Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Analysis and development of a multiphase flow model for choke valves
Submission Author:
Matheus Henrique Pestana de Carvalho , SP
Co-Authors:
Matheus Henrique Pestana de Carvalho, Jorge Luis Baliño
Presenter: Matheus Henrique Pestana de Carvalho
doi://10.26678/ABCM.COBEM2023.COB2023-0140
Abstract
Choke valves are designed to generate flow restriction at the point where they are installed. Choke valves are commonly used in oil wells as flow or upstream pressure control equipment, as well as to stabilize production. Additionally, choke valves can be used for estimating the flow rate of oil, water, and gas using mathematical models. However, most existing models require an adjustment parameter, known as the discharge coefficient, which is the ratio between the actual mass flow rate and the flow rate predicted by the model. The discharge coefficients reported in the literature have the disadvantage of resulting in constant values and being obtained based on the experimental data to be correlated. One difficulty in modeling flow through choke valves is predicting the critical flow condition, where the sonic velocity is locally reached at the restriction. Additionally, slip between phases is also directly responsible for a better model precision. The geometric complexity of flow through a choke valve is addressed through mathematical relationships defined in standards. For single-phase flow conditions, the IEC60534-2-3 standard provides the characterization of choke valves, performed by laboratory testing to obtain flow coefficient curves. These tests are conduct with single-phase flow of water (incompressible) or air (compressible), according to a standardized specific procedure. This study aims to present a methodology for estimating multiphase flow rate through choke valves using the characterization curves obtained for the single-phase flow condition to calculate the discharge coefficient applicable to multiphase flow. As an intermediate step, an equivalence between the approach of flow coefficient and discharge coefficient for single-phase flows was derived. For this purpose, a model was defined based on an isentropic evolution in the convergent region and a Borda-Carnot flow in the divergent region. The proposed model will be validated with 67 experimental data points corresponding to an orifice-type choke with a restriction diameter of 11mm for multiphase flow (oil, water, and gas). With the proposed model, it is expected to estimate the multiphase flow rate by only knowing the concentration and characteristic curve of the valve, without the need for adjusting data parameters.
Keywords
multiphase flow, CHOKE VALVES, petroleum production, Discharge Coefficient, flow coefficient
