Study On Flooding Characteristics Of Hydrophobic Associative Partial Hydrolyzed Polyacrylamide For Heavy Oil With Different Hydrophobic Monomer Content

Polymer flooding, a chemical flooding method of enhanced heavy oil recovery,is relatively poor sensitive for on severe heterogeneity reservoir. Therefore, polymer flooding shows good characteristics on heavy oil reservoir exploitation. Hydrophobic associating polymer is a useful water-soluble polymer material for oil and gas exploitation,which can overcome HPAM’s defect of shear degradation and poor suitability for temperature and salt.However,there is less reports about heavy oil flooding regularity of hydrophobic associating polymer with different content of hydrophobic monomers. If gets the appropriate regularity results, it can provides theoretical foundation and experimental basis for both enriching and perfecting mechanism of Hydrophobic Associating Polymer flooding of heavy oil and designing and synthesising oil-displacing agent for EOR.As a result,this thesis investigates on system’s reasonale selection, seepage characteristics and flooding effects of hydrophobically modified polyacrylamide with different content of hydrophobic monomers(DP series) and rheological properties of analog crude oil.Finally, I can get the heavy oil flooding regularity of Hydrophobic Associating Polymer with different content of hydrophobic monomers. The main contents are as follows:Firstly,a screening method of contrast different types of polymer properties resasonablly is established. For the four samples of hydrophobically modified polyacrylamide with different content of hydrophobic monomers is screened by Rheometer.which have close shearing viscosity and power-law index(n).It shows that.the polymer can reach close shear rate in similar pore structure distribution of porous media compare to the same flow rate.which provides a reasonable comparison of the conditions for the subsequent experimental study.Secondly, this article studied the rheological properties of the simulated oil for displacement experiment, the experiments showed that the test oil showed strong temperature sensitivity, which raised more strict requirements of temperature control when carrying on displacement study. Different viscosity of stimulated oil showed some architectural feature at low shear rate (or low frequency), presenting the characteristics of non-newtonian fluid,but when the shear rate increased to a certain value.the stimulated oil presented the characteristics of Newtonian fluid, the shear rate that displacement experiment achieved was just within the range of Newtonian fluid, so the results of displacement experiment were less affected by rheological properties of simulated oil.At the same time, through different permeability under the condition of similar shear viscosity system research of seepage characteristics, found in the study of the permeability range, the injection performance of partially hydrolyzed polyacrylamide DP-0 is best; Under the condition of the same flow rate, with the increase of content of hydrophobic monomer, achieve finally balance the number of PV is larger, the interval of reaching stability state of polymer injection pressure also increases accordingly, and the resistance coefficient and residual resistance coefficient increase in turn; In permeability below a certain value, the hydrophobic association of partially hydrolyzed polyacrylamide injection performance becomes poor. Get the seepage properties of these differences, for oil displacement experiment has very important reference value, and is also the basis for oil displacement effect analysis of reasonable explanation.At last, from the seepage characteristics and homogeneous models experiments, we found that under the premise of good performance injection, the polymer solution exhibited higher drag coefficient and stronger ability of improving water and oil mobility ratio with the increasing of hydrophobic monomer content, which result an enhancement of oil recovery, while the oil recovery would be decreased as the hydrophobic monomer content higher than a certain value. The hydrophobic association of partially hydrolyzed polyacrylamide provided a non-real drag coefficient when the injection performance poor, but at the same permeability the partially hydrolyzed polyacrylamide displayed a good oil recovery due to the better injection ability. Under a particular penetration, the polymer flooding leading edge parallel advanced significantly with the increase of the hydrophobic monomer in a small injection rate, which was beneficial to improve the swept volume. Form non-homogeneous layer seepage model oil recovery experiments, we found that with the increasing of hydrophobic monomer, the polymer could improve the injection profile significantly, and thus made a larger mining area of low penetration region, which was conducive to the ultimate recovery of low permeability area. Oil displacement analysis of the results for different reservoir conditions of oil displacement agent after screening provides the theoretical reference value.