Construction Of Inclusion Complex Supramolecular Gel And Its Plugging Performance

For oilfields developed during the high water cut period,plugging water channels is a necessary measure to achieve stable crude oil recovery rate.Organic chromium gel has excellent properties such as low cost and simple use process,which has attracted wide attention from petroleum researchers.However,the organic chromium crosslinker mixed solution has poor shear resistance,and it is difficult to achieve a good plugging performance when it reaches the target reservoir.The host-guest inclusion complex gel based on the host-guest inclusion effect can overcome the above shortcomings and provide a new type of plugging agent for the further development of high water-cut oilfields.This article takes the high temperature and high salinity reservoir as the research target reservoirs.Firstly,the cyclodextrin polymer and amphiphilic polymer were synthesized,and the host-guest inclusion complex was constructed.The optimal inclusion ratio of the host-guest inclusion complex was obtained by viscosity,and the thickening mechanism of the host-guest inclusion complex was studied using scanning electron microscope,atomic force microscope,rheometer and other instruments.Secondly,the host-guest inclusion complex gel was prepared after adding the organic chromium crosslinker,and the strength and gelation time of the hostguest inclusion complex gel were measured by using micro-rheometer;using rheometer and dynamic light scattering instrument evaluated its anti-shear ability and at the same time the gel forming mechanism is clarified.Finally,the indoor physical model was used to evaluate its injectability,plugging property and erosion resistance,and the formation adaptability of the host-guest inclusion complex gel was obtained.The research results show that the optimal inclusion ratio of the host-guest inclusion complex was 1:1.Because of synergistic effect of host-guest inclusion effect of the cyclodextrin polymer and hydrophobic association of the amphiphilic polymer,inclusion complex have excellent thickening ability.The optimal organic chromium crosslinker concentration was 0.4%,the gelation time of the host-guest inclusion complex gel was 9 days.After gelation,the vacuum degree can reach 0.04 MPa and the water loss rate is less than 1.5% within 60 days.The organic chromium crosslinker will crosslink cyclodextrin polymer with a shorter molecular chain firstly and at the same time they generate micro micelle precipitation,and then crosslink amphiphilic polymer.so the host-guest inclusion gel requires a higher organic chromium crosslinker concentration,and the gelation is longer.The cyclodextrin polymer in the host-guest inclusion complex gel can re-link break down amphiphilic polymer through the host-guest inclusion effect,which weakens the shear effect.The indoor physical experiment of host-guest inclusion complex gel shows that in medium-high permeability reservoirs,after shearing it has good injectability and good plugging ability,and the plugging rate can reach 96.9%,after 30 PV scouring,its plugging rate decreases less than 5%.In heterogeneous reservoirs,its profile improvement rate can reach 71%.The host-guest inclusion gel has good shear resistance and excellent plugging performance.Its has broad application prospects in oilfields.