Petroleo Brasileiro S.a. - Petrobras

Celso Rodrigo De Souza

Carlos Nagib Khalil

Alberto Cunha Da Silva

Claudio Silvio Martins

Maria Cristina Brum

Sonia Maria De Menezes

An improved method is provided for the thermo-chemical dewaxing a large dimension line or conduit using a Nitrogen Generation System/Emulsion. The method involves introducing an emulsion into the conduit to be waxed. The emulsion comprises an internal aqueous phase and an external organic phase. The aqueous phase comprises an oxidizing nitrogen salt, a reducing nitrogen salt and water. The organic phase comprises a non-polar organic liquid, such as kerosene, and a delayed action activator for inducing the reaction of said oxidizing nitrogen salt and said reducing nitrogen salt. The improvement comprises a delayed action activator which may be a copolyanhydride such as poly(adipic-co-sebacic)anhydride solubilized in a polar organic solvent such as chloroform. The solubilized delayed action activator is easily and accurately pumped into the conduit to be dewaxed. The emulsion is maintained in the conduit until the delayed action activator induces the reaction of the nitrogen salts to generate nitrogen and heat, thereby fluidizing wax in the conduit.

Method for the thermo-chemical dewaxing of large dimension lines

A method is provided for thermo-chemical dewaxing a large dimension line or conduit using a Nitrogen Generation System/Emulsion. The method involves introducing an emulsion into the conduit to be dewaxed. The emulsion comprises an internal aqueous phase and an external organic phase. The aqueous phase comprises an oxidizing nitrogen salt, a reducing nitrogen salt and water. The organic phase comprises a non-polar organic liquid, such as kerosine, and a delayed action activator for inducing the reaction of said oxidizing nitrogen salt and said reducing nitrogen salt. The delayed action activator may be a linear, aliphatic polyanhydride, such as poly(adipic anhydride). The emulsion is maintained in the conduit until the delayed action activator induces the reaction of the nitrogen salts to generate nitrogen and heat, thereby fluidizing wax in the conduit. The fluidized wax is then removed from the conduit. The emulsion may be prepared on a production platform or on nearby equipment. Well production may be resumed after the dewaxing treatment.

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Rio de Janeiro, Brazil

Celso Rodrigo De Souza