	US 11,945,997 B2
	Composition useful in sulfate scale removal
Clay Purdy, Medicine Hat (CA); Markus Weissenberger, Calgary (CA); Stig Magnor Nordaa, Sandnes (NO); and Adrienne Lee, Calgary (CA)
Assigned to DORF KETAL CHEMICALS FZE, Fujairah (AE)
Filed by Fluid Energy Group Ltd, Calgary (CA)
Filed on Mar. 18, 2020, as Appl. No. 16/823,025.
Claims priority of application No. CA 3038556 (CA), filed on Apr. 1, 2019.
Prior Publication US 2020/0308472 A1, Oct. 1, 2020
Int. Cl. C02F 5/08 (2023.01); C02F 5/10 (2023.01); C02F 5/12 (2023.01); C09K 8/528 (2006.01); C02F 101/10 (2006.01); C02F 103/08 (2006.01); C02F 103/10 (2006.01); E21B 37/06 (2006.01)

CPC C09K 8/528 (2013.01) [C02F 5/125 (2013.01); C02F 2101/101 (2013.01); C02F 2103/08 (2013.01); C02F 2103/10 (2013.01); E21B 37/06 (2013.01)]

12 Claims

1. An aqueous composition for use in removing petroleum-contaminated barium sulfate scale from a surface contaminated with such, said composition consisting of:

a chelating agent having chelating agent components, said chelating agent components including Ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), Tetraethylammonium hydroxide (TEAR), and Tetrabutylammonium hydroxide (TBAH)

said chelating agent and a counterion component selected from the group consisting of: Na₅DTPA; K₅DTPA; Cs₅DTPA; Na₄EDTA; K₄EDTA; TEAH₄DTPA; and TBAH₅DTPA;

a scale removal enhancer;

a non-ionic surfactant;

distilled water;

potassium hydroxide; and

wherein the non-ionic surfactant is a linear alcohol ethoxylate surfactant having a chain length of at least 6 carbon atoms and wherein said aqueous composition has a pH ranging from 10 to 11.