Publications

A thorough program of interference testing, bottom hole buildup and drawndown tests, flowing bottom hole pressure surveys and reservoir gradient surveys can provide data critical in determining horizontal and vertical pressure communication and the need for well stimulation as well as data useful in material balance calculations and in determining a reservoirs optimum producing plan. P.T. Stanvac Indonesia has applied these techniques in the Jene field, a recent Baturaja Limestone Discovery in South Sumatra. This field is an excellent candidate for this type of study as it is a reefal buildup consiting of several layers of limestone with varying physical properties.Analysis techniques such as bounded reservoir simulation of an interference test, Horner plots and type curve analysis of buildup and drawdown tests, and reservoir gradient surveys used to quantify the permeabilities of the respective reservoir layers in both the horizontal and vertical direction are presented, as they were applied to the Jene reservoir. With known pressure drawdown applied in the individual wells, as measured with flowing bottom hole pressure surveys, and relative horizontal and vertical pemeabilities as determined above it is possible to accurately simulate both the reservoir pressure response to production and pressure maintenance and to simulate the producing water cut for various production rates in each well at any stage in the depletion process.The results of applying these data to the operation of the field allow for the maximizing of ultimate recovery by,1) assuring that the fluid production rate will not cause premature water breakthrough, thereby leaving low residual oil saturations in the reservoir as all regions will be efficiently swept,2) determining if a well should be stimulated to reduce the pressure drawdown in the reservoir and/or allow increased production,3) determine at an early stage of depletion if there is a need for, and optimum location of, wells for pressure maintenance or other secondary recovery systems.A field model based on these results can be used to plan field development in considerable detail, assuring timely investment for drilling and completing wells and for assisted recovery projects, if needed. It also allows identification of wells and/or projects which will not benefit the field development and hence helps in avoiding unnecessary expenditures.