Source Rock Analysis-- Evaluating Exploration Potential

S ummaryPetroleum source rocks are fine-grained, organic-rich rocks that have the potential to generate petroleum. All oil and gas fields require source
rocks as an element of their petroleum system. Source rock potential is evaluated based on three parameters (organic amount, organic type, andmaturity). Analytical instruments, such as elemental analyzers, Rock-Eval® instruments, and vitrinite reflectance microscopes, are used foranalysis of outcrop samples, well cuttings, and cores. The resulting data are fundamental for oil and gas exploration.

Type of Organic Carbon (Rock-Eval®)

Amount of Organic Carbon

I900

Oil-prone

G unitF unitE unitD unitC unitB unitA unitII600

Oil-prone

H.I.
300

Gas-prone Rock-Eval® is a unique instrument

Total Organic Carbon (TOC) content is the most importantparameter to indicate the amount of petroleum generation. Carbon
in source rock samples is converted to carbon dioxide (CO2) gas
during oxidative combustion. Organic carbon content in the sourcerock can be calculated by measuring the amount of CO2 produced.

IV00100200O.I.

Source Rock Kinetics Analysis
㻺㼛㼞㼙㼍㼘㼕㼦㼑㼐㻌㼞㼑㼍㼏㼠㼕㼛㼚㻌㼞㼍㼠㼑

Maturity (Vitrinite Reflectance)

used in the petroleum industry.
The organic types (oil-prone orgas-prone) and maturity of source
rocks can be estimated using
Rock-Eval® pyrolysis.

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We can evaluate how and when in
their depositional history theorganics in source rocks generated㻞㻡㻭㻌㻩㻌㻡㻚㻜㻜㻡㻠㻱㻗㻝㻞
petroleum by calculating the㻞㻜kinetic reactions of kerogens.
㻝㻡More detailed features (the timing㻝㻜
of generation, for example) can be㻡
identified with this method thancan be identified based on the㻜㻠㻜 㻠㻞 㻠㻠 㻠㻢 㻠㻤 㻡㻜 㻡㻞 㻡㻠 㻡㻢 㻡㻤 㻢㻜 organic type analysis described㻭㼏㼠㼕㼢㼍㼠㼕㼛㼚㻌㻱㼚㼑㼞㼓㼥㻘㻌㼗㼏㼍㼘㻛㼙㼛㼘
above.

Vitrinites, which are carbonaceous materials derived from the woodyparts of plants, are found in most source rocks. Vitrinite reflectancecan be used as an indicator of source rock maturity because of its
high correlation with the thermal record of the rock. Evaluation of
the thermal history of a basin is conducted through basin modelingusing maturity data derived from vitrinite reflectance measurements.

Application
ppin ExplorationpGeologygy㻼㼑㼞㼏㼑㼚㼠dKern/dt = - Anexp(-Ean/RT) 䞉 Kern

Key Points
Source rock analyses are mainly conducted for evaluation of thethree factors described below:(1) The amount (quantity) of organics: the more organics, the more
petroleum generation(2) The type (quality) of organics: oil-prone or gas-prone(3) The maturity of organics: whether they could generate or havealready generated petroleum

Exploration studies, such as basin modeling,
are conducted using data from source rockanalysis. These studies contribute to theevaluation of new exploration areas andbasins, the selection of wildcat welllocations, and other exploratory endeavors.

We cannot properly evaluate petroleum systems without sourcerock analysis because source rock data are fundamental topetroleum exploration.
Our source rock data are carefully analyzed to accurately enhance
exploration studies, such as basin modeling, migration andaccumulation analysis, and the selection of wildcat well locations.

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