Banca de QUALIFICAÇÃO: CLÁUDIO REGIS DOS SANTOS LUCAS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : CLÁUDIO REGIS DOS SANTOS LUCAS
DATE: 28/02/2020
TIME: 14:00
LOCAL: Auditório do Nupeg
TITLE:

Development of Retarded Microemulsion Systems for Acid Stimulation in Carbonate Rocks Application 

KEY WORDS:

Matrix acidizing, microemulsions, Pore Volume to Breakthrough - PVBT, Wormholes, Indiana limestone

PAGES: 155
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

The necessity to make oil wells increasingly profitable, especially in conditions with high production costs, leads to continuous technological development. In December 2019, about 61% of Brazil's oil production came from wells in pre-salt carbonate rocks reservoirs. Matrix Acidification is a stimulation technique widely used in carbonates to increase its production as a result of the formation of high conductivity channels around the well called wormholes. Anisotropy, heterogeneity and acid reaction speed in carbonates and even oil saturation lead to difficulties in controlling its formation resulting in ineffective treatments. Microemulsion systems consist of thermodynamically stable auto associative structures and low surface tension. These systems have already been subject of studies to retard acid-rock reaction speed, but with little conclusive results. This work aims to develop and test, through well-known techniques and brand-new techniques, the use of oil in water microemulsified systems in standard carbonate rock and considering the oil saturation, generally neglected, for application in the matrix acidification. In this work, microemulsion systems using ALKONAT-L100 as a surfactant, n-butanol co-surfactant, xylene nonpolar phase and polar phase 1.54 w/w%, 8.27 w/w% and 15  w/w% aqueous solutions were developed and characterized; Standard carbonate rocks called Siluriam, Winterset, Edwards White, Indiana, Desert Pink, in addition to the Pirabas from a Brazilian outcrop, characterized in terms of composition, porosity, permeability and reactivity; the effects of concentration and the types of treatment systems on the behavior of the contact angle analyzed; experimental plans conduced to verify the influence of HCl concentration, temperature and reaction time on the reaction speed carried out in different conditions; and Pore Volume to Breakthrough (PVBT) curves were produced followed by subsequent dissolution patterns analyses by high resolution microtomography (micro-CT) and NMR.  The results showed that even at high HCl concentrations, microemulsion systems were formed close to the polar phase apex and they are thermally resistant, reaching over 100 OC. The rocks composition is decisive for reaction speed between carbonates and HCl. The treatment with surfactant content systems, especially the microemulsified ones, showed a great contact angle reduction related to distilled water and to systems without its presence. Through the experimental planning it was observed that the reaction speed of the systems surfactant free were basically governed by the HCl concentration whether in the condition where there was or not saturation in mineral oil, whereas the time factor became also important in surfactant content systems. The produced models were both predictive and significant for all scenarios analyzed, except for the scenarios where HCl solution was used as treatment fluid. The results of NMR and Micro-CT showed effective wormholing morphologies when using microemulsion systems. In this way, microemulsified systems were obtained and showed to be efficient in retard the acid-rock reaction for application in the acid matrix stimulation of the carbonate rocks

BANKING MEMBERS:
Externo ao Programa - 347289 - AFONSO AVELINO DANTAS NETO
Externo ao Programa - 1754344 - MARCOS ALLYSON FELIPE RODRIGUES
Externa à Instituição - MARIA CARLENISE PAIVA DE ALENCAR MOURA - UFRN
Presidente - 347057 - TEREZA NEUMA DE CASTRO DANTAS
Interna - 1531209 - VANESSA CRISTINA SANTANNA