Abstract New areas of oil exploration in Colombia are usually located in complex geological settings where conventional surface seismic data is traditionally of poor resolution. The recent improvements in borehole seismic software applications has made it possible for real-time vertical seismic profile (VSP) processing at wellsite to provide time-critical information with improved vertical resolution. This advancement has promoted the use of VSP applications in complex areas, as is the case of the zero-offset vertical seismic profile (ZVSP) data that was acquired in an exploration well in the Cordillera basin of Colombia. The real-time results obtained by processing the VSP data at the wellsite shortened the decision-making process (reduced NPT); in this case, it aided in the decision to invest additional resources to continue to drill a reflector observed on the VSP below the initial target. This case history describes the real-time wellsite application of acoustic impedance inversion of the upgoing waves and prediction ahead of the bit. In this example, the new target was encountered 5 ft below the prediction. The acquisition and processing of this data reduced uncertainties and verified the new target below the bit. The results of the theoretical model and the actual data demonstrate that the method is effective for pre-drilling predictions using borehole seismic data; these results also make the VSP a powerful tool for making decisions during the drilling stage of the project. This paper describes the acquisition, processing, and method used to help improve subsurface imaging and to predict the depth to the reflectors ahead of the bit.