Conclusion

Using a dataset from South America, we generated a 3-D histogram to conveniently evaluate the uncertainty of AVA attributes in this area. The variability of the AVA attributes was assessed using the multiple realizations method developed by Clapp 2002. From the gamma ray log we found the well with low shale volume has high AVA uncertainty, which made us guess the low shale/sand ratio may cause high AVA uncertainty. Further work should be done using more real data to explore empirical relationships between AVA uncertainty and rock information, such as shale/sand ratio, impedance or velocity.