自然伽马能谱录井数据的影响因素

Influence factors of natural gamma energy spectrum logging data

自然伽马能谱录井技术在岩性识别、地层划分、储层识别等方面发挥了重要的作用,然而操作人员的操作差异、钻进过程中钻井取心以及井漏等钻井复杂导致的岩屑量不足均会造成测量数据出现偏差。通过开展自然伽马能谱数据影响因素实验,分析了检测时长、岩屑样品充填方式、岩屑颗粒粗细、样品干湿程度、样品质量对测量数据的影响程度,认为样品质量是影响自然伽马能谱录井最重要的因素,其辐射伽马总剂量率与岩屑质量呈线性关系。基于实验结果,形成了一套适用于现场的规范性操作,在取样条件受限导致样品质量不足时,利用辐射伽马总剂量率与样品质量线性关系可进行参数校正。

Natural gamma energy spectrum logging technology plays an important role in lithology identification,stratigraphic division,reservoir identification and other aspects.However,operational differences among operators,drilling coring during the drilling process and insufficient cuttings caused by drilling complexities such as lost circulation can all lead to measurement data deviations.By conducting experiments on influence factors of natural gamma energy spectrum data,the influence degree of the sensing time,cuttings sample filling pattern,the coarse or fine of the cuttings grains,the dry or wet degree of the samples,and sample mass on measurement data were analyzed.It is considered that sample mass is the most important factor influencing natural gamma energy spectrum logging,and the total dose rate of its radiation has a linear relationship with cuttings mass.Based on the experimental conclusions,a set of standardized operations suitable for the field has been formed.When the sampling conditions are limited and the sample mass is insufficient,parameter correction can be performed using the linear relationship between the total dose rate of the radiation gamma and the sample mass.