U.S. Department of the InteriorU.S. Geological Survey

Natural Gas Assessment of the Arkoma Basin, Ouachita Thrust Belt, and Reelfoot RiftRegional Geologic Framework

Dave HouseknechtComplete Bouguer Anomaly Map Centered on Arkoma Basin

(Hildenbrand et al., 2002; Keller et al., 2002; Saltus, 2009)

Regional Setting

Houseknecht, 1986

Thomas et al., 1989

DNAG Tectonic Map

Tectono-Stratigraphy

Inferred Tectonic Evolution

Houseknecht, 1986

Chesterian Paleogeography

Houseknecht, 1983, 1986Houseknecht & Kacena, 1983

Morrowan Paleogeography

Houseknecht, 1983, 1986Houseknecht & Kacena, 1983

Atokan Paleogeography

Houseknecht, 1983, 1986Houseknecht & Kacena, 1983

Early Desmoinesian Paleogeography

Houseknecht, 1983, 1986Houseknecht & Kacena, 1983

Chronostratigraphy

Arbenz, 2008

Oklahoma Nomenclature

Geologic Map – Southern Arkoma Basin & Ouachita Mountains

Arbenz, 2008

Arbenz, 2008

ABCD

A

B

C

D

Structural Cross Sections – Southern Arkoma Basin & Ouachitas

Arbenz, 2008

Inferred Structural Evolution –Southern Arkoma Basin & Ouachitas

Early Desmoinesian

Late Atokan

Middle Atokan

Early Atokan

Late Morrowan

Mississippian - middle Morrowan

Cambrian - Devonian

50 km

No Vertical Exaggeration

Regional Petroleum Systems

Arkoma Basin Accommodation History – Organic & Petrofacies

Houseknecht, 1987

Stratigraphy – Main Source and Reservoir Rocks

Stratigraphy after Arbenz, 2008; McFarland, 2004

Arbenz, 2008

OK

AR

S

S

S

S

S

S

SRR

RRRRRR

RR

R

R

R

Oil ProneGas Prone

Mixed

Source Rocks

SandstoneCarbonate

Shale

Reservoir Rocks

Regional Thermal Maturity – Surface & Shallow Subsurface

Houseknecht, 1987

Regional Thermal Maturity – Subsurface Profiles, West to East

Houseknecht & Weesner, 1997

Oxy Danville – Depth vs. TOC & Vitrinite Reflectance

Houseknecht, 1992; Houseknecht & Weesner, 1997

MF

F CS

M, Morrow?; F, Fayetteville; C, Chattanooga; S, Simpson

Summary of Isotope Geochemistry Analysis of Produced Gas

• Strong indication of multiple gas sources with variable thermal histories

• Ethane & propane C-isotopic composition is typical of thermogenic gas

• Methane C-isotopic values are too heavy to be consistent with the ethane and propane values

• A later, higher maturity source (oil or heavy gas cracking?) is the most likely cause for the observed methane carbon isotopic signature

• A more comprehensive interpretation of the geochemistry of gases from the Arkoma Basin could be achieved with the addition of more geologic data and additional gas data

Conclusion: Composite Petroleum System

Based on recent USGS work plus results presented publicly by the petroleum industry and universities: