Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (8): 80504-080504.doi: 10.11889/j.0253-3219.2015.hjs.38.080504


γ-ray spectrometry to identify the classification of well drilling debris of sedimentary rocks based on SPSS

GU Runqiu1 LAI Wanchang1 LIN Hongjian1 YAN Ronghui2 WANG Gang2 ZHANG Lijiao1 ZHU Meiying1 HUANG Zijian3 HUANG Jinchu1   

  1. 1(The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China) 2(Exploration Department of Petro China Changqing Oilfield Company, Xi’an 710018, China) 3(Panjin Recorded in Oil and Gas Technology Services Ltd, Panjin 124010, China)
  • Received:2015-04-28 Revised:2015-05-21 Online:2015-08-10 Published:2015-08-13

Abstract: Background: The application of gamma ray spectroscopy on the classification for the sedimentary rocks is helpful to solve the problem of small classification and the long cycle for chemical analysis of the sedimentary rocks. Purpose: This study aims to introduce a method of determining the content of natural radionuclides K, U, Th in the well drilling debris with the low background gamma ray spectroscopy for dipartition among dark gray ash mudstone, dark grey calcareous mudstone and grey calcareous mudstone. Methods: Count rates of K, U, Th in the energy ranges of 1.37–1.56 MeV, 1.66–1.86 MeV and 2.41–2.81 MeV were selected to represent the intensity of radioactivity of K, U, Th. The fisher discriminant criterion was applied to measured count rates of various samples for classification of sedimentary rocks using the Statistical Product and Service Solutions (SPSS) software. Results: According to the count rate of K, U, Th and total count rate of the three mudstones carry out the discriminant analysis of rock lithology by using SPSS software, the accuracy rate reached 100%, 76.47% and 60%, respectively. Conclusion: Gamma ray spectrometry method is of great significance for the division of sedimentary rocks in small class. It could be used to completely identify the dark gray mudstone and the identification effect for dark grey calcareous mudstone, and grey calcareous mudstone is good, but not distinguish them completely.

Key words: Gamma ray spectrometer, Analysis of cores, Discriminant analysis