Calculating capillary pressure curve from single-speed centrifuge experiments

Autor: Antonio Carlos Moretti, M Cristina C Cunha
Rok vydání: 2000
Předmět:
Zdroj: Inverse Problems. 16:1897-1906
ISSN: 1361-6420
0266-5611
DOI: 10.1088/0266-5611/16/6/318
Popis: We present a method for the calculation of the capillary pressure curve in porous media using centrifuge single-speed experimental data. The mathematical model is based on the hydrostatic equilibrium equation for capillary pressure and the inverse problem for finding the saturation distribution along the sample from the displaced fluid volume when all the flow has ceased. The capillary effects are interpreted as constraint forces which keep the oil trapped in the pores of the sample. We use the Lagrangian formulation to find the equilibrium configuration of the oil in the sample. The great advantage of this formulation is that the explicit inclusion of forces is not necessary. Mathematical properties of the capillary pressure curve and centrifuge data are used as constraints of the kinetic energy minimization procedure. The discretized problem is solved using a nonlinear programming procedure using only the single-speed experimental data. Numerical results are compared with calculations in the frequently used multi-speed centrifuge tests.
Databáze: OpenAIRE