Increased Oil Production in Super Thin Oil Rim Using the Application of Autonomous Inflow Control Devices

Abstract

Despite the improved productivity and uplift in reserve recovery associated with horizontal wells, reservoir heterogeneity can cause uneven production, and early water and gas breakthrough from portions of the wellbore. Inflow control devices (ICD) create additional pressure drop to balance the production flux, but cannot restrict unwanted effluents once they break through. The Autonomous Inflow Control Device (AICD) actively delivers a variable flow restriction in response to the properties (viscosity) of the fluid flowing through it. Water or gas flowing through the device is restricted more than oil. When used in a horizontal well, segmented into multiple compartments, this design prevents excessive production of unwanted effluents after breakthrough occurs in one or more compartments. In the 2016 infill development campaign, production was improved by AICDs to ensure contribution from all reservoir sections, and limit gas and water production by postponing breakthrough and restricting unwanted effluent production after breakthrough. A nine well program was selected to demonstrate the effectiveness of AICD completions in the East Belumut and West Belumut assets, a field development offshore Malaysia. The wells are drilled with horizontal lengths typically 1.5km within the original 6-8m thin oil column for West Belumut and 10-14m thin oil column for East Belumut. The program comprised of AICD flow loop testing, performance modelling, candidate selection, completion design and comparing production results with neighbouring ICD wells in the fields. The implementation of an AICD completion was a success and full fields implementation took place in 2017. First installed in March 2016, the AICD completion was adopted as part of the standard lower completion solution at East Belumut. To date additional wells have been completed with AICD completions in East and West Belumut fields, demonstrating significant increase in cumulative oil production, reduction in GOR of the AICD wells by 50%, and achieving 50% more oil production compared to offset ICD wells. This paper describes a full field implementation for the application of AICDs in a super thin layer, oil reservoir offshore Malaysia. Nine new horizontal wells in two different fields were completed with AICDs to reduce the amount of water and gas production from these wells and to enhance the reserve recovery from the asset. The paper describes the workflow for establishing the suitability of candidates for the technology, the completion design process, and the enhanced production results of the program after 2 years production.