EXPERIMENTAL VERIFICATION OF OIL SATURATION AND LOSSES DURING SECONDARY MIGRATION
X. Luo1*, F. Zhang2, S. Miao3, W. Wang3, Y. Huang3, B. Zhou1,4, D. Loggia4 and G. Vasseur5
Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.
2 Exploration & Production Research Institute, Sinopec,Beijing, 100083；
3 MR Imaging Key Laboratory, CNPC, Langfang, 100201, China.
4 Hydrosciences, UMR 5569 CNRS-UMII, USTL, 34095 Montpellier, France.
5 SISYPHE, UMR, Boîte 123, Université Paris 6, 75252 Paris Cedex 05, France.
* author for correspondence: email xrxuluo@public.bta.net.cn
Accurate estimates of losses occurring during secondary petroleum migration are of vital importance for valid petroleum systems assessments. In this paper, we discuss the development of migration pathways and the corresponding hydrocarbon losses using data from laboratory experiments based on diphasic immiscible draining processes. These experiments permitted us to study the formation of migration pathways, the distribution of non-wetting oil along these pathways, and the re-utilization of existing pathways by later pulses of migrating oil.
The configuration of a migration pathway can be characterized
by a phase diagram whose coordinates are two dimensionless numbers: the capillary
number and the Bond number (a measure of the buoyancy force). NMR imaging was
used to measure the saturation of residual oil within the pathways. It was found
that, after migration, the average residual oil saturation within a pathway
was generally less than 40% at a resolution of 0.4mm.
Hydrocarbon losses during migration were estimated as the product of the volumetric
proportion of the migrating cluster structure, defined using this spatial resolution,
multiplied by the average residual oil saturation in the pathway.