Study on the channel flow control mechanism of an equidensity particle agent in fractured-vuggy carbonate reservoirs

To define the channel flow control (CFC) mechanism of the equidensity particle agent, the effect of CFC treatment in fractured-vuggy carbonate reservoirs was systematically analyzed by visual simulation experiments and field tests. The typical visual experimental model of the fractured-vuggy reservoir was designed based on the fractured-vuggy reservoir outcrop characteristics. It overcomes the shortcomings of the conventional model, whose experimental results are greatly affected by subjective factors. The water breakthrough in the dominant flow channel caused substantial shielded remaining oil to be left in the reservoir, resulting in violent flooding of the oil well. The shielded remaining oil accounted for approximately 43.8% of reserves, which is the potential point of the CFC treatment. The CFC treatment can effectively enhance the shielded remaining oil recovery by 22.2% in laboratory experiments. Based on its own efficient suspension and migration ability, the equidensity particle agent can be transferred to the whole dominant flow channel in the fractured-vuggy carbonate reservoirs. By using the multistage distributed shrinkage joint at the outlet of each vuggy and inside of each fracture to control the flow capacity, the equidensity particle agent can equably control the dominant flow channel along the path to realize a wide range of water flooding in the fractured-vuggy carbonate reservoirs.