Simulation and application analysis of gravel packing in deepwater HT/HP wells

Abstract

Gravel packing is one of the main sand control methods for deep-water hightemperature and high-pressure (HT/HP) reservoirs. According to the specific characteristics of deep-water HT/HP and multichannel, considering the influence of slurry flowing through long-distance multichannel and the slurry temperature alternation along the flow path, based on α-β wave packing theory, a coupling model of gravel packing in deep-water HT/HP horizontal wells is established. The packing simulation algorithm and calculation process are designed to realize the gravel packing temperature pressure simulation and multistage refined friction calculation of deep-water HT/HP horizontal wells. The influence of each packing parameter on the packing process is fully studied. Furthermore, the application simulation of the A10H well of the South China Sea deepwater HP well is carried out. The simulation results show that in the slurry injection stage and α wave packing stage, the packing pressure is low and the residual pressure window is large. In the β wave packing stage, the packing pressure increases rapidly, the residual pressure window shrinks rapidly, and finally, at the end of β wave packing, the residual pressure window becomes narrow. The viscosity of carrier fluid has a significant impact on the pressure window of packing operation. For the design pump rate of 5.6 bpm, the packing cannot be completed with 5.0 cp viscosity carrier fluid. For the carrier fluid with high viscosity, the multi-β wave packing technique of pump reduction control pressure at the end of the β wave packing stage is used, and this process is simulated in this paper.Considering three constraints: not sand packed in the drilling string, without premature bridging in the α wave packing stage, and α and β wave packing pressure control conditions, the safe range of pump rate is determined under different operation safety margin conditions, which can provide technical support for on-site operation.