The Peregrino field is a heterogeneous heavy oil field located offshore Brazil in the Southern Campos basin. The field is planned to be developed with 30 geosteered long horizontal producers completed with ESPs for lift and 7 water injectors. As per July 2013, 19 producers and 3 injectors are on stream. The reservoir deposits are characterized as complex shallow marine and gravity driven sedimentation processes in shore phase to offshore environments.
Information deduced from the pressure transient analysis (PTA) are highly valuable in complex and heterogeneous reservoir deposits for increased reservoir understanding enabling optimization of the production and development strategy. The well test information has the potential to provide average rock properties on a larger scale related to permeability, sand continuity, fluid properties and distance to reservoir boundaries (such as erosional features, faults and fluid contact) that can be used as conditioning points for reservoir modeling and characterization.
This paper provides a description of the PTA acquisition strategy and the advanced interpretation methods for ensuring high quality data and maximized derivation of information that can be used to optimize the production and development strategy for the Peregrino field. High viscosity oil, wells with long reservoir sections, ESPs for lift and well interference makes this especially challenging. Since the pressure waves propagate slowly through the reservoir, the deconvolution technique has been implemented in order to maximize the value of repeated PTA in the same well and thereby enabling identification of reservoir features with the minimum amount of downtime for the production wells and also enhancing its value as a predictive tool. The reservoir information is used to update the reservoir model, optimize the well spacing and optimize placement of wells in relation to the oil water oil. The importance of prioritizing this type of data acquisition from day one in the field development will also be presented.
The Peregrino Field is located in block BM-C-7, in the southernmost part of the Campos Basin (Figure 1). The area is located 85 km southeast of the nearest coastline, approximately 100 km southeast of Macaé, Brazil. The Peregrino Field was discovered in 2004, with production start-up in 2011. The water depth in the area varies from 95 to 135 meters, over an area of approximately 350 km2. The reservoir depth in the field is between 2150 and 2350 meters TVD. The Peregrino Field is one of the heaviest offshore oil developments in Brazil. PVT properties for Peregrino are shown in Table 1.