Measurement and Correlation of Gas Condensate Relative Permeability by the Steady-State Method

Abstract

High-pressure core flood experiments using gas condensate fluids in long sandstone cores have been conducted. Steady-state relative permeability points were measured over a wide range of condensate-to-gas ratios (CGR; volume of condensate per unit volume of gas, both at test pressure and temperature), and the velocity and interfacial tension (IFT) were varied between tests to observe the effect on relative permeability. The experimental procedures ensured that the fluid distribution in the cores was representative of gas condensate reservoirs. Hysteresis between drainage and imbibition during the steady-state measurements also was investigated, as was the repeatability of the data.A relative permeability rate effect for both gas and condensate phases was observed, with the relative permeability of both phases increasing with an increase in flow rate. The relative-permeabilityrate effect was still evident as the IFT increased by an order of magnitude. The influence of end effects was shown to be negligible under the IFT conditions used in the tests, with the Reynolds number indicating that flow was well within the so-called laminar regime under all test conditions. The observed rate effect was contrary to that of conventional non-Darcy flow, where the effective permeability should decrease with increasing flow rate. A generalized correlation between relative permeability, velocity, and IFT has been proposed.The results highlight the need for appropriate experimental methods and relative permeability relations where the distribution of the phases are representative of those in gas condensate reservoirs.

Microscopic Mechanisms of Oil Recovery By Near-Miscible Gas Injection

“…Previous works including our own experimental and theoretical work (e.g., Bardon and Longeron 1980;Asar and Andy 1988;Henderson et al 1996Henderson et al , 2001 have shown that the flow behaviour at nearmiscible conditions is fundamentally different from conventional (high-IFT immiscible) gas oil flow and for the oil and gas to be considered as near-miscible the gas-oil IFT should be under 1 m Nm −1 with the effects being more pronounced with further reduction of IFT. However, at complete miscibility (IFT equal to zero), two-phase flow can no longer exist and hence flow mechanisms would be different compared to near-miscible systems.…”

Visualisation of Residual Oil Recovery by Near-miscible Gas and SWAG Injection Using High-pressure Micromodels

“…Bardon and Longeron 1980;Asar and Handy 1988;Henderson et al 1996Henderson et al , 2001Jamiolahmady et al 2000Jamiolahmady et al , 2003 have shown that the flow behaviour at near-miscible conditions is fundamentally different from conventional (high-IFT immiscible) gas-oil flow. Jamiolahmady et al (2000Jamiolahmady et al ( , 2003 studied the flow of low IFT gas-oil systems mechanistically.…”

Relative Permeability Estimation for Rich Gas-Condensate Reservoirs

“…This approach to modeling multiphase flow through porous media has been validated by numerous investigators through coreflood experiments (Chen et al, 1995;Henderson et al, 1995). For gas condensate fluids it has experimentally been shown that the mobility of both the gas and condensate phases increases with increasing capillary numbers.…”

“…Gas and condensate relative permeabilities are typically determined by steady state linear coreflood experiments (Henderson et al, 1995;Whitson et al, 1999;Mott et al, 2000). Coreflood derived relative permeabilities represent rock properties of the selected core sample.…”

“…Investigators have experimentally demonstrated an improvement in both gas and condensate relative permeability at high velocities (Chen et al, 1995;Henderson et al, 1995). A greater enhancement was observed in the gas relative permeability as compared to the condensate relative permeability.…”