Study On Formation And Migration Of ASP Emulsion

In the process of chemical flooding,oil-water two-phase emulsification system with different forms is formed under the action of formation shear and emulsifier.The research shows that the oil flooding system with emulsification can further improve oil recovery.At present,the emulsification ability of the produced liquid has become an important standard for evaluating the oil flooding system.In order to further study the regularity of formation,stability and migration in the process of ternary compound flooding,this paper carried out two modules of static emulsion stability analysis and dynamic emulsification migration.The research of static emulsion stability mainly includes the analysis and preparation of the produced liquid.The effects of different forming conditions on the stability of emulsion were studied by using the omni-directional infrared stability analyzer,microscope and water precipitation method.The study of dynamic emulsification migration law mainly carried out simulation experiments of formation flow.Based on the established long core model and micro oil displacement model,the migration and loss of chemical agents in asp process was studied.By combining with the migration law of chemical agents,the migration intensity,starting time,duration distance and mining degree of emulsion were further analyzed.The main research results were as follows:(1)The high-speed shear emulsifier has a shearing speed of 3000 r/min and a shearing time of 15 min.The prepared emulsion is close to the performance of the in-situ emulsion;the increase of the polymer concentration can improve the stability of the emulsion.The optimum polymer concentration for emulsion stability is 2000 mg/L;the stability coefficient,average particle size and surfactant concentration of the emulsion are approximately linear,and the concentration increase can increase the stability of the emulsion;the alkali concentration should be suitable If the concentration is too high or too low,it is not conducive to the stability of the emulsion,and the optimum alkali concentration for improving the stability of the emulsion is 0.4%;the increase of temperature and salinity is unfavorable for the stability of the emulsion.(2)Chemical agent concentration peak and viscosity peak are both moving to the lower right,The difference between the maximum peak value and the minimum peak value was calculated by a multiple,and it could be seen that the loss of chemical concentration andviscosity was(6 times)> surfactant(4 times)> polymer(3 times)> base(2 times).Due to the excessive viscosity loss,the composite system lost its role in controlling the mobility ratio in the back 1/12 well spacing.(3)Emulsification is accompanied by the whole process of ternary composite flooding.The migration process of the composite system in the formation can be divided into three migration stages: emulsion enhancement,emulsification reduction and emulsification disappearance.The emulsification strength of the emulsion system in the formation can be divided into strong.The emulsification enhanced continuous distance is 35% of the whole,the emulsification is weakened,and the emulsification disappears by 40% and 25%respectively;the timing of entering the medium-strong emulsification at each sampling point is continuously delayed,and the duration of the medium-strong emulsification is continuously weakened,by the largest 0.9 PV is reduced to 0.3 PV.(4)The residual oil of water flooding mainly exists in the form of column,blind end,cluster and oil film.The composite system with different emulsification strength has different degrees of use of residual oil.Medium emulsion strength can be used for displacement of residual oil in large channel and film in channel,Strong emulsion can dislodge the residual oil in the channel and blind end.