Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-18T15:15:54Z No. of bitstreams: 1 RAQUEL SANTOS LEITE - DISSERTAÇÃO PPG-CEMat 2014..pdf: 1921020 bytes, checksum: 963eb1edee3115174a9a06b4af8c7f59 (MD5) / Made available in DSpace on 2018-04-18T15:15:54Z (GMT). No. of bitstreams: 1 RAQUEL SANTOS LEITE - DISSERTAÇÃO PPG-CEMat 2014..pdf: 1921020 bytes, checksum: 963eb1edee3115174a9a06b4af8c7f59 (MD5) Previous issue date: 2014-08-27 / Os fluidos inibidos são empregados na perfuração de folhelhos hidratáveis para evitar que as argilas encontradas sejam hidratadas e causem prisão de ferramentas. O conhecimento das propriedades de filtração dos fluidos é importante durante a perfuração de poços, uma vez que o controle dessas propriedades garante menos problemas de perfuração e melhora a produtividade dos poços. Assim, este trabalho teve como objetivo estudar e aperfeiçoar as propriedades de filtração de fluidos aquosos, inibidos com sal de potássio isentos de cloro (citrato de potássio), visando sua aplicação na perfuração de formações argilosas e folhelhos hidratáveis e dispersivos. Para tanto, foram estudados fluidos de perfuração com e sem adição do inibidor citrato de potássio. Foram determinadas as propriedades reológicas (viscosidades aparente (VA) e plástica (VP), limite de escoamento (LE) e força gel (FG)), filtração (volume de filtrado (VF), spurt loss (SL), espessura de reboco (ER) e permeabilidade (k)) e o poder de inibição (ensaios de dispersibilidade e o teste de inibição de bentonita) dos fluidos estudados. De acordo com os resultados obtidos conclui-se que os fluidos estudados apresentaram comportamento pseudoplástico e a adição do citrato de potássio ao fluido não ocasionou mudança no comportamento pseudoplástico dos fluidos. Concluiu-se ainda, que o uso conjunto dos aditivos amido, CMC BV e calcita reduz de forma mais efetiva as propriedades de filtração dos fluidos de perfuração estudados e que as propriedades de filtração dos fluidos inibidos com citrato de potássio foram otimizadas, uma vez que os valores de VF obtidos foram inferiores ao do fluido tido como base. As formulações que apresentaram eficientes propriedades de filtração e inibição foram preparadas com altas concentrações de citrato de potássio. As mesmas apresentaram baixos valores de VF e menores valores de SL. / The inhibited fluids are used in drilling hydratable shales, to prevent found clays to be hydrated and cause stuck tools. The knowledge of the filtration properties of the fluids is important during drilling, since the control of these properties ensures less drilling problems and improves well productivity. This work aimed to study and improve the filtration properties of aqueous fluids inhibited with potassium salt chlorine-free (potassium citrate), for their application in drilling hydratable and dispersive clays and shales. For this purpose, the drilling fluids with and without addition of the inhibitor potassium citrate were studied. It was determined the rheological properties (apparent viscosity (AV), plastic viscosity (PV), yield limit (YL) and gel strength (GS)), filtration (filtrate volume (FV), spurt loss (SL), cake thickness (CT) and permeability (k)) and the inhibition power (dispersibility test and the bentonite inhibition test) of the studied fluids. According to the obtained results it was concluded that the study fluids showed pseudoplastic behavior and addition of potassium citrate to the fluid did not cause changes in the pseudoplastic behavior of fluids. It was concluded that the combined use of additives starch, CMC LV and calcite reduces more effectively the filtration properties of drilling fluids studied and the filtration properties of the fluids inhibited with potassium citrate were optimized since the FV values obtained were lower than the considered base fluid. The formulations which showed efficient filtration and inhibition properties were prepared with high concentrations of potassium citrate. They have presented low values of FV and lower values of SL.

In this thesis was designed, manufactured and tested the fourth evolution of a slit-flow rheometer with another necessary parts, eg. rheometer`s holder, drive frame and important jig tools. The rheometer is able to measure rheological properties of magnetic and non-magnetic fluids at very high shear rates, which commercial rheometers can not reach. It is designed for 200 bar pressure and maximum load 15 kN. The construction of the slit-flow rheometer with it`s holder and drive frame improves user friendliness, accelerates change of the fluid sample and expands research opportunities thanks to a big space for additional adjustments. It is possible to use different length of the slit and thanks to a changeable inserts it is possible to change parameters of the slit (roughness of the walls, wall material, thickness of the slit). A part of this thesis was focused on illation of necessary equations for planning calibration measurements. Aim of these measurements is to obtain minor pressure losses dependence on Reynolds number for specific slit.