Hydraulic simulations of the mud tank in drilling process based on MRF model for early kick detection

Abstract The exploitation of deep and ultra-deep oil and gas reservoirs has problems such as complex pressure system, narrow safety density window and high overflow risk. High-precision overflow monitoring methods help improve drilling efficiency. In this paper, high-frequency radar is proposed as a tool for monitoring the mud level of the tank, which is not affected by steam and can monitor the mud level with high precision. In view of the monitoring position, the numerical simulation method is used to calculate the surface of the mud tank, the actual size of the mud tank is scaled in equal proportions, the size of the agitator, the stirring speed and the inlet and outlet flow are numerically calculated, and the fluctuation characteristics and influencing factors of the dynamic mud surface are analyzed, and a reasonable monitoring position is analyzed. It is found that the mud surface in the center of the agitator decreases, the mud surface near the wall of the mud tank rises, The mud surface fluctuation is mainly affected by the stirring speed, the impeller diameter, and the mud height, and is less affected by inlet and outlet flow rates. Moreover, the lower the mud height, the greater the impact of the agitator; the higher the stirring speed the more intense the mud surface fluctuation; the larger the impeller diameter, the more intense the mud surface fluctuation. it was found that the mud surface near the wall between the two agitators is relatively stable, where is less affected by agitators and the mud height. It is recommended to place it at this position when using high-frequency radar for monitoring, aiming to improve the accuracy of-frequency radar mud surface monitoring.