Application of Saturation Height Model in Case Of Depletion in Paleo Times

Abstract

In recent years, an increasing number of Middle East oil reservoir are believed to show indications of imbibition in paleo times as the result of tilting, quite possibly related to Late Tertiary orogeny (M Al Kindi, AAPG GEO 2016). Characteristics are 1) differences in apparent transition zone in opposite sides of the oil field, 2) misfit of core based (drainage) SHF to computed oil saturation, 3) ‘typical’ residual oil observations (20-40%) below free water levels based on pressure data. If present day free water level differs from the paleo free water level, estimates of in place oil volumes would benefit from a SHM that incorporates both the drainage and the imbibition stage. A publication by C.H. Pentland (SPE 2016) presents the concept based on reduction of the ‘connected oil volume’ during the imbibition stage, utilising drainage based SHFs, FWL, PaleoFWL, and residual oil saturation. This poster will aim to present: 1) graphics that explain the concept, 2) the required equations broken down in easy steps, and 3) the (petrophysical) workflow to obtain the input variables required. The poster is the result of its recent application to the reservoirs in the Shuaiba, Kharaib, and Lekwair of a Middle East oil field for an Abu Dhabi based EP co. The poster is intended for the benefit of petrophysical and geomodelling work and but will also try to incorporate the initial findings of the Reservoir Engineering team.

AAPG Datapages/Search and Discovery Article #90370 ©2020 AAPG Middle East Region Geoscience Technology Workshop, 3rd Edition Carbonate Reservoirs of the Middle East, Abu Dhabi, UAE, January 28-29, 2020