New 2D and 3D Acoustic Tools and Techniques for Underwater Metrology and Inspection
Authors: Thompson R. Lee , Lesnikowski Nick , Rush Ben , Potrzebowski Erin Elizabeth , Richardson Donald 
Published: April 2012

Abstract
This paper focuses on improved techniques for conducting detailed underwaterthree-dimensianal (3D) metrology and structure inspections using new highresolution 2D and 3D acoustic sensors that provide analogous results to 2Doptical video cameras and 3D optical laser systems, but are independent ofwater clarity conditions. These new tools and techniques can improveefficiency, reduce time and costs, reduce rework, and improve safety andenvironmental performance when developing, exploiting, and producing offshoreoil and gas resources.
A series of high fidelity, U.S. Department of Defense (DOD)-fueled 2D and 3Dacoustic sensors and technologies have been commercially matured over the lastdecade and are now being used increasingly in a wide range of oil and gasapplications. In 2010 BlueView Technologies, Inc. and Chevron Energy TechnologyCompany began jointly pursuing a project funded by the Research Partnership toSecure Energy for America (RPSEA) to leverage the high sensitivity andresolution of these new products and technologies specifically for O&Gapplications. This paper discusses applications such as pipeline inspection, detection and quantification of product leaks, and spool piece metrology. However, particular attention is given to techniques developed and resultsachieved during multiple offshore spool piece metrology tests andoperations.

Introduction
Converting offshore oil and gas resources into economic reserves can be a timeconsuming and expensive process. In addition, pipeline failures, flowrestrictions and production downtime can further increase costs of exploitingthese reserves. These costs can all be reduced with faster, more efficient, andmore effective techniques for underwater survey and inspection. Existingmethodologies involve visual inspections, and/or the use of lower frequencysonar equipment that generally does not have the resolution and sensitivity todetect subtle features. Visual inspections require divers or video cameras, both of which are limited by poor visibility. Underwater laser systems cansupply excellent results, but are also vulnerable to poor water qualityconditions. Existing acoustic measurement (metrology) solutions can either takemany steps to complete or lack the resolution and sensitivity necessary(conventional multibeam sonar) to enable detailed measurements and detectsubtle features such as corrosion, leaks, or heat plumes. New approaches canreduce costs, increase efficiency, and enhance environmental performance. Specifically, this paper addresses results achieved as part of the RPSEA-fundedproject. Among the applications developed, this project addressed multibeamimaging sonar-based ROV dynamic positioning for improved inspection of risers, enhanced pipeline survey that can improve flow assurance, enhanced storm damageassessment that can reduce downtime and shut-in, and early warnings on problempipeline areas that can improve safety and environmental performance. Inaddition, improved spool piece metrology techniques were rapidly developed aspart of this project and subsequently demonstrated in multiple actual offshoreoperations to accelerate completions. Therefore, this application is givenparticular attention. This rapid successful maturation of this particularapplication solution from concept to demonstrated offshore operation toolillustrates the potential gains in safety and efficiency that can be realizedfrom further development of the other promising applications that have alreadybeen identified and initiated as part of this RPSEA project.