oa The Land-Streamer Acquisition System to Map the Sand Dune Base

Complex near-surface structure is a major problem in land seismic data. This is more critical when<br>acquisition takes place over Sand dune surfaces, where the base of the Sand acts like a trap for energy<br>and depending on its shape can considerably distort conventionally acquired seismic data. Estimating<br>the base of the Sand Dune surface can help model the Sand dune and reduce its harmful influence on<br>conventional seismic data. Among the current methods to do so is drilling upholes and using<br>conventional seismic data to apply static correction. Both methods have their cost and limitations. For<br>upholes, the cost factor and its inability of upholes to provide continuous model is well realized.<br>Meanwhile, conventional seismic data lack the resolution necessary to obtain accurate modeling of the<br>Sand basement. We develop a method to estimate the Sand base from Land streamer seismic<br>acquisition that is developed and geared to Sand surfaces. Land streamer acquisition not only provides<br>a more efficient data acquisition system than the conventional spiked geophone approuch, but in our<br>case the land streamer provided better quality data, with broader frequency bandwidth. Such data<br>enabled us to do proper near surface velocity estimation that resulted in velocities that are very close<br>to those measured using uphole methods. This fact is demonstrated on a couple of lines acquired near<br>upholes, and the agreement between the seismic velocities and the upholes is high.