Oil and Gas Fracture Liquid Tracing with Oligonucleotides

摘要

Methods of tracing fracking liquid in oil or gas bearing formations using plural unique oligonucleotide markers. Method includes pumping the plural volumes of fracking liquid, each marked with a unique oligonucleotide, into the formation, thereby defining plural fracture zones in the formation, and, pumping fluids out of the formation while taking plural fluid samples. Then, analyzing the concentration of the unique oligonucleotides in each of the plural fluid samples, and, calculating the ratio of each of the plural volumes of fracking liquid recovered for each of the plural fluid samples according to the concentration of the unique oligonucleotides present in each of the plural samples. And, then, establishing the quantity of the plural volumes of fracking liquids removed from the plural fracture zones.

主权项

1. A method of tracing the movement of plural volumes of fracking liquid pumped into an oil or gas bearing formation through a first stage of perforations in a well casing that is coupled to a wellhead, by using plural unique oligonucleotide markers, comprising the steps of:
sequentially marking plural volumes of fracking liquid, correspondingly, with plural unique oligonucleotides, each at a predetermined concentration; sequentially pumping each of the plural volumes of fracking liquid through the first stage of perforations and into the formation, thereby sequentially advancing each of the plural volumes of fracking liquid outwardly into plural fracture zones, correspondingly, of the formation; pumping formation fluids to the wellhead, which may contain portions of the plural volumes of fracking liquid, while monitoring the periodic volume thereof; gathering, periodically, plural formation fluid samples as the formation fluids are pumped to the wellhead; correlating each of the plural formation fluid samples, correspondingly, to plural periodic volumes; analyzing the concentration of the plural unique oligonucleotides in each of the plural samples; calculating the quantity of each of the plural volumes of fracking liquid recovered during each of the plural periodic volumes according to the concentration of the plural unique oligonucleotides present in each of the plural samples, and thereby establishing the movement of the plural volumes of fracking liquids out of the plural corresponding fracture zones.