New 3D Acoustic Scanning Tools and Techniques for Underwater Metrology and Inspection
Authors: Thompson R.  Lee 
Published: May 2011

Abstract
Converting UDW resources into economic reserves can be a very expensive process. In addition, pipeline failures and downtime can further increase costs of exploiting reserves. These costs can be reduced with more effective techniques for underwater survey and inspection. This paper discusses improved techniques for conducting detailed underwater 3D metrology and structure inspections using new, high resolution 3D acoustic sensors that provide analogous results to 3D optical laser systems, but are independent of water clarity conditions. These new tools and techniques can improve efficiency, reduce time and costs, reduce rework, and improve safety and environmental performance when developing, exploiting, and producing UDW resources.
A series of high fidelity, 2D and 3D acoustic sensors have recently been commercially matured over the last 5 years and are now being used increasingly in a wide range of oil and gas applications. In 2010 BlueView Technologies, Inc. and Chevron Energy Technology Company began jointly pursuing a project funded by the Research Partnership for Secure Energy America (RPSEA) to leverage the high sensitivity and resolution of these new products and technologies specifically for O&G applications. This paper discusses and shows initial results for applications such as spool piece metrology, pipeline inspection, detection and quantification of product leaks, and early detection and identification of subtle indicators for conductor insulation cracks and corrosion. In addition, this paper discusses anticipated operational improvements based on initial results of controlled and offshore testing and operations and new directions planned for continuing testing and development.

Introduction
Converting UDW resources into economic reserves can be a time consuming and expensive process. In addition, pipeline failures, flow restrictions and production downtime can further increase costs of exploiting these reserves. These costs can all be reduced with faster, more efficient, and more effective techniques for underwater survey and inspection. Existing methodologies involve visual inspections, and/or the use of lower frequency sonar equipment that generally does not have the resolution and sensitivity to detect subtle features. Visual inspections require divers or video cameras, both of which are limited by poor visibility. Underwater laser systems can supply excellent results, but are also vulnerable to poor water quality conditions. Existing acoustic measurement (metrology) solutions can either take many steps to complete or lack the resolution and sensitivity necessary (conventional multibeam sonar) to enable detailed measurements and detect subtle features such as corrosion, leaks, or heat plumes. New approaches can reduce costs, increase efficiency, and enhance environmental performance. Specifically, this paper addresses improved metrology that can accelerate installations, enhanced pipeline survey that can improve flow assurance, enhanced storm damage assessment that can reduce downtime and shut-in, and early warnings on problem pipeline areas that can improve safety and environmental performance. This paper discusses initial controlled and offshore test results using new, high-frequency acoustic sensing tools for these applications. These initial results help to validate new capabilities that can lead to new levels of safety and efficiency.