twenty-five thousand barrels a day under two hundred and sixty-five pounds pressure; but more than double this amount could be taken from the well were there shipping facilities from Tampico. "Casiano Number 6" was flowing fifteen thousand barrels a day when it was closed in a month before Number 7 came in.
It is possibly immaterial from which well the Casiano district is tapped, for no man knows to what extent in this valley Number 7 is drawing from the territory of Number 6, as the geology in these oil fields is not analogous to anything else known on the continent. Number 7 cannot be shut in more closely without danger, for any increased restraint causes the ground to break forth with oil a few hundred feet distant.
Nearly twenty miles farther south by the Mexican Petroleum Company's railway and pipe, water and gas lines is the greatest oil well in the world to-day, Cerro Azul, which means "blue hill," and which "blew in" February 9, 1916, and shot 1,400,000 barrels of oil into the air before it could be capped. One half of this was saved by a quickly constructed reservoir. The column of oil measured six hundred feet, and when it was shut in the delivery was at the rate of more than 260,000 barrels per day.
