Polymer Recycling Complex Profile System And Properties In Offshore Polymer Flooding Oil Field

A great deal of residual polymer in formation produce after polymer flooding in offshore oilfield,in addition,heterogeneity of the formation is more and more serious,so the reutilization techniques of the residual polymer in Bohai Oilfield is studied.Aiming at the limitations that the inorganic recycling particles are prone to clogging and the organic recycling agent plugging is weak intensity,through the use of two types of polymer flocculant complex,it is preferable to apply to offshore oil recycling complex system.The residual polymer for offshore recycling complex profile system of inorganic flocculants and organic flocculants are finally optimized to 1% and 0.5% of modified starch YG340-1,the best ratio of 5: 2,the dry complex system concentration of 0.86%.Complex suspension system is good,low concentration,low cost.High,medium,and low permeability filling sand tube core injection pressure are finally stabilizing at about 0.025 MPa,0.1 MPa and 0.42 MPa,indicating that the injectivity of complex system is good.Complex profile system has excellent sealing properties,preferentially blocking the high permeability layer,residual resistance factor at 10.5 to 60.5.When the subsequent water flooding starts after a plurality of pore volume,injection pressure is still maintained at a high level,the closure rate remains above 97%,indication that the optimal complex profile system has excellent scour resistance.Reduce the production of polymer concentration at 10% to 30%,the system has good ability to reduce the concentration of polymer output.Flooding experiments showed that,Polymer recycling recovery(64.12%)increases more 10.22% than that of polymer flooding(53.90%).The microscopic visual simulation model experiments showed that after water flooding residual oil mainly distributes in the far area of diagonal of the main injection wells and production wells.Through SEM images,it can be found that recycling complex system not only has the features of an organic floc microstructure,but also interspersed with the "rod-like" structure,through which three-dimensional network structure formed in this space,so that flocculant has a better blocking performance in high permeability layers.The optimal construction well is W6-4.It is optimized that the recycling complex system injection method,injection amount,injection rate and injection slug design for the targets oilfield,which provide technical support for the construction site.