Authors: Mahdi Mahmoudi, University of Alberta; Vahidoddin Fattahpour, University of Alberta; Alireza Nouri, University of Alberta; Saad Rasool, University of Alberta; Michael Leitch, RGL Reservoir Management Inc.
The quantification of fines migration in the vicinity of sand control screens in SAGD wells is of paramount importance to operating companies, who require the wells to operate under optimum conditions for a period of 10-15 years. Fines migration can lead to the plugging of pore spaces around the liner and result in reduced permeability in the liner’s vicinity, hence, lowering the wellbore productivity. This paper investigates the fines migration in relation to slot width and density in SAGD wells. A series of laboratory experiments was performed by using a Sand Retention Testing (SRT) facility which accommodates a sand pack sample and a multi-slot coupon to represent the near-wellbore high-porosity zone and sand control liner, respectively. As fluid was pumped through the sand pack and across the slotted coupon, the pressure drop across the sand pack and coupon was measured, along with the mass and Particle Size Distribution (PSD) of produced fines and sand. After the flow test, the sand pack was dissected, and the PSD of fines portion of sand pack was measured to assess the movement and concentration of fines over the course of the test. Test observations indicate that the slot width, slot density, and the flow rate highly affect the fines migration/production and the PSD of the migrated and produced fines. Larger slot widths increase the mass of the produced and migrated fines. Further observations indicate that the mass and size of produced fines is highly dependent on the flow rate and that there is a critical rate below which little amounts of fines are produced or move in the porous medium.
