Preparation Of High Temperature Resistant Superabsorbent And Its Application In Steam Stimulated Reservoirs To Solve The Steam Breakthrough Problems

With the rapid development of the world economy,the energy is more and more important to a country.As a kind of strategic energy,the oil resource is a vital factor on the country's economy.With the further exploitation of oil resources,heavy oil has become an integral part of petroleum resources in China.Due to the difficulty in the exploitation of heavy oil resources,how to develop heavy oil has become the top priority in our country.Now,thermal recovery is the most widely used technology in the exploitation of heavy oil,and steam channeling occurs frequently in the process of steam injection.So it is urgent to find an effective way to block the steam channeling.In this paper,three different kinds of high temperature resistant superabsorbents were prepared through aqueous solution polymerization,using tetrapropylammonium chloride and tripropylammonium chloride as crosslinkers,AA/AMPS/AM as monomers.The structure of the superabsorbents was characterized through infrared spectrum(IR),scanning electron microscopy(SEM),thermogravimetric analysis(TGA).Besides,the water absorbencies of the above superabsorbents at different temperature and different solutions were determined.The results showed that the three superabsorbents performed different swelling ratios in distilled water and saline solutions,the swelling ratios of the superabsorbents are all above 200 g/g in distilled water and 50 g/g in 1 wt% NaCl solutions,which can meet the appliciation in oil fields in terms of swelling ratios.However,after the study of three kinds superabsorbents' swelling rates,it is found that the three different kinds of superabsorbents performed fast swelling rates,which was hard to meet the construction application.So we must find an effective technology to prepare a kind of superabsorbent which both can meet the requirements of high temperature resistant and can satisfy the slowly swelling rate.There are two traditional methods of inhibiting rapid dilatation of superabsorbents:(1)physical package;(2)introducing hydrophobic monomers.However,the above two methods did not work here after the experiments.So we tried new means to prepare such a kind of superabsorbent.The combination of NMBA and TAAC crosslinkers in the polymerization of acrylamide has been shown to create a novel SAP material with a temperature switch to control its water absorbencies.The swelling experiments and microstructure characterization have shown that these new SAPs containing an appropriate amount of crosslinkers offer slow and minor water absorbency at 25 oC,but a significantly increased water absorption capacities with excellent thermal stability at 300 oC.It has been demonstrated by crosslinking density and morphology studies that the hydrolysis of amide bonds played a critical role in creating these previously unreported SAP.This kind of SAPs meet the requirements for application as a cost-effective plugging material in steam stimulated reservoirs to solve the steam breakthrough problems,and thus have high industrial application potentials.Finally,a preliminary field test indicated that this technology was feasible in blocking steam breakthrough channeling and has the potential to enhance heavy oil production.No blocking steam breakthrough channeling was observed.