Day2 on reading the paper

Well Log Data Preprocessing

Normalization: it's necessary because different types of well log data have different units. The equation is as follows:

x_(i,norm)=(x_i-μ_i)/(σ_i*‖x_i ‖_∞ )

In the equation, the most confusing part is ‖x_i ‖_∞, I find out that ‖x_i ‖_∞=sup|x_n |, it means that ‖x_i ‖_∞is the biggest among |x_n | if I am right.

PCA: it allows the reduction of the dimensionality (number of the columns) of the well log data but retains most of the variability of that data.The equation is as follows:

X_PCA=XV^T

Well Log Data Ming

Data mining is the computation process of discovering patterns in large data sets involving methods at the intersection of artificial intelligence, machine learning, statistics and database. The figure of data mining technologies is as follows:

In my opinion, although it may be an ideal tool in the automatic pseudo-density log generation system, it is challenging for people to combine so many kinds of complex methods together.

Lithofacies & Electrofacies

Electrofacies are calculated based on statistical analysis, having a correlation with lithofacies.

Gaussian Mixture Model

I am still trying to understand it. To be continued on next Monday.