Petroleum Potential in Arkansas Bekki White Director and State Geologist Arkansas Geological Survey June 16 th, 2014
Outline General petroleum geology Crude oil in south Arkansas History of discovery and exploration Conventional vs. Unconventional reservoirs Production and reserves Natural gas in north Arkansas History of discovery and exploration Types of natural gas Production and reserves Conclusions
The Origin of Petroleum Organic-rich Source Rock Thermally Matured Organic Matter (Kerogen) Oil
Petroleum System
Source Rock Evaluation Quantity (Organic Richness) Quality (Kerogen Type) Thermal Maturity
Total Organic Carbon (TOC) Petroleum Potential TOC Rock-Eval Pyrolysis (wt.%) S 1 S 2 Poor 0-0.5 0-0.5 0-2.5 Fair 0.5-1.0 0.5-1 2.5-5 Good 1.0-2.0 1.0-2.0 5.0-10.0 Very Good 2.0-4.0 2.0-4.0 10.0-20.0 Excellent >4 >4 >20 TOC= Total organic carbon S 1 =free hydrocarbon S 2 =residual hydrocarbon potential Organic Matter
Source Rock Evaluation Quantity (Organic Richness) Quality (Kerogen Type) Thermal Maturity
Kerogen Type
Source Rock Evaluation Quantity (Organic Richness) Quality (Kerogen Type) Thermal Maturity
Thermal Maturity
Crude Oil in South Arkansas
Arkansas State Geologic Map
History of Oil Discovery and Exploration in South Arkansas Historic photograph of the S.T. Busey well that marked the beginning of south Arkansas oil production in 1921. (Photo courtesy of the Arkansas Natural Resources Museum, Smackover, Arkansas)
TRIASSIC UPPER MIDDLE JURASSIC Louark UPPER Cotton Valley MESOZOIC LOWER CRETACEOUS COAHULIAN Nuevo Leon COMANCHEAN Trinity Lower Glen Rose Upper Glen Rose Tusca UPPER CRETACEOUS Eagle Ford GULFIAN Austin Taylor Navarro ERA SYSTEM SERIES GROUP FORMATION Arkadelphia Nacatach Saratoga Marlbrook Annona Ozan Brownstown General Geology of South Arkansas Oil Area Tokio Eagle Ford Tuscaloosa (Woodbine) Washita-Fredericksburg Paluxy Mooringsport Ferry Lake Rodessa James Pine Island Sligo Hosston (Travis Peak) Schuler Smackover Bossier Haynesville (Buckner Member) Upper (Reynolds Lime) Norphlet Louann Salt Werner Lower (Brown Dense) Reservoir Rocks (Sandstone/Limestone) Source Rock/Unconventional Reservoir (Lime Mudstone) Eagle Mills
Conventional vs. Unconventional Reservoir Rocks A) B) C) Conventional: A) Oolitic grainstone & B) Pisolitic grainstone of upper Smackover Unconventional: C) Lime mudstone of lower Smackover (Brown Dense)
Oil Fields in South Arkansas
Brown Dense Wells Location
Arkansas Production of Crude Oil
Production and Reserves Cumulative oil production in south Arkansas is about 1.87 billion bbls. Annual oil production for 2012 is 6.6 million bbls with corresponding associated gas production of 11.5 Bcf. Arkansas is ranked the 18 th oil-producing state. Oil and condensate proved reserve for Arkansas is 53 million bbls that accounts for 0.2% share of U.S. (according to U.S. EIA 2013 report).
Natural Gas in North Arkansas
Arkansas State Geologic Map
History of Gas Discovery and Exploration in North Arkansas Natural gas was first discovered in 1887 at Fort Smith, but commercial development did not begin until 1902 when two gas wells were completed near Mansfield in Sebastian County. Dry natural gas from the Arkoma basin fields has a heating value of 986 to 1,016 Btu per cubic foot, and is used principally as fuel.
Ordovician Silurian Mississippian Morrowan P e n n s y l v a n i a n A t o k a n D e s M o i n e s i a n Stratigraphy of North Arkansas Gas Area PERIOD OZARKS & ARKOMA BASIN OUACHITA MOUNTAINS Boggy Savanna McAlester Hartshorne Principal conventional gas-producing units Atoka Atoka Bloyd Johns Valley Prairie Grove Unconventional gas-producing unit Hale Cane Hill Pitkin Fayetteville Batesville Hindsville Moorefield Jackfork Stanley Boone Devonian St. Joe Chattanooga Clifty *Penters *Hunton (Lafferty, St. Clair) Arkansas Novaculite Missouri Mtn Blaylock Dolostone Limestone Limestone with chert *Sylvan (Cason) *Fernvale *Viola (Kimmswick) *Simpson (Plattin, Joachim, St. Peter, Everton) Polk Creek Bigfork Womble Blakely Novaculite Novaculite with shale Sandstone Cambrian *Arbuckle (Powell, Cotter, Jefferson City, Roubidoux, Gasconade, Eminence, Potosi Derby-Doerun) Mazarn Crystal Mtn Collier Sandstone with limey partings Sandstone with shaley partings Shale Shale with chert
Types of Natural Gas Conventional Gas Dry gas (Arkoma Basin) Wet gas/associated gas (South Arkansas) Unconventional Gas Shale gas (Fayetteville Shale) Coalbed methane (Arkoma Basin)
Fayetteville Shale Exploration and Development Area
Outcrop of Fayetteville Shale Clay 33% Carbonates 15% Others 9% Quartz 43% Organic-rich siliceous shale
Structure Contour Map of the Fayetteville Shale
Fayetteville Shale Producing Wells By Top 3 Operators
Horizontal Drilling & Hydraulic Fracturing A drilling rig in Van Buren County
Arkansas Production of Natural Gas Fayetteville Shale gas production began booming
Fayetteville Shale Gas Annual Production By County
Coalbed Methane Wells
Production and Reserves Marketed natural gas production in Arkansas more than doubled from 2008 to 2012 due to the contribution of the Fayetteville Shale gas; in 2012 it accounted for 4.5% of U.S. marketed production and is ranked the 8 th natural gas-producing state. Cumulative production in the Arkoma basin for conventional gas and Fayetteville Shale gas wells is 6.80 Tcf and 4.57 Tcf, respectively. Annual production of conventional gas and Faytteville Shale gas for 2012 is 115 Bcf and 1.03 Tcf, respectively.
Production and Reserves (Cont.) Cumulative production of coalbed methane is 25.6 Bcf. Annual production of coalbed methane for 2012 is 2.0 Bcf. Proved reserves for conventional gas, shale gas, and coalbed methane in Arkansas are 1.57 Tcf, 14.8 Tcf, and 21 Bcf, respectively, the total of which accounts for 3.6% share of U.S. (according to U.S. EIA 2013 report). Fayetteville Shale contains 31.96 Tcf of technically recoverable gas resource.
Conclusions & Observations Arkansas led the nation s crude oil production in the 1920s with the discovery of the Smackover oil field. Although most of crude oil was extracted from stripper wells that produced less than 10 barrels per day in the south Arkansas, Arkansas has two giant oil-producing fields: Smackover field (600 million bbls) and Magnolia field (172 million bbls). Arkansas is among the top 10 natural gas-producing states. The state's dry natural gas proved reserves now account for almost 5% of the U.S. total. The increases in the Fayetteville Shale's reserves and production, the current focus of shale gas exploration in Arkansas, are the result of horizontal drilling and hydraulic fracturing.
Arkansas Geological Survey Contact Information Bekki White Director and State Geologist Tel: (501) 296-1877 E-mail: agc@arkansas.gov Website: www.geology.ar.gov/home/index.htm