Study On The Novel Preformed Particle Gel With High Temperature Resistance And Retarding Swelling

Heavy oil has been an important portion of petroleum resource with the exploitation of conventional crude oil.Due to high viscosity and poor fluidity of heavy oil,it is more difficult to exploit with conventional exploiting method.Now,Heavy Oil Thermal Recovery is commonly used in heavy oil exploration in domestic.The technology of steam soaking is the most effective method in the heavy oil thermal recovery and is widely used in heavy oil blocks in our country.At the late stage of development,the heterogeneity of the reservoir led to the steam channeling and seriously influences the heavy oil recovery.So we need to find an effective way to block the steam channeling to enhanced oil recovery.In this paper,the designing ideas come from the perspective of water shutoff and profile control.Swellable particle has been used in formation water plugging,but it is seldom used in high temperature reservoir and some heavy oil blocks.There are two main problems which are high absorption rate in the former preparing stage and water loss of decomposition at high temperature.In order to expand the scope of application of swellable particles in thermal recovery of heavy oil,at first,Poly(acrylic acid-g-acrylamide)/ montmorillonite(MMT)preformed particle gel(PPG)is prepared in aqueous solution with MMT and high temperature crosslinking agent teraallylammonium chloride(TAAC).The swelling ratio at the optimum conditions is 17 g/g and 112 g/g at 25 ? and 200 ?,respectively.The structure of PPG is characterized with Fourier transform infrared spectroscopy(IR),X-ray diffraction(XRD).The results show that the chemical and physical cross-linkages of –OH of MMT participate in the formation of the polymeric network the PPG.Then using mixed crosslinkers which are stable and unstable cross-linking agent in combination,poly(ethylene glycol)diacrylate-400(PEGDA-400)and teraallylammonium chloride(TAAC),respectively.The novel preformed crosslinked water-soluble swellable particle hydrogel(PPG)with the character of high-temperature resistant is prepared by solution polymerization of monomer of acrylamide(AM)and acrylic acid(AA).Under optimum conditions,swelling ration of the PPG of poly acrylamide(PAM)in distilled water is less than 10 g/g at 25 °C,but it significantly increases to 230g/g and 63 g/g in 1 wt% NaCl solutions at 250 °C;swelling ration of the PPG of poly acrylic acid(PAA)in distilled water was about 25 g/g at 25 °C,but it significantly increases to 340g/g in distilled water and 85 g/g in 1 wt% NaCl solutions at 250 °C.TAAC in system provides a strong network skeleton at high temperature and high-concentration PEGDA-400 ensures relatively low swelling ratio because of its high crosslinking degree.The both which are prepared with mixed crosslinker technology expresses such excellent characters of low thermal expansion rate at low temperatures and high water absorption at high temperatures.The PPG has been applied to heavy reservoir oilfield.It has enhanced heavy oil recovery.