A Case Study on Integrated Downhole Logging Suite to Diagnose Multi-phase Flow and Improve Multi-Reservoirs Flow Allocation

Abstract

Abstract This paper discussed Operator's experience on integrated downhole logging suite to diagnose multi-phase flow and to improve multi-reservoirs flow allocation in deviated wells, offshore Borneo Island. Field A is located in the West Balingian geological province of the Sarawak Basin, 140km offshore Bintulu in a water depth of 165ft. It was discovered in by Exploration Well #1 (EW#1), followed by downflank Appraisal Well #2 (AW#2) in 1982 and second Appraisal Well #3 (AW#3) in 2000, to address some of the significant subsurface uncertainties impacting on the field development plan. Phase-1 development wells (e.g. DW#1 and DW#2) was drilled and completed in 2014, with 7″ × 4-1/2″ cemented liner as lower completion across the clastic reservoirs. During pre-development in 2016, additional perforation in DW#1 oil zones were added whereas additional perforations in DW#2 oil zones were added in 2019. The two (2) relatively new wells produce commingled from several oil-bearing and gas-bearing zones. Developing highly compartmentalized multi-stacked reservoirs via simplified well completions, poses a great challenge for subsurface data acquisition when it comes to determining production allocation, managing flow assurance issues, understanding reservoir connectivity, surveillance of individual well performance and generating total field production forecasting. Conventional production logging result conducted in 2016 was unsatisfactory to explain some of the wellbore and reservoir flow peculiarities. Since it was important to know which zones contributed to the production, diagnostic of wellbore/reservoir flows and coupled with well integrity issues, Spectral Acoustic Logging with Thermo-Hydrodynamic Modeling was conducted to obtain the valuable information and to perform well/reservoir diagnostic. Remote platform location put an additional challenge to the logging campaign, as such the logging program was customized to satisfy the logging objectives while comply with HSE requirement. The collaborative approach between Operator and Service provider as solution partners, established a new finding for the formulation of remedial treatment to increase production and recovery from the wells by ensuring that each well operates to the maximum of its abilities.