Improved Techniques for Fluid Diversion in Oil Recovery – 1994

R.S. Seright – 1994

Abstract

Second year of the fluid diversion comparison project. Foam placement is modeled using the limiting-capillary-pressure concept: foams are effective for gas coning reduction but have limited applicability for matrix water shutoff. Emulsions and particulate blocking agents are assessed and compared. Aluminum-citrate-HPAM gel propagation through porous rock is characterized as a Cr-free alternative. Gel properties in fractured systems are extended, including gel placement in unfractured anisotropic flow systems. DPR mechanism studies continue. The project supports a consortium of 10 oil companies.

Key Takeaways

  • The limiting-capillary-pressure concept governs foam mobility in porous media; foams are effective blocking agents for gas coning but face constraints for water shutoff in matrix rock.
  • Dilute oil-in-water emulsions provide modest permeability reduction; concentrated water-in-oil emulsions achieve better plugging but with greater formation damage risk.
  • Preformed xanthan gel particles show selective entry into high-permeability channels but cannot achieve the deep penetration possible with polymer solutions under typical field pressure gradients.
  • Aluminum-citrate-HPAM gels propagate effectively through porous rock and provide a viable alternative to Cr(III)-based gelants for environmentally or regulatorily constrained applications.
  • Permeability anisotropy in unfractured systems can provide modest placement advantages but cannot replace mechanical zone isolation in radial-flow injection wells.
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