No abstract

In oil and gas production, solid particles can be entrained in the produced fluid. While sand is widely considered as the most common source of solid particles, calcium carbonate particles can also be entrained in the flow, especially in carbonate formations. These entrained solid particlescan erode steel pipe surfaces and protective corrosion products, such as iron carbonate (FeCO3) scale that forms on the steel surface as a result ofthe CO2 corrosion process. The removal of protective layers can lead to high corrosion rates. Extensive research has previously been conducted to study the effect of sand erosion on removing protective iron carbonate scales. However, little is known about the erosion resistance of iron carbonate scale for calcium carbonate particles. The goal of the research presented in this paper is to study the erosion resistance of iron carbonate scale when eroded by calcium carbonate particles, and compare this erosion behavior with scale eroded by sand. Additionally, this research reports data and modeling that describe under what conditions removal of iron carbonate scale and the resulting erosion-corrosion are anticipated by solid particles such as sand or calcium carbonate. Results, for the conditions considered in this study, show that CaCO3 particles can cause considerable damage to iron carbonate scale leading to severe corrosion. For these conditions, sand was found to be more erosive than CaCO3 particles. Results from the erosion model developed in this study showed good agreement with current and previous experimental data.

Effects of particle velocity, impact angle and particle size and shape on erosive behavior of Fiberglass Reinforced Plastic (FRP) and Polyethylene were investigated. Experiments were carried out with two particle velocities (18 and 32 m/s) and different impact angles ranging from 15 to 90 degrees. Silica sands with sizes of 75, 150 and 300 μm was utilized as erodent to study effects of sand shape and size. Results revealed erosion data of FRP and Polyethylene are similar to ductile materials as they display maximum erosion ratio at 30 degrees impact angle. However, Polyethylene showed an interesting behavior at 75 and 90 degrees; sand particles were embedded into the specimen and mass gain of specimen has been observed. 3D scan of wear patterns of specimens was obtained by 3D profilometer in order to evaluate the erosion depth and wear pattern of the surface.

Cavitation and choked flow conditions can occur when high-pressure drops are encounters in various types of valves, which prevent them to work properly and may cause severe erosion damage inside the valves that decrease their lifetime. Prediction of these critical conditions leads to the prevention of cavitation and helps to improve the design of the valve geometries to delay and prevent these critical flow conditions. Computational Fluid Dynamics (CFD) is a powerful tool that can be used to simulate flow conditions and to predict the incipient of cavitation and consequently choked flow in the valve through solving the Time Averaged Navier-Stokes equations under multi-phase flow conditions. Therefore, CFD simulations have been conducted for two types of excess flow valves. The mixture multi-phase flow solution method along with the k-ε realizable turbulence model has been utilized to solve the behavior of vapor flow inside the valve and simulate the cavitation phenomenon. It was observed that CFD could capture the inception of cavitation and choked flow inside the valve successfully. Simulated CFD results also indicated a good agreement with experimental data that were obtained under lower pressure drop conditions. The effects of various inlet pressures on the cavitation intensity have been also studied, and it was concluded that at higher inlet pressure with constant pressure outlet the cavitation strength is greater than lower inlet pressures.