Research On The Combination Of Polymer Blocking Removal And Fracturing Technology

Polymer flooding has been widely popularized in oil field of China and the amount of polymer using increasing gradually.But this phenomenon is brought lots of problems to oil field,such as inject pressure ascended obviously,pump efficiency decreased,energy consumption increasly,investment cost rising year by year,and the most serious problems will cause wells blocking.These issues affect the production of oil field,and restrict the development of oil field.Faced with these serious problems,the oilfield take a variety of means to increase the amount of polymer injection,such as fracturing and acidizing technology.Although these measures that easing conflicts between polymer injection amount is less and injection pressure is too high in a certain degree,it does not solve the problem of increase note amount is low,validity period is short and any other problems.A new type of less pollution,and long validity period in order to enhance the polymer injection measures has fundamental significance.This paper focuses on the problems of polymer blocking and validity period is short in polymer flooding of the sixth plant of Daqing oilfield.Through the analysis and discussion of essential component of the polymer blocking,selecting a suitable block-removing agent,and synthesizing a kind of low molecular weight cationic polymer in order to applied in high concentrations of polymer injection wells.Through the indoor core simulation experiment,reducing the solution viscosity of the blockage,in order to determine the composition of block-removing agent.Combined with on-site process requirements and the situation of block-removing to adjust the block-removing agent.The experiment shows that the result is good,and the efficiency of block-removing is more than 80%.The adsorbance reached saturation adsorption when the concentration of low molecular weight cationic polymer is greater than 0.3%and the adsorption time is over 40h.Through the indoor core simulation experiment,under different conditions that different permeability of core,after the process of block-removing,inject the 1PV 0.3%concentration of low molecular weight cationic polymer,and inject block solution again,depressurizing is over 40%,the rate of prevent is over 70%.The block-removing agent in this paper is safety and no pollution,the result of block-removing is good,and these have a certain reference value for the problems caused by the high concentration of polymer.