Delayed polymer gelation using low total dissolved solids brine
AssigneeSaudi Arabian Oil Company
InventorsAmar J. Alshehri, Jinxun Wang
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Abstract
A method for placing a gel deep inside a subterranean formation includes combining a crosslinkable polymer, a chromium (III) crosslinking agent, and a brine to form a gelation solution. The gelation solution is pumped within a subterranean wellbore. The gelation time of the gelation solution is elongated by reducing the total dissolved solids of the brine so that the gelation solution penetrates deep into the subterranean formation away from the wellbore before a gel is formed.
Claims14
A method for placing a gel inside a subterranean formation, the method including:
- providing a brine and reducing the total dissolved solids of the brine to form a brine solution, where the brine solution comprises a sodium chloride (NaCl), a sodium sulfate (Na3SO4), a sodium bicarbonate (NaHCO3), a sodium acetate (NaAc), and an ammonium chloride (NH4Cl), wherein the brine solution is free of divalent cation salts;
- combining a crosslinkable polymer, a chromium (III) crosslinking agent, and the brine solution to form a gelation solution;
- pumping the gelation solution within a subterranean wellbore to form a permanent plug within the subterranean formation away from the subterranean wellbore;
- wherein
- an initial onset of gel formation of the gelation solution is elongated by reducing the total dissolved solids of the brine so that the gelation solution penetrates into the subterranean formation away from the wellbore before the initial onset of gel formation.
A method for placing a gel inside a subterranean formation, the method including:
- providing a synthetic seawater comprising a sodium chloride (NaCl), a sodium sulfate (NagSO1), a sodium bicarbonate (NaHCO3), a sodium acetate (NaAc) and an ammonium chloride (NH4Cl) to form a brine, wherein the brine is free of divalent cation salts;
- combining a crosslinkable polymer, a chromium (III) crosslinking agent, and the brine solution to form a gelation solution;
- pumping the gelation solution within a subterranean wellbore to form a permanent plug within the subterranean formation away from the subterranean wellbore;
- wherein a viscosity of the gelation solution within the subterranean wellbore is less than 10 cp;
- and
- an initial onset of gel formation of the gelation solution is elongated so that the gelation solution penetrates into the subterranean formation away from the wellbore before the initial onset of gel formation.
Dependencies are inferred from the claim text.