Findings

Today, I read the paper again to understand the logic of the methodology in it and find some relationship between pseudo density log and pseudo NMR.

Since Density Log is often run over as a small portion of the well and log data of it is missed often, the methodology is constructed in pseudo-density log generation.

The methodology is concluded as following steps:

Data Preprocessing

1.     Normalization of well log data

2.     PCA for dimension reduction

Data Mining

3.     Electrofacies correlated with lithofacies are calculated by statistical analysis

4.     GMM transform well log data into Gaussian distribution so the mixture model becomes GMM

5.    EM can approximate  accurately after several iterations

6.     MBC do not define clusters of data, which improves GMM

7.     Sampling and discriminant analysis select sample points for well correlation

Data Postprocessing

8.     ANN extracts and recognizes the underlying dominant patterns and structural relationships among data

9.     Model is built up for pseudo density log data prediction and regeneration.

The figure of pseudo density log generation workflow is as follows:

Relationship between pseudo density log and pseudo NMR

Considering every step of the methodology, it is constructed for the compensation of Density Log weaknesses. Density Log is often run over as a small portion of the well and log data of it is missed often. Some parts of the methodology may be used in pseudo NMR.

Since real NMR is so expensive, we may also run over as a small portion of the well. We can construct a similar methodology step by step. The small portion of the data gotten by real NMR can be utilized to build up a model by ANN finally. As a result, the data of real NMR can be predicted and regenerated.

However, if we do not do any real NMR, the methodology may not be used into pseudo NMR. In addition, a small portion data of real NMR may just reflect the reservoir characterization in a portion part of the well, so the model built up by the methodology may not be able to predict the whole reservoir characterization accurately.

I will read more papers tomorrow, trying to find something more useful for pseudo NMR.