This paper presents the various challenges faced by a 10-km waxy crude oil pipeline at Field 23, as the pipeline has not been able to be pigged for almost one year due to recurring pigging issues such as broken/damaged pigs, vibrations and high pressures that were close to trip settings. The implemented pigging frequency as per operating philosophy is every two weeks. However, the frequency has been extended based on field experience. Due to these issues, Operation team immediate action is to devise a pigging program that works and to avoid recurring issues. Flow Assurance (FA) engineers working together with Operation team devised a plan that incorporates lab analysis and conducted desktop studies which include field data analysis and application of various FA simulation tools. The main challenge is to develop a robust FA model that is reliable enough to use for detailed analysis, be able to reproduce field data and use it to develop the most suitable pigging program. Additionally, it is worth noting that the pipeline has gone through rigorous wax chemical optimization that potentially contribute towards wax incremental issues in the pipeline. It was also observed that the fluid has changed tremendously from initial design basis due to fluid blending from non-associated gas (NAG) and oil zone and production header temperature mixing effects. Therefore, the initial operating envelope was found to be no longer suitable for this pipeline. From extensive lab analysis, fluid modelling update, metocean data calibration and wax deposition tuning, the FA models were able to match the field conditions within < 10 % variance. A field tuned baseline model was developed. Several options have been proposed and analyzed such as varying pig types, pigging and chemical methods where extensive FA modeling were performed to evaluate the suitability of each method/application to develop a more suitable pigging program. A detailed workflow on the chosen program was then produced based on a progressive pigging method utilizing multiple pig types at a reduced flowrate with chemical application. Although wax dissolution effects from wax dissolver chemical was not modeled, this model-based approach was a success in that we were able to reduce pig stuck risk during actual field implementation. The success of the waxy crude oil pipeline pigging campaign has sparked an immediate interest among the Production/Operation engineers especially on the application of a robust FA models, in which when it is well calibrated, enable effective and immediate troubleshooting of issues at site. This work has set a benchmark for FA engineers to update/develop a well-calibrated FA model during operation phase to facilitate optimization and troubleshooting programs.

Traditionally, a field’s wax management and operating philosophy have been developed by conducting a rigorous Flow Assurance (FA) study. Optimization at field level warrants the study to be updated from time to time to reflect the actual field performance. This accounts for overall field performance but does not incorporate variations due to operational changes. Rather, the operating philosophy is based on representative scenarios where conservative measures are often used to safeguard operations. With the increasing number of waxy crude oil pipelines within company that demands immediate attention, an online prediction/monitoring tool that quickly adapts to operational changes is one important enabler, not only to optimize operations and address the huge Operating Expenses (OPEX), but also to address remote/unmanned operation’s requirement especially for subsea operation. Unfortunately, to date, such a tool is not commercially available or deployed widely. To address this gap, this paper aims to present the Online Wax Smart Meter development concept and to showcase the performance of an online wax monitoring tool which enables fast and optimum wax management.