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Drilling Hazards Assessment from 3D Exploration Seismic Data
In deep water it is often possible to use 3D exploration seismic data as an alternative to acquiring a pre-drilling hazards survey from a
conventional hazards survey vessel. Generally this method can be used in water depths greater than around 200 meters / 600 feet. In some
cases further processing of the data may be required in order to optimize data quality in the shallow section but, increasingly, we are able
to use the regular exploration seismic data.
Data is loaded and interpreted using a PC based system and Kingdom Suite software from Seismic Micro Technology. The interpretation process
consists of mapping seabed and significant horizons, examining amplitudes and attributes and performing interpretation of the near surface
geology with an emphasis on describing expected drilling conditions and possible hazards. Sub-seabed interpretation is carried out over the
entire block. Data from adjacent blocks may also be loaded and used to perform seabed only analysis in cases where the anchors are expected
to cross into the adjacent blocks
Reports may be tailored to client preference but generally consist of two distinct components, a general analysis and discussion of the seabed
and sub-seabed conditions and individual well analysis/anchoring condition assessments for each specific planned well.
The general analysis will contain some discussion on the data and the interpretation process followed by discussion on the interpretation and on
any potential drilling hazards. This will be followed by relevant data examples and a series of charts showing:-
- Seabed depth
- Seabed amplitude
- Seabed Relief
- Attribute extractions between horizons
- Horizon structure maps
- Geohazard Summary map
The location specific portion of the report will contain a site clearance letter and anchoring assessment for each planned well.
For Gulf of Mexico work these are provided in MMS approved format and can be incorporated by the client into the well planning permits.
Location specific reports will include letter sized data examples, top hole prognosis and plats and full sized charts of the seabed depth,
morphology and amplitude around the proposed locations.
Gardline Surveys Inc, 8556 Katy Freeway, Suite 104, Houston, Texas TX 77024, USA
Tel: + 1 713 973 2855 Fax: + 1 713 464 8275 |
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Michael Pentland, President
• michael.pentland@gardline.com
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