Publications

Three Vertical Seismic Profiles (VSPs) were collected for deep -water exploration wells to influence the decision making in the casing programs. Having accurate VSP data insured that the two wells were drilled in a safe manner.The first VSP was collected to predict ahead-of-thebit to the top of the exploration target. However, the initial VSP corridor stack results were discouraging and did not reduce uncertainties. Using the ExxonMobil integrated VSP quality control approach a thorough evaluation of all aspects of acquisition and processing were performed. The integrated quality control identified deconvolution, a normal step in the VSP processing flow, to be damaging some of the up-going primary events. Additional parameter testing and optimization was conducted based on the recommendations of an integrated client and contractor team. Based on past ExxonMobil VSP experiences the integration of all available information, including seismic and synthetic seismograms, is critical in identifying and resolving VSP problems during quality control. The result of the integrated teams efforts was to produce high quality VSP results for all three VSPs after parameter optimization.Applying the lessons learned it was possible to quickly and efficiently produce high quality VSP images for a second and third VSP. In the second deep-water well, the high quality ahead-of-the-bit VSP corridor stack image justified dropping the VSP planed at TD. In addition to reducing uncertainties related to depths of exploration targets, significant cost savings were realized as a result of the high quality VSP results.Quality control from ExxonMobil VSP experts with the proper technical and operational VSP experience aided in the successful optimization of processing parameters to produce high quality VSP results. The ability to recognize problems in VSP results and resolve those problems is a team effort and an important element to a successful VSP project.