Gas Saturation Detection Model Applied To heterogeneous Eservoir Using TDT

摘要

The Zeit Bay field reservoir units consist of sandstone and carbonates, partially overlaying a tilted block of fractured basement reservoir with a complex deive mechanism. A secondary recovery scheme of gas re-injection into the original gas cap was initiated to maintain reservoir energy and minimise pressure decline. Hence accurate detection of gas movement is very critical. Several difficulties to monitor gas-oil contacts were encountered in a considerable number of wells. Some of these difficulties were, gas channelling behind the casig, gas coning, wellbore fluid changes, porosity and lithology changes, wellbor fluid invasion into the reservoir and the presence of formation stimulation fluid (HCl). The application of conventional methods using the response of gas indicator curves could result in a false indication of formation gas-oil contacts.