多探头高分辨率自然伽马测井数据处理方法研究

发布时间：2018-05-12 01:01

本文选题：高分辨率 + 自然伽马　；参考：《东北石油大学》2015年硕士论文

【摘要】：自然伽马测井的基本原理是利用不同岩性中天然放射性元素含量上的差异,通过放射性探头——NaI晶体直接测量井轴上的自然伽马射线强度在井眼周围的变化,借此进行泥质含量计算、地层对比、地层剖面划分,以及追踪射孔和探寻放射性矿物等。自然伽马测井曲线作为常规解释中最常用的岩性曲线,而薄互层中自然伽马测井曲线受到上下围岩的影响不能准确反映地层的真实情况,所以准确识别这样的储层,提高储层参数的计算精度,尽量使自然伽马曲线的测值接近于真值是十分必要的。由于自然放射性强度受地层条件影响,通常不能满足自然伽马探测器的计数率要求,为了克服放射性统计涨落效应等影响曲线精度的因素,保证足够的探测精度,当前国内外自然伽马探测器常选用较大的单一NaI晶体作为探头,其自然伽马测井曲线的纵向分辨率最高仅达到0.6m左右,而今大部分油田已到勘探开发后期,已无法满足对薄差储层勘探开发的需要。找到一种即能克服自然伽马曲线放射性统计涨落误差,同时可以提高自然伽马曲线纵向分辨率的数据处理方法,为油田挖掘薄层开采潜力,有着重要的实际意义。本文结合自然伽马核物理理论基础,以及多探头自然伽马测井仪器设计原理,建立自然伽马探测器体积模型,验证多探头自然伽马仪器相较于传统单一探头自然伽马仪器的优点。利用高分辨率处理方法对测井资料进行预处理,同时对多探头自然伽马测井数据进行深度校正,进一步提高本文章的研究在实际应用上的效果。以自适应滤波理论为基础,确立多变量非线性自适应滤波方法,求取增益调整权系数,合成多条自然伽马曲线。通过处理测井资料,与微梯度、微电极等测井资料以及常规单探头自然伽马测井曲线进行对比,分辨率明显提高,对薄层的响应明显,通过岩心分析泥质含量对比进行应用效果验证,平均误差小于4%,应用效果良好。
[Abstract]:The basic principle of natural gamma logging is to make use of the difference of natural radioactive elements in different lithology and directly measure the change of natural gamma ray intensity around the borehole through the radioactive probe-Nai crystal. It is used to calculate muddy content, stratigraphic correlation, stratigraphic profile division, and to trace perforation and explore radioactive minerals. The natural gamma log curve is the most commonly used lithologic curve in conventional interpretation, but the natural gamma logging curve in thin interbed can not accurately reflect the real situation of the formation by the influence of the upper and lower rock, so the reservoir can be accurately identified. It is necessary to improve the calculation accuracy of reservoir parameters and make the measured value of natural gamma curve approach the true value as far as possible. Because the natural radioactivity intensity is affected by the formation condition, it usually can not meet the requirement of the natural gamma detector's counting rate. In order to overcome the factors that affect the precision of the curve, such as the effect of radioactive statistical fluctuation, we can ensure the sufficient detection precision. At present, the natural gamma detectors at home and abroad often choose a large single NaI crystal as the probe. The vertical resolution of the natural gamma log curve is only about 0.6 m. Now most oilfields have reached the late stage of exploration and development. Can not meet the thin reservoir exploration and development needs. It is of great practical significance to find a data processing method that can overcome the statistical fluctuation error of radioactivity of natural gamma curve and improve the vertical resolution of natural gamma curve. It is of great practical significance to exploit the potential of thin layer exploitation for oil field. Based on the theory of natural gamma nuclear physics and the design principle of multi-probe natural gamma logging tool, the volume model of natural gamma detector is established in this paper. Verify the advantages of multi-probe natural gamma instrument compared with traditional single-probe natural gamma instrument. The high resolution processing method is used to preprocess the logging data and the depth correction of the multi-probe natural gamma logging data is carried out to further improve the effect of the research in the practical application of this paper. Based on the theory of adaptive filtering, the multivariable nonlinear adaptive filtering method is established, the gain adjustment weight coefficient is obtained, and many natural gamma curves are synthesized. By processing logging data and comparing them with microgradient, microelectrode and conventional single probe natural gamma logging curves, the resolution is improved obviously and the response to thin layer is obvious. The average error is less than 4 and the application effect is good.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.817

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