Research On Resin Dispersion For Water Plugging

Aiming at the requirements of high temperature(130?)and high salinity(220000 mg/L)reservoir water blocking,the petroleum resin was used as the main initial material to develop the petroleum resin dispersion selective water shutoff system.The viscosity characteristics of petroleum resin with different softening points were researched by rheological experiments.According to the stability and temperature resistance,the dispersant and stabilizer were used to construct the petroleum resin dispersion.The particle size analysis was used to characterize the petroleum resin dispersion under different conditions.Finally,the further study of the injection performance and plugging performance through physical simulation experiments.The matching relationship between the softening point of the petroleum resin,the particle size of the dispersion and the injection performance and plugging performance was clarified.The application of the dispersion water-shutoff system on the field was guided.The experimental results showed that the petroleum resin changes from solid to high viscosity fluid when the temperature is higher than the softening point of the resin.According to the rheological properties of petroleum resin under different conditions,it behaved as the Newtonian fluid characteristics above the softening point temperature.The viscosity modulus of the system is higher than 90 Pa.And its viscosity is greater than 100×10~3 m Pa·s.Preferably,0.2wt%amphoteric surfactant OB-18+0.2wt%cationic polymer P832 was used as a dispersion stabilizer by high temperature stability test,and the system can ensure stable dispersion of the petroleum resin system at 130?for more than 10 h.Finally,the applicable conditions and plugging mechanism of the resin dispersion were studied by physical simulation flow experiments.The result showed that when the ratio of resin particle size to pore medium throat diameter is less than 0.35,the dispersion has good injection performance.When the temperature is lower than that of petroleum resin,the temperature does not affect the injection performance of the petroleum resin dispersion.When the temperature is higher than the softening point of the resin,the coalescence of the petroleum resin dispersion causes the coalescence adsorption to increase the injection pressure.The plugging experiment showed that the petroleum resin dispersion-blocking agent has excellent water blocking performance for the water channel with a permeability of more than 10?m~2,the water-blocking rate is more than 80%.The damage rate to the oil layer is only 5%.The plugging pressure gradient of the 0.05-0.5 mm water raft can be up to 5 MPa/m.The scouring test showed that the blocking rate of the water phase decreased by 10%after the injection of water for 24 PV,indicating that the petroleum resin dispersion plugging agent has a better selective sealing performance and erosion resistance.The study showed that the petroleum resin dispersion undergoes a phase transition at high temperature,that is,a transition from a solid to a highly viscous fluid.The water channel is blocked by mutual coalescence and adsorption on the rock surface.For high temperature and high salt reservoirs,the petroleum resin should be selected as a water shutoff system,whose softening point was lower than the formation temperature by 10?.Under the premise of ensuring the injection capacity,the water blocking effect was improved.The research of this system has great application value for the plugging of water raft under harsh reservoir conditions.