Investigation of a Choke Valve Erosion in the Gas Lifted Systems

Abstract

Erosion is one of the common causes of failure in subsea operations. However, erosion of subsea systems has many patterns, trends and uncertainties. This has led to production losses due to the failure of prediction of the useful life of the components in the gas lifted system. This work experimentally studied the effect of flow rate and pressure variations on the erosion of the choke valve in the gas lifted system by using flow streams containing either liquid or liquid injected with gas. Cameras installed on both sides of the erosion box captured images of the probe after every one second, followed by image analysis using the RGB model in MATLAB. Erosion consistently occurred after 120 minutes, followed by a significant reduction of the probe area with time. Severe erosion was observed on the liquid streams with no injected gas. Differential pressure in the erosion box varied with higher flow rates. High volumetric flow rates are found to increase erosion of the choke valve. Adding sand in the rig is crucial on establishing the trends of the erosion of the choke valve because of eminent production of sand in the matured gas wells.