NUMERICAL MODELING OF FILTRATION PRESSURE FIELDS IN AN ISOLATED HOMOGENEOUS ISOTROPIC IMPERFECTLY STRIPPED SEAM

Filtration fl ows arising on the uptake of hydrocarbons from imperfectly stripped seams-collectors are investigated. The problem on the pressure fi eld in an isolated isotropic homogeneous seam localized in the interval from H_1d to –H_2d and perforated in the range –H_d < z_d < H_d, fully contained in the interval of the seam, has been considered. The problem is formulated in dimensional and dimensionless values for functions of pressure deviation from its nonperturbed distribution normalized to the amplitude value of depression. Dimensionless relations are constructed for the problem considered. A fi nite-difference program is created for calculating the fi elds of pressure and velocity in a seam with imperfect stripping when the seam boundaries do not coincide with the boundaries of the perforation interval. Graphical dependences have been constructed for the pressure fi eld, vertical and horizontal components and velocity modulus of the fl uid fi ltering from the periphery to the well. The level lines for the indicated fi elds are presented and, based on their analysis, important laws governing the fl ow have been revealed. A computational experiment has shown that at the exit into the well in the perforated part of the seam vertical fl ows are absent, and at increasing distance from the well they differ from zero. This means that interlayer overfl ows exist even in homogeneous imperfectly stripped seams. At the center of the symmetrically perforated bed such overfl ows are absent, since the transverse velocity component vanishes. At the same time, infl ow from an imperfectly stripped homogeneous isotropic seam, which is produced in the regime of assigned depression, is not uniform, and the maximum of the modulus of the horizontal velocity component on all of the curves is attained at the boundaries of the perforation interval. It is shown that at the center of a symmetrically perforated and imperfectly stripped seam, a minimum specifi c infl ow is observed.
   
Author:  A. I. Filippov, A. A. Koval′skii, O. V. Akhmetova, and M. R. Gubaidullin
Keywords:  fi ltration, imperfect stripping, two-dimensional fl ow, fi nite-difference program, pressure fi eld, velocity fi eld
Page:  36