A Universal Saturation Height Function for Siliciclastic Rocks

Abstract

Summary Reservoir models require accurate estimation of hydrocarbon saturation for correct initial inplace hydrocarbon volume estimation and for initialization of simulation model. There are two fundamental limitations with capillary pressure measurements i) It is unable to measure poor quality rocks (low RQI) therefore samples are inherently insufficient to represent all type of silicicalstic rocks present in subsurface ii) It is expensive and time consuming therefore not necessarily all the rocks and fields have this kind of measurement available for reservoir modelling. The cost of these limitations leads to errors in STOIIP and uncertainties in reservoir simulation. The common method used to populate hydrocarbon saturation in reservoir model is J function ( Leverett, 1941 ). This model is meant for clean rocks only. Therefore can not predict saturation in shaly sands. To overcome these issues we have designed a saturation height function which captures the saturation height behavior for all kind of siliciclastic rocks. Saturation estimated through this saturation heigt function matched very well with resistivity derived saturation. Therefore we propose to utilize this saturation height function which can overcome the measurement insufficiency and can also can be applied to the reservoir models where core measurements are not available at all.