When producing hydrocarbons from an oil well, managing erosion of both surface and subsurface components caused by solids in the flow stream is critical to maintaining operations integrity in both land and offshore assets. Although component lifetime prediction has advanced in the past few decades, the prediction's accuracy remains a major oil and gas industry challenge. Current computational models only provide an initial erosion rate which is usually assumed constant until equipment failure. However, observed erosional rates vary as a function of time due to the geometrical changes caused by equipment material loss, which result in variations in solid particle impingement velocity [
This paper presents an implementation of an erosion dynamics model in ANSYS FLUENT, a commercial computational fluid dynamics (CFD) software, to capture the progression of transient erosion. The model has the capability to capture the effects of surfaces receding from erosion at each time interval. By dynamically adjusting these surfaces and recalculating the local flow conditions in the area, this method can predict new erosion rates for each time interval and achieve fully coupled geometry-flow-erosion interactions.
This new erosion dynamics model was validated against experimental data from both literature and physical testing, and was determined to have accurately captured the observed erosion trends over time in terms of location and magnitude. The model was then employed to study two real world applications: 1) in evaluating the erosion risk for a high-rate water injector, it predicted the evolution of damage to a coupler designed to connect different diameter pipes, and 2) in analyzing facility piping systems connected to an unconventional well, it predicted the transient erosion trend from proppant flowback, which allowed for pipe geometry optimization to increase in erosional life expectancy.
McKeon, C. Dalton (Southwest Research Institute®) | Nelson, Seth M. (Southwest Research Institute®) | Gallo, Federico (ExxonMobil Upstream Research Company) | Mayer, Christian (ExxonMobil Upstream Research Company)
When estimating the erosion damage from passed fines through wire-wrap sand screens, variables such as approach velocity and gap velocity are often considered to be the main design considerations. Additional variables, such as the gap between the screen and base pipe, are often neglected. For the purpose of the experiments presented in this paper, two main objectives were defined. The first objective was to gain a better understanding of the location and progression of erosion in a conventional wire-wrap sand screen. In particular, inspection of the inlet and outlet surfaces of the screen was conducted in order to evaluate the erosion effects on both boundaries. The second objective was to evaluate the erosion effects of allowing flow to pass underneath the screen’s axial rib wires by introducing various standoff distances between the base pipe and the axial rib wires. The selected standoff distances were similar to a drainage layer typically included in metal-mesh type sand screens. To achieve these two objectives, eight experiments were conducted in an erosion test flow loop with varying experimental standoff geometry stack-ups. Any damage to the sand screen was quantified by calculating the specific erosion of the screen, which is the screen’s total mass loss divided by the total mass of particles passed for a given test duration. Photographs of the coupons before and after each test were used to qualitatively identify affected areas of erosion. The results of these experiments and a brief description of the testing approach are provided herein.