.500 Kbps, Telemetry Natural Gamma Logging Tool Developed

A new type of natural Gamma-ray logging tool is developed in order to realize natural Gamma-ray logging compatible with SOOkbps telemetry system.at nrst,the basic conception, methods,conditions,latest developments, resear::ldrr and developing countermeasures should be taken are briefly introduced. The basic principle of natural Gamma-ray log is stated,the developing background, developing ways and developing situation of natural Gamma-ray tools are introduced.the researching task of the paper is presented through analyzing the using situation and questions exsisted in inner natural Gamma-ray tools, the researching work is started from three aspects, they are logging tool development, reliability design and reliability assuring methods,and the data processing methods, in the course of logging tool development, instrument indexes are presented based on the compatible property of SOOkbps telemetry system and environmental property, the analog measuring chanel and the interface circuit which realizing the compatible performance are designed according to the instrument mdexes.the detecto* design.the plateau property testing of the detector and the analysis of it's affecting factors are stated,the measuring property of the tool is discused,a new type of single chip microcomputer is selected when designing the interface circuit, and the laboratory experiments has fulfiled conmunieating standard signals between the interface circuit ,the universal interface unit of SOOkbps telemetry system and also 500kbps telemetry system . When dicussing reliability design and reliahbAiiy ensuring methods, a new reliability calculating model of petroleum logging tools is presented, reliability assurimg technologies should be taken in petroleum logging tools and their using approaches are presented and stated from electricity design and mechanical design,reliability system model of petroleum logging tool is set up according to the latest reliability theory,reliability indexes of petroleum logging tool and their acquiring ways are discussed,the reconmended reliability indexes (MWTURE, NOLWNM, MTBF, MTTF) of petroleum logging tool are presented:the mean working time under rated error(MWTURE) of the new tool is obtained through experiments.when studying data processing methods,the property of Gamma-ray signal is stated and the type of it's measuring error is examined using statistical method,the basic theory of digital filtering and the basic situation of digital filtering methods are introduced and analyzed, the factors affecting digital filtering effect to Gamma-ray signal and the effect of digital filtering to logging curve are analyzed, the evaluting criteria (RVI, RMSE, SFI) of digital filtering effect are set up from two aspects,named as real value acquiring of steady section and the formation boundary checking and processing ,the related filtering methods and examining methods are given out.the design methods of digital filter used to process Gamma-ray signal are discussed,the mixed filtering scheme of natural Gamma-ray log is presented,the realization ways are discussed.the selective filtering system and it's realization flow are given out through quantitive reseaching to part of digital filters,three new filtering sheme will be used to process Gamma-ray signal in ERA2000 logging system. At last ,the researching work is summarized, and the key orientation of future researching work is forecasted.