Finite Element Modeling of Annular Flows With Application to Slim Hole Drilling Hydraulics

dc.contributor.advisorPodio, Augusto
dc.contributor.advisorSepehrnoori, Kamy
dc.creatorRoberto Ribeiro, Paulo
dc.date.accessioned2020-04-15T00:25:52Z
dc.date.available2020-04-15T00:25:52Z
dc.date.issued1994-05
dc.description.abstractDuring the exploration and exploitation phases of an oil field, it is necessary to drill wells at strategic points of the field in order to obtain information about the geology, lithology and oil bearing potential of the reservoir. Due to the financial and technical advantages of applying slim hole drilling and coring to exploration, increased effort in the analysis of the performance, safety and environmental impact of the operation has been observed. One of the major issues in slim hole drilling and coring operations is the accurate prediction of pressure losses in the annulus, in order to guarantee optimum operating conditions. As has been pointed out in the literature, the small annular clearance and the high rotational speeds of the drillstring are factors which preclude the vii common assumption of unidimensional axial flow in the annulus, which has been applied for conventional pressure drop computations. In order to address the effect of rotational speed, eccentricity of the drillstring, variation in borehole diameter due to cased and open-hole sections, and drillstring upsets, 2D and 3D finite element schemes were applied. The numerical modeling results showed good agreement with available laboratory data for laminar, axial-rotary flows of power law fluids in concentric annuli and axial flows in an eccentric annulus. The simulations revealed that the rotation of the inner cylinder causes a decrease in the pressure differential along the concentric annuli, which is due to the contribution of the tangential shear rate in the viscosity function of the generalized non-Newtonian constitutive equation for the fluid. The eccentricity caused a decrease in the pressure differential along the annulus for both purely axial and axial-rotary flows. The simulation of complex annular flow geometries revealed that the flow constraint imposed by the inner cylinder external upset introduces a significant pressure gradient increase. Despite the satisfactory performance of the numerical modeling under the scope of its assumptions of laminar regime and steady flow configuration, it was found to be limited in its ability to evaluate the pressure behavior in the annulus of the field case. This was due to the fact that in field operations, the pressure loss in the annulus is affected by flow turbulence and dynamic behavior of the drillstring.en_US
dc.description.departmentPetroleum and Geosystems Engineeringen_US
dc.format.mediumelectronicen_US
dc.identifier.urihttps://hdl.handle.net/2152/80636
dc.identifier.urihttp://dx.doi.org/10.26153/tsw/7652
dc.language.isoengen_US
dc.relation.ispartofUT Electronic Theses and Dissertationsen_US
dc.rightsCopyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.en_US
dc.rights.restrictionRestricteden_US
dc.subjectDrilling hydraulicen_US
dc.subjectAnnular flowen_US
dc.titleFinite Element Modeling of Annular Flows With Application to Slim Hole Drilling Hydraulicsen_US
dc.typeThesisen_US
dc.type.genreThesisen_US
thesis.degree.departmentPetroleum and Geosystems Engineeringen_US
thesis.degree.disciplinePetroleum Engineeringen_US
thesis.degree.grantorUniversity of Texas at Austinen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US

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