How pre-conditioning the reservoir before large-scale injection permanently changed the economics of Field A.
Client: Client B
Field: Field A
Technology: Polymer-Disperse Systems (PDS)
Innovation Focus: A proactive paradigm shift from remedial “fix” to preventive “design” in waterflood management.
Резюме
In a groundbreaking departure from conventional industry practices, Client B pioneered a large-scale proactive application of Polymer-Disperse Systems (PDS) at the very early stage of the field’s waterflooding life cycle. Instead of waiting for large-volume injection to cause premature water breakthroughs and then reactively plugging the channels, Client B deployed this cutting-edge technology during the initial conversion phase of injection wells, before a stable injection profile could even form.
The staggering results of this large-scale, early-stage implementation speak for themselves: over a 3-year campaign (2017–2020), this strategy delivered a combined net incremental oil production of over 4.13 million barrels from independently reacting producers. More than the impressive barrels, the campaign successfully rewrote the playbook on reservoir management, proving that the timing and scale of conformance control are the ultimate keys to preventing catastrophic premature water breakthroughs.
The Industry Challenge: The Reactive Trap
The oil and gas industry is traditionally caught in a costly “break-and-fix” cycle. In highly heterogeneous reservoirs like Field A, newly converted injection wells naturally channel 100% of their injected water into narrow, high-permeability “thief zones.”
For example:
- Injector A-1 initially directed 52% of its total injection into a single 2.5-meter interval.
- Injector A-2 had 83% of its water escaping through a single bottom zone.
The standard industry approach: Start injection, wait for water to breakthrough at producing wells (often causing severe reservoir damage and economic loss), and then apply remedial isolation techniques).
The Breakthrough: Large-Scale Implementation at the Earliest Stage
Client B rejected the reactive approach. Instead, they pioneered a large-scale proactive deployment of PDS immediately after converting production wells to injection, while the waterflood profiles were still being established. This innovative approach represents a paradigm shift in Enhanced Oil Recovery (EOR) because it addresses the root cause of poor sweep efficiency before large-scale water injection begins.
What is PDS?
PDS is a breakthrough two-component conformance control technology that achieves true sweep correction through autonomous targeting. Its unique mechanism operates as follows:
- Autonomous Targeting & Water Triggered Reaction: PDS components preferentially enter high-permeability water-swept thief zones. Flocculation is triggered exclusively by formation water. In oil-saturated zones, the components remain completely inert.
- Scalable Flocculation & DPR: Once triggered by water, a scalable flocculation process begins, forming a durable, water-tight barrier deep inside the thief zone. This leads to Disproportionate Permeability Reduction (DPR), where water permeability is drastically reduced while oil permeability remains unaffected.
- The Result: Formation water acts as a chemical switch, ensuring a permanent barrier is created only where it is needed, leaving oil-rich zones untouched and ready for the redirected waterflood.
The Game-Changing Advantage: Early-Stage Pre-Conditioning for Large-Scale Waterflooding
The crucial distinction of this project was that PDS was applied on a large scale, at the very beginning of the waterflooding lifecycle. This proactive “pre-conditioning” of the reservoir provided three substantive, long-term improvements:
🔹 Preventing Early Water Breakthrough: By isolating thief zones at the very start of the large-scale injection plan, the injected water was forced into oil-bearing intervals immediately. This ensured that the surrounding producing wells did not suffer from premature water cuts—a staggering improvement compared to fields with similar permeability contrasts.
🔹 Dramatic Increase in Vertical Sweep Efficiency: The large-scale application led to an immediate and sustained expansion of the productive intervals. Post-treatment production logging confirmed that previously inactive, oil-rich layers were successfully brought into the injection network, significantly boosting the overall reservoir utilization.
🔹 Smooth and Controlled Pressure Build-Up: During the early-stage PDS treatments, injection pressure rose smoothly and predictably (e.g., from 0 to 1,470 psi, or 588 to 1,323 psi) rather than spiking erratically. This proves that the large-scale PDS implementation successfully created resistance only in the correct zones, safely conditioning the entire reservoir to accept large water volumes without fracturing the wellbore.
The Campaign:
Over the course of 24 total treatments across 6 injectors (with 5 yielding a distinct net independent effect), the team injected over 235,000 barrels of PDS solution.
Results: Staggering Outcomes in Injection and Production
1. Fundamental Redistribution of Injection Profiles
Field data demonstrates a remarkable, unprecedented shift in fluid flow dynamics. The large-scale plugging of “thief zones” forced injectors to open entirely new intervals immediately:
- Injector A-1: The dominant 52% flow interval was successfully blocked. After treatment, the water was forced into a new interval, capturing 40% of the total injectivity—proving the technology’s precision.
- Injector A-4: Production Logging Tools (PLT) revealed that 80% of the water was previously channeling down the annulus to a water-saturated zone. After PDS, this path was completely sealed, returning full injection to the targeted reservoir.
- Injector A-2: The treatment increased the effective working thickness of the reservoir by 2.4 meters and boosted the vertical sweep coefficient by 9.6%.
- Injector A-5: Experienced a +34% growth in vertical sweep coefficient, adding 1.7 meters of new working thickness.
- Injector A-2 (repeat): Maintained its improved profile with a +28.8% increase in vertical sweep coefficient for over 11 months after the first treatment, proving the long-lasting stability of the barrier.
2. Massive Incremental Oil Production
The ultimate measure of this large-scale breakthrough is the accelerated oil recovery. To ensure rigorous accounting, joint effects were carefully allocated. Two producing wells, located between Injector A-1 and Injector A-3, exhibited a combined response to both treatments. These wells are attributed exclusively to the Injector A-3 cluster to prevent double-counting. The totals below reflect only the “clean” net effect attributable to each independent injector.
| Responding Well Cluster | Net Incremental Oil Production |
|---|---|
| Injector A-1 Cluster | 1,593,342 bbl |
| Injector A-3 Cluster | 1,406,009 bbl |
| Injector A-2 Cluster | 821,330 bbl |
| Injector A-4 Cluster | 234,432 bbl |
| Injector A-6 Cluster | 75,818 bbl |
| TOTAL NET INCREMENTAL OIL | ~4.13 million bbl |
(Additionally, the 6th injector, A-5, demonstrated response only in combination with neighboring wells and, as such, is not included in the independent net totals.)
The effect is not transient; numerous wells within the cluster are reporting continuous production growth well into the project’s later stages, demonstrating the long-term reliability of this early-stage PDS innovation.
3. Validation of the Proactive Approach in a Highly Heterogeneous Reservoir
Field A is characterized by severe geological heterogeneity and a natural predisposition to early water breakthrough. Notably, several producing wells were already experiencing water cuts caused exclusively by formation water and bottom-water drive — prior to the initiation of any water injection.
The most compelling evidence of the breakthrough lies in the response of these already-watered-out producers. After the large-scale PDS treatment, the injected water was successfully redirected into oil-bearing intervals, effectively increasing reservoir pressure where it was needed most. The injected water began to displace oil and improved the performance even on wells that had already watered out from formation water — water cuts declined, and oil production rates increased.
These results confirm that early-stage, large-scale PDS application successfully provides critical pressure support to the oil column, counteracting formation water influx and delivering tangible production gains even in the most challenging geological conditions.
Conclusion: Pioneering a New Standard for Waterflood Optimization
The large-scale, early-stage PDS campaign at Field A is a clear breakthrough in reservoir engineering. It successfully shifted Client B from a costly, outdated “break-and-fix” reactive cycle to a highly efficient, revolutionary “shape-and-optimize” preventive model.
Key Breakthrough Takeaways:
- Operational Innovation: Implementing PDS on a large scale prior to establishing a stable injection profile and before large-scale water injection was the game-changer, avoiding severe economic losses from premature water breakthroughs.
- Autonomous DPR Technology: The use of formation water as a chemical switch ensures that only water-bearing thief zones are blocked, completely preserving oil permeability and maximizing the efficiency of the redirected waterflood.
- Staggering Long-Term ROI: The cumulative incremental oil of over 4.13 million barrels proves that proactive, large-scale EOR is not just a temporary production spike—it is a sustainable, high-ROI strategy that is redefining the future of field development.