Estimating Oil/Water Relative Permeability at SAGD Steam Chamber Edge

Abstract

Fluid flow at the edge of SAGD chamber where most of bitumen drainage occurs is of great importance. In this region, water condensate co-flows with the falling bitumen towards the production well. Since the bitumen viscosity varies at different locations due to temperature gradient across the edge of steam chamber, new correlations are required to consider the influence of fluid viscosity on the relative permeability curves. In this study, the objective is to remedy this deficiency by developing a new set of correlations for relative permeability estimation addressing in particular such effect at SAGD steam chamber edge. Various datasets from literature were obtained at different temperatures and oil viscosities. The data were used to develop new correlations which are a modification of the well-known Corey's equations for relative permeability estimation. Two mathematical approaches were applied and evaluated to achieve the best correlations: (1) at each temperature, herein substituted by viscosity ratio, relative permeabilities are functions of saturation, and (2) relative permeability is a function of viscosity ratio at a fixed saturation. Furthermore, different mathematical equations were used in the regression procedure in order to optimize the objective function and achieve the most reliable correlations. Results indicated a combined power and quadratic functionality of relative permeability to the phases’ viscosity. The viscosity ratio was used in the new correlations as a dimensionless parameter which represents fluids’ viscosities at different temperatures. The new correlations were compared against the original Corey's equations for various experimental datasets. Various statistical error formulation were employed: average relative error, average absolute relative error, root mean squared, correlation coefficient, and standard deviation. The accuracy of the new correlations was also graphically compared with Corey's model using cross-plot illustrations. Comparative evaluation of these correlation error analyses revealed that relative permeability estimations have been significantly improved when new correlations were employed which incorporate different temperature profiles and accordingly the viscosity variations. The application of the new correlation could improve the flow prediction in thermal simulators.

Review of the effect of temperature on oil-water relative permeability in porous rocks of oil reservoirs

“…Even a small increase in temperature can reduce the viscosity of heavy oil sufficiently [2][3][4][5][6][7]17] to affect the nature of flow. The temperature increase in thermal recovery operations causes the oil viscosity to change by several orders of magnitude [2-8, 15, 17, 26, 38].…”

“…Heating the rock from original reservoir temperature to the high temperatures, which can exceed 300 o C in steam injection and much higher in in-situ combustion processes [1], brings about changes in rock-fluid properties that can have a large impact on the flow behavior. The viscosity of heavy oil decreases by several orders of magnitude [2][3][4][5][6][7] and this by itself can significantly change the flow characteristics [8][9][10][11]. Furthermore, such large increase in temperature can also change other rock-fluid properties, including wettability [4,[12][13][14][15][16][17][18][19][20], interfacial tension [7,14,16,[21][22][23][24][25] and pore geometry.…”

“…There are published reports that contradict each other on the temperature impact on two-phase relative permeability for various systems [2-4, 6, 7, 12, 25]. In addition, numerous studies have attempted over the years to present the effect of temperature on relative permeability by proposing some useful relative permeability models even for a particular system [5,25,[37][38][39][40][41][42]. The objective of this study is to critically review such published articles [2-4, 6-8, 12, 13, 15-17, 19, 21, 24, 25, 38, 40-53] on the effect of temperature on two-phase relative permeability and distill useful information and insights into the changes in behavior that occur as a function of the temperature.…”

Modeling temperature dependency of oil - water relative permeability in thermal enhanced oil recovery processes using group method of data handling and gene expression programming

“…Therefore, in recent years, addressing these issues by establishing cheap and simple-to-use methods to gain the impact of temperature on Kr has triggered a huge amount of scientific inquiry. (Zhang et al, 2017), (Mosavat, Mohsenzadeh, & Al-Wahaibi, 2016), (Torabi, Mosavat, & Zarivnyy, 2016), and (Bennion, Thomas, Schulmeister, & Ma, 2006) are among the well-known predictive correlations that consider the temperature influence on Kr in oil -water systems. A summary of the aforementioned correlations is given in Table 1.…”

Modeling Temperature Dependency of Oil-Water Relative Permeability in Thermal Enhanced Oil Recovery Processes Using Group Method of Data Handling and Gene Expression Programming

“…Therefore, in recent years, addressing these issues by establishing cheap and simple-to-use methods to gain the impact of temperature on Kr has triggered a huge amount of scientific inquiry. Zhang et al (Zhang et al 2017), Mosavat et al (Mosavat et al 2016), Torabi et al (Torabi, Mosavat, and Zarivnyy 2016), and Bennion et al (Bennion et al 2006) are among the well-known predictive correlations that consider the temperature influence on Kr in oil -water systems. A summary of the aforementioned correlations is given in Table 1.…”