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The super-giant ACG field lies in the Azerbaijani sector of the south Caspian Sea. The significant complexity of the geohazards setting over the field was realized in 1993 when negotiations for the PSA to develop the field were still ongoing. This resulted in the need to understand geohazard risks being recognized in the Minimum Obligatory Work Program terms set out in the "Contract of the Century" in September 1994. Over the last twenty years work to define and refine understanding of the multiple geohazard issues has been ongoing. Work started in early 1995 with the completion of two deep geotechnical boreholes and a PSA contract area wide geophysical and geological geohazards campaign that delivered an early, first pass geohazards stop-light map and supported delivery of the Early Oil Project (1997). The results of these two initial pieces of work formed the basis of the first PSA contract area wide integrated geohazard study that addressed the threats of individual sources of geohazard to Full-Field Development planning. These included, amongst other issues: slope instability, mud volcano stand-offs and fault risks, all being included in the first integrated geohazards risk map of the PSA's contract area in 1999. Since this time, direct experience, in drilling and facilities installation, has driven the need for an ongoing update of data and improvement in geohazard understanding. New sources of hazard, such as the implications to riser-less drilling from super-saline soils, have had to be assessed and new data acquired to assist in mitigation of the risks identified. Most recently HR3D data has been acquired across the entire PSA which, tandemed with AUV seabed and shallow profiler imagery has been used to guide a further series of geotechnical campaigns. These results have been used to drive an update to the geohazards zonation addressing, in particular, slope instability in field areas previously considered too sensitive for development. This paper provides a timeline of geohazards activity on the ACG PSA over the past twenty years as a background to other papers being offered in the technical session that discuss how specific geohazard data acquisition and analysis issues have been addressed.

Challenges face the geotechnical engineer in the ACG Field in the Caspian Sea, from data acquisition, through soil characterization, to foundation design and installation. This paper seeks to address some of these challenges and describes some case examples from the authors' experiences, particularly in the treatment of geohazards and their threat to foundation integrity.Limited guidance exists within industry codes and standards to address the interaction of geohazards with jackets and with subsea infrastructure. As such, quantified risk assessment becomes complex. This paper suggests some solutions to these problems, borne out of more than 20 years' operating experience in the Production Sharing Agreement (PSA) and the need to consider development in some of the more geohazardous areas.Unusual methods of geotechnical data acquisition are presented along with tools and novel analytical techniques specific to the needs of Caspian soils. Finally, the paper presents some approaches to quantify the impact of geohazards, including the influence of unusual soil conditions as they present themselves today.

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This paper describes the design development and installation of a novel concept used to repair the piles at Valhall Water Injection Platform in the Southern Norwegian Sector of the North Sea. The paper describes the concept, design principles, the tolerances required to account for known and potential dimensional variations, a test programme to verify key activities and the installation.