Gaining Insight into Drilling Conditions in Challenging Extended-Reach Drilling Wells by Analyzing Downhole Mechanical and Dynamic Measurements

Abstract

This paper presents a case study on the real-time monitoring of hole conditions in challenging extended reach drilling (ERD) wells using drilling dynamics data, including downhole mechanical measurements, pressure data, and logging data. This is of great value to the drilling team for a better understanding of the hole condition. This ultimately contributes to drilling safely and securely, avoiding surprises, and successfully delivering the well. To effectively manage drilling operation risks, real-time monitoring of drilling conditions is crucial. Hole condition analysis can be subject to uncertainties when relying primarily on surface drilling parameters. To gain a more comprehensive understanding of drilling conditions, downhole mechanical measurements are invaluable for providing immediate and precise information about the Bottom Hole Assembly (BHA) and its surrounding environment. The methodology for evaluating drilling conditions was developed through the utilization of downhole mechanical measurements, such as axial loading, torsional loading, annulus pressure, and differential pressure, in conjunction with surface drilling parameters. The pipe stuck rate is close to 30% in ERD operations for wells beyond 8000m in the offshore region of China. Downhole mechanical measurements (DMM) tool was utilized for drilling condition monitoring in the longest ERD well recently completed in China offshore. The well was drilled and cased successfully, setting several new records in China. These records include the longest production well, the longest 12-1/4 in open hole section of 5124 m, and the deepest 9-5/8 in casing setting depth at 8125m. Real-time analysis using downhole mechanical measurements and drilling dynamics data plays a crucial role in drilling surveillance and decision-making in this record-breaking ERD well. The abnormal drilling conditions such as weight hanging, string buckling, hard backreaming, inadequate hole cleaning, pack off, and mud losses, etc., were identified and properly addressed. In some conditions, standard industry practices did not work, so innovative practices were implemented to proceed based on the reliable real-time downhole information. A comprehensive analysis of drilling mechanical measurements can significantly enhance the understanding of downhole conditions, narrow down hypotheses, and enable timely implementation of corresponding measures for complex downhole situations. The methodology can be referred to for other wells.