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CNPC R&D workshop on waterflooding in carbonate reservoirs
I had the privilege of participating in a workshop organized by CNPC R&D on waterflooding in carbonate reservoirs in Dubai in November 2024. The topic was “Development Strategy and Waterflood Design in Carbonate Reservoirs”. I gave a presentation of the first day about the status of Primary, Secondary, Tertiary development mindsets at the light of psychology and field data… Strange combination one could say. I let you have a look at the slides of the presentation.
The abstract: Rethinking the ‘Primary, Secondary, Tertiary’ Approach
Words shape our thoughts, influence perceptions, and drive actions. The language we use frames how we interpret experiences and make decisions, actively shaping realities and guiding industry practices.
An example in the oil industry is the “Primary, Secondary, and Tertiary Oil Recovery” approach which is a deeply ingrained concept. While this method has driven field development for decades, its results warrant scrutiny.
- Low Recovery Rates: Despite advancements, secondary recovery leaves up to 70% of oil untapped (IEA). A 30% recovery rate demands a reevaluation of current methods. Why not employ all available techniques to improve recovery from the start?
- High Water Production: Secondary processes yield excessive water, requiring energy-intensive management. Engineers should question the heavy reliance on waterflooding without integrating additional techniques upfront.
- Diminishing Returns Post-Water Breakthrough: Reservoir heterogeneity leads to early conformance issues, making it difficult to resolve problems once water breakthrough occurs. Ignoring these challenges early on limits the effectiveness of subsequent recovery methods and overlooks the inherent unpredictability of reservoirs.
Why does the industry continue to follow the same patterns despite advances in knowledge and technology? The primary reason often comes down to economics and profitability. Parameters like discounted cash flow or net present value (NPV) are commonly used to gauge financial success. However, a high NPV doesn’t always equate to maximum recovery efficiency and can be energetically inefficient (Farajzadeh, 2019; van Essen, 2019; Farajzadeh, 2021). When water cuts exceed 90%, a significant portion of the energy derived from oil is consumed in managing injected and produced water, resulting in high CO2 emissions. Essentially, at such high-water cuts, the energy needed to handle large water volumes relative to the oil produced increases sharply. Below a 70% water cut, extraction remains efficient and could be driven by Net Present Value (NPV). However, it still demands a careful, engineering-based approach. Proactively combining Enhanced Oil Recovery (EOR) techniques with conformance control is crucial to prevent the system from reaching an irreversible decline in performance.
In this presentation, we will explore recent evidence highlighting the benefits of incorporating Enhanced Oil Recovery (EOR) techniques early in a field’s development or at least not delaying their implementation. We’ll examine case studies from Argentina, Alaska, and the Middle East, demonstrating the advantages of early chemical EOR adoption. A comparison of secondary versus tertiary polymer flooding implementation by Hilcorp in Milne Point will showcase the clear benefits of the optimal strategy. We will also discuss the potential challenges to quicker implementation in sandstone and carbonate reservoirs, focusing on a holistic approach to address these issues.
Bibliography
van Essen, G., Zandvliet, M., Van den Hof, P., Bosgra, O. & Jansen, J.-D. Robust waterflooding optimization of multiple geological scenarios. SPEJ. 14, 202–210 (2009).
Farajzadeh, R., Kahrobaei, S., Eftekhari, A.A. et al. Chemical enhanced oil recovery and the dilemma of more and cleaner energy. Sci Rep 11, 829 (2021). https://doi.org/10.1038/s41598-020-80369-z
Farajzadeh, R. Sustainable production of hydrocarbon fields guided by full-cycle exergy analysis. J. Pet. Sci. Eng. 181, 106204 (2019).
Farajzadeh, R., Zaal, C., van den Hoek, P. & Bruining, J. Life-cycle assessment of water injection into hydrocarbon reservoirs using exergy concept. J. Clean. Prod. 235, 812–821 (2019).
Farajzadeh, R., Wassing, B. L. & Lake, L. W. Insights into design of mobility control for chemical enhanced oil recovery. Energy Rep. 5, 570–578 (2019).
Farajzadeh, R., Kahrobaei, S. S., de Zwart, A. H. & Boersma, D. Life-cycle production optimization of hydrocarbon fields: Thermoeconomics perspective. Sustain. Energy Fuels 3, 3050–3060 (2019).
IEA : https://www.iea.org/commentaries/whatever-happened-to-enhanced-oil-recovery#
The Excel Or Routine Podcast with Randy Seright – Part 5: Water shut-off and conformance
Welcome to our latest podcast episode featuring Randy Seright! Randy is a renowned expert in the field of Polymer Flooding and Water Shut-Off, and in this episode, we discuss the basic (yet important) concepts behind water shut-off and conformance technologies. We discuss:
- Differences between conformance and water shut-off
- Water-cut: How did I decide there was a problem?
- What did I do to diagnose the problem – the importance of diagnostic
- When gel treatments apply best
- Sizing, implementation, success in fractures
- Conformance technologies: microgels, nanogels, etc.
EOR Podcast: Polymer Flooding Simulation
Welcome to our latest podcast episode featuring Randy Seright! Randy is a renowned expert in the field of Polymer Flooding and Water Shut-Off, and in this episode, we discuss simulation of polymer flooding. Are commercial simulators able to predict polymer injectivity? What inputs are required? What are the common mistakes when modeling polymer injection? Why good lab studies are paramount to de-risk polymer injection?
Changes to the way polymer is modeled are required to better match what actually happens in the field.
Additional discussions on injectivity can be found here.
Polymer Flooding: Current Status and Future Directions (Randy Seright)
Polymer Flooding Current Status and Future Directions provides a great overview of the technology and remaining challenges. This review presents our perspective on the factors that have brought polymer flooding to its current state. Insights are provided on why HPAM is the dominant polymer used as well as what is needed to make alternative polymers and mobility-control methods viable. Explanation is given for why large polymer banks are needed for polymer flooding, and design of the injected polymer viscosity is detailed for cases with/without crossflow. The role of fractures and horizontal wells are discussed for improving injectivity and extending polymer flooding to recover oils with viscosities as high as 10,000 cP. Operational improvements are described to minimize mechanical and oxidative stability to allow HPAM polymers to be viable to 70 °C and ATBS polymers to 120 °C. Key factors affecting polymer retention are summarized. The paper points out unresolved issues and future directions for polymer flooding.
More information on the technology at polymer-flooding.com
Excel Or Routine with ChatGPT – Navigating PowerPoint Presentations
For a long time, one of my biggest challenges was not knowing how to code. It held me back from turning my ideas into reality or optimizing my days. I tried learning Python on Udemy, but dedicating enough time to really master it was tough… And I was not interested in becoming a developer anyways.
Then I discovered ChatGPT.
Now, I use it (almost) daily to help me write code (VBA, Python) for everything from building databases and my own CRM, creating graphs from large Excel files, streamlining PowerPoint presentations, organizing and summarizing papers on my computer, and more.
In addition to sharing knowledge on EOR, I’ll put out some videos explaining how I use ChatGPT to make my life easier and focus on what I like doing.
The first video shows how I use it to navigate large PowerPoint presentations and even homogenize them (when you have 600 slides coming from different versions and don’t want to change the title font on each and every one of them manually 😎).
With this tool, the only limit for now is my imagination 😂
Excel or Routine – ChatGPT for PowerPoint presentations
I’ve always been frustrated by my lack of coding skills, especially when I see how much it could simplify and accelerate my work. Learning to code felt daunting, but with ChatGPT, this frustration has turned into progress. Now, I can rely on it to help me write and understand Python code, troubleshoot problems, and streamline my tasks. It’s become an invaluable tool, allowing me to accomplish in minutes what would have otherwise taken hours, making complex processes much more accessible and efficient. n this short video, I explain how I use ChatGPT to build and navigate my long PowerPoint presentations.
Excel Or Routine Podcast: Injectivity with Randy Seright
Injectivity in polymer floods. Here’s the second episode of the Excel Or Routine podcast with Randy Seright.
In this one, we spend another 1h30min discussing very hot topics in Polymer Floods including injectivity, reservoir response, monitoring, fractures, geomechanics, shear-thickening, mobility ratio and reservoir simulation.
I put the timestamps for those who prefer jumping from one topic to another.
Next episode, still with Randy, will be about laboratory tests: the good, the bad, the must, and the avoidable. And another is being prepared specifically on Polymer Flood simulation (October).
Don’t hesitate to reach out for ideas, comments or to participate.
Here’s another video on the injectivity topic, providing a great introduction on the matter.
EOR/IOR terminology – time for a (real) change?
On August 1, 2024, the SPE community issued a call for public input on proposed changes to IOR/EOR terminology. Surveys showed limited understanding of these terms, prompting the need for clarity. However, upon reviewing the new proposals, including the introduction of an additional term (AOR), some found the changes even more confusing. The question arises: why not completely overhaul the terminology to simplify things instead of adding more complexity?
Words hold immense power in shaping how people think, perceive the world, and ultimately, how they act. The language we use not only reflects our thoughts but also influences them, creating frameworks within which we interpret our experiences and make decisions. This performative aspect of language means that the words we choose can actively shape realities, guiding collective attitudes, behaviors, and even the direction of entire industries.
An example lies with the well-established “Primary, Secondary, and Tertiary Oil Recovery” approach is deeply ingrained in the oil industry, and it is a foundational concept in all reservoir and petroleum engineering handbooks. This wording and methodology have undoubtedly guided the development of oilfields since the industry’s inception. While the rationale behind this approach is not necessarily in dispute, it is worth questioning the outcomes it has produced:
A lot of oil is left in the ground after secondary recovery, especially after waterflood.
A few years ago, the IEA reported that the average recovery factor for oil-bearing formations was around 30%, leaving 70% of the oil untapped in the ground (source: IEA). In the scientific and engineering communities, a 30% yield should prompt a critical evaluation of the methods and strategies used in oilfield development. Despite nearly a century of experience and significant technological advancements, this low recovery rate remains the norm for most oilfields. Why continue to rely on approaches that have consistently proven to be insufficient? Why not include all techniques available to improve recovery?
A lot of water is produced and must be dealt with
Similar reports indicate that secondary processes yield between 5 and 14 barrels of water per barrel of oil produced. This energy- and CO2-intensive process should lead engineers to reconsider why so much emphasis is placed on waterflooding alone, without the immediate support of additional enabling techniques.
Once water breakthrough occurs and the field becomes brown, economics of additional techniques and their ability to fix the issues decrease
All reservoirs, whether sandstone or carbonate, share a critical characteristic: they are inherently heterogeneous. This means that any injected fluid will naturally follow the paths of least resistance unless specific measures (such as conformance treatments, viscous polymer floods, foams, or Water-Alternating-Gas (WAG) injections) are taken to promote a more uniform sweep of the reservoir. Consequently, conformance issues are inevitable, often emerging sooner rather than later. Once water fingering occurs, it becomes exceedingly difficult to resolve, largely due to the same challenges in reservoir characterization that prevented early detection. Ignoring these potential problems, despite knowing they will arise, overlooks the fact that we sample less than a fraction of the reservoir and will never fully understand it—except to know that it is heterogeneous, and challenges are certain to follow.
Having terms like AOR, EOR, IOR just makes things even more complicated. To simplify terminology and encourage a more scientifically grounded approach, it is important to revisit the established terms used in production/reservoir engineering. Drawing from the extensive knowledge, field cases, and research available through the SPE, we suggest the following changes:
-
- Eliminate the terms “primary,” “secondary,” and “tertiary” recovery: These outdated terms and their sequential definitions fail to reflect the depth of experience and knowledge gained over the years. They often lead engineers to repeat practices that should no longer be considered best practice.
- Introduce two main categories with relevant subdivisions: This updated framework better reflects contemporary scientific insights and encourages the adoption of more effective, evidence-based strategies in oilfield development. By doing so, we also avoid relying on the “baseline” concept, which reinforces the outdated notion of staged production—an approach that, as discussed, has significant limitations. Furthermore, there is growing evidence that companies initiating Enhanced Oil Recovery (EOR) immediately after so-called Primary production are achieving outstanding results, often surpassing those of traditional waterflooding. A prime example of this is Hilcorp’s success at Milne Point.
Some terminology ideas
Baseline Oil Recovery (BOR) or Baseline Recovery (BR):
It is the oil recovered by means of unassisted natural depletion-drive mechanisms using conventional vertical wells and completions. Mechanisms include solution-gas drive, fluid expansion, aquifer drive, gas-cap expansion, and/or rock compaction.
Assisted Oil Recovery (AOR)
- Surface-Controlled Recovery (SCR) or Reservoir Access Enhancements (RAE)
- This name reflects the methods that manage and optimize recovery through surface-level interventions and well operations, focusing on enhancing the wellbore or surface facilities rather than altering the reservoir itself. It includes:
- Pattern and fluid sweep adjustments
- Drilling and well intervention
- Production Mechanics
- They can be applied at any time during the field’s life.
- Subsurface Injection Recovery (SIR) Or Injection-Based Enhancements (IBE)
- This category encompasses all methods that involve injecting fluids into the reservoir to enhance oil recovery. These techniques are further divided based on whether the injected fluids are native to the reservoir or non-native.
- Native Fluid Injection (NFI)
- Definition: This subcategory includes recovery methods where the injected fluids are naturally occurring in the reservoir. The primary purpose of these techniques is to maintain reservoir pressure and improve displacement efficiency by reintroducing the same types of fluids that the reservoir originally contained.
- Key Techniques:
- Water Injection: Reinjection of produced water or other water sources to maintain pressure.
- Gas Injection: Reinjection of produced gas, such as natural gas or associated gas, to enhance oil recovery.
- Non-Native Fluid Injection (NNFI)
- Definition: This subcategory involves the injection of fluids that are not originally present in the reservoir. These techniques typically aim to alter the reservoir’s characteristics or the fluid properties within it to improve oil recovery.
- Key Techniques:
- Chemical Injection: Polymer (+SP/ASP) flooding, microbial enhanced oil recovery (MEOR).
- Gas Injection (Non-Native): CO2 injection, nitrogen injection, hydrocarbon gas injection (e.g., propane, butane), Water-Alternating-Gas (WAG).
- Thermal Methods: Steam injection, in-situ combustion, cyclic steam injection, SAGD (Steam Assisted Gravity Drainage).
- Other Energy-Based Techniques: Microwave energy, acoustic wave energy.
- Native Fluid Injection (NFI)
By focusing on the nature of the intervention rather than adhering to traditional stages of recovery (primary, secondary, tertiary), these names simplify the approach and avoid the pitfalls of segmenting production into too many rigid stages. Such an approach moves away from the myopic focus on optimizing Net Present Value (NPV) by stage and instead emphasizes optimizing the full lifecycle of the reservoir. By doing so, we open up the possibility of achieving higher recovery rates, reducing water production, and addressing conformance issues before they become insurmountable—all by leveraging the full range of available techniques in a more cohesive and strategically sound manner. However, we must acknowledge that changing established terminology and practices will not be easy. The power of words and the frameworks they create in our minds is immense, influencing how we approach challenges and make decisions. Yet, with the work already begun and the momentum building, this could be the right moment to reexamine and reshape the language and strategies we use in oilfield development. This is an opportunity to align our practices with the realities of today’s industry and set a course for greater efficiency and success in the future.
An introduction to Injectivity in Polymer Floods
I’ve just recorded a one-hour video where I dive into the injectivity challenge in polymer floods.
💡 What exactly is the injectivity issue, and why does it matter so much? What key factors should you be investigating? And why do 3D simulations often fall short when it comes to predicting the critical parameters needed for business decisions? And finally, who’s really afraid of fractures? 🧐
This video serves as a primer for topics I cover in my training courses, and it sets the stage for an in-depth session with Randy Seright that I’ll be sharing next week, where we explore these concepts further.
I hope you find it insightful and that it encourages you to “stay away from black magic and benchmark your simulation against field evidence” – wise words from Randy.
You can also refer to this page for more.
The Excel Or Routine Podcast is on!
There it is, the first episode of the Excel Or Routine Podcast with Randy Seright, ready to watch on YouTube! 🎧 Check it out here: https://lnkd.in/edsPv-MY
In this episode, I sit down with Randy Seright, who has been a significant mentor throughout my career. We dive into his early career, his recent research, and key aspects of designing polymer flooding projects. Randy’s insights are invaluable, and I’m excited to share our conversation with you all. You can find the conversation’s timestamps in the video description if you prefer to skip around instead of watching the entire 1 hour and 23 minutes or want to speed up the playback. 🙂
This podcast aims to foster knowledge sharing and spark discussions in the field of polymer flooding. I’m looking forward to bringing you more episodes featuring industry experts and academics to broaden our perspectives and enhance our understanding. Next in line also with Randy about injectivity and reservoir simulation.
And for more resources, check out the Polymer Flooding Academy on my revamped website at polymer-flooding.com.
Thank you for your support, and I hope you find these resources helpful! 🙌
PS: It’s DIY: intro music is homemade 🎸🎼🎤, as well as the editing.