An associative seawater⁃based fracturing fluids with temperature resistance of 180 ℃ was formed by thermostable and salt⁃resistant thickening agent containing hydrophobic groups, physical crosslinking agent with ionic surfactant, high temperature stabilizer and high efficiency chelating agent. The fracturing fluid forms a high⁃strength network structure through the physical association between the hydrophobic groups on the molecular chain of thickener and cross⁃linker, which enhances its viscoelasticity and takes elasticity as the dominant factor. The viscosity of the fracturing fluid can be maintained above 30 mPa•s for 90 minutes at 180 ℃ and 170 s-1, which has good static sand⁃carrying and wall⁃building properties. The viscosity of gel breaking fluid is 3.3 mPa•s, the residual content is 45 mg/L, and the damage rate of core permeability is less than 10%. The seawater⁃based fracturing fluid meets the requirements of fracturing for offshore ultra⁃high temperature deep reservoirs.

At present, the main block of Changyuan in Daqing has entered the late period of development, with the characteristics of high water cut and high extraction degree. The remaining oil is highly dispersed, and the difficulty of adjusting the potential of tapping the potential is gradually increasing. In order to delineate the P reservoir area of the south west slope of A zone, the reservoir structure, reservoir and oil and water distribution are studied by means of logging seismic joint tectonic interpretation, reservoir prediction and oil and water identification. The research shows that the horizontal surface distribution of P oil reservoir is controlled by structural units, the type of vertical reservoir is controlled by the characteristics of sedimentary evolution, oil enrichment is controlled by fault sealing, and oil and gas accumulation is difficult to be determined by the relationship between fracture and sand body configuration. According to the research results, the potential area of I, II and III is delineated in the P oil layer of the west slope, and the total geological reserves are obtained.

New clean fracturing fluid VES⁃YF was prepared by mixing the betain type amphoteric surfactant YF⁃1 and cosurfactant YF⁃2 with KCl. By measuring the influence of different concentration of YF⁃1, YF⁃2 and KCl on the viscosity of fracturing fluid, the optimized formulation was obtained, which is 2.0%YF⁃1+1.0%YF⁃2+2.0%KCl. The research and evaluation of the system's construction mechanism and its applicable performance were conducted. The results show that VES⁃YF clean fracturing fluid has shear thinning property and good viscoelasticity. The rheological measurement shows that the network structure of worm⁃like micelle exists in the system and can be recovered after shear failure. The apparent viscosity of VES⁃YF clean fracturing fluid is still higher than 80 mPa·s after shearing for 2 h at the temperature of 45 ℃ and the shearing rate of 170 s-1. The system has the advantages of strong sand carrying capacity, good gel breaking property and low core damage rate. VES⁃YF clean fracturing fluid has a broad application prospects in the fracturing operation of low permeability reservoir.

To solve the problem of polymer plugging of polymer injection well area in the bohai sea, a kind of efficient composite depolymerization additive is screened in the paper. Laboratory experiments show that the degradation rate of 5 000 mg/L polymer solution can reach more than 99%, and the polymer scale samples with crude oil from oil well in Bohai can be degraded in 72 h because of the low interfacial tension and good oil washing effecthigh effect of washing oil. Meanwhile, the high chelating ability of this depolymerization additive is good for the depolymerization of the crosslinking polymer, and the degradation progress can be as less as 3 h.The plug removal application in one oil well well shows that the efficient depolymerization additive has remarkable capacity of enhancing liquid and oil.

Mesoporous SBA-15 materials were functionalized with amine groups through postsynthesis, and resulting functionalized material was investigated as matrix for controlled drug delivery. The structure, composition and framework of the material were investigated by means of X-ray diffraction (XRD), intelligent weight analyzer (IGA), transmission scanning electron microscopy (TEM), infrared spectrometer (IR), and molecular simulation software. Ibuprofen (IBU) was selected as model drug and loaded onto the unmodified and functionalized SBA-15. It was revealed that the adsorption capacities and release behaviors of this model drug were highly dependent on the surface properties of SBA-15 materials. The release rate of IBU from SBA-15 functionalized by postsynthesis is found to be effectively controlled as compared to that from pure SBA-15 due to the ionic interaction between carboxyl groups in IBU and amine groups on the surface of SBA-15.