Effect of compositional grading on reservoir performance

Abstract EN

In reservoirs with thickness exceeding fifty metres, tomnositimial grading ha* been found to cause a significant variation In performance.

Mam fluid properties, governing the magnitude of reservoir perlbrmancc, such as density, formation volume factor and fluid \isci>siis experience variation due to varving fluid composition along the huhocarbon column.

These variations cause erroneous esnrnation of stock-tank oil in place and may infer reservon engineers to consider inappropriate secondary oil recovery methods^ ftr-cxamplc In the presence of gravity segregation within Uie oil column, heavy ends will lonu a heavy oil blanket in the lower part of thereservoir Such a scenario ma\ result m poor displacement and an earlier breaktlitough when water drive is Uiedommanl lluid How mechanism In tins jKipcr, reservoir performance due to varying reservon fluid coin position, has been examined using reservoir simulation analysis and recommendalions for better characterisation ol reservoir fluid sampling are outlined