Reservoir Characterization and Production Modeling/Evaluation of a Rose Run Sandstone Reservoir

By

ARCHER, PAUL, L.

Geopetro, LLC, Worthington, OH,

DAVE FREEMAN

Marietta College, Marietta, OH,

JOHN R. BLOMBERG

Blomberg Engineering, Parkersburg, WV,

TIM KNOBLOCH

James Engineering, Inc., Marietta, OH

     Five wells produce oil and gas from the Colfax Field in Fairfield County, Ohio. The primary production is from the Rose Run Sandstone preserved in an erosional remnant created at the Knox Unconformity.

     The main Rose Run sand body within the Colfax remnant appears to be fairly consistent in terms of thickness and porosity based on log and sample evaluations, however production varies dramatically from one part of the remnant to another.  Detailed core analysis is available from sidewall cores taken in one well, the poorest producing well.  Quartz is by far the dominant framework grain. The only other significant framework grain is potassium feldspar.  Cementation is moderate, with quartz overgrowths as the predominate cement.  Primary intergranular porosity accounts for the bulk of total porosity.  Secondary dissolution porosity only amounts to 1% to 3% of total porosity in this poorly producing well.

     A reservoir engineering study evaluated various methods for depletion of the Rose Run Formation. The study reviewed the productive geologic intervals, estimated the original oil in place, and then estimated the drainage area affected by the five existing wells. The estimates of the ultimate recovery of the oil and gas reserves associated with each well were completed through performance/decline trend analysis, volumetric analysis, material balance, and computer modeling.  Finally, the study evaluated the possible impact of additional conventional drilling, horizontal drilling, re-stimulation, and water flooding.  Preliminary indications are that closer well spacing may best increase primary recovery and that water flooding may be a viable secondary recovery option.