The integrity of subsea pipelines and trunklines is of paramount importance and shall be ensured starting from the offshore pipelay operation. This paper will provide an overview of Saipem Integrated Acoustic Unit (I.A.U.), an innovative and non-intrusive tool developed to detect, in real time, accidental deformations (e.g., buckle), lost devices or presence of water that may occur along the pipeline catenary during offshore laying. The I.A.U. exploits acoustic reflectometry.
During offshore installation, in case of accidental events, significant loads may occur inducing pipe deformations above the allowable limits. The I.A.U. can detect and quantify these deformations using the Piggability Detection function. The system emits acoustic chirps and performs the digital processing of the back reflected signal that is compared with the echoes of several simulations of possible pipe deformations stored in a data base specifically built for this purpose. In case of unexpected pipe deformations, the I.A.U. console shows to the Operator the related position and the percentage of the associated pipe diameter reduction. Furthermore, two additional functions are available: the Extended Acoustic Radar (EAR) to localize obstructions along the pipeline and the Water Level Monitoring (WaLeM) to detect the presence of water.
The achieved accuracy by the I.A.U. for pipeline piggability is comparable to the one of Mechanical Buckle Detector (MBD) that is commonly used during pipeline laying.
This paper will describe the I.A.U. technology background, the main components and functions, the different versions, the available I.A.U. prototypes, the technical demonstrator and the performance achieved during the experimental tests executed as part of the Third-Party qualification process with DNV. Finally, the application of I.A.U. that is foreseen in a real Project case will be described.
