Multi-parameter logging method while drilling based on controllable neutron source

Abstract

The invention relates to a multi-parameter logging method while drilling based on a controllable neutron source, which includes the steps of utilizing a multi-detector measuring system consisting of the D-T controllable neutron source, two thermal neutrons and two gamma detectors, sufficiently utilizing fast neutrons transmitted by the controllable neutron source to militate with atomic nucleuses of formation elements by means of special pulse and measuring timing sequence design, recording gamma energy spectrums, gamma time spectrums and thermal neutron time spectrums at different positions, and performing simultaneous measurement of multiple parameters such as formation density, formation porosity, formation fluid saturation, formation element content and the like with a nuclear logging instrument in a drilling process by means of different spectral resolution and data processing, so that valuation on formation lithology, formation porosity and formation fluid saturation while drilling are realized, the same parameter of the formation porosity and the formation fluid saturation can be measured by various methods, logging interpretation ambiguity is decreased, and accuracy and reliability of logging data interpretation are enhanced.

Description

technical field [0001] The invention relates to the technical field of logging-while-drilling systems, in particular to a multi-parameter logging-while-drilling method based on a controllable neutron source. Background technique [0002] In recent years, with the increasing number of highly deviated wells and horizontal wells, logging while drilling technology has developed rapidly. In the process of logging while drilling, the formation has just been drilled. At this time, the formation is basically not invaded by mud or the invasion is relatively shallow, and the measurement results can more truly reflect the formation parameters. If multiple formation parameters can be measured simultaneously during drilling, the well logging data can be used to accurately evaluate the formation and reduce the ambiguity of well logging interpretation. [0003] The controllable neutron source is playing an increasingly important role in logging while drilling. The high-energy and high-yie...

AI Technical Summary

Problems solved by technology

However, the current logging-while-drilling tool with a controllable neutron source is limited to compensated neutron porosity measurement, the measurement parameters are single, and it cannot make full use of the nuclear reaction of fast neutrons emitted by the controllable neutron source interacting with the formation. Obtain as many formation parameter measurements as possible when the formation is just drilled; even with a simple combination of multiple instruments, multi-parameter measurement can be achieved, but the measurement time and location are different, and the measurement results are not comparable

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