PSI - Issue 37

A. Kostina et al. / Procedia Structural Integrity 37 (2022) 431–438 A. Kostina/ Structural Integrity Procedia 00 (2019) 000 – 000

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comparison with a red curve. The decreasing stage in the red curve is observed after 88th day while the black curve starts to decrease only at the end of the simulation.

(a)

(b)

Fig. 5. (a) Porosity evolution at the point located near the top of the reservoir, (b) ratio of current permeability to initial value at the point located near the top of the reservoir.

Fig. 6. Oil recovery rate for plastic and elastic problems.

5. Conclusions The work proposes a three-dimensional mathematical model of steam-assisted gravity drainage The developed model can be considered as a part of system providing intelligent monitoring and control at large oil-producing complexes. The ideology of intelligent monitoring requires the presence of an adequate physical model which can predict evolution of the controlled object in various conditions including accidents. The proposed model describes development of a steam chamber, evolution of the stress-strain state as well as an increase in porosity and permeability and can be used as a basis for SAGD intelligent monitoring systems. The key feature of the proposed model is coupling between flow, thermal and mechanical processes which enables us to associate improvement of reservoir properties with an increase in plastic volumetric strains. It has been demonstrated that a single mechanism of thermal expansion could not provide significant values of the vertical heave of the reservoir cap. A comparative study with a thermo-elastic problem has shown that there is a threefold increase in vertical displacement when shear dilation is taken into account. Moreover, the shear dilation effect leads to a faster steam chamber propagation and higher increase in reservoir hydraulic properties. It is observed a slight decrease in porosity and permeability values after propagation of the steam chamber when plastic strains are not considered. In addition, neglecting shear dilation can lead to the underestimation of the oil recovery rate and its retardation.