Fracture Capillary Pressure Based on the Liquid Bridge Dynamic Stability Study

Abstract

Performance study of gas oil gravity drainage in stacks of overwhelmed blocks in a gas-invaded zone of naturally fractured reservoirs presents difficult challenges to petroleum engineers. It is believed that there exists some degree of block-to-block interaction that may lead to capillary continuity in fractured reservoirs. Effect of such continuity in gravity drainage is much more pronounced as it increases the height of the continuous fluid column in a reservoir and thereby the recovery of oil as height is a key parameter in gravity drainage mechanisms. It has been experimentally proven that liquid or solid bridges in horizontal fracture can contribute to wetting phase transfer across the horizontal fracture, but there is no mathematical model that predicts the probability of such continuity. In this article, a mathematical model developed by using 1-D Navier-Stock for the free surface flow equation and Young-Laplace of capillary for breakage of the stable liquid bridge held between two pairs of support while stretching. The model gives critical length of fracture aperture, which surely provides capillary continuity. Moreover, the developed model shows flow dependency of fracture capillary pressure and predicts a nonzero value for this parameter, while in the past many researchers used zero fracture capillary pressure for history matching of fractured reservoirs.

Keywords::

• capillary continuity
• fractured reservoirs
• gravity drainage
• liquid bridge
• simulation