Experimental studies of fluid flow at adverse mobility ratio have quantified the development of viscous fingers. CIPR have developed an experimental set up for 2-D in-situ saturation measurements. The X-ray scanner can quantify saturations over a large 2-D area and can also image saturation changes of up to 1 × 1 m rock slabs. The 2-D scanner is designed specifically to study viscous unstable displacements for both miscible and immiscible processes. Experimental knowledge of stability criteria and generation of viscous fingers is necessary to improve competence in handling viscous instability under displacement in reservoirs. The experiments performed describe finger growth for miscible displacement with unfavourable mobility ratio (viscosity ratio 1:100). Dispersion and diffusion are known to limit finger growth in the miscible systems. The results obtained have shown that established fingers grow mainly from the tip of the finger and that established fingers are reinforced in preference to formation of new fingers. The main mechanisms observed were solvent fingers sweeping oil and production in fingers move oil to very low oil saturation. Conventional reservoir simulators have difficulty in modelling viscous unstable displacements, and especially the shape and development of viscous fingers. The paper discusses several approaches to model viscous fingering. In all cases heterogeneous permeability field was introduced by stochastic variation, but always respecting the average permeability. The best approach involves applying a solvent mixing zone viscosity, estimation fractional flow, and derives an analytical relationship for the relative permeabilities.
|Number of pages||12|
|Publication status||Published - Apr 2009|
|Event||15th European Symposium on Improved Oil Recovery 2009 - Paris, France|
Duration: 27 Apr 2009 → 29 Apr 2009
|Conference||15th European Symposium on Improved Oil Recovery 2009|
|Abbreviated title||IOR 2009|
|Period||27/04/09 → 29/04/09|