Study On Nano-MMT-polymer Composite Material And Its Application In Reducing Viscosity In Heavy Crude Oil

The use of chemical viscosity reducer to improve the mobility of heavy oil at low temperature is commonly used in heavy oil production and transportation.Its advantages include easy operation,less addition,low cost,less energy consumption,and no post-processing.Therefore,it is considered to be the most economical and effective method for reducing viscosity and pour point depression.Nano viscosity reducer is a new developed viscosity reducer in recent years.Due to the small size effect and unique nucleation effect of nanomaterials,the crystallization and aggregation behavior of recombined components in heavy oil can be affected.So it can become the nucleation point of paraffin in heavy oil and co precipitation with paraffin.The formation of smaller wax crystals increases the mobility of heavy oil and reduces the freezing point.The long chain molecules of viscosity reducer are introduced into the surface or interlayer,and the organic polar long chain acts on the colloid and asphaltene in heavy oil,which forms hydrogen bonds,hinders the agglomeration of the colloid and asphaltene,and plays the role of viscosity reduction.Therefore,the nano composite viscosity reducer can be prepared by grafting and polymerizing them.Montmorillonite is a layered silicate mineral with nanometer size.After the organic modification of surface active agent,the interval between layers becomes larger and the interlayer environment changes from hydrophilicity to oiliness,which is beneficial to the introduction of organic matter in the layer.In this paper,eighteen alkyl methacrylate(SMA)and acrylamide(AM)were introduced into the organic modified montmorillonite(OMMT)layer,and the nano PSMA-AM/OMMT composite viscosity reducer was prepared.The orthogonal test was designed to explore the optimum preparation conditions.At this time,the freezing point is reduced to 6.5 degrees,and the apparent viscosity reduction rate of heavy oil is 68.4%and the net viscosity reduction rate is 30.3%at 40 C.In order to improve the grafting rate of organic matter among the montmorillonite,eighteen alkyl methacrylate(SMA),N-hydroxymethylacrylamide and maleic anhydride were introduced into the organic montmorillonite layer.In situ polymerization of monomer solution under the action of initiator was used to prepare nano C18-MAH-HA/OMMT composite viscosity reducer.The high grafting rate,and under the same conditions(40 C,100ppm plus dose),has better viscosity reduction and degrading effect,and the net viscosity reduction rate is up to 51.45%,higher than that of the former 30.3%,and the crude oil condensation point is reduced by 6.8 degrees C,slightly higher than the former at 6.5.This is due to the increase of organic matter content,the effect of viscosity reduction is improved,but the effect of pour point depression is not obvious.