Reducing Formation Damage through Two-Stage Polymer Filtration

Abstract

ABSTRACT Formation damage resulting from the use of unfiltered polymers during gravel pack completion operations has been addressed as it relates to НЕС completion fluids.1–5 However, other filtered polymer systems exhibit properties which, in specific applications, may out perform НЕС systems. Thus, the performance characteristics of six commonly used polymer systems, hydroxyethyl cellulose (НЕС), clarified xanthan gum (XC), HEC/XC blends, crosslinked carboxymethyl hydroxyethyl cellulose (CMHEC), hydroxypropyl guar (HPG), and standard xanthan gum (XCD), required additional evaluation. Fluid modelling was employed using a new two-stage filtration process (gel filtration) in which the viscosified fluids were optimally sheared and fine-filtered to improve sand placement efficiency and reduce formation damage. The data obtained from this study establishes mixing and filtration design criteria for optimizing completion techniques such as gravel packing, sand washing, polymer diverting, and lost circulation control.