ClearPAC Polymer-Free Fluid for Gravel Packs

Polymer-Free Fluid for Gravel Packs

The ClearPAC fluid system for gravel packing extends existing viscoelastic surfactant (VES) fluids to high-temperature, high-pressure environments. Low friction and compatibility with enzyme and chelating agents make ClearPAC surfactant useful for simultaneous gravel packing and filtercake cleanup.

With an absence of damaging polymeric residues and complete viscosity loss upon contact with most crude oils, ClearPAC surfactant has the same high retained-permeability characteristics as existing VES fluids. Low friction pressures as compared with other fluids make ClearPAC fluid system and other VES fluids ideal for use with the Alternate Path® technique for gravel packing long horizontal intervals.

The ClearPAC fluid system has been created to overcome density and temperature limitations. ClearPAC fluids incorporate a chelating agent and are compatible with potassium chloride, sodium bromide, and sodium chloride. Temperature limit depends upon the brine type and density.

ClearPAC surfactant can be formulated at densities to 11.6 ppg with a temperature stability approaching 250 degF. Compatible with chelating agent solutions U106, U820, U821, and incompatible with chelating agent solution U105, ClearPAC surfactant can be used with enzyme breaker J503. The fluids can be either batch-mixed or prepared by continuous mixing.

ClearPAC fluids require enzyme J559 as the gelling agent, and chelating agent U820 as a cogelling agent. The incorporation of the chelating agent solution into the gravel carrier allows simultaneous gravel packing and cake cleanup operations where removal of calcium carbonate bridging-weighting agents is required. ClearPAC fluids are ideal in openhole completions drilled with either water-based reservoir drilling fluids or a reversible synthetic or oil-base reservoir drilling fluid such as the FAZEPRO system.

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