Equation for defining hydrodynamic oil-water contact surface and an alternative approach, structure surface transformation for mapping hydrodynamic traps.pdfVIP

Marine and Petroleum Geology 78 (2016) 701e711 Contents lists available at ScienceDirect Marine and Petroleum Geology journal homepage: /locate/marpetgeo Research paper Equation for de?ning hydrodynamic oil-water contact surface and an alternative approach, “structure surface transformation” for mapping hydrodynamic traps Yunlai Yang a, *, Khalid A. Mahmoud b a EXPEC Advanced Research Center, Saudi Aramco, Dhahran 31311, Saudi Arabia b Area Exploration Department, Saudi Aramco, Dhahran 31311, Saudi Arabia article info Article history: Received 16 December 2015 Received in revised form 1 August 2016 Accepted 22 September 2016 Available online 22 September 2016 Keywords: Hydrodynamic effect Tilted oil-water contact Hydrodynamic trap Equation Mapping abstract Flowing groundwater beneath an oil accumulation causes the oil-water contact (OWC) to be tilted. In this study we present an equation de?ning the surface of a tilted OWC: Zowc ? ZOWC 0 t rw erw àro T ehw 0 à hwT Where, ZOWC, ZOWC_0 are the depth of the OWC at a given location and a reference location (e.g. a well location), respectively; rw, ro are the density of formation water and oil, respectively; hw, hw_0 are the hydraulic head at the given location and the reference location, respectively. This equation can be used directly to delineate the tilted OWC of an oil accumulation. It can also be employed to map hydrodynamic traps. Based on the equation, an alternative approach, essentially the same as Hubberts (1953) minimum energy level methodology, for mapping hydrodynamic traps is derived from an easy-to-understand concept, “Structure Surface Transformation”. A ?eld example from the Arabian Basin is presented to illustrate the proposed approach for mapping hydrodynamic traps and the signi?cance of hydrodynamic effect on trap size and volume. For this particular example, the traps boundaries and volumes are signi?cantly enlarged owing to a favorable hydrodynamic condition. ? 2016 Elsevier Ltd. All rights reserve