UTAH GEOLOGICAL SURVEY DEPARTMENT OF NATURAL RESOURCES PARADOX FORMATION RESERVOIR CHARACTERISTICS • Net pay – 9 to 57 ft (3-17 m); 165 ft (50 m) at Greater Aneth field • Primary producing zones – Ismay and Desert Creek • Depositional environments – shallow-shelf and shelf-margin marine, carbonate buildups (phylloid algal and bryozoan mounds), oolitic banks, beach, and stabilized grain flats • Carbonate fabrics – bafflestone, grainstone, packstone, and wackestone (limestone and dolomite) • Pore types – shelter, moldic, intercrystalline, vugs • Porosity - averages 8-12% • Permeability – less than 1 md to greater than 500 md, averaging 25 md • Diagenesis – early marine cementation, dolomitization (early and late), freshwater dissolution and cementation, and anhydrite and bitumen plugging PARADOX FORMATION OUTCROP CHARACTERISTICS MERIDIAN Cherokee 33-14 NW SE Sec. 14, T37S-R23E KB 5,572 ft Hovenweep Shale Lower Ismay Gothic Shale Desert Creek Chimney Rock Shale Akah Upper Ismay Completed 6/9/1987 TD 6,115 ft IPF 336 BO, 346 MCF, + 0 WTR CORE 6100 6000 5900 5800 5700 5600 63 80 09 43 10% Type Log Porosity GR DPHI NPHI Typical gamma ray-compensated neutron-litho density log of the Paradox Formation, Cherokee field, San Juan County, Utah. N Cherokee Monument Cajon Mesa Ismay Ismay Tower Greater Aneth Clay Hill Flodine Park Cache Desert Canyon Marble Wash Roadrunner Towoac Sage Hen McElmo Mesa Rockwell Flat Cone Rock Tin Cup Mesa Squaw Canyon Cutthroat (McClean) Hatch Kachina Patterson Canyon Little Nancy Squaw Point Bug Bradford Canyon Dove Creek Cahone Papoose Cajon Lake Mustang Flat Wild Station Rock Canyon Grayson Alkali Point McCracken Spring Caballo Alkali Canyon Deadman Canyon Cave Gothic Mesa Brown Hogan Desert Creek Chinle Wash Cleft Boundary Butte Tohonadla Hogan Turner Bluff Recapture Bluff Bench Broken Hills Bluff Rabbit Ears Anido Creek River Bank Yellow Rock Akah Ucola Squaw Creek Bannock Kiva UTAH COLORADO Cowboy Deadman Boundary Butte East Heron UTAH ARIZONA UTAH 0 0 3 6 9 km 6 mi 3 Jack Canyon Runway Heron North Anasazi Mule Blue Hogan Island Butte Ismay mound trend (predominantly limestone) Northern Desert Creek beach/ mound trend (predominantly dolomite) Desert Creek shelf margin trend Sleeping Ute T 41 N T 43 S R 26 E R 27 E R 28 E R 29 E R 30 E R 21 E R 22 E R 23 E R 24 E R 25 E T 36 S T 37 S T 38 S T 39 S T 40 S T 41 S T 42 S R 26 E R 19 W 20 W T 32 N T 39 N T 38 N T 37 N T 36 N T 35 N T 331/2 N T 33 N T 34 N T 35 S T 40 N Map of Paradox Formation play area and fields within the Ismay and Desert Creek zones producing trends, Utah and Colorado. Location of Paradox Formation outcrops in the Eight-Foot Rapid area and The Goosenecks/Honaker Trail, San Juan River, southeastern Utah. Goosenecks of the San Juan River. Photograph by Tom Till, courtesy of the Utah Travel Council. Stacked complex of four phylloid-algal mounds in the Akah and Barker Creek zones of the Paradox Formation, river mile 39.8. Ismay zone algal banks near Eight-Foot Rapid Paradox Formation algal bank/mound topography, morphology, and facies relationships as seen along the San Juan River, Utah (from Brinton, 1986). Schematic diagram of Paradox Formation algal banks (from Brinton, 1986). Photomosaic of a large phylloid-algal mound complex composed of algal bafflestone, skeletal grainstone, and packstone in the Barker Creek zone of the Paradox Formation, river mile 40.5. Typical cement-rich algal bafflestone exposed in a phylloid- algal mound, Ismay zone, Eight-Foot Rapid area. Original sheltered pore spaces were filled with mud; cement rinds are developed around algal plates. Well-developed cross-bedding in peloidal and oolitic grainstone in the cap and intermound facies of the Barker Creek zone of the Paradox Formation along the Honaker Trail. Close-up shown in inset photo. Mound flank material – part of the large phylloid-algal mound complex in the Barker Creek zone, river mile 40.5. Schematic diagram of drilling targets in a Paradox carbonate buildup by multilateral (horizontal) legs from an existing field well. Block diagram displaying depositional interpretation of a mound complex and associated features in the Eight-Foot Rapid area. This interpretation is a composite of inferences made from outcrop and subsurface data. Flooding surface (4th-order sequence boundary), Ismay zone along the Honaker Trail. Note abundant intact and fragmented productid brachiopods in the medium gray limestone matrix. Pennsylvanian Paradox Formation Reservoir, Paradox Basin – Outcrop Analogs along the San Juan River Pennsylvanian Paradox Formation Reservoir, Paradox Basin – Outcrop Analogs along the San Juan River