Study On Dynamic Change Characteristics Of Two-flood Pressure System In Three-stage Oil Production

Since the scale of polymer and ASP flooding in Sazhong Oilfield is expanding and the interference of water flooding,polymer flooding and ASP flooding is getting more and more obvious,the existence of abnormal pressure area and other issues which are caused by the three flooding methods mentioned above are getting more and more prominent.How to optimize the adjustment of injection pressure system,maintain a balanced production,reduce the interference of water flooding,polymer flooding and ASP flooding becomes particularly important.In the thesis,the Class Two oil layers with polymer flooding(SII10-PII7)and ASP flooding layers(SII1-SII15+16)in the transition zone of East Sazhong Zone and eastern zone in Daqing oilfield were selected as the main research objects.The geological structure model,sedimentary facies model and the facies controlled property model were established by using the related geological modeling software,and the fitting error was-0.253%.The numerical simulation software was used to fit the oil production,water cut and pressure of the whole research area,the typical well group and the single well.The fitting error of whole research area was less than 3% and the single well fitting error was ± 3%,single well oil production coincidence rate was 84.3%,the fitting precision was high.At the same time,the numerical simulation method was also used to study the factors for influencing the pressure distribution of the two-flood layer,and the main controlling factors were determined according to the orthogonal design and combining the index of pressure disturbance.The pressure change under the interference of different periods for water-polymer,water-ASP,polymer-ASP flooding was studied in vertical and horizontal direction.The results show that the pressure distribution in the vertical and horizontal in different periods were uneven,and the inter-layer interference was generated.Besides the interference in the transition zone was especially serious and the pressure change was very obvious;for the uneven distribution of formation pressure,there were five adjustment measures raised including the raise of the well injection,the extract of production wells,blocking,fracturing and perforation,and the effect of the adjustment measures mentioned above was evaluated by numerical simulation method.For the production wells of low pressure in the region,one can raise the amount of injection wells;In the production well of the best time to take the measures by taking the pump to achieve the best oil effect;The blockage is mainly for the watershed;It can be used in the case of fracturing measures when the injection wells pressure are high while the permeability is still low;The well can be perforated in the horizon when the production well is at a higher pressure.Through the research of this thesis,the technical methods of optimizing the adjustment of pressure system of water,polymer and ternary flooding were systematically summarized,and it draws lessons and guidance to the production practice of other successive development of Class Two oil layers.