This invention discloses a method for constructing an
enhanced geothermal system for abandoned oil and gas wells, characterized by the following steps:
logging and testing the target abandoned oil and gas well to assess
wellbore integrity, reservoir parameters, and the type, content, and
spatial distribution of residual
alkyl compounds; injecting an igniter and
oxygen-containing gas into the reservoir, followed by the injection of high-pressure
nitrogen for ignition, thereby igniting the residual
alkyl compounds to establish an initial
combustion zone; injecting an oxidizer into the
combustible gas enrichment zone, mixing it with the
combustible gas therein to form an explosive mixture and detonating it; periodically or continuously injecting an oxidizer and
water vapor alternately into the reservoir through the fracture network, continuously heating the reservoir through
combustion and gasification reactions; stopping the injection of oxidizer, injecting a low-temperature
working fluid into the artificial
geothermal reservoir space through injection wells, and subsequently extracting it from production wells for
thermal energy utilization; thus, this invention achieves in-situ energy upgrading and enrichment of abandoned resources.