Design Criteria and Performance Evaluation of Wire-Wrapped Screens for Steam Assisted Gravity Drainage (SAGD) Wellbores

• Author / Creator

  Montero Pallares, Jesus David

• This thesis presents the experimental results obtained using a large Pre-packed Sand Retention Testing (SRT) facility. Analysis of the results funds the elaboration of novel design criteria for wire-wrapped screens (WWS) in Steam Assisted Gravity Drainage (SAGD) applications. The SRT data improves the understanding of different parameters controlling sand production and flow impairment. The final design criteria combine both sanding and flow performance indicators in a Traffic Light System (TLS) displaying optimum, marginal and adverse slot ranges. Additionally, empirical formulations are introduced to predict and provide the lower and upper boundaries of the optimum aperture window.
  The assembly and operational procedures were custom-built to improve existing sand control testing protocols. The facility employs the largest scale-test facility available in the literature allowing better representation of the sand control device (SCD). The operational procedure includes both single-phase and multiphase injection to cover a wide range of production scenarios across the horizontal well. Moreover, a consistent sand preparation method ensures uniform samples in every test with negligible variance among the set of experiments. Flow performance findings are contrasted with fines migration and production analysis. Post-mortem analysis of samples tracks the change in fines percentage after the test and fines production is also evaluated from fluid samples. Remarkably, the data analysis applies relative permeability measurements to estimate the final impact on sand retained permeability. Retained permeability guarantees a normalized indicator of formation impairment that allows the comparison of different formation sands. Previous works employed fixed pressure drop values to evaluate flow performance without considering the effect of permeability.
  Test matrix includes a wide range of aperture sizes to cover the existing PSD based criteria (i.e., D10, 2XD50). Furthermore, this research employs three categorized sand classes from McMurray formation with different PSD and fines content. The PSDs represent a fine, medium-coarse and coarse type of sands. Produced sand and plugging measurements for the different PSDs showed that a specific range for slot aperture could provide an effective sand control while keeping the plugging at a minimum. The optimum range of aperture size narrows down with finer PSD and higher fines content, especially at high flow rates and aggressive production scenarios such as steam-influx.
  The effect of water cut proves to be stronger in pore plugging than in sand production. A substantial amount of fines are mobilized at high water cuts which can lead to pore plugging and low wellbore productivity. Fines migration and skin buildup are reduced by increasing the aperture width. Beyond a specific aperture size, there is no improvement regarding flow performance and the risk of excessive sand production increases at high flow rates.
  Gas injection showed that steam-breakthrough scenarios represent the most adverse conditions when aperture sizes are too wide. The selection of aperture size is drastically dependent on the operating conditions. Existing design criteria provide conservative aperture recommendations that are more suitable for challenging conditions at elevated flow rates.
  
  The study leads to the elaboration of an optimum screen design that accounts for the effect of flow rate, fluid ratio, fines content, and particle size. Notably, the results denote the importance of good production practices to avoid excessive sand production and plugging. Moreover, laboratory testing allowed the elaboration of performance correlations that adequately predict the response of wire-wrapped screens.

• Subjects / Keywords

  • design criteria
  • wire-wrapped screens
  • sand control

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-w32h-7192

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.