“There will be blood” is hard to pin down. Hard to explain. The movie tells us a very realistic and very depressing story of a lonely prospector turned entrepeneur and his son. The movie moves along real slow, with beautiful images of the land contrasted by the way the oil-companies and entrepeneurs of that age conquer, divide and exploit that very same land. The detached and “rational” way the main character acts made the movie only come to live more. The main character is a self-made man that claims to hate most other people, and thinks like a true businessmen only in term of competition. His relationship with his son is a center-stage struggle, will he find something of worth beyond this meaningless production or not seems to be a big question. The story also deals with community and religion in a very bleak manner. It seems the characters are lost in the new world and there is no one to guide them, and if there was they wouldnt recognize as such.
These are quite subjective thoughts on the movie, you should really watch it yourself as the movie relies heavily on atmosphere mood and emotion.
Cheers!