f Porosity mapping in a devonian reef using 3D seismic waveforms and neural networks

Porosity information can be reliably derived from core or well log measurements. However, the sparsity of well bores in a reservoir makes it difficult to predict porosity away from well locations. Seismic coverage, particularly 3-D surveys can provide valuable information regarding the distribution of porosity away from the wellbores. Changes in porosity can induce variations in the character of seismic data such as amplitude, frequency content, interval velocity and impedance. It is natural to use such seismic attributes along with geostatistical techniques to attempt to map porosity. The complexity of the earth system and the limited understanding of many aspects of rock physics in the seismic regime make it difficult to assess the optimality of such attributes in predicting porosity. For example, variations in amplitude could be caused by variations in the thickness of a formation rather than its porosity.