Data-Constrained Screening and Simulation Design of Alkali–Surfactant and Alkali–Surfactant–Polymer Flooding in the Bu-Attifel Lower Nubian Sandstone Reservoir
DOI:
https://doi.org/10.65405/6g8b6345Keywords:
alkali–surfactant flooding; ASP flooding; chemical EOR; Lower Nubian Sandstone; Bu-Attifel Field; CMG–STARS; interfacial tension; adsorption; mobility control; water cut.Abstract
Background: Chemical enhanced-oil-recovery performance is reservoir-specific because IFT reduction, soap generation, adsorption, phase behavior, mobility control, and injectivity interact nonlinearly. The Bu-Attifel Field has a history-matched reservoir foundation, but its AS/ASP chemical description has not been calibrated.
Methods: This study preserves the field, well, geological, dynamic, and base-case information reported in the author’s thesis. AS is defined as alkali plus surfactant without polymer; ASP adds polymer for mobility control. A mechanism-constrained screening workflow was developed from the documented base-case endpoints and published analogue evidence. The workflow explicitly separates thesis-derived data, external analogue observations, and new engineering assumptions. No original polymer-only result is reused as an AS/ASP result, and no executable CMG–STARS AS/ASP run is claimed.
Results: The documented base-case oil rate declines from 7,136 to 5,184 bbl/d between 1 October 2021 and 30 September 2031, while the reported model water cut at the start of prediction is 77.2%. The screening envelope indicates 0.5–4.0 percentage points of incremental recovery factor for AS and 1.5–7.0 percentage points for ASP. Assumed end-period oil-rate endpoints range from 5,443 to 6,480 bbl/d for AS and from 5,702 to 7,258 bbl/d for ASP. These values are engineering scenarios, not CMG–STARS outputs, measurements, or probabilistic quantiles. AS is expected to provide primarily microscopic-displacement benefits; ASP can add sweep improvement through polymer mobility control but carries higher risks of pressure increase, retention, degradation, incompatibility, and injectivity loss.
Conclusions: The central technical distinction is not the chemical label but the additional transport mechanism supplied by polymer. AS is the lower-complexity screening option. ASP should be advanced only after oil/brine compatibility, IFT, phase behavior, adsorption, polymer rheology, retention, coreflood, and injectivity data are available. The resulting manuscript is a transparent field-specific screening and simulation-design study; a Q1-level original numerical claim requires the missing chemical dataset and a verified CMG–STARS deck.
Research highlights
· A field-specific AS/ASP screening framework is built on the Bu-Attifel history-matched reservoir foundation.
· AS and ASP are separated by mechanism: IFT-driven microscopic displacement versus combined displacement and polymer mobility control.
· All new numerical values are labelled as engineering estimates rather than simulator outputs or probability quantiles.
· A falsifiable laboratory-to-CMG–STARS workflow is specified for upgrading the screening study to a numerical investigation.
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References
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