Institut Francais Du Pe'trole

Eric Heintze

Emmanuel Duret

Isabelle Faille

Isabelle Rey-Fabret

Véronique Henriot

Véronique Lachet

V&eacute;ronique Henriot

Veronique Henriot

Claude Leibovici

Pierre Duchet-Suchaux

An automatic pipe gridding method allowing implementation of codes for modelling fluids carried by pipes is disclosed which has for example an application for oil pipes. The method comprises, considering a minimum and a maximum grid cell size, subdividing the pipe into sections including bends, positioning cells of minimum size on either side of each bend, positioning large cells whose size is at most equal to the maximum size in the central portion of each section, and distributing cells of increasing or decreasing size on the intermediate portions of each section between each minimum-size cell and the central portion. The method preferably comprises a prior stage of simplification of the pipe topography by means of weight or frequency spectrum analysis, so as to reduce the total number of cells without affecting the representativeness of the flow model obtained with the grid pattern.

Automatic pipe gridding method allowing implementation or flow modelling codes

The invention is a method and system for real-time estimation of the flow mode, at all points of a pipe whose structure is defined by a certain number of structure parameters, of a multiphase fluid stream defined by several physical quantities providing simplified implementation of hydrodynamic modules that can be integrated in modelling tools. A non-linear neural network is formed with an input layer having as many inputs as there are structure parameters and physical quantities, an output layer with as many outputs as there are quantities necessary for estimation of the flow mode and at least one intermediate layer. A learning base is created with predetermined tables connecting various values obtained for the output data to the corresponding values of the input data, with iterative determination of the weighting factors of the activation function allowing to properly connect the values in the input and output data tables. In order to avoid singularities of the network output data likely to distort the determination of the weighting factors, a sorting procedure is used to eliminate non-pertinent data. The main advantages of the method are: modelling simplification and time saving.

Method and system intended for real-time estimation of the flow mode of a multiphase fluid stream at all points of a pipe

Method intended for continuous detection and control of hydrate formation at any point of a pipe carrying multiphase petroleum fluids. The method uses a compositional code allowing to simulate the circulation modes and conditions at any point of the pipe, considering that the fluid mixture is substantially continuously at equilibrium, that the composition of the multiphase mixture is variable all along the pipe and that the mass of each constituent of the mixture is globally defined by a mass conservation equation regardless of its phase state. The thermodynamic hydrate formation conditions are detected after a particular stage of grouping the petroleum fluids into pseudo-components so as to isolate the hydrate forming components, with definition for each one of a mass fraction and of a certain number of characteristic physical quantities, and the data relative to these particular fractions are applied to the modules so as to determine at any point the hydrate dissociation temperature (Td). A control device (C) can also be used to compare the temperature of the petroleum fluids with this dissociation temperature (Td), and measures designed to fight hydrate formation can be applied under the control of this control device (C). The method can be applied for deep-sea petroleum production for example.

Method for detecting and controlling hydrate formation at any point of a pipe carrying multiphase petroleum fluids

A method for forming a module (hydrodynamic or thermodynamic for example) intended for real-time simulation of the flow mode, at any point of a pipe, of a multiphase fluid stream comprising at least a liquid phase and at least a gas phase. The method comprises using a modelling system based on non-linear neural networks each having inputs for structure parameters and physical quantities, outputs where quantities necessary for estimation of the flow mode are available, and at least one intermediate layer. The neural networks are determined iteratively to adjust to the values of a learning base with predetermined tables connecting various values obtained for the output data to the corresponding values of the input data. A learning base suited to the imposed operating conditions is used and optimized neural networks best adjusted to the imposed operating conditions are generated.

Method for forming an optimized neural network module intended to simulate the flow mode of a multiphase fluid stream

The invention provides a model representative of steady and transient flows, in a pipe, of a mixture of multiphase fluids, which takes account a set of variables defining the properties of the fluids and of the flow modes having separate phases which are dispersed and intermittent, and the dimensions and slope of the pipes. The modeled quantities characterizing the flow are determined by solving a set of transport equations, an equation of mass conservation per constituent and an equation of momentum of the mixture, and by using a hydrodynamic model and a hydrodynamic model of the fluids. The models are formed by considering the mixture to be substantially at equilibrium at all times and that the constituents of the multiphase mixture are variable all along the pipe. The method can be applied to hydrocarbon transportation network study and to determination of characteristics of flow of the multiphase mixture in the pipe.

Method for constituting a model representative of multiphase flows in

The invention relates to a method for forming a simulation model of two-phase flow in pipelines and notably in pipelines carrying hydrocarbons. The method comprises solving mass conservation equations for each of the phases and an equation of momentum conservation of the flow, while complying with closing relations. An explicit solution is used on slow waves (corresponding to the propagation of a gas phase) and fast waves (corresponding to the propagation of the pressure waves), which has the advantage of allowing time interval control by the slow waves while keeping the accuracy on these waves inherent in an explicit scheme. The method thus combines model execution speed and accuracy of results. The method can be applied to the design of a hydrocarbon transportation network.

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Meudon, France

Eric Heintze