论文部分内容阅读
为研究D-D源密度测量过程中俘获γ计数对密度测量的影响,本文首先分析D-D源密度测量的原理,其次研究D-D源与地层反应产生的γ射线类型,并采用蒙特卡罗模拟方法对比分析了D-D源和D-T源密度测量过程中次生γ强度高低。结果表明,D-D源密度测量过程中次生γ以俘获γ为主;尽管D-D源的中子产额远低于D-T源,但在源距大于50 cm后低孔隙地层中D-D源俘获γ计数高于D-T源非弹γ计数;此外,高孔隙地层中D-D源俘获γ计数也可以通过调整源距大小满足密度测量的要求。因此,使用D-D源测量的次生γ计数能够满足密度测量的统计精度要求。
In order to study the influence of capture gamma counting on density measurement during the measurement of DD source density, this paper firstly analyzes the principle of DD source density measurement, and secondly studies the type of gamma ray produced by DD source and formation reaction, and uses Monte Carlo simulation method to compare and analyze Secondary gamma intensity during DD source and DT source densitometry. The results showed that secondary gamma was the predominant γ in the source density measurement of DD source. Although the neutron yield of DD source was much lower than that of DT source, the DD source capture γ count was high in low porosity reservoirs with source spacing greater than 50 cm At the DT source, the non-bomb gamma counts; in addition, the DD source capture γ counts in high-porosity formations can also meet the density measurement requirements by adjusting the source separation size. Therefore, secondary gamma counts using D-D source measurements meet the statistical accuracy requirements of density measurements.