The Quaternary Aquifer Permeability Structure Analysis Of Weining Plain

For the analysis of regional penetration structure,the traditional approach is qualitatively divided permeability structure according to the study area zoning hydrogeological conditions and borehole data.But for large regional study area,it’s inevitably some distortion, especially the area of insufficient borehole data and complicated geological conditions, the uncertainty will enlarge and the uncertainty of establishment of a numerical model will be enlarged, permeability structure data also will be distorted. To avoid the above situation,with the continuous development of geostatistics theory and computer technology,to make up for the disadvantage of kriging valuation theory, conditional simulation is gradually been widely used in mining,oil,water and other aspects for the advantages ofreflecting the volatility of spatial data. It also provides an effective way for a change of the directionfrom the uncertainty to the quantification of the traditional permeability structure.In this paper,Weining Plain as the example. The region area is larger with the rather complicatedgeologic structure and few drilling data.So this use the 28 geophysical explorationprofile datacombined with borehole data,establishing a three-dimensional geological model of the Quaternary. Firstly,carrying out lithologic variation structure analysis,andthen sequential gaussian simulationfor A and B area respectively.According to the relationship between resistivity and lithology,use the hydrology geological profile and drilling histogram to vertify the model.Finally,choose the simulation results of the area A 16 th and B zone 20 th to analyze penetration structure of the Weining plain. The conclusion is as follows:(1)A zone: Perpendicular to the section of the Yellow River, from the border to the Yellow River in thestudy area, mainly composed of the piedmont pluvial,alluvial-diluvialsediments and the alluvial-diluvial deposits of the Yellow River.Resistivity change is not obvious, so the vertical permeability structure change is not obvious; Along both sides of the Yellow River, the resistivity presents high and low resistanceinterval distribution, this is mainly due to the dual structure of the river, the lower is composed of coarse sand and gravel bed sediments and the upper for the floodplain sediments composed of fine sand and clay;The resistivity ofthe western desert area composed of the sand and fine sandis lower, quaternary thickness is bigger and betterpermeability;The Zhongwei area presents a single Quaternary sand clay with gravel layer and better water conditions, along both sides of the Yellow River in the Zhongning area, presents multi-rhythmic structure, thelarger resistivity is substantially sand and gravel, the smaller is sand clay, fine sand and the region has aquifers with multilayer structure.(2)Bzone: The hill platform in the Northwest has thin quaternary covering, occasionally the Tertiary or Paleozoic strata outcrops, poor permeability, and in the aquifer, water yield property also is weaker.Near the Enhe,Mingsha and Qukou inthe Southeast,the simulation result of the resistivityis larger and the region is mainly composed ofthe Quaternary sand clay with gravel layer.