CRITERIA FOR THE STABILITY OF DISPLACEMENT PROCESSES DURING THE PRODUCTION OF HYDROCARBONS

Consideration has been given to the stability of the process of displacement of oil by water in piston-like and multiphase approximation with account for gravitational forces. By analogy with a gravitation-free regime, a critical parameter determining a stable displacement process has been introduced. This parameter is characterized by the relation of mobilities of fluids separated by a displacement front. However, it has been shown that in case of accounting for gravitational forces, this parameter cannot provide a sufficient condition for the formation of an unstable process, since gravitational forces can have a stabilizing or destabilizing effect on the stability of displacement. Therefore, a second critical number accounting for the above-mentioned effect has been introduced. To identify the critical numbers for a two-phase model, it is necessary to solve a Buckley–Leverett problem, for which purpose use was made of the Weldge graphical technique in this investigation, which made it possible to calculate water saturation on the displacement front after whose determination the calculation and analysis of the critical numbers were conducted. The calculation was conducted on model values of input parameters. It has been shown that the stabilization of the displacement front with gravitational forces is possible at rather low flow velocities.
   
Author:  Ya. A. Kryazhev, V. A. Kryazhev, A. P. Shevelyov, A. Ya. Gil′manov
Keywords:  piston-like displacement model, two-phase displacement model, Buckley–Leverett′s problem, displacement front stability, exposure to gravitational forces, rheology, mechanics of multiphase systems
Page:  1156