--> Case Study: Impacts of TTI PSDM Reprocessing from the Preparation and Drilling of the Pazflor Development Wells, Bullen, Michael; Charles, Thierry; Giriansyah, Bayu, #90100 (2009)

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Case Study: Impacts of TTI PSDM Reprocessing from the Preparation and Drilling of the Pazflor Development Wells

Bullen, Michael1
 Charles, Thierry1
 Giriansyah, Bayu1


1
DB17/GSR, Total E&P Angola,
Luanda, Angola.

The deep water Pazflor project (B17 Angola) is now entering into the development phase with the drilling of its first wells targeting the Acacia Oligocene reservoirs. This communication reviews the results from a new PSDM TTI (Tilted Transverse Isotropy) which proved critical for planning the development wells on this complex field.
Acacia is buried at more than 2000 m with anticline flanks dipping up to 45°, and the seismic resolution is less than half that of adjacent fields; these characteristics make the development of Acacia a challenge for geophysicists.

Taking special care to preserve Class II AVA response and correctly position the structural flanks, the PSDM TTI gives considerably better focus than the previous data down to base salt and thus allows for improved well planning. The depth difference compared to the previous PSDM ranges from +/-30 m on the structural crest to +/-150 m on the flanks. Given such variations, a update of models and wells was required, which was not without challenges given the late availability of the new seismic dataset (6 months before first drilling)
This presentation therefore strives to review the geophysical basis for the PSDM TTI, the methods and workflows used for its rapid integration, and its various impacts on reservoir model construction and well planning.

It will also present an innovative way to quantify the depth uncertainties linked to the TTI processing (flattening of the gathers) and will explain how the drilling sequence was adapted to progressively reduce the remaining uncertainties.
The proof of concept will be tested in the second half of 2009, by which date 6 development wells will have reached their primary objectives. Preliminary results and key learnings concerning the planning of these wells will be discussed.



AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil