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Pushing technological boundaries in ultradeep waters
Published on Apr 7, 2011 - by Pre-salt.com - Source: Schlumberger
The discovery of a giant oil accumulation in ultradeep waters off Brazil’s southeast coast is opening a new frontier for exploration and production. This pre-salt play, in the Santos basin, contains potentially recoverable reserves ranging from 795 million m3 to 1.3 billion m3 of oil equivalent. Just one of several structures found beneath a thick layer of salt, the Tupi structure, is pushing technological boundaries as E&P teams seek to define its geographic limits.
Types of reserves
Pre-salt, postsalt and subsalt formations are all capable of forming traps and seals for migrating hydrocarbons. Pre-salt wells target reservoirs beneath the layer of autochthonous salt. Subsalt wells target reservoirs beneath the mobile allochthonous salt canopy. Postsalt wells target formations above the salt.
Geology
From a geologic perspective, this play is a product of interminably slow tectonic and depositional processes involving continental rifting, seafloor spreading, and sedimentation. These processes were associated with the split between South America and Africa during the Cretaceous breakup of Gondwana. The depositional processes created source, reservoir, and sealed layers necessary to successfully produce an active petroleum system.
Technology
From a technological perspective, the feasibility of the pre-salt play is a result of operator experience gained through overcoming the challenges of constructing wells in deep and ultradeep waters off the coast of Brazil. Just as important are improvements to seismic imaging, which allow geophysicists to identify potential structures masked beneath layered evaporites that may be as thick as 2,000 m [6,560 ft].
E&P challenges
Expertise and techniques developed to exploit deepwater fields of the Campos basin have been adapted to wells in the Santos basin. Exploration models from the Santos basin pre-salt play, in turn, have led to significant discoveries in neighboring basins. This article discusses the geology and history of Brazil’s pre-salt play. It describes challenges associated with exploration and production of presalt carbonate reservoirs and their impact on the advancement of new models.
Available at: <http://www.slb.com/news/inside_
news/2011/2011_0310_brazil_pre-salt.aspx>.
Retrieved on: 14 Nov. 2011. Adapted.
Text II
Successful appraisal well in the pre-salt of block BM-C-32 in Brazil
The Consortium of block BM-C-32 in Brazil, operated by BP - British Petroleum (NYSE:BP,LON:BP) that owns 40%, Anadarko (NYSE:APC,FRA:AAZ), with 33.3% and Maersk Oil (CPH:MARSK B,PINK:AMKBF) with the remaining 26.7%, announced today (November 9, 2011) the successful Itaipu-2 pre-salt appraisal well.
Located in block BM-C-32 in the Campos Basin offshore Brazil, the well was drilled to total depth of approximately 4,877 meters in 1,420 meters of water, and encountered a gross petroleum column of approximately 18 meters in a pre-salt carbonate reservoir.
According to Anadarko’s press release of December 17, 2009, originally this consortium was operated by Devon Energy Corp. (NYSE:DVN) with 40% working interest, Anadarko with 33.3% and SK Energy Co., Ltd. (Private) holds the Remaining 26.7% working interest.
“The pre-salt Itaipu-2 well is an aggressive stepout from the Itaipu discovery well, which is located 4 miles (7 kilometers) northwest,” Anadarko Sr. Vice President, Worldwide Exploration, Bob Daniels said. “The Itaipu-2 well established a fluid contact and appears to have successfully extended the accumulation 120 meters downdip from the discovery. Accordingly, the appraisal well significantly increases the areal extent of the vast Itaipu field, and we believe incorporating the data from both the appraisal well and the original discovery well we will increase our previous resource estimates for the field. We are very pleased with these results and look forward to continuing our activity on the block.”
Available at: <http://www.pre-salt.com/pt/pre-sal-no-brasil/
successful-appraisal-well-in-the-pre-salt-of-block-bm-c-32-
-in-brazil-2172>. Retrieved on: 14 Nov. 2011. Adapted.
What kind of relationship could be established between Texts I and II?
