COBEM99

S4 Ciências e Engenharia do Petróleo

Title:

ESTUDO DO COMPORTAMENTO MECÂNICO DE COMPOSIÇÕES DE FUNDO DE POÇO PELO MÉTODO DE ELEMENTOS FINITOS

Summary :

THIS WORK TREATS THE FINITE ELEMENT MODELING OF THE MECHANICAL BEHAVIOR OF BHAS EQUIPPED WITH UNBALANCED DRILLCOLLARS. THE ASSEMBLY WAS DISCRETIZED IN 2-D BEAM-COLUMN ELEMENTS AND THE GEOMETRIC NON-LINEAR PROBLEM WAS HANDLED BY NEWTON S METHOD WITH AN INCREMENTAL LOADING SCHEME. THE MODEL WAS VALIDATED BY SOME CLASSICAL LARGE DISPLACEMENT AND SMALL DEFORMATION BEAM PROBLEMS AS WELL AS PUBLISHED DATA FOR THE STATIC BEHAVIOR OF STABILIZED DRILLCOLLARS. THE CONSTRAINT IMPOSED BY THE BOREHOLE WALLS WAS IMPLEMENTED BY BILINEAR SPRING ELEMENTS. THE ANALYSIS OF THE VARIATION OF THE MAGNITUDE OF THE REACTION FORCE AT THE BIT, DUE TO DRILLSTRING ROTATION, WAS PERFORMED BY APPLYING A BODY FORCE TO THE BHA WHICH WAS EQUIVALENT TO THE UNBALANCED FORCE. THIS KIND OF APPROACH ALLOWED A SIMPLIFIED TREATMENT OF THE DYNAMIC BEHAVIOR OF THE SYSTEM IN A STATIC POINT OF VIEW. THE EFFECT OF THE UNBALANCED FORCE IN THE REACTION FORCE AT THE BIT WAS INVESTIGATED AND AN EFFECTIVE TENDENCY OF REDUCING INCLINATION OF THE WELLBORE WAS VERIFIED, WITH AN INCREASING ROTATIONAL SPEED OF THE DRILLSTRING. KEY WORDS: FINITE, ELEMENT, DRILLING, WELLBORE, PETROLEUM

Author :

Costa, Francisco de Sales M
Ribeiro, Paulo Roberto

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