Brookshire Field, Waller County, Texas: Bypassed Pay at 2000 Feet

Ray Blackhall
Cosara Energy Company, Spring, TX

On October 28, 1996, a wildcatter from Midland, Texas completed an oil well on a forgotten and under-explored saltdome, called San Felipe Dome, in Waller County, Texas, the “dome in the hole”, better known as Brookshire Field. How he picked that first location is a small, but interesting, part of a much larger story. This gentleman used the ultimate in scientific method to select the precise location to drill a significant well that touched off a nineteen-twenties type rush to capture the shallow prolific prize. He walked the forty-four-acre pasture and found a fresh cow patty in the northeast corner of the lease, placed his flagging, an empty Coors Lite beer can, atop a broken oak branch, drilled that location, and the rest is history. Over 350 completions and 7 million barrels later, the discovery well made its steady 200 barrels a day from 2000' without losing a pound of pressure for the first two years. There were several near misses, and there are numerous stories about the oil having been bypassed or being unrecognizable in the “fresh” water interval in which it occurs. There are some good assumptions, but the basics of log analysis do not always hold true, because salinity can vary from sand to sand vertically, and within a correlative sand in adjacent fault blocks. Faults play tricks too, and when they are nearly vertical, surprises abound for drillers and geoscientists working the complexly faulted, supracap section.