高温高压酸性天然气中饱和含水量理论模型研究

发布时间：2018-01-10 13:14

  本文关键词：高温高压酸性天然气中饱和含水量理论模型研究　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 酸性天然气 饱和含水量 支持向量机 BP神经网络 灰色关联分析 遗传算法 异常点检测

【摘要】：在常规和高含H_2S、CO_2酸性天然气藏开采、集输、加工过程中,防堵、防腐和防水合物生成是贯穿整个天然气藏开采工作的重中之重。而这三类问题的产生,都与天然气饱和含水量有密切联系。天然气饱和含水量是天然气生产、加工和运输过程中最重要的参数之一,直接影响着天然气加工工艺设计及天然气开采、集输与处理等过程中工艺计算的准确性。本文将遗传算法(GR)、灰色关联分析、异常点检测等方法与支持向量机(SVM)、BP神经网络(BP-ANN)相结合,采用GA-SVM和BP-ANN模型对常规天然气,纯H_2S和纯CO_2气体,H_2S、CO_2混合气体及高含H_2S、CO_2酸性天然气等多个体系饱和含水量进行了系统的研究。模型主要以体系的温度和压力,CH4、H_2S、CO_2摩尔分数及天然气相对密度等为输入变量,饱和含水量为输出变量。模型所有数据的适用范围为:温度 0～325℃,压力 0～150MPa,H_2S 摩尔分数 0～100%,CO_2 摩尔分数0～100%。在GA-SVM和BP-ANN模型计算过程中,在316个文献实验数据点训练的基础上,进行了 83个数据点的多体系饱和含水量预测。计算结果表明:采用GA-SVM模型计算常规天然气,纯H_2S和纯CO_2气体及高含H_2S、CO_2酸性天然气饱和含水量的绝对平均偏差(AAD)分别为 1.38%,2.6%,4.3%和 6.28%;采用 BP-ANN 模型计算 H_2S、CO_2混合气体饱和含水量的绝对平均偏差为11.93%。通过实例计算及与已用的ANN模型,半经验模型,Bukacek模型,Awad模型,AQUAlibrium软件,简化热力学+Bahadori模型,简化热力学+Mohammadi模型,Bahadori+Khaled模型,王俊奇模型,修正热力学模型等计算结果进行对比表明:GA-SVM和BP-ANN模型预测精度高、泛化能力强、稳定性好,更能满足工程精度要求。最终,基于杠杆方法开展了所有数据的异常点检测。其检测结果表明:GA-SVM和BP-ANN新模型所有检测数据点中出现异常点的个数最少,模型的稳定性最强,从而为常规天然气,纯H_2S和纯CO_2气体,H_2S、CO_2混合气体及高含H_2S、CO酸性天然气等多个体系饱和含水量准确计算提供了一种新的综合分析方法。
[Abstract]:Prevention of plugging in conventional and high H2S- CO2 acid natural gas reservoirs for recovery, gathering, transportation and processing. Anticorrosion and hydrate prevention are the most important problems in the whole exploitation of natural gas reservoir, and these three problems are closely related to the saturated water content of natural gas, which is the production of natural gas. One of the most important parameters in the process of processing and transportation has a direct impact on the accuracy of process calculation in the process of natural gas processing design, natural gas extraction, gathering, transportation and treatment. In this paper, genetic algorithm (GA) is introduced. The methods of grey correlation analysis and anomaly detection are combined with support vector machine (SVM) and BP neural network (BP-ANN). GA-SVM and BP-ANN models are used for conventional natural gas. Pure H2s and pure CO_2 gases H2SCOS2 mixed gas and high H2S content. The saturated water content of several systems, such as CO_2 acid natural gas, was systematically studied. The model was mainly based on the temperature and pressure of the system. The molar fraction of CO_2 and the relative density of natural gas are input variables, and the saturated water content is the output variable. The applicable range of all data of the model is: temperature 0 ~ 325 鈩，

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