ENSURING THE OPTIMAL MODE OF LIQUID REMOVAL FROM THE GAS GATHERING NETWORK OF FIELDS UNDER CONDITIONS OF FORMATION PRESSURE DROP

Relevance One of the main problems of gas fields operation in the final stage is high water cut of produced gas. This leads to the appearance of water accumulations in low sections of gas gathering network plumes, complicating their operation due to the formation of ice and hydrate plugs. This problem is especially acute in winter due to extremely low temperatures in the Far North, where most fields are located. This circumstance leads to the need to somehow remove accumulations of liquid. Despite the fact that this problem is common to all fields, there is no single approved methodology, so different methods are used. The most widespread is the method of periodic blowing of wells into the atmosphere, which leads to its contamination and loss of marketable product. It is most expedient to carry out removal of liquid by the flow of gas itself, but for this purpose it should have a velocity not lower than some certain value. Aim of research The main aim of the research is to study the factors influencing the gas velocity in the plume and to obtain a mathematical model for determining its critical value, which ensures removal from the plume by the gas flow. Research methods The π-theorem was used to obtain the model, and the model was studied in the COMSOL Multiphysics program on the basis of experimental data obtained at the Urengoy oil and gas condensate field. Results In spite of a large number of methods of water removal from gas gathering network plumes, none of them is without disadvantages. From the point of view of providing maximum energy efficiency of gas field operation the most expedient is the removal of liquid by the gas flow itself. For this purpose, it is necessary to ensure a certain velocity, the so-called critical velocity. Since liquid accumulations are most often formed in the depressed sections of the plume, the pipeline diameter, the angle of inclination of the depressed section of the pipeline, liquid and gas densities, liquid viscosity, and the volume of liquid accumulation were chosen as parameters affecting the value of the critical velocity. As a result of this research, the criterion equation for determining the critical gas flow velocity, which is able to ensure the removal of water from the U-shaped elbow, was obtained. Modeling of the process of carrying out of liquid accumulation by gas flow was carried out in COMSOL Multiphysics program. Verification of the obtained model was performed on the experimental data obtained at the Urengoy oil-gas condensate field. Practical significance of the obtained results lies in the possibility of building an automatic control system of a gas well cluster on the basis of this model.