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Monte Carlo Study on Gas Pressure Response of He-3 Tube in Neutron Porosity Logging

TIAN Li-li;ZHANG Feng;WANG Xin-guang;LIU Jun-tao   

  1. School of Geosciences, China University of Petroleum, Qingdao 266580, China
  • Online:2016-05-20 Published:2016-06-03



  1. 中国石油大学(华东)地球科学与技术学院,山东 青岛266580


Thermal neutrons are detected by (n,p) reaction of Helium-3 tube in the compensated neutron logging. The helium gas pressure in the counting area influences neutron detection efficiency greatly, and then it is an important parameter for neutron porosity measurement accuracy. The variation law of counting rates of a near detector and a far one with helium gas pressure under different formation condition was simulated by Monte Carlo method. The results showed that with the increasing of helium pressure the counting rate of these detectors increased firstly and then leveled off. In addition, the neutron counting rate ratio and porosity sensitivity increased slightly, the porosity measurement error decreased exponentially, which improved the measurement accuracy. These research results can provide technical support for selecting the type of Helium-3 detector in developing neutron porosity logging.

Key words: Helium-3 tube, counting area gas pressure, neutron, Monte Carlo simulation



关键词: He-3管, 灵敏区气压, 中子, 蒙特卡罗模拟