Drill Bit Seismic: A Drilling Optimization Tool

Abstract

Abstract In recent years a new drilling optimization technique has emerged. Drill bit seismic uses the acoustic energy radiated by a working drill bit to provide time-to-depth and look-ahead information while drilling. This information, available in real time at the wellsite, significantly reduces uncertainty. It enables the depth to casing and coring points to be more precisely defined, leading to elimination of some casing strings and ensuring vital horizons are cored. Integrating the data with other measurements can help in monitoring pore pressure trends, with obvious implications for safety. The technique requires only surface sensors, and does not interfere with the drilling process, hence no rig time is lost. This paper aims to give a complete picture of the drill bit seismic technique. The deployment of the sensors and methodology for data acquisition are described in some detail. An overview of the signal processing techniques is given, illustrated with real data from both onshore and offshore rigs. The benefits drill bit seismic can bring are demonstrated by means of several field examples, showing how the data can be used to reduce drilling costs and improve efficiency. The current limitations of the technique are also discussed, and possible directions for future development proposed. P. 177