The uneven distribution of the production influx from the reservoir into the wellbore has been identified as the main issue in the management of production in heavy oil wells. This occurs due to a drastic difference between the mobility of oil and water i.e. water flows faster than oil in these reservoirs. This can be exacerbated by reservoir heterogeneities resulting in very high water production rate requiring large water treatment facilities which may be limited in offshore developments, resulting in reduced oil production.
Advanced well completions utilizing Inflow Control Devices (ICDs) and Autonomous Inflow Control Devices (AICDs) have proven to be robust solutions for these problems. Both devices help to enhance the performance of heavy oil wells by delaying the water production, however, AICDs are more capable to reduce the water production and increase oil production even after water breakthrough.
This paper examines the heavy oil/water production control by ICDs and AICDs and discusses the flow loop test data (single and multiphase flow) to describe the performance of devices for various fluids under downhole conditions. Using an example model, the reasons for the superiority of AICD over ICDs is investigated under different scenarios. An optimisation workflow was used to optimise the well completion design i.e. the size and number of devices plus packer placements and numbers.
The results of several field applications of AICDs, from retrofitting the existing completions of the wells with very high water cuts (e.g. 98%) to brand new wells in heavy oil fields, will be discussed. AICD completion as a proactive-reactive device was found to be the most efficient completion at controlling the water production from high productive zones or the fractures, compared to the wells equipped with ICDs and other conventional completions while increasing oil production.
This paper provides insights about inflow control device applications in heavy oil wells and provides a comprehensive guideline on the selection of appropriate completions for the wells in these challenging reservoirs.