Experimental investigation on the water hammer characteristic of stalling fluid in eccentric casing-tubing annulus

Abstract

This study aims to analyze the water hammer characteristics of water hammer on tubing offset center in oil project for providing reference for water injection and well washing. An analysis is conducted by utilizing a test apparatus, particle image velocimetry, and a transient pressure measurement system. The characteristic of dynamic fluid loss is investigated in eccentric annulus flow channel and tubing and in flow line in terms of velocity, vorticity, and pressure field. Results show that water hammer occurs, and the pressure of oil casing annulus increases at the inside and outside walls with the increase in eccentricity. The water hammer pressure forms double imbalance in the internal and external walls of eccentric annulus tubing. With the increase in eccentricity, flow velocity decreases in the small flow passage, and flow velocity attenuation is fast at oil casing annulus.