Development of the fractured granite reservoir of the Nam Rong-Doi Moi field, offshore Vietnam

The Nam Rong-Doi Moi field is located in the south of the Cuu Long basin, which produces oil from the fractured granite reservoir. The pore system within fractured granite was investigated based on the well data, and a hypothetical reservoir model was proposed.The fractured granite reservoir consists of “fault breccia”, “damaged zone” and “un-deformed zone”. Both “fault breccia” and “damaged zone” show low to fair permeability while “un-deformed zone” shows very low permeability nature. There occasionally be high permeable “channel structures” within “fault breccia”, and this mixed pore structures create a high permeability contrast within granite, and the fluids in the fractured granite reservoir behave as a dual porosity reservoir.In order to predict the fault/fracture distributions within the granite, the “Controlled Beam Migration” technique was applied to the 3D seismic data in the NR-DM field. The results of reprocessing show an improvement to image high-dip structures within the granite, which corresponds to the actual flow zones in the well.The NR-DM field is still under development and will be studied further with newly acquired data to optimize the development and production.