Subcritical CO2 effects on kaolinite fines transport in porous limestone media

Autor: S. Mahalingam, Venkat Pranesh, B. Kanimozhi, Vivek Thamizhmani, T. Arun Selvakumar
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Journal of Petroleum Exploration and Production Technology, Vol 10, Iss 3, Pp 883-891 (2019)
Druh dokumentu: article
ISSN: 2190-0558
2190-0566
DOI: 10.1007/s13202-019-0739-1
Popis: Abstract Carbonate reservoirs account for 60% share in global oil reserves, and CO2-EOR process is employed in these carbonate fields for effective oil recovery and retention as well. Recent research reports that fines migration may lead to reservoir formation damage in oil bearing limestone and dolomite rocks. Although carbonate reservoirs are poor in clay minerals, some mass of clay fines existence in certain carbonate formations will cause severe damage to permeability and well productivity. This paper reports the single-phase flow of subcritical CO2 in porous limestone rock core containing kaolinite clay fines. Fines are natural reservoir minerals (example, quartz) and clay particles such as kaolinite, illite, feldspar, smectite, and montmorillonite. But, this paper explores this CO2-clay fines behavior in limestone rock as a function of kaolinite. So, two sets of core flood experiments were performed in the rock temperatures 120 °C and 160 °C. Initially, kaolinite clay has been injected into the limestone core in the form of suspension and then dried for hours in order to retain the solid fines in the internal pore chambers of the core. After that, the CO2 under subcritical condition has been injected into the porous limestone core for fines mobilization and injected gas recovery. The major observations that are reported from the experimental tests are there is an increase in gas saturation for increasing injection time. Steady rise of heat transfer coefficient and enthalpy was noted for increasing gas saturation and time. Concentration of fines linearly soars with respect to elevating PVI and permeability declines for rising time. Pressure in the limestone core shows abnormal and nonlinear variation. Finally, gas discharge rate declines for increasing injection time. Experimental data are tested against the statistical model (regression), and the outcome indicated good agreement. Overall, this paper has successfully established the CO2 effects on kaolinite clay fines behavior and its impact on oil recovery in carbonate fields.
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