Optipac packing tube leak-off inhibiting methods

Provided is a method of restricting flow loss through a packing tube 16. The method involves transporting a gravel pack slurry in a shunt tube system, which has transport 14 and packing 16 tubes; using the slurry to pack gravel 18 into the packing tube(s) 16; and reducing fluid loss through the packing tube(s) 16. Fluid loss can be reduced by injecting a multivalent metal into the packing tube 16 to react with the polymeric carrier fluid to form a hardened bridge (Fig. 4); or by actuating a guillotine 30 that slides across the packing tube 16 (Fig. 6). The gravel pack slurry includes a carrier, such as the polymer Xanthan; and proppant or gravel. Injection/actuation may be initiated by a burst disc 28 located on a control line 14; and the guillotine may be spring-loaded by a spring 34.