Geochemical studies of crude oil generation, migration, and destruction in Mississippi salt basin

Conference · Tue Sep 01 04:00:00 EDT 1987 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:5753552

Sassen, R; Moore, C H; Nunn, J A; Meendsen, F C; Heydari, E

The main source for crude oil in the Mississippi salt basin is the laminated lime mudstone facies of the lower Smackover. Crude oil generation and migration commenced at a level of thermal maturity equivalent to about 0.55% vitrinite reflectance. Short-range lateral migration of crude oil was focused on upper Smackover and Norphlet reservoirs, but vertical migration also charged some overlying Cotton Valley, Rodessa, lower Tuscaloosa, and Eutaw reservoirs. Following migration from the lower Smackover, thermal maturity history of reservoir rocks controls the preservation of crude oil, gas condensate, and methane. Slow thermal cracking of crude oil occurred in deep upper Smackover reservoirs, resulting in formation of gas condensate and precipitation of solid bitumen. The maximum thermal maturity for preservation of condensate is equivalent to about 1.3% vitrinite reflectance. Only methane, pyrobitumen, and nonhydrocarbon gases, including hydrogen sulfide, persist at higher levels of thermal maturity. Early destruction of methane in deep upper Smackover reservoirs near the Wiggins arch is driven by thermochemical sulfate reduction. Lesser availability of sulfate in Norphlet reservoirs could account for methane preservation at higher levels of thermal maturity. One basic geochemical strategy for further exploration of the Mississippi salt basin is to focus exploration effort on traps with reservoirs in the thermal maturity window for hydrocarbon preservation. Another strategy is to avoid drilling traps with overmature reservoir rocks.

• Research Organization: Louisiana State Univ., Baton Rouge
• OSTI ID: 5753552
• Report Number(s): CONF-8710198-
• Conference Information: Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 71:9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
CHEMISTRY
ENERGY SOURCES
FEDERAL REGION IV
FOSSIL FUELS
FUELS
GEOCHEMISTRY
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
MACERALS
MATURATION
MIGRATION
MINERAL RESOURCES
MISSISSIPPI
NORTH AMERICA
OPTICAL PROPERTIES
ORIGIN
PETROLEUM
PETROLEUM DEPOSITS
PHYSICAL PROPERTIES
RESOURCES
SOURCE ROCKS
USA