000			02030nab a2200193 4500
005			20260520001830.0
008			260224s2010 xxu
245	0	0	_aSpontaneous countercurrent imbibition and forced displacement characteristics of low-permeability, siliceous shale rocks
260			_a _b _cmar. 2010
270			_a12/07/2010 ; 12/07/2010
300			_a9 p. ; 47-55
520			_aTranscripción del resumen del autor. Enhanced oil production from naturally-fractured low-permeability reservoirs is challenging. Spontaneous countercurrent imbibition in such reservoirs is an important oil recovery mechanism and has been widely studied in the oil and gas industry. Nevertheless, complicated rock properties such as low permeability, wettability, and other factors controlling flow mechanisms make it difficult to understand the flow characteristics and to generalize expected recovery. Spontaneous countercurrent imbibition and forced displacement tests were completed using siliceous shale core plugs that have low permeability, relatively high porosity, and intermediate to oil-wet surfaces. Four brine formulations were examined: carbonated synthetic brine, acidic (pH of 3), neutral, and alkaline (pH of 12). The siliceous shale core used in this study is an intermediate to oil-wet rock as gauged from the oil recovery by spontaneous imbibition in the neutral pH brine. With pH-controlled synthetic brine, the final oil recovery increases; especially using high pH brine. This suggests that the wettability shifts to a condition of greater water-wetness and the residual oil saturation decreases by exposing the system to a high pH brine. In the simulation study, it is inferred that the oil recovery characteristics change by changing the capillary pressure characteristics and the interfacial tension.
581			_a1-2
773	0		_tJournal of Petroleum Science & Engineering _g71
942			_cARTICULO
100	1		_aTakahashi, S. _945602
100	1		_aKovscek, A.R. _912097
999			_c174937 _d174937