H. Sabeti - Department of Mining, Petroleum and Geophysics, Shahrood University of Technology
A. Moradzadeh - Professor, School of Mining, College of Engineering, University of Tehran, Tehran, Iran Attendant professor, Faculty of Mining, Petroleum and Geophysics, Shahrood University of Technology, Shahrood, Iran
F. Doulati Ardejani - Professor, School of Mining, College of Engineering, University of Tehran, Tehran, Iran Attendant professor, Faculty of Mining, Petroleum and Geophysics, Shahrood University of Technology, Shahrood, Iran
A. Soares - Petroleum Group, CERENA, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal

Stochastic seismic inversion is a family of inversion algorithms in which the inverse solution was carried out using geostatistical simulation. In this work, a new 3D stochastic seismic inversion was developed in the MATLAB programming software. The proposed inversion algorithm is an iterative procedure that uses the principle of cross-over genetic algorithms as the global optimization technique. The model perturbation towards the objective function is performed recurring to direct sequential simulation and co-simulation. This new algorithm was applied to a synthetic dataset with and without noise. The results obtained for the inverted impedance were satisfactory in both cases. In addition, a real dataset was chosen to be applied by the algorithm. Good results were achieved regarding the real dataset. For the purpose of validation, blind well tests were done for both the synthetic and real datasets. The results obtained showed that the algorithm was able to produce inverted impedance that fairly matched the well logs. Furthermore, an uncertainty analysis was performed for both the synthetic and real datasets. The results obtained indicate that the variance of acoustic impedance is increased in areas far from the well location.

Seismic, Acoustic Impedance, Direct Sequential Simulation, Stochastic Seismic Inversion, Genetic Algorithm