Abstract

There is a growing interest in seismic surveys in arctic areas. Normally 2Dsurveys can be carried out with limited risk, as long as the area is reasonablyfree of ice. However, 3D seismic surveys are an essential tool for explorationin order to de-risk prospective areas ahead of expensive and challengingdrilling operations. Acquisition of 3D surveys, with multiple streamers, is farmore difficult than single streamer 2D surveys, as the amount of in-seaequipment is an order of magnitude higher and the data density for a given areacovered is far greater: the physical footprint of a 3D equipment spread beingtowed behind a vessel can be about a kilometer wide by several kilometers long. This significantly increases the risk of equipment damage due to ice. Thispaper summarizes experiences from several 3D surveys in the Arctic, andaddresses how the use of new equipment and techniques can reduce such risks toacceptable levels.

Introduction

There are a number of operational challenges for surveys in arcticwaters:

  • Short seasonavailable for operations

  • Ice in the water andextreme weather impacting efficiency and data quality

  • Logistics in remoteareas

  • Low temperatureeffects on equipment

  • Crew safety andcomfort in severe conditions

  • Poor visibility -fog and snow showers

The focus of this paper is risks associated with ice in the water. This isoften the most critical issue for surveys in arctic areas. Ice conditions canvary significantly from year to year, creating major uncertainties regardingsurvey duration and potential equipment damage. This paper outlines how thesechallenges have been addressed on several 3D surveys that have been acquired inarctic conditions offshore Greenland, Canada and Russia. Methods and technologyto improve efficiency will be outlined; experiences of ice damage riskmitigation will be shared; data quality issues will be addressed and areas forfuture development focus will be identified. Opportunities for equipmentmanufacturers to further improve their products will be highlighted.

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