Journey of Waterflood Excellence in a Matured Field, North of Sultanate of Oman
Authors: Chatterjee Someshwar , Riyami Nasser , Ruqaishi Ali 
Published: March 2022

Objective/Scope

The studied field is located in North Oman asset and developed through waterflood line-drive since 1980s with top quartile recovery factor. In the period between 2010 and 2012, production has declined faster than expected reaching to a peak decline rate of 19% per year resulted to significant associated oil production loss. This abstract summarizes the recovery process for waterflood development supported with lean approach by WRFM team not only to arrest production decline but also to flip the coin to production incline in 2015-2016.

Lean Approach

The major reasons that led to the ineffective waterflood performance in this field were several surface and subsurface issues related to water distribution, low injection efficiency and low level of integration within the team. The success achieved through focused proactive waterflood management (Asset's WRFM Plan, 2016) and seamless integration with field operations and asset leadership with below key steps:

Setting a firm WRFM Waterflood Strategy focusing on waterflood management, field/reservoir operating envelope and pressure maintenance. Goal Deployment value stream metrics aimed to improve reservoir operating envelope compliance by improving water-injectivity compliance that ensures effective and even injection water distribution etc. The pressure maintenance strategies include priorities the injection optimization in the low-pressure blocks and continuous monitoring of reservoir pressure through periodic acquisition of pressure surveys. This resulted in significant improvement of average reservoir pressure. Standardized regular field, pattern/ sector and well reviews (Chatterjee, Someshwar et.al., 2017) resulted in effective sweep monitoring strategy by using latest FDP static and dynamic models calibrated with recent surveillance data (RST, MPLT etc.). This process helps to generate and optimize the WRFM opportunities to maximize the production. Periodic waterflood health checks by external and internal experts mainly focused on accessing waterflood improvements and benchmarked with other fields of the asset during 2014, 2016 and 2018. The waterflood health check score improved with time and field achieved the highest score across all the other matured fields in North Oman. More importantly, the noticeable improvement in integration between different teams i.e. petroleum, operation, and engineering on daily to weekly basis ensures stability of the WI performance, meeting injection target and honest transparent communications to work as ONE TEAM through different session using Leader Standard Work (LSW).

Results and Conclusion

These efforts by the integrated team resulted in:

Arresting the production decline from 19% annual effective to 6% within 3 years Reversing the decline trend of 3% between 2015-2016 Safeguard more than a mln m3 of asset's reserves A gain of average oil rate for reversing the decline trend

This project is an excellent example of being innovative with lean structure and simple "Going Back to Basics" principle for water flood management. The projects delivered with commercial mindset to arrest the decline and safeguard reserves; external focus by benchmarking with waterflood assessment and strong integration- displaying highest standard of improved organizational behavior.