Banca de DEFESA: STÉPHANIE CAVALCANTE DE MORAIS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : STÉPHANIE CAVALCANTE DE MORAIS
DATE: 11/03/2021
TIME: 08:00
LOCAL: Remotamente pelo google meet
TITLE:

Evaluation of polyelectrolytic complexes based on poly(epichlorohydrin-co-dimethylamine) and poly (4-styrene-sulfonic acid-co-maleic acid) in the delivery of polyphosphates for the control of CaCO₃ scale in oil wells

KEY WORDS:

 Polyelectrolyte Complex; Scale; Calcium carbonate; Squeeze Treatment

PAGES: 122
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Polímeros e Colóides
SUMMARY:

Polyelectrolytic complexes (PEC) based on poly(epichlorohydrin-co-dimethylamine) (EPI-DMA) and poly(4-styrene-sulfonic acid-co-maleic acid) (PSSMA) for polyphosphate encapsulation were first prepared in the literature. The PEC was developed in order to increase the durability of the treatment of scale in oil wells. Sodium hexametaphosphate (SHMP) was used as a model polyphosphate in this work and evaluated as a calcium carbonate scale inhibitor. The relationship between pH and CaCO₃ formation was evaluated by static tests, dynamic precipitation in capillary and scanning electron microscopy (SEM) images. At pH 6.5, excellent results were found with complete inhibition of CaCO₃ deposition in the capillary with only 2.5 mg L^-1 of SHMP and a deformed structure of the CaCO₃ crystals by SEM images was observed. In turn, at pH 7.5 and above, SHMP showed a significant decrease in the efficiency of scaling inhibition even at high concentrations. These results were attributed to the precipitation kinetics of CaCO₃ under the drastic conditions evaluated. To optimize the PEC formulations, a 2³ factorial design was applied. The resulting PEC suspensions were characterized by dynamic light scattering (DLS), zeta potential and SHMP encapsulation efficiency (EE). The best results were found by the formulation using 1% (w/w) of EPI-DMA, 0.1% of PSSMA and addition of SHMP before PSSMA. This optimized formulation was applied in real oil well conditions and showed good stability at 25 °C and reduced stability with increasing temperature. The PEC showed excellent inhibition efficiency against calcium carbonate scale with minimum effective concentration (MCE) of 2.0 mg L^-1 using the same concentration of SHMP at 100 °C and 1000 psi. The PEC suspension also showed exceptional performance in the evaluation of the interaction with sandstone, improving not only the adsorption of the material in the rock grains, but also the durability of the treatment by 100%.

 

BANKING MEMBERS:
Presidente - 1149440 - ROSANGELA DE CARVALHO BALABAN
Interno - 1198847 - JOSE LUIS CARDOZO FONSECA
Externo ao Programa - 1859346 - MIGUEL ANGELO FONSECA DE SOUZA
Externo à Instituição - ALESSANDRO FRANCISCO MARTINS
Externo à Instituição - MARCOS ANTONIO VILLETTI - UFSM