Patent ID: 9206683
Filing Date: 2015-12-08
Classification: E21B

Abstract:
1. A method of tracing fracking liquid in oil or gas bearing formations using plural unique DNA sequences as fluid markers, comprising the steps of: a) for each of the plural unique DNA sequences, encapsulating one of the plural unique DNA sequences within tracing particles, which range in size between 1 nm and 10 μm, by; b) pumping plural volumes of fracking liquid, each marked with a predetermined quantity of the encapsulated DNA particles, into the formation, thereby defining plural fracture zones; c) pumping fluids out of the formation while taking plural well fluid samples; d) for at least one of the plural well fluid samples; e) determining ratios of the plural volumes of fracking liquid recovered in the at least one of the plural well fluid samples based on the quantity of the plural unique DNA sequences in the solution.