Pulse neutron logging method and pulse neutron logging device

Abstract

An embodiment of the invention provides a pulse neutron logging method and a pulse neutron logging device. The pulse neutron logging method includes: performing logging through the pulse neutron logging technology and acquiring a time spectrum of each depth point; determining capture spectroscopy according to the time spectrums of the depth points, wherein the capture spectroscopy is used for representing a macroscopic-capture cross section corresponding to continuous multiple thermal neutron lifetime for each depth point; performing recognition processing on a water flooded layer according to the capture spectroscopy. With the method, the macroscopic-capture cross section can be represented comprehensively and accurately through the capture spectroscopy, and down-hole recognition processing can be assuredly performed accurately.

Description

technical field [0001] The embodiment of the present invention relates to oil and natural gas production logging technology, in particular to a pulse neutron logging method and device. Background technique [0002] figure 1 Schematic diagram of the principle of the pulsed neutron logging method provided for the prior art, such as figure 1 As shown, the principle of the pulse neutron logging method is: the logging tool emits fast neutrons (14.3MeV) into the formation, and gradually loses energy after a series of inelastic and elastic collisions. This process is called moderation. When the energy of the neutron is in thermal equilibrium with the atoms that make up the formation, the neutron no longer decelerates. At this time, its energy is about 0.025eV and its velocity is 2.2×105cm / s, and it mainly undergoes a capture reaction with the nucleus of the formation. [0003] At present, when the capture cross section is determined by the pulse neutron logging method, for each d...

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Problems solved by technology

However, in fact, the downhole formation structure is relatively complex, and for each depth point, the capture cross section corresponding to each thermal neutron lifetime is also different

[0004] Therefore, the pulse neutron logging method provided by the prior art cannot accurately perform downhole identification processing

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