Application of dynamic positioning techniques to working classremotely operated vehicles (ROVs)

摘要

There are three principal reasons for the increase in the use ofnremotely operated vehicles (ROVs) to replace divers for subseanoperations in offshore oil and gas production during the past severalnyears. First, there has been an increased emphasis on safety. Second, annROV and its associated support vessel can be leased for about one thirdnof the day rate cost of that associated with divers to perform the samenfunction. And third, hydrocarbon production is taking place in waterndepths greater than that accessible by divers. This replacement ofndivers by machines to accomplish more complex tasks has resulted in thendevelopment of more sophisticated intervention equipment and morenpowerful ROVs. The increase in the complexity of the subsea work couplednwith more powerful vehicles has placed greater burdens on the ROV pilot.nMuch of the fatigue could be reduced by supplying the pilot with betterninformation and control. With a fully developed real time navigationnsystem, a representation of the structure could be displayed on a videonmonitor with the ROV shown as a moving icon on the screen. A snail'sntrail from the ROV icon could also be displayed indicating the locationnof the umbilical. The navigation task is then reduced to monitoring thenvideo representation and verification of position by observing compassnheading, and television or sonar displays. Two specific areas which havenbeen addressed are looked at in the paper: the design of a SONAR-CADnNavigation Package and the implementation of a dynamic positioningnsystem used in conjunction with the Marquest Group EXACT system