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New Sand Control Design Criteria and Evaluation Testing for Steam Assisted Gravity Drainage (SAGD) Wellbores
- Author / Creator
- Mahmoudi Eshkaftaki, Mahdi
This thesis presents experimental results obtained using a novel Sand Retention Testing (SRT) facility. The testing results and interpretations provide an improved understanding of the parameters that affect sand control performance in Steam Assisted Gravity Drainage (SAGD) operations. The SRT testing data are used to develop a set of new design criteria for slotted liners based on parametric testing. The SRT facility was designed and commissioned to address limitations in existing testing methods for sand control evaluation. The facility uses multiple slots in the slotted liner coupon instead of a single slot in the existing facilities. Measurements are also improved by obtaining pore pressures along the sand pack in addition to the pressure drop across the liner coupon to assess the retained permeability and flow convergence. More realistic methods are designed and used for sand pack preparation, fluid injection, and sample saturation than the existing practices. The testing also includes post-mortem analysis to measure fines/clay content above the screen and in the produced fluids to evaluate fines migration and the potential for pore plugging. Slotted liner coupons in this research vary in slot size and density and are tested for select PSDs. Testing data are analyzed to evaluate existing heuristic liner design models and propose new design criteria. Test measurements and observations indicate that the sand packs preparation procedure, injected fluid velocity, and ionic concentrations highly affect the testing results. For typical field porosities and PSDs, sand production is observed to stay within acceptable limits for the screens designed based on existing models. Data also indicate improved retained permeability for higher slot density, which levels off at high slot densities. The optimum slot width is also determined for minimal plugging and acceptable sanding levels. Measurements indicate that the skin buildup due to pore plugging caused by fines migration is reduced by increasing the slot width. However, the increase of the slot width beyond a certain level does not reduce the skin any further and only contributes to higher levels of sanding. The parametric testing allows finding the limits for the slot width beyond which the plugging condition is not further improved and, at the same time, the sanding is kept within acceptable levels. These findings lead to the formulation of an optimum liner design model that would result in minimal plugging, coupled with acceptable amounts of sand production.
- Graduation date
- Type of Item
- Doctor of Philosophy
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.