MATHEMATICAL MODEL AND DYNAMICS OF A VARIABLE THROTTLE (CHOKE VALVE) FOR X-MAS TREES

Abstract

One of the main elements of the subsea production system (SPS) is an adjustable throttle that regulates the supply of the medium (liquid) moved along the wellbore. The drive that controls the position of the shut-off-and-regulating element (SCE) of the throttle should provide increased requirements for reliability and dynamics, based on the requirements for the stability of the SCE, since the occurrence of self-oscillations can be the cause of the «start of disasters». Modern methods for the development and analysis of technical systems are based on the widespread use of mathematical models based on detailed knowledge of the processes and phenomena occurring in the systems under consideration. The use of a mathematical model is of great and urgent importance – it allows not to carry out expensive and costly physical experiments both in terms of time and money. The results obtained in the course of computer simulation can be used to optimize systems, determine operating modes and the causes of possible failures. The article presents the developed mathematical model of the adjustable choke of the X-mas tree. The mathematical model, unlike the existing ones, takes into account the non-stationary nature of the emerging hydrodynamic force on the SCE, as well as the nonlinearity of the hydraulic equipment – the actuator and control distributor. The paper presents the results of a numerical experiment and compares the proposed mathematical model with the results of a numerical experiment. The scientific novelty of the work lies in the creation of an object-oriented mathematical model of an adjustable choke of X-mas trees, taking into account the non-stationary load on the actuator, as well as the non-linearities of the control equipment.