Pilar oil and gas field, located onshore northeastern region of Brazil, had the production peak by 1985, when produced 1300 m3/d of oil, decreasing since then until reaching 350 m3/d in 1997. Forecasts at that time indicated a very low oil production of about 200 m3/d by year in 2002.
A study was launched in 1997, strongly focused on the characterization of sealing fault planes that control the oil and gas accumulations, which resulted in the projects of deviated wells, following the fault planes. This approach has made possible to drill one single well crossing multiple sets of reservoirs, increasing the possibility of finding virgin reservoirs along trends of producing reservoirs.
As a result, the oil rate has been rising since 1998, reverting the declining tendency of the period between 1985 and 1997. In 2003 the oil rate reached 1100 m3/d. In the period of revitalization, the OOIP has increased 50%.
Pilar oil and gas field is located at Sergipe-Alagoas Basin, in the northeastern region of Brazil, 20km from Maceió city (Figure 1). Discovered in 1981, the field reached the production peak of 1300 m3/d in 1985, after the initial drilling campaign. A strong declining in oil production then happened which was slightly attenuated after 1990, due to the beginning of secondary recovery by gas and water injection.
The field forecast in 1994 pointed to a very low production around 200 m3/d by year 2000 (Figure 2).
The field is made up of hundreds reservoirs that resulted from deltaic sedimentation and heavy faulted compartmentalization. The small values of oil-in-place of the many reservoirs, as well as high geologic risks, discouraged drilling new wells either targeting a single reservoir or trying to hit new undiscovered accumulations that might exist within the field.
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