Effects Of Temperature On Heavy Oil-Water Relative Permeability Of Sand

Abstract

HEAVY OIL Effects of temperature on heavy oil-water relative permeability of sand BRIJ B. MAINI Petroleum Recovery Institute and T. OKAZAWA Esso Resources Canada Limited ABSTRACT Although a number of studies have reported significant effects of temperature on relative permeabilities no consensus has emerged on the generality of such effects nor on possible mechanisms causing such effects. Some of the recent studies have found relative permeability to be independent of temperature and have suggested that most of the reported temperature effects can be attributed to artifacts of the unsteady-state technique. The objective of this study was to critically examine the use of the unsteady-state technique for measuring relative permeability in heavy oil systems and to ex-perimentally determine the effect of temperature on relative permeability curves for a clean silica sand/heavy crude oil deionized water system. Unsteady-state measurements were carried out in a 45 cm tong, 5.6 cm diameter sand core at five different temperatures ranging from room temperature to 200'C using a heavy crude oil and deionized water. It was found that the unsteady-state technique when employed in heavy oil systems is more suscep-tible to experimental artifacts (compared to its use in light oil systems), however, a careful analysis of the displacement data can provide meaningful relative permeability curves in spite of the inevitable artifacts.The relative permeability curves derived from production and pressure drop histories of the displacements at different temperatures showed that, in this system, relative permeability curves vary with temperature. The endpoint water permeability as well as the effective water permeability at intermediate satura-tions increased with increasing temperatures. The endpoint oil permeability was found to be independent of temperature-While the shape of the oil relative permeability curve displayed a complex dependence on temperature, its significance remains uncertain due to the presence of several artifacts. Introduction Production of oil from petroleum reservoirs usually involves simultaneous flow of two or more immiscible fluids through a porous rock. Multiphase flow in porous media is a complex process that depends on a number of factors including the Keywords: Heavy oil, Relative permeability, Temperature, Flowin porous media. absolute permeability, pressure drop, capillary pressure, fluid viscosities, and relative permeabilities of each phase. Of these, the relative permeability is probably the most important para-meter in determining reservoir performance. For modelling thermal recovery processes for heavy oil recovery, one needs to know not only the relative permeabilities at the original reser-voir conditions but also the effect of increasing temperature on the relative permeability curves.A number of studies have discussed the temperature effects on oil/water relative permeabilities. Unfortunately, no con-sensus has emerged on the generality of reported temperature effects nor on possible mechanisms ...

Temperature effects on the heavy oil/water relative permeabilities of carbonate rocks

“…The relative permeabilities we obtained for dolomite rocks showed a similar trend as those reported by Maini and Okazawa (1987) for sandstone and heavy oil systems (Fig. 16).…”

“…The effect of temperature gradient on relative permeability measurement was studied by Watson and Ertekin (1988). Maini and Okazawa (1987) analyzed the unsteadystate experiments conducted on unconsolidated silica sand using Bodo stock tank oil and by history matching technique. They concluded that the obtained relative permeability increased with temperature.…”

Effect of Temperature on Athabasca Type Heavy Oil – Water Relative Permeability Curves in Glass Bead Packs

“…Davidson (1969) has indicated the effect of temperature on the relative permeability, while not mentioning anything about the end point saturations. Maini and Okazawa (1987) have considered fixed end point saturations and have confirmed the change in k r values with temperature. Schembre et al (2006) have proposed that the rock becomes more water wet at higher temperatures and that affects the relative permeability curves.…”

“…Polikar et al (1990) also stated that it is not possible to predict theoretically what the effect of temperature on relative permeabilities could be, and the results are system specific. Maini and Okazawa (1987) have also concluded that due to several artifacts involved in the experiments no effect of temperature could be justified.…”

Well and Inflow Performance Relationship for Heavy Oil Reservoir under Heating Treatment

“…A published simulation study has shown that recovery will increase as ratio of µo/µw gets lower (Maini and Okazawa, 1987). The outcome of this research shows that brine viscosity reduction is not as drastic as oil, from 0.55 to 0.47 cP and from 68 to 46 cP, for brine and oil respectively.…”