Print this pageApplication of Reservoir Geochemistry in Oman
NEDERLOF, PETER J. R. and MARK P. ORMEROD
After a brief introduction on the petroleum systems of Oman, this paper describes the successful application of reservoir geochemistry in reservoir continuity studies and in production reconciliation in commingled wells.
In Petroleum Development Oman, molecular oil compositions are routinely studied to assess the continuity of oil accumulations and to validate the field wide projection of oil-water contacts. in North Oman, most accumulations are completely homogenized and step-wise changes in composition are interpreted in terms of reservoir discontinuities. Compositional gradients have been observed in biodegraded oil accumulations in South Oman. Once a compositional gradient has been identified, deviations from the trend are again seen as evidence for reservoir compartmentalization.
Reconciliation of oil production by geochemical methods has proven to be economically very attractive. Several pilot studies have successfully demonstrated the accuracy of the technique and allowed production from pay zones that otherwise would have been shut in.
Oil analyses are routinely carried out on a multi-dimensional gas chromatograph (MD-GC), custom built by Shell Research and Technology in the Netherlands. The MD-GC system consists of two linked gas chromatographs, which together allow separations of all aromatic C[8] and C[9] isomers, compounds which have been shown to be powerful oil/oil correlation parameters at the reservoir level.