«Equipment and technologies for oil and gas complex»

Algorithmization of calculating the multiphase flow movement in the collection network for solving integrated modeling problems

UDC: 622.276
DOI: 10.33285/1999-6934-2023-6(138)-59-64

Authors:

¹ National University of Oil and Gas "Gubkin University", Moscow, Russia
² LUKOIL-Engineering, Moscow, Russia

Keywords: multiphase flow, collection system, surface network, integrated modeling, nodal analysis, software algorithm, iterative calculation, VLP, IPR

Annotation:

Calculation of the surface collection network is a non-trivial task during integrated modeling of oil and gas fields. The complexity of the calculations is caused by the variability of the fluid physical-chemical properties during transportation from wells bottom to the separator due to pressure and temperature changes. The article presents an algorithm that demonstrates the relationship of the mathematical apparatus for describing the processes of multiphase flow movement in a collection system. The algorithm allows performing iterative calculations applying Newton's method when varying well flow rates using the Jacobian matrix to linearize the calculation. A system of nonlinear equations solution comes down to pressure losses calculation by multiphase flow correlations, taking into account heat transfer, as well as nodal analysis solution when constructing an inflow curve. The article details Beggs&Brill correlation efflux curve (VLP) modeling using a simplified temperature model based on the overall heat transfer coefficient. The calculation of the friction coefficient is represented by the empirical Colebrook – White equation. The inflow curve, which characterizes the dependence of bottomhole pressure on well flow rate, is constructed using the Vogel equation adjusted for water cut. The fluid physical-chemical properties are described by the Black Oil model using correlation dependencies. Standing correlation is used to calculate saturation pressure, gas content, volumetric coefficient and oil viscosity. The correctness of the developed algorithm was assessed by testing two collection models using 11 calculation cases: a tree collection system and a closed one. A comparison of the calculated indicators with the results obtained in commercial simulators is provided. The reasons for possible discrepancies are assessed.

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