Line balance method helps protect offshore crude lines

Shell Pipe Line Corp. began a program in 1991 to install line integrity on pipelines it operates in the Gulf of Mexico. Shell Pipe Line studied a variety of means to do this, and selected the line-balance method to provide line integrity. The line-balance method sums all inputs and compares these to the outputs to determine the integrity of each pipeline segment. Shell developed and installed a system that uses recently introduced technology to implement this system in the offshore environment. The system has been in operation on many of the pipelines Shell operates in the Gulf of Mexico, and has proven to be a successful design. Shell will complete the installation of the line integrity system on all offshore pipelines within the next 2 years. Flow measurement accuracy influences the system's release sensitivity. The custody transfer meters at each platform used as the primary meters for each pipeline segment help keep the measurement as accurate as possible. Using these meters enabled Shell to obtain temperature-compensated barrels, which reduces volume variations due to temperature changes as the crude oil leaves the platform. The flow computer collected all measurement data as well as the status or control of pumps or valvesmore » from the platform.« less