Tracers for petroleum reservoirs
The disclosure features methods of analyzing a fluid extracted from a reservoir, the methods including introducing a first composition featuring a first complexing agent into a reservoir at a first location, extracting a fluid from the reservoir at a second location different from the first location, combining the fluid with a second composition featuring a concentration of a lanthanide ion to form a third composition featuring a concentration of a complex formed by the first complexing agent and the lanthanide ion, exposing a quantity of the complex to electromagnetic radiation for a first time period ending at a time t 0 , detecting fluorescence emission from the quantity of the complex for a second time period starting at a time t 1 >t 0 , where t 1 −t 0 is greater than 2 microseconds, and determining information about a fluid flow path between the first location and the second location.
1. A complexing agent of Formula (II), or an anion or salt thereof:
wherein:
each of X 1 and X 2 is absent;
each of R 1 and R 2 is —NR a R a ;
each occurrence of R a is C 1-8 alkyl optionally substituted with from 1-3 independently selected R b ; and
each occurrence of R b is C 1-4 alkoxy.
2. The complexing agent of claim 1 , wherein:
at least one R a is different from another R a .
3. The complexing agent of claim 1 , wherein each R a is the same.
4. The complexing agent of claim 1 , wherein at least one R b is different from another R b .
5. The complexing agent of claim 1 , wherein each R b is the same.