing consisting essentially of a sulfonated dispersant and a free water controlling agent which is a soluble salt of magnesium, tin, lead, bismuth or a transition metal other than Zn, or combination thereof.
Dependencies are inferred from the claim text.