Logging while drilling

Abstract

The engineering of well logging sensors into drill collars is stimulating a revolution in logging and drilling. It gives the driller more comprehensive real-time information, and gives the geologist a look at the formations while invasion is taking place. This technology will affect logging hard-ware, interpretation methodology, ecnomics of drilling and logging, and the roles played by drillers, geologists, petrophysicists and log analysts. It is expected to afford savings for oil companies by increasing the efficiency and effectiveness of their drilling programs. This article introduces the Prospector* * Mark of Schlumberger logging-while-drilling (LWD) system, which provides measurements of resistivity, neutron, density and spectral gamma ray from new tools built into special drill collars. It can be run simultaneously with Anadrill's measurements-while-drilling (MWD) systems and can access Anadrill's mud-pulse telemetry and the Advisor† † Mark of Anadrill surface system. We explain how the LWD system is engineered, how it integrates real-time drilling and logging information, and its complementarity with wireline measurements. The Prospector system is a rapidly evolving technology. This article appears as the system enters commercialization. Further developments will respond to industry demands and the perennial drive of research and engineering. © 1989.