Solid-state NMR characterization of Mowry Formation shales

Technical Report · Wed Apr 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/7095074· OSTI ID:7095074

Miknis, F P

Solid-state [sup 13]C and [sup 29]Si NMR measurements were carried out on a series of petroleum source rocks from the Mowry Formation of the Powder River Basin in Wyoming. The objectives of this study wereto use CP/MAS [sup 13]C NMR measurements to monitor changes in the carbon structure of the kerogen that result from depth of burial, and to examine the feasibility of [sup 29]Si NMR for studying the thermal alteration of clay minerals during diagenesis. Carbon and silicon NMR measurements were made on a suite of samples covering a present-day depth interval of 3,000 to 11,500 ft.In general, the NMR results endorsed other geochemical analyses that were performed on the source rocks as part of another study to examine pressure compartmentalization in the Mowry Formation. The carbon aromaticity of the kerogen increased with depth of burial, and at depths greater that approximately 10,000 ft the kerogen showed little capacity to generate additional oil because of the small fraction of residual aliphatic carbon. By combining NMR and Rock-Eval measurements, an estimate of the hydrogen budget was obtained. The calculations indicated that approximately 20% of the kerogen was converted to hydrocarbons, and that sufficient hydrogen was liberated from aromatization and condensation reactions to stabilize the generated products. The [sup 29]Si NMR spectra were characterized by a relatively sharp quartz resonance and a broad resonance from the clay minerals. With increasing depth of burial, the clay resonance became broader and shifted slightly downfield. These changes qualitatively support X-ray analysis that shows progressive alteration of illite to smectite with depth of burial.

• Research Organization: Western Research Inst., Laramie, WY (United States)
• Sponsoring Organization: DOE; GRI; USDOE, Washington, DC (United States); Gas Research Inst., Chicago, IL (United States)
• DOE Contract Number: FC21-86MC11076; FG05-89ER75506
• OSTI ID: 7095074
• Report Number(s): DOE/MC/11076-3196; ON: DE93000235; CNN: 5089-260-1894
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
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& Exploration
58 GEOSCIENCES
580000 -- Geosciences
BITUMINOUS MATERIALS
CARBON 13
CARBON ISOTOPES
CARBONACEOUS MATERIALS
CHEMISTRY
CLAYS
DATA
DEVELOPED COUNTRIES
DIAGENESIS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
GEOCHEMISTRY
GEOLOGIC DEPOSITS
ILLITE
INFORMATION
ISOTOPES
KEROGEN
LIGHT NUCLEI
MAGNETIC RESONANCE
MATERIALS
MATTER
MINERAL RESOURCES
MINERALS
NMR SPECTRA
NORTH AMERICA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ORGANIC MATTER
PETROLEUM DEPOSITS
RESONANCE
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SHALES
SILICATE MINERALS
SILICON 29
SILICON ISOTOPES
SMECTITE
SOURCE ROCKS
SPECTRA
STABLE ISOTOPES
STRUCTURAL CHEMICAL ANALYSIS
USA
WYOMING