Pushing Injectivity Limits via Waterflooding in Fractured Injection Conditions – An Automated Approach to Make Fractured Injection Safe, Manageable and Sustainable
Authors: Kattukaren Kurian , Hernandez Erika R. , Tarang Ravie Tajit Anak , Bong Charlene , Rosli Syazwina , Zaman Alifah , van der Heyden Frank 
Published: February 2025

This work describes the full field deployment of fractured injection (FI) to overcome severe injectivity issues hindering the efficiency of a waterflood and high stimulation costs in a sizeable, multi-well, complex brown field offshore in Brunei Darussalam. It details the methods used to derive a low-risk portfolio of wells for FI; the surveillance and mitigation measures to manage risks and field results from deploying the new injection philosophy.

Safety critical risks linked to FI were identified and novel automated tools developed to screen injector candidates and derive a low-risk candidates’ portfolio for implementation. The portfolio was ranked using multiple criteria covering both HSSE risks & value generation opportunities to finalize a portfolio of wells to move from matrix to FI conditions.

Novel Surveillance techniques based on Wellbore Storage to manage life cycle risks inherent to FI were identified, trialled and surveillance plans tailored to injector types to manage FI risks. A surveillance management tool and a unique escalation model deployed via automated tools to manage the offshore logistical challenge.

Automating the screening of safety critical risks allowed the subsurface team to build a low-risk portfolio of wells inexpensively and quickly when compared to checking in a "manual" conventional way. This allowed the team to accelerate the execution phase by a year, while making sure that all HSSE risks were accounted for. The use of an automated tool to manage surveillance requirements for FI wells, allowed the subsurface team to systematically derive a surveillance plan covering the full field swiftly, in less than 2 hours, compared to the conventional approach requiring at least 2 months. The creation of an escalation process gave clear line of sight as to when minimum safety surveillance requirements were not being honoured requiring a deviation. The tool permits managing deviations from the surveillance plan for the full field both comprehensively and in a timely fashion. In the absence of surveillance, the escalation process ensures temporary change of injection strategy (from FI to matrix) to ensure safe injection operations under all conditions.

The safe deployment of FI in this massive field brought an injection rate increase of +50% and the start of producer-injector connections not previously observed while injection was carried out on matrix conditions.

In contrast to manual/conventional approaches, the automated methodology allowed significant time-savings to deliver a portfolio of wells to swiftly start FI and facilitated the creation of custom-tailored surveillance plans to keep injection operations safe.

The methodology could also suit other massive reservoirs around the world for which FI can be an alternative to mitigate injectivity losses at low costs, as FI reduces the need for frequent well stimulations for injectivity restoration, allowing significant OPEX reductions.