Improved Drilling Performance: Downhole Dynamic Logging Tools Break Paradigm in Ecuador

Resumen

Abstract In today's high cost drilling environment, vibrations are recognized as the primary contributor to drilling inefficiency. As such, accurate prediction, identification, and quantification of vibration along the drill string has become increasingly important in order to reduce drilling costs. Near-bit measurements are also particularly important, as the drill bit is often predicted to be an important cause of vibration. This paper reviews a project within Ecuador, where high vibration and mechanical damage to drill bits has been observed, clearly affecting performance. This application is drilled with Fixed Cutter (FC) bits on a Rotary Steerable System (RSS) through a challenging sequence of formations including sandstone, shale, limestone, and conglomerates. Initial steps had been taken to optimize the drill bit design in terms of cutting structure, gauge geometry, and cutter technology. However, in order to truly understand the vibration issues, a unique downhole dynamic logging tool was utilized. This tool records drilling dynamics data at a high frequency sample rate, enabling lateral and torsional events to be accurately identified and recorded. Due to its size, and thus flexibility in string placement, the tool was located in two different points in the BHA. Evaluation and interpretation of the vibration data led to the recommendation of new drilling parameters, very different to traditional practices in this application, in a critical section for the next well in the same pad. This resulted from detection of torsional vibration, not only at the bit, but also at points along the BHA. Implementation of the recommended drilling parameters resulted in significant mitigation of torsional vibration at the bit and in the BHA. This resulted in reduction of wear to components within the BHA, as well as both time and cost savings in excess of $200K.