Double-LaBr3 detector element energy spectrum logger based on controllable neutron source and logging method

Abstract

The invention discloses a double-LaBr3 crystal detector element energy spectrum logger based on a controllable neutron source. The double-LaBr3 crystal detector element energy spectrum logger comprises a cylindrical shell, wherein the cylindrical shell is internally provided with a LaBr3 detector I and a LaBr3 detector II from top to bottom, the controllable neutron source is connected with a photomultiplier at the top part of the LaBr3 detector I, a chromium foil is arranged between the LaBr3 detector I and the LaBr3 detector II, and the photomultiplier, the LaBr3 detector I, the chromium foil and the LaBr3 detector II are arranged in a boron sleeve body which is positioned in the cylindrical shell; a tungsten shielding body is arranged between the controllable neutron source and the boron sleeve body, and the controllable neutron source is connected with a neutron detector through a neutron acceleration part. According to the double-LaBr3 crystal detector element energy spectrum logger based on the controllable neutron source, disclosed by the invention, by utilizing the controllable neutron source and the double LaBr3 detectors with high resolution, the content measuring accuracy of elements such as C and Mg and the longitudinal resolution can be increased, the measurement information can be increased, and the purpose of simultaneously determining parameters of stratum element content, mineral content, porosity degree and the like can be realized; the double-LaBr3 crystal detector element energy spectrum logger has the characteristics that the environmental hazard is reduced, effective stratum information is enriched, and the like.

Description

technical field [0001] The invention relates to the field of oil and natural gas exploration, in particular to a controllable neutron source using D-T and double LaBr 3 The element energy spectrum logging tool of the detector and the logging method. Background technique [0002] With the deepening of exploration and development of oil and gas fields, more and more attention has been paid to the research and evaluation of unconventional reservoirs such as igneous rocks, metamorphic rocks, and shale gas. One of the problems is that the element capture spectrum logging can obtain the element content by recording the captured gamma spectrum, and obtain the standard mineral according to the conversion relationship between the element content and mineral content, so as to identify and classify complex lithology. In complex lithology and shale It plays an important role in the evaluation of unconventional reservoirs such as natural gas. [0003] At present, the logging methods th...

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Problems solved by technology

[0004] Existing element spectrum logging tools mainly use Am-Be neutron sources, which are likely to cause radioactive damage to people and the environment; due to the low average energy of neutrons emitted by Am-Be neutron sources, the non-elastic gamma spectrum is not obvious, and cannot Accurately determine the content of C, Mg and other elements, but cannot determine the content of organic carbon and identify dolomite

Although the FLS uses a pulsed neutron source, it still uses a BGO single detector, which cannot determine parameters such as porosity; the gamma-ray energy resolution of the BGO detector used is low, and the gamma-ray interference is serious

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