Complex acid-solvent treatment design and practice for Jurassic-Cretaceous carbonate formation of the Varadero oilfield (the Republic of Cuba)

UDK: 622.276.63
DOI: 10.24887/0028-2448-2022-7-102-107
Key words: acid treatment, Varadero, the Republic of Cuba, matrix treatment, acid composition, solvent, high viscosity emulsion, high-molecular weight components, matrix treatment simulator
Authors: A.E. Folomeev (RN-BashNIPIneft LLC, RF, Ufa), A.R. Khatmullin (RN-BashNIPIneft LLC, RF, Ufa), A.A. Imamutdinova (RN-BashNIPIneft LLC, RF, Ufa), L.E. Kashtanova (RN-BashNIPIneft LLC, RF, Ufa), S.V. Nazarova (RN-BashNIPIneft LLC, RF, Ufa), A.R. Sharifullin (Ufa State Petroleum Technical University, RF, Ufa), A.V. Mityukov (RN-Exploration LLC, RF, Moscow), M.V. Krylova (RN-Exploration LLC, RF, Moscow), A.I. Voloshin (RN-BashNIPIneft LLC, RF, Ufa), F.S.Echevarria Pestana (CEINPET, the Republic of Cuba, Havana), L.V.Lesmes Garrido (CEINPET, the Republic of Cuba, Havana)

Foreign projects for Rosneft Oil Company are one of the key areas for the hydrocarbon resource base development. Currently, Rosneft is running projects in Myanmar, Egypt, Iraq, Cuba and offshore of Mozambique. One of the special projects is the Varadero field on the territory of the Republic of Cuba. The oil bearing capacity at the field is found in the Upper Jurassic and Lower Cretaceous carbonate formations. The Varadero oil is a typical representative of the naphthenic oils of the North Cuban Oil Basin by its physico-chemical properties. It is characterized by high viscosity and density, significant content of resin-asphaltene compounds and sulfur. One of the essential activities during oil production at the Varadero field is the well stimulation and mitigation response in well operation. In relation to the object under consideration, it is possible to distinguish the fight against the formation of high-viscosity oil-water emulsions, the deposition of high molecular weight components and oilfield equipment corrosion. To restore the wells productivity and keep oil production at required level, it is recommended to use complex acid treatment technologies with use of organic solvents.

The article provides an algorithm for designing complex acid treatment technologies for the conditions of the Varadero field, based on a series of laboratory studies on the selection of acid compositions and solvents for cleaning the critical matrix from asphaltene deposits. The results of acid treatments are presented and an analysis of their effectiveness is performed.


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