The increasing necessity for hole enlargement while drilling (HEWD) technology has resulted in an essential need for engineers to fully understand the interaction between the drill bit and the hole opening tool. Inefficiency and damaging bit and bottom hole assembly (BHA) vibrations, caused by improper bit and reamer selection when drilling through interbedded formations and formation transitions, are a leading cause of inconsistent performance including excessive torque, low rate of penetration (ROP) and downhole tool failures (DTF). To mitigate vibrations, operators required a comprehensive analysis system/process that would allow them to model the complex BHA interaction in a virtual environment and quantitatively compare the performance of various design scenarios.

To solve the challenge, the drilling team utilized a comprehensive, 4-D finite element model that couples laboratory results with a sophisticated computer simulator that calculates the drilling system’s dynamic performance from the bit back to surface in a real-time domain. Unlike other modeling programs that assume the contact forces between the cutter and rock, this advanced model utilizes exact cutting structure details coupled with the laboratory-derived rock mechanics to accurately predict the behavior of the bit and reamer with the entire drill string and bottom hole assembly. The effects of each specific BHA component and variations in drilling parameters on vibrations, ROP, and directional tendency can then be quantitatively evaluated.

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