Dissolving barium sulfate scale with aqueous solutions of salts of phosphomethyl and amino-substituted macrocyclic polyethers

Patent · Tue Sep 08 04:00:00 EDT 1981

OSTI ID:5934290

Van Zon, A; de Jong, F; Torny-Schutte, G J

Barium sulfate scale can be removed from remote locations such as those in or around the borehole of a well extending into a subterranean earth formation by contacting the scale with an aqueous solution consisting essentially of water, a monovalent cation salt of a macrocyclic polyether containing at least 2 nitrogen- linked phosphomethyl groups and enough monovalent basic compound to provide a solution pH of 8. The barium sulfate is soluble in such solutions. Barium sulfate scale can be deposited or formed from pressure and/or temperature changes in the flow of oil, or by the commingling of individually stable waters, of which one is rich in sulfate ions and the other in barium ions. Also, fine barite particles that have been included in the drilling mud applied in drilling the well and that have invaded the pay-zone of the formation cause a permanent impairment of the well productivity which requires cleaning of the formation parts.

• Assignee: Shell Oil Co.
• Patent Number(s): US 4288333
• OSTI ID: 5934290
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
ALKALINE EARTH METAL COMPOUNDS
AQUEOUS SOLUTIONS
BARIUM COMPOUNDS
BARIUM SULFATES
BOREHOLES
CAVITIES
CONTROL
DISPERSIONS
ETHERS
MIXTURES
OIL WELLS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
POLYMERS
SALTS
SCALE CONTROL
SOLUTIONS
SULFATES
SULFUR COMPOUNDS
WELLS