Characterization of Carriers for Hydrocarbon Migration: An Example from the Dongying Sag, Bohai Bar Basin, China
Xiaorong Luo¹, Likuan Zhang¹, Yuhong Lei¹, Guoqi Song², and Fengui Sui²
¹Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
²Shengli Oilfield Branch Company, China Petroleum & Chemical Corp., Dongying, Shandong, China
Secondary hydrocarbon migration in carriers and reservoirs is a highly heterogeneous process (Harms, 1966; Berg, 1975; Schowalter, 1979), which restricts mostly the quantity and position of hydrocarbon accumulations. At a microscopic scale, the occurrence of migration depends on the importance of driving force relative to resistances of carriers, so that random distribution of pores and pore throats will cause uneven selection of a migration pathway (Lenormand et al., 1988; Hirsch and Thompson, 1995; Luo, 2007a). And such heterogeneity will be enhanced by heterogeneous porous media comprising the carriers at various scales (Luo, 2011). Hence, quantitative analysis of hydrocarbon migration should consider not only the driving force but also the properties and characteristics of carrier beds (England et al., 1987).
Based on our previous attempts at quantitative researches on migration paths and pathways, the authors propose in this work a concept of carrier formation (Fig. 1a) for realizing the characterization of migration carriers, by taking the scale of migration and maneuverability into account. The carrier formation is defined as a lithologic formation, beneath a regional seal, that offers the paths for hydrocarbon migration in a certain geological period when hydrocarbon migration process happened. Such a carrier formation may contain a few or multitudinous permeable geological bodies, hydraulically connected among themselves.
In order to characterize the hydraulic transmissibility of a detrital sediment carrier at basin scale, such a carrier formation is vertically separated, by a grid, into quadrate prisms. The petrophysics properties of all the strata in one prism may be marked on the upper-surface stratum (element) by using geostatistic methods, then the carrier formation may be modeled as a 2D layer (Fig. 1b). After then, all the treatments for characterizing the carrier formation’s transmissibility will be done on the layer.
AAPG Search and Discovery Article #120098©2013 AAPG Hedberg Conference Petroleum Systems: Modeling the Past, Planning the Future, Nice, France, October 1-5, 2012