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Collaborating Authors
Saeedi, M.
The idea is to create Poor quality sands often contain interbedded shales with sufficient increase in horizontal stress to induce shear areal extent which can significantly impair vertical failure and increase in vertical permeability across the communication and drastically reduce recovery in barrier. The implementation could be via induction or conventional SAGD or related hybrid processes. Several microwave electric heating, or one can also consider use methods have been envisioned to provide vertical of resistive heating elements in the wells with heat communication through the shales, but none of these transfer into the formation mainly by conduction.
- North America > United States (1.00)
- North America > Canada > Alberta (0.30)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- North America > Canada > Alberta > Athabasca Oil Sands > Western Canada Sedimentary Basin > Alberta Basin > McMurray Formation (0.99)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Clearwater Formation (0.94)
- North America > Canada > Alberta > Athabasca Oil Sands > Western Canada Sedimentary Basin > Alberta Basin > Pelican Lake Field (Wabasca Field) > Wabiskaw Sandstone Formation (0.94)
ABSTRACT ABSTRACT: The main goal of this research was to investigate the risk of caprock failure due to the SAGDOX process, a hybrid steam and in-situ combustion recovery process for oil sands. A temperature dependency extension to the linear and non-linear constitutive models was developed and implemented in the GEOSIM software. The analysis has shown that there is no increased risk of caprock failure for SAGDOX process compared to SAGD. The study has shown that the overlying Wabiskaw formation experiences shear failure during both SAGD and SAGDOX due to its low initial cohesion, friction angle and proximity to pressure and temperature front, although the failure was mainly driven by pressure propagation. However, Clearwater shale above Wabiskaw can still provide proper zonal isolation to the steam/combustion chamber under SAGDOX operating conditions. Uncertainty in the analysis is due mainly to the sparse nature of geomechanical properties data for the oil sand reservoir and the caprock formations, especially at temperatures over 200 C. 1. INTRODUCTION Nexen Energy ULC (Nexen) has been evaluating SAGDOX - a post SAGD oxidation process (Kerr, 2012; Jonasson and Kerr 2013) - to improve the recovery and project economics of its Long Lake SAGD operation. SAGDOX is meant to be used after several years of SAGD operations when the bitumen between two SAGD well-pairs is mobile. In SAGDOX process (applied to a row of parallel well pairs) oxygen is coinjected with steam in every other SAGD injector well and starts an oxidation process by reacting with residual oil around the injection well. At this point the SAGD production well below the oxygen-steam injector is shut in and steam along with oxygen and combustion gasses fill the steam chamber voidage and push hot bitumen towards the neighbouring SAGD well-pair. The neighbour injection well is also shut-in and could be converted to a producer if need be. Various other well arrangements have been considered including those with vertical injection wells and infill horizontal production wells. Since oxygen is co-injected with steam, very high oxidation temperature of a pure combustion process are not generated as steam carries a large portion of the heat of combustion away from reaction front and temperatures are thereby moderated. Nonetheless, temperatures in the range of 400-600 deg C are expected in the oil sand zone. The high temperature combustion front where the oxidation reactions are active moves away from the oxygen injection wells as the residual oil left behind after steam displacement is consumed. The high temperature reaction zone has a tendency to move upward towards the cap rock under the influence of gravitational forces.
- North America > United States (0.93)
- North America > Canada > Alberta (0.71)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.76)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.67)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Wabiskaw Formation (0.99)
- North America > Canada > Alberta > Athabasca Oil Sands > Western Canada Sedimentary Basin > Alberta Basin > Pelican Lake Field (Wabasca Field) > Wabiskaw Sandstone Formation (0.98)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Clearwater Formation (0.97)
- North America > Canada > Alberta > Athabasca Oil Sands > Western Canada Sedimentary Basin > Alberta Basin > McMurray Formation (0.94)
Abstract Measurement of drainage relative permeability by the centrifuge method was first introduced by Hagoort. It has been shown that capillary end effects can cause errors in the measurements if a minimum rotational speed is not honored. To determine the ωmin, we propose maintaining the value of capillary-gravity number, N cg min, to be of the order of 10 or smaller, at which the capillary end effect becomes negligible. The above conclusions were determined by applying a forward numerical simulator developed for centrifuge experiments and applying Hagoort's method as a backward model. These forward and backward models form a forward-backward loop which is a powerful tool for error analysis such as determining the impact of capillary end effects. Introduction Measurement of drainage relative permeability using the centrifuge method was first introduced by Hagoort. He viewed the gravity drainage process as a gravity stable Buckley- Leverett displacement with the same set of assumptions. In addition, he assumed constant centrifugal acceleration along the core length and infinite mobility for the gas phase. In the full version of this paper, it will be shown that these assumptions are reasonable. Nevertheless, error caused by capillary end effect is one of the issues in relative permeability measurements. In the centrifuge method, if the rotational speed, ω, of the experiment is not maintained above a critical minimum, the calculated relative permeability values will be underestimated. Although Hagoort proposed a correction procedure for cases where the measurements are affected by capillary end effects, it has been shown that this procedure introduces some noise into the calculated relative permeability values. Further, it is not easy to perform Hagoort's correction procedure in core analysis laboratories; rather, it is much easier and preferable to avoid the problem entirely by designing the experiment with a proper rotational speed from the beginning. On the other hand, since the target of such measurements is usually in modelling gravity drainage processes, one would desire that the relative permeability measurements be obtained under a capillary dominated flow regime. That is to say, if the measurements are performed under severe rotational speeds, the de-saturation flow regime would not be a capillary dominated flow. The objective of this work is to introduce a criterion for designing relative permeability experiments so that the minimum rotational speed that minimizes capillary end effects is honoured. To find this criterion, a forward-backward modelling scheme is developed. The forward numerical model accepts arbitrary capillary pressure and relative permeability functions as inputs and simulates the centrifugal displacement process. The simulated centrifuge drainage results is then used as raw centrifuge data and processed by Hagoort's method as the backward model. The resulting relative permeability curve is then compared with the original input relative permeability to quantify the capillary end effect. Figure 1 shows the forward backward loop schematically.