Print this pagePrioritizing Mature Reservoirs for Characterization Studies: A Quick-Look Analysis
KNOX, PAUL R.
An important niche for domestic independent oil and gas operators in the future will be the identification and recovery of remaining gas and mobile oil from untapped and incompletely drained compartments in mature reservoirs. For instance, the U.S. Department of Energy estimates that nearly as much mobile oil remains to be recovered from fluvial-deltaic reservoirs (10.8 Bbbl) as has been produced to date (14.4 Bbbl). Converting part of this huge resource to reserves will depend increasingly on independents and will require comprehensive reservoir characterization studies. The successful independent will focus characterization dollars first on those reservoirs with significant remaining potential.
A semiquantitative methodology for using readily available information to prioritize reservoirs for detailed study has been developed. Factors important in this analysis are those that would have controlled the efficiency of past production, including well spacing, structural and stratigraphic heterogeneity, and hydrocarbon mobility (hydrocarbon viscosities and reservoir permeability). Factors influencing the economic attractiveness of a reservoir include depth (drilling cost) and the matching of operator oil-versus-gas bias and reservoir content. An equation using these parameters has been developed, and the Reservoir Characterization Advisor- Fluvial Deltaic software, which incorporates the relationship and user-friendly data-entry screens, is publicly available for use on a personal computer. Use of the quick-look analysis can reduce risk and increase the volume of hydrocarbons identified by characterization studies.