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 . 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.