Albacora Leste (ABL) Oil Field development, in Campos Basin, is based upon the exploitation of a heavy oil (16.5 to 21.5° (API) from a miocene highly unconsolidated sandstone, which depositional model is interpreted as a complex turbidity system, mainly represented by channels, lobes and overbank facies. Water depth ranges from 800 to 2,000m and net thickness from 5 to 35m. The existing interbeds, both due to shale or dirty sands on the channel borders, give additional complexity to the well construction related to well placement strategy and sand control execution.
The implementations made by the construction of 30' horizontal wells (being 16 producers and 14 injectors) are described in the paper. Amongst the most important items are the modifications on TSR, allowing one-trip production string installation, the massive application of front end directional and MWD/LWD technologies, resulting in successful landing and navigation in the reservoir, and the use of support ROV vessels to deploy and retrieve the transponders. All the above implementations increased reliability of offshore operations.
The paper also describes the experience in integrated drilling and completion project (meaning integrated commitment from service companies) and the follow-up of a pending item list.
As a main contribution to the industry, one can mention the implementation of a ‘Torpedo Base’ replacing jetting 30' casing, which reduces rig operational time. Furthermore, the use of light proppant, to pack the screens, opens up new horizons to the construction of long horizontal wells, which are highly desirable in the exploitation of future heavy oil fields.
ABL deep water giant oil field is located on the northern part of Campos Basin, southeast of Brazil, about 120km from the SÃ£o TomÃ© Cape, Rio de Janeiro State coast, in water depths ranging from 800 to 2,000 meters. The reservoir depths range from 2,300 to 2,600m referenced to sea level. ABL reservoirs are high quality siliciclastic turbidite reservoirs from the Tertiary (Miocene sandstones) (Ref. 1). The average gravity of oil ranges from 16.5 to 21.5°API.
A consortium was formed by PETROBRAS and REPSOL in order to develop the field. PETROBRAS is the operator and holds 90% of working interest, while REPSOL holds 10%.
ABL Field was discovered in 1986. The challenging field environment ' deep water, low API oil, highly friable sandstones with net reservoir thicknesses ranging from 5 to 35 meters, low fracture gradients ' slowed field development, since it would be supported only by emerging technologies at that time, such as long horizontal and gravel-packed wells. Drilling of the development wells only started in 2002 and the last development well will be completed in September 2006. In the first quarter of 2006, the first well will start production. P-50, an 180,000 bbl/day oil capacity FPSO, will collect the production from the field. The production peak will be reached by the end of 2006, when all production wells will be on stream.