基于SPRT的水合物生成风险评价方法——应用于火驱尾气集输管道

Risk Assessment of Hydrate Formation Based on Sequential Probability Ratio Test(SPRT):Applied to Exhaust Gas Gathering Pipeline for Fireflooding

火驱尾气集输过程中极易引发水合物冻堵事故,科学评价集输管线水合物生成风险对于保障安全生产和制定防治策略具有重要意义。采用Chen-Guo模型和SRK方程预测水合物生成条件,并编制了水合物预测软件;引入基于可靠性的水合物生成极限状态方程,参考行业报警技术规范,提出基于序贯概率比检验法(SPRT)的水合物生成风险定量评价方法和报警机制,并将其应用于尾气集输管线。采用拉丁超立方抽样法(LHS)抽取尾气管道入口随机变量样本,使用HYSYS软件完成水力热力计算,对该评价方法进行了仿真与验证。结果表明:注入入口压力、温度及流量上、下行波动后,该方法对入口参数波动的响应机制良好,评价结果符合客观规律,可为火驱尾气集输管线水合物的生成风险评价提供理论支持。

Hydrate freezing and blocking accidents are very easy to occur in the gathering and transportation process of fireflooding exhaust gas.Scientific evaluation of hydrate generation risk in fireflooding exhaust gas gathering and transportation pipelines is of great significance for ensuring safe production and formulating prevention and control strategies.Chen-Guo model and SRK equation are used to predict hydrate formation conditions,and corresponding software is developed.By introducing the reliability-based hydrate formation limit state equation and referring to the industrial alarm technical specifications,a quantitative evaluation method and alarm mechanism for hydrate formation risk based on sequential probability ratio test(SPRT)are proposed and applied to the fireflooding exhaust gas gathering pipeline.A simulation and verification of the evaluation method were carried out by sampling random variables at the pipe inlet using Latin hypercube sampling(LHS)method and carrying out hydraulic and thermal calculation using HYSYS software.The results show that the method has a good response mechanism to the fluctuations of inlet pressure,temperature and flow-rate,and the evaluation result is consistent with the objective law.The research can provide theoretical support for the risk assessment of hydrate formation in the exhaust gas gathering and transportation process for fireflooding.