Title : Case story of smart dual lift solutions: Enhancing well productivity & unlocking by-passed reserves
Abstract:
Objectives/Scope: Dual-producer wells using conventional long-string gas lift face three persistent challenges:
- Static injection: Cannot adapt to changing reservoir conditions.
- Cross-string interference: Complicates allocation and destabilizes drawdown.
- Intervention-dependent optimization: Increases NPT, OPEX, and HSE exposure.
This paper presents the brownfield conversion of a dual-producer well from single-string gas lift to a dual-string, digitally governed system. Downhole digital valves (DDVs) were installed on both strings and integrated with surface automation. The workflow covers:
- Candidate selection
- System design
- Controls integration
- Commissioning and step-tests
- Closed-loop optimization
- Digital Surveillance and governance
Objective: Deliver a repeatable pathway to:
- Restore Inactive String production;
- Faster optimization cycles
- Improved gas utilization
- Higher and more stable oil rates in watery environments
- Fewer interventions
- Full compliance with ADNOC Gaslift / ALS standards
Methods, Procedures, Process: Architecture & Operating Philosophy
- Downhole hardware: DDVs installed at prescribed injection depths on both the long and short strings, enabling independent, electronically selectable injection settings without pulling the completion.
- Surface controls: Integration to wellsite PLC/SCADA for command, telemetry, interlocks, and auditable change logs; data streamed to production surveillance dashboards.
- Closed‑loop control: Surveillance (rates, WHP/WHT, Infinite choke opening & control points) informs set‑point proposals; DDV set‑points are executed remotely; responses are validated against pre‑defined operating envelopes.
Pre‑Job Assurance & Risk Controls
- Wellbore hygiene: targeted clean‑out and magnet runs with debris sampling to protect seats/orifices and ensure injectivity reliability.
- Readiness & governance: RACI for set‑point authority; Management of Change (MOC) for persistent shifts; rollback plans for unexpected responses.
Commissioning & Characterization
- Step‑test matrix per string (ascending DDV positions) to derive injectivity curves and quantify cross‑string influence.
- Stabilization windows and fixed choke policy used to decouple transient effects and establish reliable before/after comparisons.
Optimization & Surveillance
- Precision gas injection‑allocation solver constrained by field gas‑lift supply availability, completions fall‑through limits.
- Remote monitoring & surveillance from control room and HQ
Performance Evaluation
- KPIs: total liquids and oil‑rate stability, gas‑per‑barrel (SCF/BO), intervention frequency, uptime, and time‑to‑optimize after production upsets.
- Verification: matched pre/post windows with outlier screening to minimize seasonal/operational bias.
Results, Observations, Conclusions: Dynamic Control & Stability
- Independent DDV control on both strings eliminated trial‑and‑error gas swaps and compressed optimization cycles from days/weeks to hours.
- Commissioning quantified cross‑string coupling; coordinated adjustments maintained each string within its safe, high‑leverage operating envelope, improving rate stability and reducing oscillations.
Production Efficiency & Gas Utilization
- On‑demand rebalancing of injection reduced over‑injection episodes and improved gas‑lift utilization efficiency (lower SCF/BO at target output).
- Operating closer to stable FBHP targets deferred water advancement in the more sensitive string and recovered deferred production following process upsets.
Interventions, Uptime & HSE
- Routine mechanical changes were eliminated; wellsite visits shifted from “adjust” to “audit,” cutting intervention frequency and associated NPT/HSE exposure.
Conclusions
- Converting from conventional to dual‑string, digitally governed gas lift with DDV provides a practical, rig‑light path to materially better responsiveness, efficiency, and operating continuity in mature onshore carbonate wells.
- The methodology, controls, and KPI framework establish a defensible business case for multi‑well scale‑up within ADNOC’s production system.
Novel/Additive Information:
Case story of the first deployment globally of downhole digital valves with infinite variable position to achieve truly independent, digital gas lift control on both strings of a dual producer well. Instead of just controlling one string, we now have full, real-time management of both—unlocking new levels of flexibility and efficiency.
