The Katy field is a major Gulf Coast gas accumulation with over 6 trillion cubic feet (170 Gm3) originally in place in the Cockfield (Yegua) formation. After more than 40 years of cycling and production operations, induction logs from recently drilled wells indicated uneven water advance within several sands which had, in the past, been treated as single reservoirs. A comprehensive geologic/ engineering re-evaluation resulted in defining 48 sand members within an interval which had been described as 14 producing zones. Extensive computer modeling applications aided the geologists and engineers in describing the many vertical and areal reservoir heterogeneities which must be understood in order to maximize ultimate recovery.

The Katy field is a major Gulf Coast gas accumulation with over 6 trillion cubic feet (170 Gm3) originally in place in the Cockfield (Yegua) formation. After more than 40 years of cycling and production operations, induction logs from recently drilled wells indicated uneven water advance within several sands which had, in the past, been treated as single reservoirs. A comprehensive geologic/ engineering re-evaluation resulted in defining 48 sand members within an interval which had been described as 14 producing zones. Extensive computer modeling applications aided the geologists and engineers in describing the many vertical and areal reservoir heterogeneities which must be understood in order to maximize ultimate recovery.