Relative Permeability Characteristics During Carbon Capture and Sequestration Process in Low-Permeable Reservoirs

Abstract

The injection of carbon dioxide (CO2) in low-permeable reservoirs can not only mitigate the greenhouse effect on the environment, but also enhance oil and gas recovery (EOR). For numerical simulation work of this process, relative permeability can help predict the capacity for the flow of CO2 throughout the life of the reservoir, and reflect the changes induced by the injected CO2. In this paper, the experimental methods and empirical correlations to determine relative permeability are reviewed and discussed. Specifically, for a low-permeable reservoir in China, a core displacement experiment is performed for both natural and artificial low-permeable cores to study the relative permeability characteristics. The results show that for immiscible CO2 flooding, when considering the threshold pressure and gas slippage, the relative permeability decreases to some extent, and the relative permeability of oil/water does not reduce as much as that of CO2. In miscible flooding, the curves have different shapes for cores with a different permeability. By comparing the relative permeability curves under immiscible and miscible CO2 flooding, it is found that the two-phase span of miscible flooding is wider, and the relative permeability at the gas endpoint becomes larger.

Experimental investigation of the displacement flow mechanism and oil recovery in primary polymer flood operations

“…During the USS method, displacement of one fluid phase by another immiscible fluid phase takes place and can be characteristic of the multiphase flow behaviour in reservoirs [33,34]. The USS relative permeability measurements are simpler than the SS methods with the measured variables being time dependent.…”

Parameters Variation and Flow Characteristics When CO2 Displacing Brine in Four Micromodels Simulating Carbon Sequestration in Saline Aquifers

“…At present, a large number of experimental and simulation studies on CO 2 /brine two-phase flow have been conducted. − Pore structure is one of the main factors, affecting flow behavior in porous media . CO 2 displacement of brine in real cores is carried out by the conventional high-temperature-high-pressure experimental system to study the effects of temperature, pressure, injection flow rate, and salinity of brine on the permeability and displacement efficiency. − However, the understanding of the transport mechanism is limited by the difficulty of monitoring fluid flow in opaque media . With the development of the technology, this problem is overcome by non-invasive image techniques such as optical imaging, gamma imaging, synchrotron X-ray microtomography, and magnetic resonance imaging, which allow the visualization study of two-phase flow in real porous media at the core or pore scale.…”

Prediction of Minimum Miscibility Pressure for CO2 Flooding Based on Microscopic Pore-Throat Structure

“…Geological storage of CO 2 is a mature technology with high potential for storage (Wang et al, 2021). The main sites for underground storage are depleted oil and gas reservoirs (CO 2 -EOR/EGR), deep saline aqufier, unrecoverable coal seams (CO 2 -ECBM), and gas hydrate reservoirs (Hassanpouryouzband et al, 2018;Bai et al, 2020). CO 2 -EOR, also known as CO 2 flooding, is a technology that uses CO 2 flooding for enhanced recovery while trapping CO 2 in the reservoi for a long term, referred to as CO 2 sequestration process (Rezk et al, 2019;Wang et al, 2019).…”