Carbonate Reservoir Characterization: Part 14
1. How exactly to have a control over gravity drainage displacement in low permeable rock-matrix, where, the oil will move downward by gravity forces, whereas, the capillary forces will oppose fluid exchange because the entrance of gas into the matrix as a non-wetting phase remains opposed by capillary forces, due to the differences in specific weights of gas and oil? Given the fact that capillary forces may remain to be constant with depth, while gravity forces increases with depth, whether the combined effect of gravity-capillary forces under imbibition displacement would have a significantly different behavior in the displacement history of the drainage or imbibition field process – associated with a fractured carbonate reservoir?
2. When exactly a counter-flow (where, the production of a non-wetting phase has an opposite direction of flow to that of the imbibing wetting phase) gets developed in a fractured carbonate reservoir?
Whether the role of oil buoyancy would remain to be very critical in dictating the counter-flow?
3. Given the fact that when a non-wetting phase fluid (oil) enters a wetting phase (water) porous system, then, the oil gets filled up at the centers of the largest, well connected pores, while, the wetting phase (water) is found lining the pore walls and filling the smallest pores; and, thereby essentially reducing the pore space available for flow of either wetting-phase or not-wetting phase.
If so, do we require a correction for permeability values (resulting from the varying saturations of water, oil and gas) in a carbonate reservoir as well?
4. Whether the concept of end point method (which assumes that a reasonable estimate of the curvature could be made) be used to measure effective permeabilities @ irreducible water saturation and residual oil saturation in a carbonate reservoir?
5. Since, restoring core samples @ laboratory scales to the actual field carbonate reservoir conditions remain to be challenging; and, since, the pore surfaces remain to be reactive to changes in fluids, and in turn, these reactions could alter the wettability state in a carbonate reservoir, to what extent, the measurement of relative permeability for a carbonate reservoir @ laboratory-scale would remain to be justified?
6. As it is known, oil becomes mobile only after attaining a saturation defined by the relative permeability curve that equates to a reservoir height defined by the capillary pressure curve. Does this level exactly define the oil-water contact in a real field (carbonate reservoir) scenario?
How easy would it remain to delineate a transition zone in a carbonate reservoir?
Suresh Kumar Govindarajan
https://home.iitm.ac.in/gskumar/
https://iitm.irins.org/profile/61643
- Badges
- Science topic
- Similar topics
- Mathematics
- Algebra
- Matrix