Study On The High-resolution Method Of Processing On Multi-detector Natural Gamma Log Data

The basic principle of natural gamma logging is to use the differences of natural radioactive elements in different lithologies, by direct measurement of the radioactive probe(NaI crystal) natural gamma ray intensity variations in the well shaft around the borehole,thereby conduct clay content calculation, stratigraphic correlation, stratigraphic section division, and tracking perforating and explore radioactive minerals. Due to the natural radioactivity by strata conditions, often can not meet the natural gamma detector count rate requirements, in order to overcome the factors that affect the accuracy of radioactivity curve statistical fluctuation effects, etc., to ensure adequate detection accuracy, the current domestic and foreign natural gamma detector often used as a large single crystal NaI probe, the vertical resolution of its natural gamma logs up to only about 0.6m, and now most of the oil fields to exploration late development, has been unable to meet the exploration and development of thin and poor reservoir It needs. Find a gamma curve that is able to overcome the natural radioactivity statistical fluctuation error, while improving data processing method of natural gamma curve of vertical resolution, a thin layer of oil mining exploration potential, has important practical significance.In this paper, the theoretical basis of natural gamma nuclear physics, as well as multi-probe gamma ray logging tool design principle, the establishment of natural gamma detector volume model, the advantages of multi-probe gamma ray verification instrument compared to the traditional single-probe gamma ray instrument. Using high-resolution processing method for logging data preprocessing, while the multi-probe gamma ray log data depth correction to further enhance the effect of study of this article in the actual application.Adaptive filter theory, the establishment of multi-variable nonlinear adaptive filtering method,obtaining the right to adjust the gain coefficient, a number of synthetic natural gamma curve.By logging data processing, and micro-gradient, microelectrodes and other logging data as well as conventional single probe gamma ray log comparison, the resolution improved significantly, the response to a thin layer of clear contrast clay content through core analysis for application the effect of certification, the average error of less than 4%, with good results.