准确预测天然气井产量对开发决策优化具有重要意义.现有预测方法大多侧重整体建模,难以适应天然气井“增产—稳产—减产”的生命周期演变特征;且现有数据驱动模型大多忽略储层渗流场随时间演化的物理规律,难以准确反映物性的时序变化....准确预测天然气井产量对开发决策优化具有重要意义.现有预测方法大多侧重整体建模,难以适应天然气井“增产—稳产—减产”的生命周期演变特征;且现有数据驱动模型大多忽略储层渗流场随时间演化的物理规律,难以准确反映物性的时序变化.本文从生命周期视角出发,提出气井产量预测方法(Full life cycle gas production forecast model,FGPM).首先,通过断点检测算法划分气井生命周期,结合产量相对波动率判别气井生产阶段;随后,构建基于编码-解码结构的预测模型,针对生产阶段进行特征匹配训练,并集成为全生命周期模型;最后,从模型超参数优化和渗流规律融合两方面展开模型优化.实验证明:(1)全生命周期模型相较于单一周期模型预测精度更高.与LSTM、GRU、TCN和TimeMixer等方法对比,FGPM的预测精度分别提升了28.47%、26.55%、29.63%和41.20%.(2)面向FGPM设计的优化措施对模型性能提升起正向作用:(a)优化超参数后的模型,其百分比误差(MAPE)、平均绝对误差(MAE)和均方根误差(RMSE)分别降低了9.9%、16.2%和19.4%;(b)融合渗流规律约束的FGPM,其MAPE仅为4.874479%,模型性能得到进一步提升.展开更多
Tow-phase flow mixed variational formulations of evolution filtration problems with seawater intrusion are analyzed. A dual mixed fractional flow velocity-pressure model is considered with an air-fresh water and a fre...Tow-phase flow mixed variational formulations of evolution filtration problems with seawater intrusion are analyzed. A dual mixed fractional flow velocity-pressure model is considered with an air-fresh water and a fresh water-seawater characterization. For analysis and computational purposes, spatial decompositions based on nonoverlapping multidomains, above and below the sea level, are variationally introduced with internal boundary fluxes dualized as weak transmission constraints. Further, parallel augmented and exactly penalized duality algorithms, and proximation semi-implicit time marching schemes, are established and analyzed.展开更多
将VRPTW(Vehicle Routing Problem with Time Window)通过D-W分解划分为主问题为集合划分以及子问题为带资源约束的基本最短路径问题,对子问题以割平面回调形式加入两点加强割集不等式来消除网络流中的子回路,并通过二维车流模型代替分...将VRPTW(Vehicle Routing Problem with Time Window)通过D-W分解划分为主问题为集合划分以及子问题为带资源约束的基本最短路径问题,对子问题以割平面回调形式加入两点加强割集不等式来消除网络流中的子回路,并通过二维车流模型代替分支定界过程求得精确解,对有效的提升算法求解速度提供了一种新思路。展开更多
During the past decade, increasing attention has been given to the development of meshless methods using radial basis functions for the numerical solution of Partial Differential Equations (PDEs). A level set method...During the past decade, increasing attention has been given to the development of meshless methods using radial basis functions for the numerical solution of Partial Differential Equations (PDEs). A level set method is a promising design tool for tracking, modelling and simulating the motion of free boundaries in fluid mechanics, combustion, computer animation and image processing. In the conventional level set methods, the level set equation is solved to evolve the interface using a capturing Eulerian approach. The solving procedure requires an appropriate choice of the upwind schemes, reinitialization, etc. Our goal is to include Multiquadric Radial Basis Functions (MQ RBFs) into the level set method to construct a more efficient approach and stabilize the solution process with the adaptive greedy algorithm. This paper presents an alternative approach to the conventional level set methods for solving moving-boundary problems. The solution was compared to the solution calculated by the exact explicit lime integration scheme. The examples show that MQ RBFs and adaptive greedy algorithm is a very promising calculation scheme.展开更多
摘要准确预测天然气井产量对开发决策优化具有重要意义.现有预测方法大多侧重整体建模,难以适应天然气井“增产—稳产—减产”的生命周期演变特征;且现有数据驱动模型大多忽略储层渗流场随时间演化的物理规律,难以准确反映物性的时序变化.本文从生命周期视角出发,提出气井产量预测方法(Full life cycle gas production forecast model,FGPM).首先,通过断点检测算法划分气井生命周期,结合产量相对波动率判别气井生产阶段;随后,构建基于编码-解码结构的预测模型,针对生产阶段进行特征匹配训练,并集成为全生命周期模型;最后,从模型超参数优化和渗流规律融合两方面展开模型优化.实验证明:(1)全生命周期模型相较于单一周期模型预测精度更高.与LSTM、GRU、TCN和TimeMixer等方法对比,FGPM的预测精度分别提升了28.47%、26.55%、29.63%和41.20%.(2)面向FGPM设计的优化措施对模型性能提升起正向作用:(a)优化超参数后的模型,其百分比误差(MAPE)、平均绝对误差(MAE)和均方根误差(RMSE)分别降低了9.9%、16.2%和19.4%;(b)融合渗流规律约束的FGPM,其MAPE仅为4.874479%,模型性能得到进一步提升.
摘要Tow-phase flow mixed variational formulations of evolution filtration problems with seawater intrusion are analyzed. A dual mixed fractional flow velocity-pressure model is considered with an air-fresh water and a fresh water-seawater characterization. For analysis and computational purposes, spatial decompositions based on nonoverlapping multidomains, above and below the sea level, are variationally introduced with internal boundary fluxes dualized as weak transmission constraints. Further, parallel augmented and exactly penalized duality algorithms, and proximation semi-implicit time marching schemes, are established and analyzed.
摘要将VRPTW(Vehicle Routing Problem with Time Window)通过D-W分解划分为主问题为集合划分以及子问题为带资源约束的基本最短路径问题,对子问题以割平面回调形式加入两点加强割集不等式来消除网络流中的子回路,并通过二维车流模型代替分支定界过程求得精确解,对有效的提升算法求解速度提供了一种新思路。
摘要During the past decade, increasing attention has been given to the development of meshless methods using radial basis functions for the numerical solution of Partial Differential Equations (PDEs). A level set method is a promising design tool for tracking, modelling and simulating the motion of free boundaries in fluid mechanics, combustion, computer animation and image processing. In the conventional level set methods, the level set equation is solved to evolve the interface using a capturing Eulerian approach. The solving procedure requires an appropriate choice of the upwind schemes, reinitialization, etc. Our goal is to include Multiquadric Radial Basis Functions (MQ RBFs) into the level set method to construct a more efficient approach and stabilize the solution process with the adaptive greedy algorithm. This paper presents an alternative approach to the conventional level set methods for solving moving-boundary problems. The solution was compared to the solution calculated by the exact explicit lime integration scheme. The examples show that MQ RBFs and adaptive greedy algorithm is a very promising calculation scheme.