Method of scavenging hydrogen sulfide and/or sulfhydryl compounds
View Patent ↗A method of reducing the amount of sulfhydryl compounds from sour hydrocarbon fluids is described. In the method, an aldehyde-releasing compound, which is high temperature stable and is highly water-soluble, is introduced to a hydrocarbon fluid stream as a scavenger for sulfhydryl compounds. The aldehyde-releasing compound is allowed to mix with the hydrocarbon fluid stream and the aldehyde-releasing compound is allowed to react with the sulfhydryl compounds present in the hydrocarbon fluid stream, thereby reducing the presence sulfhydryl compound in the hydrocarbon fluid stream.
1. A method for reducing the amount of sulfhydryl compounds from an oil and gas production well or injection well, said method comprising
(i) providing a high temperature stable, highly water soluble aldehyde-releasing compound comprising hydantoins; and
(ii) adding an effective amount of the aldehyde-releasing compound to the production well or the injection well at a position downhole and below ground surface, the aldehyde-releasing compound being added to a hydrocarbon fluid stream downhole and below ground during production of oil or gas from the production well or injection well.
2. The method according to claim 1 , wherein the downhole addition, below ground surface, is achieved using a capillary string, umbilical cord, a perforation in the annulus of a production pipe, addition at the backside of the production or injection well.
3. The method according to claim 1 , wherein the hydantoin comprises a hydroxymethyl hydantoin, a bis(hydroxymethyl)hydantoin or a mixture thereof.
4. The method according to claim 3 , wherein the hydroxymethylhydantion is selected from the group consisting of 1-hydroxymethyl-5,5-dimethylhydantoin, 3-hydroxymethyl-5,5-dimethylhydantoin, and mixtures thereof; and the bis(hydroxymethyl)hydantoin is 1,3 -bis(hydroxymethyl)-5 ,5 -dimethylhydantoin.
5. The method according to claim 1 , wherein the sulfhydryl compound present in the hydrocarbon fluid comprises hydrogen sulfide.
6. The method according to claim 1 , wherein the aldehyde-releasing compound is continuously fed, below ground surface, to the production well or injection well.
7. The method according to claim 1 , wherein the aldehyde-releasing compound is fed, below ground surface, to the production well or injection well in a batchwise manner.
8. The method according to claim 1 , wherein the aldehyde-releasing compound is added in amount of at least 0.3 moles of the aldehyde-releasing compound per mole of the sulfhydryl present in the hydrocarbon fluid stream to be treated.
9. The method according to claim 8 , wherein the aldehyde-releasing compound is added in amount between about 1 to about 10 moles of the aldehyde-releasing compound per mole of the sulfhydryl present in the hydrocarbon fluid stream to be treated.
10. The method according to claim 1 , wherein the aldehyde-releasing compound is stable at a temperature of 80° C. for a period of at least 6 hours.