Dissertação
{en_GB=Analysis of the potential conditioning factors for a stuck pipe through the active fault of Alhama.]} {} EVALUATED
{pt=The master thesis is fully written in english., en=Failures related with borehole drilling are a very common problem when the drilled area is a fault zone. Through this work the hypothetical causes that produced a pipe sticking in two scientific boreholes drilled through the fault plane of the Alhama fault, Murcia, Spain, were analysed. Specifically in a transitional contact between the main fault rock, called “Fault Gouge” and a very fractured phyllitic formation. Several types of pipe sticking could have produced the failure in the borehole, the main causes may be differential pressures, swelling formations, unconsolidated and unstable formations, plastic-flowing formations, cuttings packoff and key seating. These causes are described in this work, with the purpose of evaluating the materials and technical characteristics that are related with each cause. Several analysis were undertaken and discussed, including in-situ test and laboratory test, namely, permeability test, free swelling test, X-Ray diffraction, plastic limits, caliper analysis, borehole deviations, dipping angles of the formations, recovery indexes and finishing with muds concentrations. The analysis of the results, allowed to eliminate most of the causes evaluated.This work concluded that the pipe sticking was produced by a cuttings packoff at the bottom of the borehole. This failure was generated by the oversaturation in the drilling muds due to an incorrect planning of the mud´s viscosity and density, and, in addition, the presence of unstable formations with inclinations of their weakness planes in the risk limits while drilling a vertical borehole. Some recommendations for future drillings are proposed in the last chapter of this work. }
novembro 24, 2016, 11:0
Publicação
Obra sujeita a Direitos de Autor
Orientação
ORIENTADOR
Maria João Correia Colunas Pereira
Departamento de Engenharia Civil, Arquitectura e Georrecursos (DECivil)
Professor Associado