Geostatistical Modeling of Permeability by Simulated Annealing in Clastic Reservoirs

Aboozar oil field is located approximately 72 km west of Khark Island in offshore Iran. The main reservoir of this field is an Oligo-Miocene stratum called Ghar which is a member of Asmari formation composed of loose sand with thin beds of shale. The present study developed the application of simulated annealing to generate stochastic model of Ghar permeability. Simulation of permeability of Ghar is based on porosity model which can be considered as secondary variable. Ordinary Kriging was used to construct the porosity model. In order to perform ordinary kriging to determine spatial distribution of porosity, 10 experimental variograms were calculated. Variograms show that the porosity in Ghar sand has both zonal and geometrical anisotropy. Then by using porosity model and permeability data of available data, 100 realizations of permeability distribution was generated by simulated annealing. At the end 3D probability model was generated from all realizations. By this model high permeable zone which indicate high reservoir quality was determined.