Mechanical analyses on and solutions to anti-channeling for gravel-packing completion string

During sand control for offshore gravel-packing completion, the performance of downhole tools is predominantly affected by their relative positions. In order to maintain accurate positions of inner string outer string, and select proper downhole load positioning tool optimal loading tonnage, forces on the completion string during and after gravel-packing operation were analyzed. Then, a mechanical model of interaction of packing fluids on the completion string was established and used to derive the optimal loading tonnage of donwhole load positioning tool. The model assumes the downhole load positioning tool as loading point and the axial channeling load of the string to be subject to circulating pressure differential of fluid, thermal expansion of string, bending of string, and other factors. Simulation tests of wells and studies of field applications indicate that the mechanical model basically tallies actual operation conditions and proves the necessity that appropriate downhole load positioning tool should be used in gravel-packing operation. This model can be used to provide supporting data for field operations and anticipate any abnormal condition, thus effectively contributing to the higher success of operations.