DrillCAM Seismic System to Aid Geosteering and Drilling Optimization

Abstract

As the number of new exploration and development wells continues to increase, guiding the bit while drilling in real time is becoming one of the most requested technologies. Seismic-while-drilling may enable accurate prediction of high-pressure zones, fractures and cavities, coring points, target depths, and geosteering in high-quality reservoir zones to optimize drilling decisions and reduce costs. A fully integrated real-time system to map and predict ahead of the bit and geosteer in high-quality reservoir zones is presented, showing application of seismic while drilling (SWD). We call this technology DrillCAM. Recent enabling technological advances were made in wireless high-channel recording, signal enhancement and imaging algorithms, as well as high-performance computational resources that are easily deployable to the field. Such technological advances open a completely new set of possibilities for real-time drill bit guidance and navigation. One key enabler for DrillCAM is the use of wireless seismic receiver stations. Compared to conventional cabled geophones and cableless nodal systems, wireless receivers can provide real-time recording and transmission without the need for extra equipment for data retrieval, flexible receiver spacing and areal coverage. This, in turn, results in a flexible lightweight system for easy mobilization and ultralow power consumption for extended battery life. We show a carefully designed field data acquisition experiment using the drill bit as a downhole seismic source and a large number of seismic receivers at the surface. The wireless receivers are arranged in flexible geometries that adapt to target bit depths. Using dedicated sensors, the bit signature (pilot signal) is recorded using high-frequency surface and downhole accelerometers. The system integrates surface seismic recordings and surface noise recordings with pilot signal recordings. The initial field experiment is conducted on a nearly vertical onshore well. This experiment demonstrates the feasibility of an integrated DrillCAM SWD system. The paper presents the motivation, objectives, numerical studies, and first field test of a novel integrated real-time SWD system. Not only does such a system detect bit signals while drilling, it also validates these signals against other measured data and drilling activities.