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Experimental Studies and Modeling of Counter-Flow Thermo-Capillary Imbibition of High-Viscosity Oil in Fractured-Porous Reservoirs

Kotenev, Maxim1; Blinov, Sergey; Kotenev, Yuriy; and Kotenev, Artem
1[email protected]

Temperature increase during the use of heat carriers significantly affects the character of filtration and mass transfer process in fractured-porous reservoirs. Process investigation allows to offer intensification factors in the form of new reagents and physical principles for the strengthening the basic thermal development technologies. Presented are the studies on optimization and regulation of processes of thermo-capillary counter-flow imbibition on the Famen and Turnei deposits in fractured-porous reservoirs. Experimental studies were conducted on natural carbonate core samples which cover all ranges of reservoir filtration-capacity properties for reservoirs with high-viscosity oil.

Thermo-capillary experimental studies have been carried out when successively four various temperature values have been set during which oil displacement dynamics has been recorded. With temperature rise displacement intensifies, what leads to counter-flow thermo-capillary oil displacement.

Counter-flow capillary displacement of high-viscosity oil is an important displacement factor in porous blocks in the fractured and porous carbonate reservoirs. When temperature rises, counter-flow capillary imbibition intensifies. During high temperatures patterns of counter-flow capillary displacement with the increase of rock permeability and viscosity reduction remain. Time of the sharp capillary adsorption deceleration allows normalization of the typical process time for the real porous blocks.

Mathematical model and calculation methods of the main parameters of steam and gas cyclical impact on wells in the fractured and porous reservoirs have been developed. Steam and gas dependency from dimensionless thermo-capillary imbibition time has extreme character, what allows identification of effective length of injection stage. Thermo-capillary imbibition efficiency rises with the increase in heat volume accumulated by the reservoir volume unit. The choice of the retention stage is realized by the comparison of the analytical solutions for the task of heated reservoir zone cooling with the maximum allowed temperature of the producing fluids during mechanized production. Results of experimental studies of end time (significant deceleration) of thermo-capillary imbibition for various temperatures are taken into consideration. To increase steam and gas cyclical treatment process efficiency, stepped production increase on the basis of calculation of heated reservoir zone cooling is offered.

 

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013