天然气组成分析中归一化对不确定度的影响  

Influence of Normalization on Uncertainty in the Analysis of Natural Gas Composition

作　　者：蔡黎[1,2] 秦吉[1,2] 迟永杰[1,2] 唐蒙[1,2] 

机构地区：[1]中国石油西南油气田分公司天然气研究院,四川成都610213 [2]中国石油天然气质量控制与能量计量重点实验室,四川成都610213

出　　处：《石油工业技术监督》2016年第3期35-38,51,共5页Technology Supervision in Petroleum Industry

基　　金：中国石油西南油气田分公司科研项目"甲烷中多组分及发热量直接测定用气体标准物质研究"(编号:210308-05)

摘　　要：常规分析中,天然气的组成分析可能包含一步归一化过程,由分析原始数据获取天然气报出结果时,天然气的组成及其不确定度均会有所改变。通过数学推导,以归一化公式和不确定度传导率为基础,得出归一化后不确定度的评估公式,包括不同组分浓度对最终不确定度合成影像灵敏系数的计算方法,以及各组分浓度之间的相关系数处理方法。在理论推导的基础上,使用国家一级气体标准物质和国家二级气体标准物质的不确定度水平和一组天然气模拟组成进行计算,得出归一化前后天然气各组成的变化规则,用于指导天然气分析和天然气质量和计量参数计算。所获取的计算原则,可有效服务于天然气物性参数计算过程中的不确定度评估。模拟计算结果表明,在进行归一化过程后,含量最高的甲烷组分不确定度降低,而其余含量较低的组分不确定度升高。计算方法的可靠性也通过将模拟计算结果与国外同类计算方法获取结果进行比较而得到了证实。The normalization process may be contained in the conventional composition analysis of natural gas, which makes the composition of the natural gas and its uncertainty will be changed. Based on the normalized formula and the conductivity of the uncertainty, the evaluation formula of the uncertainty after the normalization is obtained by the mathematical deduction, including the calculation formula of the sensitivity coefficient of the influence of different component concentration on the final uncertainty and the processing method of the correlation coefficients among the concentration of different component. On the basis of theoretical deduction, the uncertainty degree levels of the national first-grade gas standard material, the national second-grade gas standard material and a simulated natural gas are calculated, the obtained change rules of the natural gas composition before and after the normalization can be used for guiding the analysis of natural gas and the calculation of natural gas quality and measurement parameters. The obtained calculation principle can effectively serve the evaluation of the uncertainty in the calculation of the physical parameters of the natural gas. The simulation result shows that the uncertainty of the methane with the highest content reduces and the uncertainty of the other components with the lower content increases after the normalization process. The reliability of the calculation method is verified by comparing the simulation result with the results of foreign similar calculation methods.

关 键 词：天然气组成 不确定度 归一化 标准物质 

分 类 号：TE642[石油与天然气工程—油气加工工程]