Application of Crosswell Seismic Reflection Imaging for Interpretation of Connectivity

How to interpret the connectivity of thin reservoirs in A-wellsite in DB oil field has been an important topic for geophysicists, geologists and petroleum engineers to study. In the area around the wellsite, surface seismic data is of limited help because of low S/N ratio and low dominant frequency. A crosswell seismic survey was conducted in A1/A2 wellsite in order to make an attempt for analysis of some problems arising in production. The strategy for better using crosswell seismic data was focused on the application of reflection wave instead of direct wave that was generally used for crosswell velocity tomography. The reflection imaging from data processing indicates its dominant frequency is around 5 times higher than that of surface seismic imaging and can be used for interpretation of thin beds with a thickness of several meters. An interpretation incorporated with logging, production and surface seismic data was done. The conclusions based on the interpretation are that the connectivity between the two wells is controlled by faults and lateral lithological variations.