Integration of Well-Test Deconvolution Analysis and Detailed Reservoir Modelling in3D-Seismic Data Interpretation-A Case Study

摘要

This paper demonstrates how a combination of seismic datainterpretation, advanced well test deconvolution analysis anddetailed reservoir modeling helped address the concern ofreservoir compartmentalization in the E-M field locatedoffshore South Africa and thus significantly improve thehistory match. The reservoir is heavily faulted and many of thefaults have no throw across them suggesting possiblecommunication throughout the reservoir. Several simulationefforts in the past have failed to reconcile the connectedhydrocarbons initially in-place estimated from materialbalance and those calculated volumetrically leading tounsubstantiated assumptions in order to attain a reasonablehistory match.The paper draws on the strength of an integrated petroleumengineering study that included detailed fault mapping on there-processed 3D seismic dataset. The latter was guided by theoutcomes of recent deconvolution well test analyses and arevised geological model over the entire field. As a result ofthis study, a new structural and stratigraphic model thatsatisfactorily explained the historical production performanceof the reservoir was proposed.The field is located on a large tilted fault block, dominatedby extensional structures with top reservoir locally truncatedby the lower cretaceous synrift unconformity (1At1). Theprimary reservoir is synrift (pre-1At1) shallow marine andfluvio-deltaic sandstone within an upper shallow marineinterval (USM). The new stratigraphic model recommendsthat, in addition to the extensive faulting, the reservoirstratigraphy may also be compartmentalised by field widehorizontal shale barriers. These shale barriers have preventedaccess to all the hydrocarbons by the existing production wellsand presents opportunities for infill drilling in the reservoir.