The H0 formation of X Oilfield is an unconsolidated sandstone reservoir, During drilling and completion operations, it is highly susceptible to solid-phase invasion, which disrupts the original mechanical and chemical equilibrium of the reservoir, thereby triggering severe reservoir damage and restricting reservoir development benefits. To address this technical challenge, this paper conducts dynamic filtration experiments of drilling and completion fluids. By simulating the drilling and completion processes, the paper systematically evaluates the influence laws of reservoir physical properties and circulation time on the degree of reservoir damage under the action of existing drilling and completion fluid systems. Based on the experimental results, it further systematically analyzes the damage mechanism of drilling and completion fluid systems on such reservoirs in X Oilfield, and completes the optimal screening of drilling and completion fluid concentration and bridging particle ratio. The experimental results show that: reservoirs with better physical properties suffer relatively less damage; with the extension of circulation time, the invasion depth of drilling fluid and the reservoir damage rate increase continuously; the damage rate of the optimized drilling and completion fluid system to the reservoir is controlled within the range of 5.0%–11.4%, and it presents the characteristic that the lower the permeability, the better the damage control effect. The research results can provide important theoretical support for the efficient development of medium-porosity and medium-permeability unconsolidated sandstone reservoirs.
Zhu et al. (Thu,) studied this question.