Hydrocarbon-productive microbial and high energy, nearshore carbonate facies were deposited in shallow subtidal water depths in an inner ramp. The buildups are composed of thrombolites. The microbially influenced facies is present throughout the field area, but the thrombolite buildups are restricted
to the southern part of the field. The microbially influenced facies varies in texture from packstone to lime mudstone. The packstone is a reservoir in parts of the field, and the lime mudstone serves as part of the updip lateral seal in the northeastern area of the field. Upper grainstone and packstone reservoir and lower boundstone and packstone reservoir are interbedded with three lime mudstone and dolomudstone to wackestone units (upper peritidal, middle deeper water subtidal, and lower transgressive subtidal) throughout the field. And to the northeast and updip in well permit 13,976, the Smackover section essentially consists of lime mudstone and dolomudstone, supporting the interpretation that the petroleum trap for this field is stratigraphic. The thrombolites consist of clotted peloidal boundstone and include a microfauna of benthic foraminifera, ostracods, bivalves, and microtubules.