Simulation test method for gas extraction from tectonically-deformed coal seam in-situ by depressurizing horizontal well cavity

摘要

A simulation test method for gas extraction from a tectonically-deformed coal seam in-situ by depressurizing a horizontal well cavity. A coal series stratum structure reconstruction and similar material simulation subsystem (1) simulates the construction of a coal reservoir. A horizontal well drilling and reaming simulation subsystem (2) constructs a U-shaped well in which a horizontal well (1.11) adjoins a vertical well (1.12), and performs a reaming process on a horizontal section thereof. A horizontal well hole-collapse cavity-construction depressurization excitation simulation subsystem (3) performs pressure-pulse excitation and stress release on the horizontal well, and hydraulically displaces a coal-liquid-gas mixture such that the mixture is conveyed towards a vertical well section. A product lifting simulation subsystem (4) further pulverizes the coal and lifts the mixture. A gas-liquid-solid separation simulation subsystem (5) separates the coal, liquid and gas. A monitoring and control subsystem detects and controls the operation and the execution processes of equipment in real time. The method enables the simulation of completion of a large-diameter horizontal well in a loose tectonically-deformed coal reservoir, horizontal well cavity-construction stress release, effective lifting of mixed fluids, and efficient separation of produced mixtures, thereby providing guidance for efficient in-situ extraction of tectonically-deformed coal seam gas.