A non-inertial two-phase model of wax transport in a pipeline during pigging operations

Abstract

The removal of wax deposit from pipelines is commonly accomplished using pigs. In order to avoid the formation of wax plugs in pipes, bypass pigs, which create a liquid jet to disperse the scraped deposit, are employed. Despite many One-Dimensional (1D) models have been developed to predict the dynamics of bypass pigs, the details of the interaction between the liquid jet and the debris have not been investigated numerically yet. In this work the fluid dynamics of a wax-in-oil slurry in front of a moving bypass pig is studied by means of three-dimensional (3D) numerical simulations. A mathematical model which couples the pig and the wax-in-oil slurry dynamics, solved in the pig frame of reference, has been developed. The results show that the pig quickly reaches an equilibrium velocity, and the pig acceleration is proportional to the square of the mixture relative velocity. Comparing the present with previous sealing-pig results it appears that the bypass flow is more effective in deterring plug formation. Moreover, the 3D fields have the advantage of showing the wax distribution in each pipe section whereas the 1D model cannot distinguish between deposited and suspended wax.

Numerical Simulation of Hole Cleaning of a Horizontal Wellbore Model with Breakout Enlargement Section

“…Horizontal wells are easily affected by the gravitational effect of cutting and casing eccentricity, forming cuttings beds and causing high friction and torque of the drill pipe, with serious effects on hole cleaning efficiency [9][10][11][12]. When the horizontal wellbore is not sufficiently cleaned, the annular pressure increases significantly, which can easily lead to formation leaks, blowouts, and other accidents.…”