Print this pageImportant Early Cretaceous (Barremian) Sublacustrine Channel-Levee Reservoir, Taquipe Formation, Southwest Reconcavo Basin, Bahia, Brazil
STARFISH OIL & GAS participated in the exploration activities in a block located in onshore Southwestern Reconcavo Basin, Bahia State, Brazil in the Taquipe and Candeias formations reservoirs. Its main sandstone reservoir was formerly interpreted as belonging to the Caruaçu Member of the Maracangalha Formation (Rio da Serra stage, Neocomian, Early Cretaceous), but after a reinterpretation based on ostracode biostratigraphy it was considered as Taquipe Formation (Aratu stage, Barremian, Early Cretaceous), an important sublacustrine canyon-filling unit. The geological model used for the field development plan was based in cores cut in the neighbor Cassarongongo oil field, as well as in outcrops in the coastal zone of Todos os Santos Bay, near the Wanderley de Pinho Museum, in the Great Salvador region and in the Bom Despacho Ferry Station in the Itaparica Island, Bahia State, Brazil. The outcrops show channel-fill and proximal levee facies in the first locality and sheet sands in the latter. In the Cassarongongo and Taquipe oil field areas, these sands can be recognized in logs and have characteristic reflections in seismic lines. Channel cut is represented by white (negative) reflections, whereas channel fill is marked by black (positive) reflections, which onlap the channel cuts. Levees are marked by lateral elevations in relation to channels. A 3D-seismic amplitude map, which reflects the petrophysical (porosity) variations of the channel fill depicts the probable channel axis and can orient future development wells. These channels flowed Southward and down the slope of a submarine canyon and sporadically formed crevasse-splay deposits. In the Southeastern Recôncavo, channels flowed into a large splay area, whose sheet sands coalesced laterally and vertically into thick sand bodies. The Taquipe Formation and the Caruaçu Member sandstones show similar facies, due to its sublacustrine nature, and form unconventional oil and gas traps and they frequently do not present oil or gas/water contact. In the deepest part of the basin they behave as tight-gas sands.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil