4D Seismic Interpretation in the Marlim Field, Campos Basin, Offshore Brazil

The growing application and acceptance of 4D or timelapse seismic technique as a key reservoir management<br>tool has been well documented. The technique has been successfully applied to numerous mature fields in order to<br>optimize reservoir production and recovery. This paper will describe such a case study on the Marlim Field where<br>the application of 4D seismic has contributed significantly to critical reservoir management decisions. The giant Marlim field is located on the eastern Brazilian coast in water depths varying from 600 to 1200m. The reservoir is characterized by an unconsolidated sandstone turbidite related to the regressive mega sequence of the Brazilian eastern continental margin. It is the largest producing oilfield in Brazil (average 450.000 bpd), with the original oil-in-place volume of 6.4 billion STB. Production started in 1991 and injection of water in 1994. Three seismic surveys cover the Marlim Field. The first one was Confidential Page 1 3/27/2007acquired in 1986, the others in 1997 and 2005. The most recent survey was acquired using WesternGeco´s Q- Marine acquisition system and was specifically acquired for reservoir monitoring and characterization purposes. Analyses of the 4D results started in June 2006 after parallel processing of the 1997 and 2005 datasets. This paper will highlight how the results of the 4D interpretation are being used to make critical reservoir management decisions with greater confidence and<br>reduced risk.