Evaluation on performance of nano-powder plugging agent and its application in low-permeability reservoirs

In view of the problem of conventional particulated inorganic plugging agent being not suitable for Wei 360 Block which is a low permeability reservoir, an indoor comprehensive evaluation was conducted on the performance of nano-powder plugging agent. The viscosity of plugging agent fluid with density of 1.4~1.8 g/cm3 is less than 35 mPa·s, so it has good injectivity and can enter deep pores in the formation. It also has favorable suspension property, when its density is greater than 1.6 g/cm3, the fluid does not delaminate. Its curing time can be adjusted and it can be used safely. Its initial setting time is 2.7 h to 18.5 h, and final setting time is 3.1 h to 28.1 h. After being set, its volume will not shrink, its compressive strength is over 25 MPa, and the rate of plugging is up to 99.9%. It has certain solution property, and the recovery rate of permeability is over 50%. This paper introduces the field plugging technology, and knowledge of key plugging points and fine operation can increase the one-time success rate of plugging. This plugging agent has been used in 27 wells in Wei 360 Block of low permeability reservoir, and the technological success rate is 100%, and the effective rate of increase in oil production is 100%. Nano-powder plugging agent is a highly effective new plugging agent with good job safety and high success rate and can effectively seal and plug the low porosity and low-permeability formations.