Characterization of Grouts for Decommissioning of Abandoned Oil Pipelines

Due to higher demand for oil there has been increasing interest in offshore oil production. After the end of service life of oil wells based on the local, national and international rules and regulations, the entire infrastructure must be decommissioned. Generally in the offshore operations the time allocated for decommissioning has restrictions. In this study the objective was to develop a rapid method for the decommissioning of pipelines by using available grouting technology. Hence, a test protocol was developed to evaluate various types of grouts to rapidly fill and seal the pipes. Performances of the hydrophilic and hydrophobic expansive grouts were studied under simulated contamination, including the effect of salt water and oil on the curing and expansive characteristics of the polymer grouts in the abandoned pipes. Also, since the old oil pipelines will be coated with wax, plastic pipes with various sizes up to 3 in (75mm) diameter were used for the initial screening studies. The grout filled pipes were tested for leak under 100 psi (700 kpa) with air and water pressure. Based on the performance of the grouts, two grouts were selected for testing abandoned steel pipes (10 feet long 3 inch diameter) with different methods of grout injection. The performances of the grouted pipes were tested up to 100 psi (700 kpa) water and air pressure. Also the expansion of the grout in the confined pipe space was modeled using concepts such as gas production and strength development in the grout during the curing process.