If I had to guess, the house was built on top of an improperly abandoned well from many decades ago, and the plug broke. If the Longview field is using secondary or tertiary recovery methods, I'd really suspect this as the cause.
I don't know it any waterflooding is taking place around Longview, but considering the age of the field, it's probable.
We didn't plug wells forty years ago like we do today, and I might have roughnecked on that very well that is flowing into her living room.
Either scenario would fit.
The neighbors wouldn't necessarily have oil in their house if the flow from a ruptured casing was following a subsurface fracture that came to the surface under her house.
Which brings another point into play:
The house evidently is not built on a pier and beam foundation, but how is the oil coming through the concrete slab?
I hear "Twilight Zone" music playing........