Geostatistics is a method used in the petroleum industry to create maps and models using existing data. It helps estimate uncertainty and integrates different types of data like geology and engineering. Kriging, a key technique in geostatistics, not only shows spatial distribution but also predicts error-variance at unknown points. Cokriging expands on kriging by combining different data types, like porosity and seismic data. Sequential simulation techniques based on kriging can provide more diverse images of reservoirs. Geostatistics has become essential for understanding and characterizing oil reservoirs.