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DNA-Based Tracers for Fractured Reservoir Characterization (2014-2020)

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Investigator(s): Yuran Zhang

The characterization of fluid flow pathways in subsurface reservoirs is crucial for building reliable reservoir models, designing stimulation strategies, predicting reservoir performance, and optimizing production. Tracer data (artificial or natural) provide direct information on reservoir flow properties. However, conventional tracers are limited in unique variations and hence often insufficient to eliminate the many uncertainties in characterizing the complex network of flow paths in fractured reservoirs.

This study explores the use of DNA-based tracers, both artificial and natural, for fractured reservoir characterization. Artificial DNA tracer refers to short-stranded DNA molecules that are artificially designed, synthesized, injected into a reservoir, recovered at one or multiple productions wells, and quantitatively interpreted in a similar manner as traditional chemical tracers. Natural DNA tracer, on the other hand, refers to the use of the indigenous microbial community composition (i.e. genomic DNA of all microbes in a reservoir fluid sample) in a hydraulically connected reservoir compartment as a unique barcode for the fluid residing in the compartment. Both types of DNA-based tracers are characterized by their unlimited number of unique variations in DNA sequences. We studied the transport characteristics of artificial DNA tracers quantitatively in the laboratory. Additionally, we performed proof-of-concept experiments for natural DNA-based tracers (reservoir microbial community composition) as a reservoir diagnostic tool at a deep-subsurface field site 1.5-km below the ground surface.

References: 

Zhang, Y., Hartung, M. B., Hawkins, A. J., Dekas, A. E., Li, K., & Horne, R. N. (2021). DNA tracer transport through porous media—The effect of DNA length and adsorption. Water Resources Research, 57, e2020WR028382. https://doi.org/10.1029/2020WR028382 

Zhang, Y., Dekas, A. E., Hawkins, A. J.,Parada, A. E., Gorbatenko, O., Li, K., &Horne, R. N. (2020). Microbial community composition in deep-subsurface reservoir fluids reveals natural interwell connectivity. Water Resources Research, 56, e2019WR025916. https://doi.org/10.1029/2019WR025916