Uma nova proposta de fluidos de perfuração aquosos à base de polímeros vinílicos e bentonita para poços de alta temperatura e pressão
The advance of drilling in deeper wells has required more thermostable materials. The use of synthetic fluids, which usually have a good chemical stability, faces the environmental constraints, besides it usually generate more discharge and require a costly disposal treatment of drilled cuttings,...
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Formato: | Dissertação |
Idioma: | por |
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Universidade Federal do Rio Grande do Norte
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Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/21036 |
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Resumo: | The advance of drilling in deeper wells has required more thermostable materials. The
use of synthetic fluids, which usually have a good chemical stability, faces the environmental
constraints, besides it usually generate more discharge and require a costly disposal treatment
of drilled cuttings, which are often not efficient and require mechanical components that
hinder the operation. The adoption of aqueous fluids generally involves the use of chrome
lignosulfonate, used as dispersant, which provides stability on rheological properties and fluid
loss under high temperatures and pressures (HTHP). However, due to the environmental
impact associated with the use of chrome compounds, the drilling industry needs alternatives
that maintain the integrity of the property and ensure success of the operation in view of the
strong influence of temperature on the viscosity of aqueous fluids and polymers used in these
type fluids, often polysaccharides, passives of hydrolysis and biological degradation.
Therefore, vinyl polymers were selected for this study because they have predominantly
carbon chain and, in particular, polyvinylpyrrolidone (PVP) for resisting higher temperatures
and partially hydrolyzed polyacrylamide (PHPA) and clay by increasing the system's
viscosity. Moreover, the absence of acetal bonds reduces the sensitivity to attacks by bacteria.
In order to develop an aqueous drilling fluid system for HTHP applications using PVP,
HPAM and clay, as main constituents, fluid formulations were prepared and determined its
rheological properties using rotary viscometer of the Fann, and volume filtrate obtained by
filtration HTHP following the standard API 13B-2. The new fluid system using
polyvinylpyrrolidone (PVP) with high molar weight had higher viscosities, gels and yield
strength, due to the effect of flocculating clay. On the other hand, the low molecular weight
PVP contributed to the formation of disperse systems with lower values in the rheological
properties and fluid loss. Both systems are characterized by thermal stability gain up to
around 120 ° C, keeping stable rheological parameters. The results were further corroborated
through linear clay swelling tests. |
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