Specialized Well Log Acquisition of Formation Elastic Properties in Support of 4C Surface Seismic

Well logging programs are usually designed to measure<br>petrophysical properties within the reservoir and the<br>immediate surrounding formations. Rarely, if ever, is much of<br>the overburden logged. As more sophisticated surfacemeasured<br>geophysical methods are used, properties of the<br>overburden are becoming more important (fig. 1). One method<br>that is becoming more prevalent, 4C OBC seismic, can benefit<br>from logging formations from surface continuously down to<br>the reservoir. In preparation for the processing and<br>interpretation of a major acquisition of 4C surface seismic run<br>to illuminate a carbonate reservoir within Idd El Shargi North<br>Dome field located offshore Qatar (fig. 2), a specialized<br>logging program was devised and acquired on a well in the<br>field to obtain formation elastic properties of compressional<br>and shear velocity, including HTI anisotropy information,<br>continuously from the sea floor down to the reservoir.