Feasibility Study On Using DC Resistivity Method To Detect The Ordos Basin Sedimentary Facies

This article focuses on studying the feasibility of using DC resistivity sounding methodto explore Ordos basin’s sedimentary facies. At present, the geophysical methods mainlyused in detection of sedimentary facies are well logging and seismic exploration.Obtainning logging data is high cost and low efficiency, because drilling is the premise. Dueto the particularity of its region, the exploration of Ordos basin’s sedimentary facies whichcosts and risks of conventional seismic exploration method is big and difficult to meet theneeds of exploration on the area which ravines crossbar and beam. Ups and downs andchangeful, thick covered by loess and lithological facies change is larger. So this paperstudies the feasibility of using DC resistivity sounding method on the exploration of Ordosbasin’s sedimentary facies.The paper based on full understanding of geology, sedimentary environments,sedimentary facies model of the Ordos basin, statistics the parameters which are used insedimentary facies analysis method It is concluded that there was a positive correlationbetween formation resistivity with diameter median of sediment particles grain, a relevantcorrelation between formation resistivity with argillaceous sediment content throughstatistical analysis of the logging data and geological data on Ordos basin, get yanchangformation resistivity variation range is20~45m.On the basis of logging data andgeological data, establish the corresponding geophysical model (resistivity) on delta frontsedimentary facies and distributary channel sedimentary facies. Using DC resistivitymethod of three-dimensional finite element numerical simulation program, calculation andanalysis the different parts of the apparent resistivity sounding curves, profile and theanomaly characteristics of the floor plan. The results show that the apparent resistivity isobvious different between different sedimentary. The apparent resistivity is high on deltafront sedimentary facies and distributary channel sedimentary facies. So using DCresistivity sounding method is feasible for the detection of sedimentary facies in ordosbasin.Through the processing and interpretation of the banks of the measured dc sounding data and analysising of the results and the geologic information, Results show that theelectrical sounding apparent resistivity profile can better reaction the formation of thevertical distribution of the formation sedimentary facies of Yanchang group. The jointapplication of apparent resistivity plan and largest gradient contour map can determine thelocation of distributary channel and flood land sedimentary facies. Using DC resistivitysounding method is feasible for the study of the distribution of sedimentary facies. It hascertain significance for the detection of sedimentary facies in ordos basin.