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US 11,953,490 B2Granted
Age differentiation of Late Cretaceous-Tertiary sourced oils
AssigneeExxonMobil Technology and Engineering Company
InventorsChun Zhu, Weixuan Li
Life of this patent
Estimating the term…
Abstract
An angiosperm index-1 and an angiosperm index-2 are correlated to an age of a liquid hydrocarbon sample and can be used to distinguish oil age of Late Cretaceous (100-65 million years before present, or 100-65 Ma BP) vs. Paleogene (65-55 Ma BP) vs. Eocene or younger (<55 Ma BP). This method improves over existing methods that cannot distinguish oil age between Late Cretaceous and Miocene (ca. 100-5 Ma BP).
Claims12
A method comprising:
- measuring a concentration of oleanane (O), C29 30-nor-neohopane (H29Ts), bicadalenes and methyl-bicadalenes (B), and C27 22,29,30-tris-nor-neohopane (Ts) in a hydrocarbon sample obtained from a subsurface location;
- calculating an angiosperm index-1=[O]/([O]+[H29Ts]) and an angiosperm index-2=[O]+[B]/([O]+[B]+[Ts]);
- estimating an age of the hydrocarbon sample based on a relationship between hydrocarbon age and the angiosperm index-1 and the angiosperm index-2;
- using the relationship between the hydrocarbon age and the angiosperm index-1 and the angiosperm index-2 to determine a location from which to extract hydrocarbons from the subsurface location;
- and
- extracting the hydrocarbons from the determined subsurface location;
- wherein the relationship is determined by measuring the angiosperm index-1 and the angiosperm index-2 of multiple reference hydrocarbon samples having known ages and correlating the measured angiosperm indices-1 and the measured angiosperm indices-2 against the known ages of the multiple reference hydrocarbon samples.
4 more elements
A method comprising:
- obtaining a hydrocarbon sample from a hydrocarbon seep in a subsurface location;
- measuring a concentration of oleanane (O) C29 30-nor-neohopane (H29Ts), bicadinanes and methyl-bicadinanes (B), and C27 22,29,30-tris-nor-neohopane (Ts) in the hydrocarbon sample;
- calculating an angiosperm index-1=[O]/([O]+[H29 Ts]) and an angiosperm index-2=[O]+[B]/([O]+[B]+[Ts]);
- estimating an age of the hydrocarbon sample based on a relationship between hydrocarbon age and the angiosperm index-1 and the angiosperm index-2;
- and
- determining, from the estimated age, source rock from which the hydrocarbon sample originated;
- using the source rock to determine a location from which to extract hydrocarbons from the subsurface location;
- and
- extracting the hydrocarbons from the determined subsurface location;
- wherein the relationship is determined by measuring the angiosperm index-1 and the angiosperm index-2 of multiple reference hydrocarbon samples having known ages and correlating the measured angiosperm indices-1 and the measured angiosperm indices-2 against the known ages of the multiple reference hydrocarbon samples.
7 more elements
Dependencies are inferred from the claim text.