CN-120951565-B - Method and device for pumping test of radiation well based on numerical simulation

CN120951565BCN 120951565 BCN120951565 BCN 120951565BCN-120951565-B

Abstract

The invention provides a radiation well pumping test method and device based on numerical simulation, which solve the technical problems that the prior art cannot accurately determine hydrogeological parameters by using a radiation well and provide scientific basis for evaluating groundwater resource management and decision making by the water yield of the radiation well. The method comprises the steps of setting a water level observation hole according to acquired geological basic data, collecting observation data in a single deep water pumping process, initially constructing a hydrogeologic model according to the geological basic data, forming a radiation well geologic model according to the hydrogeologic model, and performing radiation well numerical simulation according to the radiation well geologic model and the observation data to form hydrogeologic parameter calibration. And drawing water by using the great descent depth, and describing the structure of the radiation well by using a numerical model. Compared with the conventional pumping test, the method can only perform one deep pumping, has the advantages of short period and low cost, utilizes the numerical model to describe the structure of the radiation well, considers the local seepage field effect of the horizontal pipe of the radiation well, and ensures that the set hydrogeologic parameters are more accurate.

Inventors

WANG MINGXIN
LIU WEI
LIAO ZILONG
WU YINGJIE
ZHANG XINJIAN

Assignees

水利部牧区水利科学研究所

Dates

Publication Date: 20260508
Application Date: 20250731

Claims (10)

1. The method for pumping test of the radiation well based on numerical simulation is characterized by comprising the following steps of: setting a water level observation hole according to the obtained geological basic data; the method comprises the steps of carrying out observation data acquisition in a single large-descent water pumping process, wherein the large-descent is 1/2 of the thickness of a submerged aquifer, and the large-descent is a confined water head for a confined aquifer; Preliminarily constructing a hydrogeologic model according to geological basic data; describing a main well of the radiation well by adopting boundary conditions of the multilayer well Multilayer Well, describing a horizontal radiation pipe of the radiation well by adopting discrete features Discrete Features, and completing a geological model of the radiation well according to the hydrogeological model; and carrying out numerical simulation on the radiation well according to the radiation well geological model and the observation data to form hydrogeological parameter calibration.
2. The method of numerical simulation-based radial well pumping test of claim 1, wherein the geological basis data comprises formation lithology data, regional hydrogeological survey results, and peripheral formation data.
3. The method for pumping test of a radiant well based on numerical simulation according to claim 1, wherein the strategy for water level observation hole arrangement comprises: -updating formation lithology information during the deployment process; -flushing the deployed observation holes to restore the natural permeability of the aquifer; -performing a direction selection based on the results of the hydrogeological survey of the area, comprising: For a homogeneous isotropic aquifer, vertical groundwater flow direction, arranging 1 observation line when the hydraulic gradient is smaller, and arranging 2 observation lines of vertical and parallel flow directions when the hydraulic gradient is larger; Aiming at a homogeneous anisotropic aquifer, arranging observation lines along different water storage and guide property directions to obtain hydrogeological parameters in all directions; If the boundary of the aquifer needs to be ascertained, the observation line is arranged perpendicular to the boundary, and observation holes are arranged at two sides of the boundary; At least 3 observation holes are arranged on each observation line to form a water level drop curve; -a set of observation hole spacings and positions comprising: The first observation hole is away from the main well hole distance to avoid the influence of three-dimensional flow, is not less than the thickness of an aquifer and is at least more than 10m; The subsequent distance is that the subsequent observation hole distance needs to ensure the difference of water level drop, the furthest observation hole needs to ensure the water level drop of more than 20cm, and the water level difference of adjacent holes is more than 20cm; the observation hole structure and depth are that the lengths of all the observation hole filters are equal and are arranged on the same aquifer and the same depth, and the observation hole depth needs to penetrate the target aquifer.
4. The method for pumping test of a radiation well based on numerical simulation according to claim 1, wherein the observation data acquisition process comprises: -recording the initial hydrostatic level of the main borehole and the observation borehole; -recording the influencing factors before the start of the deep pumping, including weather, temperature and ambient pumping activity factors; -continuous observation data acquisition with an automatic observation device; -forming a large-descent pumping-recovery process, wherein the descent depth is more than 1/2 of the thickness of the aquifer for the submerged aquifer design, and is a confined water head for the confined aquifer design; -stopping the pump after pumping down until the initial still water level is restored, and synchronously observing the water level and the water quantity of the main well and the peripheral observation holes in the pumping-restoring process.
5. The method for testing pumping of a radiation well based on numerical simulation according to claim 4, wherein the automatic observation device comprises pressure sensors for main well and observation hole water level observation, an ultrasonic flowmeter for main well pumping water volume metering, and a water level and water volume recording frequency is 1 time/min.
6. The method for pumping test of a radiation well based on numerical simulation according to claim 4, wherein the observation data are converged to an upper storage device through a communication link, and quantification of key parameters of an underground water flow field is formed through an upper computing device, and the key parameters comprise: The water level is represented by potential energy reflecting the flow direction of underground water, the submerged water level in the submerged aquifer and the pressure measuring water head in the confined aquifer; The water head difference in unit distance is the power for driving water flow to move, and the larger the gradient is, the higher the flow speed is generally; The permeability coefficient (K) reflects the water permeability of an aquifer, is closely related to lithology and directly influences the flow velocity; the permeation flow rate (v) is the actual movement speed of groundwater in the pores.
7. The method of numerical simulation-based radiation well pumping test of claim 1, wherein the forming a radiation well geologic model from a hydrogeologic model comprises: acquiring a basic framework of a geological environment of a radiation well through a hydrogeologic model, and establishing digital characterization of a periwell geologic body: -establishing stratigraphic layering and lithology distribution, providing layering basis for subsequent parameter assignment and well body characterization; -establishing a hydrogeological structure, identifying a aquifer, and a water barrier; establishing model scale and precision, considering macro area and local fineness, wherein the area scale reflects the influence of a radiation well on a peripheral underground water system, and the local scale reflects the microscopic hydraulic connection of a horizontal radiation pipe and a well peripheral stratum; -characterizing the water exchange of the main well with different strata using boundary conditions of the multi-layer well Multilayer Well, decomposing the total flow of the main well into contributions of each layer, directly coupling with the layered structure of the three-dimensional geological model, setting its specific water outlet position and well diameter; -characterizing the local strong seepage region formed by the horizontal radiation pipe of the radiation well and the discrete structure in the stratum by using the discrete features Discrete Features to represent the features of spatial discontinuity and significant differences between seepage characteristics and surrounding stratum; -co-setting the permeability coefficient (K) with the geological model, the multilaminate wells Multilayer Well, the discrete features Discrete Features by spatial distribution in the three-dimensional model to describe the rock-soil body water permeability.
8. The method for pumping test of a radiation well based on numerical simulation according to claim 1, wherein the parameter calibration process adopts linear fitting or deep learning.
9. Radiation well pumping test device based on numerical simulation, characterized by comprising: A memory for storing program code during the processing of the numerical simulation-based radial well pumping test method of any one of claims 1 to 8; and a processor for executing the program code.
10. Radiation well pumping test device based on numerical simulation, characterized by comprising: the basic data receiving module is used for setting a water level observation hole according to the acquired geological basic data; the observation data planning module is used for collecting observation data in a single large-descent water pumping process, wherein the large-descent depth is 1/2 of the thickness of the submerged aquifer, and the large-descent depth is a pressure-bearing water head for the pressure-bearing aquifer; the geological model initial construction module is used for initially constructing a hydrogeological model according to geological basic data; The well model construction module is used for describing a main well of the radiation well by adopting boundary conditions of the multi-layer well Multilayer Well, describing a horizontal radiation pipe of the radiation well by adopting discrete features Discrete Features, and forming a geological model of the radiation well according to the hydrogeological model; And the well type parameter calibration module is used for carrying out numerical simulation on the radiation well according to the radiation well geological model and the observation data to form hydrogeological parameter calibration.

Description

Method and device for pumping test of radiation well based on numerical simulation Technical Field The invention relates to the technical field of pumping tests, in particular to a method and a device for pumping a radiation well based on numerical simulation. Background The radiation well is a special well type widely applied to shallow groundwater exploitation, and consists of a vertical well with a large caliber at one glance and a plurality to dozens of horizontal water collecting pipes (horizontal radiation pipes) which are driven into the horizontal direction from the vertical well. The drainage area is enlarged through the combined structure of the main shaft and the radial branch pipes (radiant tubes), and the water yield of a single well is obviously improved. The pumping test is a core means for evaluating the water yield of a radiation well, analyzing the hydrogeological parameters of an aquifer and predicting the underground water resource amount, and is an in-situ permeability test process for forming quantized aquifer permeability parameters by measuring the data such as the water yield of the pumping hole, the water level change of an observation hole with time and the like through drilling water pumping and adopting the functional relation between the water yield and the water level drop value to carry out numerical simulation according to the steady flow or unsteady flow theory of the well and Kong Chongshui. However, conventional water pumping test methods have the following limitations for radiant wells: 1. special structural features of the radiation well cannot be fully considered The radiation well comprises a combination of a main well and a plurality of horizontal radiation pipes, and the structure significantly changes the distribution of the groundwater flow field. Conventional pumping test specifications are typically designed for single well or multi-well systems, failing to adequately account for the effects of the horizontal tubing of the radiating well on the aquifer. This results in test results that are difficult to reflect the actual water pumping capacity of the radiation well and the dynamic changes of the groundwater flow field. 2. The parameter inversion method has the defects The conventional hydraulic parameter calculation method (such as a Tess formula and a Jacob formula) is generally adopted in the conventional water pumping test specification, and a homogeneous isotropic aquifer is strictly assumed by an analytical model (such as the Tess formula) based on a steady flow or non-steady flow theory. Based on an idealized mathematical model, the method is difficult to treat the special structure of the radiation well, the radiation well is generally simplified and assumed by using the existing empirical formula (such as an equivalent large-mouth well method and a Bolton method), the seepage characteristic and the three-dimensional unsteady flow dynamic change of a horizontal radiation pipe are ignored, the local seepage field effect of the horizontal radiation pipe of the radiation well is not considered, and the unsteady seepage field and the complex seepage behavior of the radiation well are difficult to accurately simulate. It is difficult to reflect the influence of the complex structure of the radiation well (such as the length of the radiation tube, the angular distribution) on the seepage field. The parameter inversion error is obvious, and the accuracy and applicability of the test result are limited. 3. Long test period and low efficiency Radiation well pumping tests typically require a long pumping process to observe dynamic changes in water level, especially under complex geological conditions, the test period may be further prolonged. The water level and flow data are required to be monitored for a long time through a large number of field water pumping, the time consumption is long and the water level and flow data are limited by field conditions, and the result is difficult to obtain quickly. This not only increases the cost of the test, but also delays the application of the test results. The defects necessarily lead to the fact that the prior numerical simulation process cannot obtain reliable observation data and data dimension, and obvious defects exist in data precision, data distribution and data quantity. A model structure reflecting the actual geological conditions cannot be formed. Therefore, a scientific and reasonable water pumping test method is provided, and the method has important practical significance for guiding the implementation of a radiation well, determining hydrogeological parameters, evaluating the water yield of the radiation well and providing basis for water resource management. Disclosure of Invention In view of the above problems, the embodiment of the invention provides a radiation well pumping test method and device based on numerical simulation, which solve the technical problems that the prior art cannot accurately deter