Coordination of Geological and Engineering Research in Support of the Gulf Coast Co-Production Program - Final Report

Access full-text files




Jirik, Lee A.
Ambrose, William A.  
Kerr, D. R.
Light, M. P. R.

Journal Title

Journal ISSN

Volume Title



At Northeast Hitchcock field, the presence of the Skolithos assemblage and other structures has supported the interpretation of shallow-marine, tidal, distributary-mouth-bar, and channel depositional environments for most of the major reservoir sandstones. Several shaly horizons exhibit characteristics of interdistributary bays, and the Frio A is capped by a thin sequence of crevasse splays and washover sands that represent the initiation of the transgression that overlapped the Frio in Anahuac times.

The high-energy depositional environment of reworked distributary-mouth-bar sandstones is the major control of the high porosity (around 30 percent) and permeability (around 1,000 millidarcies) in Frio A sandstones at Northeast Hitchcock field. Well-winnowed sandstones with high porosities and permeabilities contain abundant authigenic kaolinite and have served as preferential conduits for migrating acid waters and major fluid flow during co-production. Authigenic clay can create fluid production problems due to its delicate structure. Dislodged clay may obstruct pore throats at high production rates, necessitating the determination of a maximum safe rate of fluid production for co-produced wells.

Middle and lower Miocene barrier island sands, buried at depths from 3,500 to 6,800 feet in Northeast Hitchcock field, have the potential to receive large volumes of co-produced brines from the Frio 1-A reservoir. These sands exhibit high permeabilities exceeding 2,000 millidarcies, are internally homogeneous, and are laterally extensive in the field area. The 6,150-foot sand (lower Miocene) was chosen for initial brine disposal in the H.D.S. Thompson No. 3 brine-disposal well based on these criteria. The 3,780-foot sand (middle Miocene) is recommended for future up-hole brine disposal in the H.D.S. Thompson No. 3 well because it is shallower, requiring less injection pressure and lower costs for brine disposal.


LCSH Subject Headings