Banca de DEFESA: GLAUCO SOARES BRAGA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : GLAUCO SOARES BRAGA
DATE: 17/08/2023
TIME: 14:00
LOCAL: Online
TITLE:

New Acid Soluble Slurry System for Loss of Circulation in Macroporous Carbonate Reservoirs

KEY WORDS:

Soluble Cement, Lost Circulation Plug, Lost of Circulation

PAGES: 113
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUMMARY:

Pre-salt drilling has brought huge challenges, among the main ones, we can highlight circulations losses. Fluid loss to the formation is one of the most critical problems that can be encountered during oil well drilling. Therefore, any circulation loss increases the total cost significantly when added to the non-productive times (NPT) to contain the problem. During the drilling of pre-salt carbonate reservoirs, when invading macroporosity intervals such as vugs and natural fractures, there is a risk of severe loss of drilling fluid, reaching in some cases a loss rate of more than 700 barrels/hour. Most of the time, traditional techniques are not effective against severe circulation losses in macroporous carbonate reservoirs with vugular structures and/or natural fractures, due to the nature of the rock formation, and it is necessary and good practice to fight with cement slurry (cement plug). Cement plugs are effective in combating loss of circulation in carbonate reservoirs, but they cause irreversible damage. The permanent damage caused by the cement plug alters the original permoporosity conditions of the reservoir, strongly interfering with the production of the reservoir in question. In order to mitigate the problems caused by the use of cement plugs, it is necessary to study and develop new alternative materials that replace the use of cement with constituents that can be reversible, regarding the damage to the formation, when applied in order to combat the loss of circulation in the reservoir. Acid-soluble slurry systems formulated with W/RM ratio were studied to evaluate their potential as a buffer against lost circulation. First, the slurries systems consistometry study was carried out at 9500 psi and 54 °C conditions, mechanical strength tests, and phase identification by x-ray diffraction of the systems cured at 9500 psi and 80 °C. The results indicate that the consistometry time and mechanical strength are consistent with the intended application. The cured Slurries systems underwent static acid attack test in 9 and 15% HCl, showing excellent results, with total dissolution of the specimen. It was also evaluated the effects of saturated CO2 atmosphere in specimens for a period of 30 and 45 days, the results indicate that the specimens have undergone changes in their microstructure causing physicochemical changes in the specimens. Finally, the plugging and acidification tests were performed, where the paste was injected under pressure into the pores of a carbonate rock testimony. This rock was previously evaluated by µtomography, in addition to the basic petrophysical properties. After the injection of the paste into the rock core, the µtomography and basic petrophysical data were collected once again. Subsequently, the buffered plug underwent acidification in coreflooding to evaluate the removal of the damage caused by the acid-soluble paste, providing the removal of the buffer with the return of the permoporosity of the rock.

COMMITTEE MEMBERS:
Interno - 1298936 - ANTONIO EDUARDO MARTINELLI
Externa à Instituição - FABÍOLA DIAS DA SILVA CURBELO - UFPB
Presidente - 1804366 - JÚLIO CÉZAR DE OLIVEIRA FREITAS
Externo à Instituição - PEDRO TUPÃ PANDAVA AUM - UFPA
Externo ao Programa - 1995142 - RODRIGO CÉSAR SANTIAGO - null