Research And Application On Core Orientation Of Drilling Cores In South China Uranium Ore Field

Core orientation plays an important role in looking for underground mineral resources and oil and gas reservoirs and so on.However,most cores are non-directional cores in actual mines and oil fields,so it is urgent to orient the cores.The paleomagnetic method has the advantages of simplicity,economy and high accuracy.And it is widely used for core orientation.However,Paleomagnetism mainly targets vertical boreholes at present,and lacks the core orientation of structure complex inclined boreholes.Take the important Xiazhuang uranium ore field in South China for example.So it is very urgent to core orientation.This paper discusses the orientation process of inclined borehole cores by designing the drilling core directional sampling device and data programming.Do some research on sample drilling,sample orientation and sample sampling in the paleomagnetic sampling of borehole cores.And extracting from core sampling at the logging site,the whole process of core orientation of inclined boreholes was studied and analyzed.At the same time,the effect of the sequence of geographic correction data processing on the results of core orientation and principal component analysis was studied.This article has achieved the following points:(1)The shortcomings of sampling the core coordinate system and sample coordinate system in the traditional paleomagnetic are analyzed,and a new method of sampling at any position on the core cylinder is proposed.At the same time,to obtain the orientation of small core samples relative to the main reference line,a micro-paleomagnetic core directional sampling device,a solar compass connector,and a small core sample sampler were designed and developed.Compared with the traditional paleomagnetic core sampling method,this method has the advantages of extracting more number of samples and stronger flexibility.(2)The principle and process of the core orientation of inclined boreholes are analyzed,and the 4 coordinate transformation formulas of core orientation of inclined boreholes are understood and derived.Because the first coordinate transformation program of the oblique borehole core orientation is consistent with the geographic correction program of the outcrop samples,and the special PMag software is used to compare the geographic correction results of the field outcrop samples with the C language programming results to verify the correctness of the first coordinate conversion procedure for the core orientation of inclined boreholes.(3)By comparing the results of geographic component correction before principal component analysis and the results of principal component analysis before geographic correction,it is found that the correction results are consistent,indicating that the order of principal component analysis and geographic correction data processing doesn't affect core orientation.(4)By using the new device and the geological correction program for the core orientation of inclined boreholes proposed in this paper,the core orientation of 8 holes in the Xiazhuang uranium ore field in South China was successfully achieved.