Gravel packing long horizontal sections is an exceptionalchallenge in itself due to the lengths now being completed.When simultaneous gravel packing and effective mud cakeremoval is considered, the complexity of the process iscompound, posing a more demanding challenge to thecompletion process. Previously, to gravel pack a horizontalwell it was necessary to seal off the wellbore from theformation to such an extent that substantial circulation couldbe maintained during gravel packing. This implied the need ofa filter cake in place that needed to be removed in a separatetreatment after the gravel packing operation to achieve anefficient completion. The introduction of screens with shunttubes eliminates the need for well circulation during the gravelpacking operation, and therefore simultaneous removal of thefilter cake while gravel packing becomes a viable possibility.In this paper we present an integrated approach to gravelpacking and removal of the drill-in fluid filter cake. This wasachieved by a combined application of a surfactant basedcarrier fluid in an enzyme and chelant breaker solution usingshunt tubes for open-hole gravel packing. The shunt tubesensure complete packing by allowing an alternate path forbypassing sand bridges that may form in the screen andformation annulus, due to excessive leak off. The carrierbreakerfluid ensures contact of the breaker with the filter cakein the entire interval during and after gravel packing.Clean up efficiency tests, fluid rheological behavior andfluid design are presented together with field case histories.These case histories demonstrate that gravel pack placementand well productivity index have been improved with respectto previous practices, while simultaneously reducing overallcompletion cost.
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