Implementation and Application of Active Slug Control on Production System: a Real Field Case Study Workflow

Abstract

Slugging is a dynamic flow behavior observed in many multiphase production systems. It is due to the rapid change in volumetric phase flowrates within a process. Various slug mitigation strategies have been implemented in production facilities over the world to ensure stable production and maximum field recovery. This paper aims to present the project overview, workflow and use cases for the implementation of an active slug control technology based on real-field project experiences. An active slug control algorithm can be used for slug mitigation on upstream production systems. The purpose is to stabilize production flow from the flowline inlet to the first stage separator so that stable and safe production is ensured within the system design constraints. This in turn has the potential to increase production flow and further extend field life of aging production facilities. This paper presents examples of feasibility assessments and field implementations, covering both conventional oil and gas-condensate production. An active slug control technology can be applied to both deep-water and shallow-water facilities. Installation of this slug control system requires only an update to the existing flow controller to include an additional algorithm for slug suppression at the riser top choke valve. This simple addition eliminates the requirement of active operators’ intervention in the event of slugging, as well as reducing the frequency of process trips. In comparison with other slug control methods, this technology is cost-effective since no additional process equipment is required to be installed and maintained. As a result, this significantly reduces the project execution time, avoids production disruptions, and minimizes potential HSE issues. The technology can be implemented within a year from the outset of a feasibility study. However, the technology is not appropriate for all situations due to differences in slugging nature and other subsurface issues and therefore its applicability needs to be evaluated on a case-by-case basis. With increasing number of aging offshore assets and competitiveness in the energy market, it is expected that active slug control technology will become a crucial tool to reduce production downtime and deferment. This paper also presents a workflow which aims to provide a general guideline for the feasibility assessments and implementation of this slug control technology on producing assets. The objectives of slug mitigation may vary from asset to asset due to differences in production conditions, slugging characteristics and facilities design. Therefore, strong client engagement is necessary to ensure the most optimal workflow for the technology to be implemented.