On the one hand, I enjoyed the juxtaposition of oil workers - not a community I associate with knowledge and lore - and Lovecraftian occultists. Of course it makes sense that anyone can have an intellectual streak, study knowledge man was not meant to know, and so on.
On the other hand, there were some significant holes that took me out of the story. Chief among them was that I didn't understand why the chief oilman was still involved with the story. I feel that the story rested on the laurels of "typical" Cthulhu stories, where the protagonist or someone in his environment is driven to discover. This story assumed the drive, but never provided a reason, which Lovecraft's stories were always careful to provide. The man is already incredibly wealthy. His wife may be gone, but his daughter seems to be safe, despite his fears. There are a plethora of potential motivations for continuing to be involved with the occult - revenge? His daughter's safety? Sheer obsession - but none of them are detailed, giving the character a lazy, "just 'cause" feel.
That said, I really liked the association of oil and death. It's bugged me for a long time. I mean, we're readers of speculative fiction! We know what happens to empires founded on death.
Unfortunately, this brings me to my final critique, which is that the Mythos stuff seemed tacked on. Something a little more necro-oriented - ghosts, zombies, dead gods, deadness - might have worked better with the themes the story had already introduced. Like the oilman's obsession, Cthulhu seemed present just because that's the sort of thing you see in stories like this, rather than having his presence explicitly justified.
Overall, though, I enjoyed the story. It was very well written and paced, even if I didn't like all of the narrative choices. The narration was, as usual, excellent and added a lot to the experience.