Method of removing calcareous or siliceous deposits or scales
AssigneeBaker Hughes Incorporated
InventorsMingjie Ke, Qi Qu
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Abstract
The productivity of hydrocarbons from hydrocarbon-bearing calcareous or siliceous formations is enhanced by contacting the formation with a well treatment composition which contains a hydrofluoric acid source, a boron containing compound and a phosphonate acid, ester or salt thereof.
Claims24
A method of removing calcareous or siliceous deposits from hydrocarbon-producing wellbores and/or downhole screens while preventing and/or inhibiting the formation of inorganic fluoride scales, the method comprising:
- (A) pumping into the wellbore penetrating a siliceous or calcareous formation a well treatment composition comprising:
- a) a boron containing compound selected from the group consisting of (i.) fluoroboric acid and/or (ii.) boron compounds capable of forming a BF4− complex when exposed to F4− or a hydrofluoric acid source;
- (b) a phosphonate acid, ester or salt thereof, wherein the phosphonate is of the formula:
- wherein R1, R2 and R3 are independently selected from hydrogen, alkyl, aryl, phosphonic, phosphonate, phosphate, aminophosphonic acid, aminophosphonate, acyl, amine, hydroxy and carboxyl groups and R4 and R5 are independently selected from hydrogen, sodium, potassium, ammonium or an organic radical;
- and
- (c) a hydrofluoric acid source;
- (B) forming a BF4− complex;
- and
- (C) removing inorganic or siliceous deposits from the hydrocarbon-producing wellbore and/or downhole screen and preventing and/or inhibiting the formation of inorganic fluoride scales
- wherein the combination of boron containing compound and the phosphonate acid, ester or salt creates a synergistic effect such that the amount of inorganic fluoride scales precipitated in the presence of the combination is less than the amount of inorganic fluoride scales precipitated when either the boron containing compound or phosphonate acid, ester or salt is used alone.
A method of removing calcareous or siliceous deposits while preventing and/or inhibiting the formation of inorganic fluoride scales from hydrocarbon-producing wellbores, well casings, downhole assembly, downhole screens, production equipment, recovery equipment, well tubular or pipelines which comprises:
- (A) pumping into the wellbore, well casing, downhole assembly, downhole screen, production equipment, recovery equipment, well tubular or pipeline an aqueous well treatment composition comprising:
- (a) a boron containing compound selected from the group consisting of (i.) fluoroboric acid and/or (ii.) boron compounds capable of forming a BF4− complex when exposed to F4− or a hydrofluoric acid source;
- (b) a phosphonate acid, ester or salt thereof, wherein the phosphonate is of the formula:
- wherein R1, R2 and R3 are independently selected from hydrogen, alkyl, aryl, phosphonic, phosphonate, phosphate, aminophosphonic acid, aminophosphonate, acyl, amine, hydroxy and carboxyl groups and R4 and R5 are independently selected from hydrogen, sodium, potassium, ammonium or an organic radical;
- and
- (c) a hydrofluoric acid source;
- (B) forming a BF4− complex;
- and
- (C) removing the calcareous or siliceous deposits from the wellbore, well casing, downhole assembly, downhole screen, production equipment, recovery equipment, well tubular or pipeline and preventing and/or inhibiting the formation of inorganic fluoride scales
- wherein the combination of boron containing compound and the phosphonate acid, ester or salt creates a synergistic effect such that the amount of inorganic fluoride scales precipitated in the presence of the combination is less than the amount of inorganic fluoride scales precipitated when either the boron containing compound or phosphonate acid, ester or salt is used alone.
A method of removing calcium fluoride, magnesium fluoride, sodium fluorosilicate, potassium fluorosilicate and/or fluoroaluminate scales from hydrocarbon-producing wellbores and/or downhole screens which comprises:
- (A) pumping into the wellbore a well treatment composition having a pH between from about 0.5 to about 2.5 and comprising:
- a) a boron containing compound selected from the group consisting of (i.) fluoroboric acid and/or (ii.) boron compounds capable of forming a BF4− complex when exposed to F4− or a hydrofluoric acid source;
- (b) a phosphonate acid, ester or salt thereof, wherein the phosphonate is of the formula:
- wherein R1, R2 and R3 are independently selected from hydrogen, alkyl, aryl, phosphonic, phosphonate, phosphate, aminophosphonic acid, aminophosphonate, acyl, amine, hydroxy and carboxyl groups and R4 and R5 are independently selected from hydrogen, sodium, potassium, ammonium or an organic radical;
- and
- (c) a hydrofluoric acid source;
- (B) forming a BF4− complex;
- and
- (C) removing the scales from the hydrocarbon-producing wellbore and/or downhole screen
- wherein the combination of boron containing compound and the phosphonate acid, ester or salt creates a synergistic effect such that the amount of scales precipitated in the presence of the combination is less than the amount of scales precipitated when either the boron containing compound or phosphonate acid, ester or salt is used alone.
Dependencies are inferred from the claim text.