Aquifer geological parameter inversion method based on underground inclined single-hole drainage test

Abstract

The invention discloses an aquifer geological parameter inversion method based on an underground inclined single-hole drainage test. The method comprises the following steps: selecting an unstable seepage motion mathematical model of underground water to carry out dynamic numerical inversion on a coal mine underground inclined borehole drainage process, discretizing an aquifer and a drainage borehole by adopting a finite element triangular tetrahedron unit subdivision method, and establishing a computer model compositely described by the aquifer and the drainage borehole; utilizing a model infinite element definition method to digitally describe the peripheral boundary of the aquifer, and adopting a Darcy seepage overflow boundary definition method to digitally describe the contact surfaceof the aquifer and the wall of the drainage borehole; carrying out real-time integration on the Darcy flow velocity U in the hole wall domain of the drainage borehole, and calculating the water drainage amount of the drainage borehole in real time; and continuously correcting the permeability coefficient and the elastic specific gravity of the aquifer in the model, so that the borehole drainage amount change curve is basically consistent with the drainage amount change curve of the drainage test borehole, wherein the hydrogeological parameters of the aquifer given in the model are the hydrogeological parameters of the actual aquifer at the moment.

Description

technical field [0001] The invention relates to a method for obtaining hydrogeological parameters of an aquifer, which belongs to the technical field of comprehensive application of hydrogeology and mining engineering, and in particular relates to an inversion method of geological parameters of an aquifer based on an inclination downhole single-hole water discharge test. Background technique [0002] At present, the analytical method is mainly used to obtain the hydrogeological parameters of the aquifer in the mining area. By drilling holes on the ground or underground in the mining area, carrying out pumping (draining) tests, synchronously observing flow and water level change data, and based on these observation data, the height of the aquifer is generalized into isotropic, infinitely small well diameter, constant flow pumping On the basis of other conditions, the hydrogeological parameters of the aquifer can be inverted by analytical method or graphical method. [0003] ...

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Problems solved by technology

[0006] like Figure 1A and Figure 1B As shown, the water discharge boreholes are generally upwardly passed through the coal seam from the opening of the coal mine underground roadway and enter the roof aquifer (abbreviated as: upward slope water discharge boreholes). Borehole water inflow is generally composed of static storage Qs and dynamic recharge Qd of the aquifer. With the prolongation of the drainage period, the water level drawdown and water volume attenuation rate become smaller and smaller, and the groundwater flow field reaches a dynamic equilibrium state. Dynamic recharge is the main factor. Therefore, the spatial structure and water gushing form of boreholes are significantly different from those of vertical wells on the ground. The water release conditions of the inclined borehole are inconsistent, and there will inevitably be large errors in the inversion results of hydrogeological parameters

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