Seismic oil-water contact detection, supported with pressure data, for hydrocarbon in-place estimation
G. Oguguah Agunwoke, C. Ogundare, S. Iyiola and N. Boness
Journal name: First Break
Issue: Vol 37, No 3, March 2019 pp. 31 - 36
Info: Article, PDF ( 1.16Mb )
With good quality seismic data, fluid contacts can be detected in an area of favourable rock physics. The oil-water contact (OWC) inferred from seismic data is validated using other independent data. Where there is an agreement between a seismically-derived OWC and other supporting data, this approach can be used as a reliable technique in reservoir delineation. A field example is presented from deepwater offshore Nigeria, typified by stacked-turbidite sands of Upper to Middle Miocene age. The volumetric estimate of in place volumes for the field was initially based on the lowest known oil (LKO) penetrated by wells as the deepest oil limit. Consequently, the actual field performance and history matching of the dynamic model suggested the oil-in-place was underestimated. The seismically-derived OWC, when supported by pressure and production data, justified an increased hydrocarbon in place estimate. In a block calibrated by wells, seismically-derived OWCs agree with results from the well pressure-depth plot and within the range of depth uncertainty. This provided confidence in using seismic OWC estimates to define oil downdip limits in blocks where the contact has not been penetrated. Thus, in place additions were achieved by extending the lowest oil limit(LKO) downdip to the seismic OWC.