Measuring Movable Oil Saturation in Reservoirs with Low-Field NMR Technology

doi:10.11938/cjmr20150310

Abstract

Abstract:

Movable oil saturation is an important parameter to consider when evaluating movable reserves. Adapted for the method to measure movable fluid saturation, a new low-field NMR method to measure movable oil saturation was developed, and demonstrated through oil-driving-water and water-driving-oil centrifuge experiments. Experiments were conducted on 24 samples from Maling oilfield. The results indicated that the reasonable centrifugal forces for low-permeability sandstone in oil-driving-water and water-driving-oil experiments were 2.28 and 0.22 MPa, respectively. The movable oil saturation was measured between 17.06% and 60.49%, and the average was 41.95%. The movable oil saturation was primarily determined by throat with a size of 0.5 μm, and the volume of movable oil increased with the throat radius. The correlation coefficient between movable oil saturation and permeability was found to be 0.845, higher than the correlation coefficient between movable oil saturation and porosity. The results of these agreed well with the actuality of the formation. It is concluded that the new method for measuring movable oil saturation is valid and practical, and represents significant improvement over the conventional approach.

Key words: NMR, movable oil saturation, optimum centrifugal force, oil-driving-water, water-driving-oil

CLC Number:

TE311

ZHOU Shang-wen1,2,3*，XUE Hua-qing1,2,3，GUO Wei1,2,3，LI Xiao-bo1,2,3，XIU Wei4. Measuring Movable Oil Saturation in Reservoirs with Low-Field NMR Technology[J]. Chinese Journal of Magnetic Resonance, 2015, 32(3): 489-498.

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