The Stochastic Simulation Of Quaternary Aquifer Structure In Yinchuan Plain

The traditional aquifer permeability structure model is based on the general data of natural geology,hydrogeological conditions,lithology and geological section to generalizes the spatial distribution of aquifer in the study area.However,in large areas with complex geological conditions,it is difficult to find a stable and continuous aquifer for the generalization.The aquifers always exist in the form of lens bodies with different morphologies.The regional survey data and drilling data is relatively scarce,especially in areas where there is little human activity.At the same time,the collected data is usually irregularly distributed with uncertainty.The hydrogeological characteristics between the drilling holes can only be determined artificially.It is difficult to characterize each grid accurately in the model.For the large area where the geological conditions are complex and the basic geological data is insufficient,using the traditional method should produce significant artificial error which affects the accuracy of the aquifer permeability model.And the heterogeneity and anisotropy of the aquifer cannot be expressed accurately.In order to further understand the aquifer permeability structure characteristics,spatial distribution and relationship between them,geostatistics theory and three-dimensional geological visualization modeling are combined in this paper to achieve hydrogeological stochastic simulation.In order to portray a more accurate Quaternary aquifer infiltration structure,mathematical description is used to transform elevation data,geophysical data and lithological data into continuous images.In this paper,the Quaternary strata in Yinchuan Plain are studied.Due to the large area and the complex geological structure,the western Helan Mountain piedmont plain and eastern parts are lack of drilling data,and the borehole data is usually irregularly distributed.Therefore,the geological data,drilling and geophysical data are combined to establish the three-dimensional Quaternary geological model,the conductivity structure model and the lithologic structure model respectively.The stochastic Gaussian simulation of the apparent resistivity data and the lithologic parameters is carried out.The influence of the stochastic simulation model of the apparent resistivity data is analyzed by comparing the exponential model with the spherical model.Finally,exponential model is used as the stochastic model for Quaternary strata.Establishing the permeability structure of the Quaternary aquifer makes it possible to further describe the spatial structure and the spatial distribution of the Quaternary reservoir which is conducive to the further research of the groundwater dynamic characteristics and promote the utilization and protection of groundwater resources,solid mineral resources and other fields.