Longer wells and increasing complexity of the bottom-hole assembly (BHA) are causing drilling operations to become harder to achieve. Combined with strict timelines and the demand for higher rates of penetration (ROP), the entire drilling system operates at its physical (loads, bending moment, etc.) and operational (drilled formation, drilling parameters, well path, etc…) limits. Exceeding these limits can induce excessive drilling vibrations and dysfunctions like whirl that can be harmful for bit, bottomhole assembly, reaming device or drillpipe. Neglecting operational limits can therefore lead to damage, wear and tool failures that ultimately result in nonproductive time (NPT) and higher cost.
Additionally, the number of reaming operations increases. The added challenge of complex reaming operations demands supplementary planning effort. In this paper, the authors focus on prejob and post-well analysis using simulation and modeling techniques. The result of the analysis leads to optimized reaming and drilling practices that are further elaborated following close interaction with field personnel. Applying the improved drilling practices result in best-in-class performance and lower nonproductive time.
In-house dynamics simulation software is used to calculate the natural frequencies and corresponding mode shapes of the BHA. Differences in BHA setup are associated, critical excitation sources identified and forced response analysis results compared.
Data from various deployments of a high-end rotary steerable system (RSS) BHA with a reaming device are analyzed and used to validate the simulation results. The data is derived exclusively from a massive salt section (similar formation being drilled) to lessen the formation’s influence on drillstring dynamics.
Incorporation of sophisticated simulation tools plus the close cooperation of field personnel resulted in excellent operational and drilling performance. In today’s challenging drilling applications, the insights gained have highlighted further opportunities for delivering optimal performance, and further assuring bit, BHA, reaming device and drillstring integrity.