Low-frequency (LF) seismic surveys are a relatively new and not well-understood addition to the geophysical toolkit. According to Spectraseis, which specializes in these surveys, targeting very low frequencies provides additional constraints to the dataset, leading to better decisions. Now the company is delving deeper. During the annual meeting of the European Association of Geoscientists and Engineers in Barcelona, the Zurich-based company announced that it has designed a new borehole tool that can take LF measurements well below the surface. Company officials are quite excited about this latest foray. “We want to see what we get when we’re away from the surface,” said Brice Bouffard, vice president of marketing for Spectraseis. “We’re curious to see how the tool works and how the signal will evolve.” The tool features six levels of high-sensitivity active receivers and has been designed for multiple downhole applications, including LF seismic surveys and microseismic monitoring projects. It is designed to be safely deployed and recovered on a tubing string in casing as small as 5 1/2 in. OD and in wells with temperatures up to 160°F (70°C). It is scheduled for delivery in October 2010. The months in between should be interesting for Spectraseis because the specifications for such a tool don’t exist. Testing, scheduled to begin in July, will determine whether or not a better LF signal can be achieved by getting away from the surface and also the feasibility of combining microseismic monitoring with LF imaging.