Abstract

Identification and evaluation of low resistivity, low contrast(LRLC) bypassed pay is a challenge. The interpretation ofthese pay using integrated log evaluation approach can have significant production and reserve implications, especially in mature fields. In the past, it was assumed that these intervals were either tight or water bearing based on conventional log evaluation. Understanding the causes of low resistivity log response is important when evaluating these zones. Some of the more prevalent causes for misinterpreted low-resistivity zones are: Inter bedded or laminated sand/ shale intervals, dispersed and structural clays, other conductive minerals such as pyrite, glauconite, and other members of the mica family, altered framework grains and finer grain sizes. In Mandhali Pay of Jotana Field located in Cambay Basin, a new detailed interpretation and formation evaluation analysis have been done to reevaluate and investigate the tight and shaly sandstone layers having low resistivity reading values. Pay was identified by investigating various resistivity water saturation models, Phalf method and correlating the results with production data. After validating the petrophysical analysis and making integration with available core measurements and production data , the potential of the LRLC pay zones in Mandhali reservoir of Jotana filed was confirmed and quantified using petrophysical attribute.