After screening the typical relative permeability curves of thin and poor reservoirs in Xing 6 area,the flow coefficient is used as the weight coefficient to compound the normalized curves of single layer, and the composite relative permeability curves are obtained. The study of composite relative permeability curve shows that thin and poor reservoirs in Xing 6 area have the characteristics of residual oil saturation, low irreducible water saturation, low oil displacement efficiency and narrow common permeability area. According to the relative permeability curve, the water cut and recovery degree are calculated. The results show that the relationship curve between water cut and recovery degree can be divided into two types: convex and S. By studying the relationship curves between displacement efficiency and permeability, crude oil viscosity and displacement pressure gradient of thin and poor reservoirs in Xing6 area, it can be seen that displacement efficiency increases with the increase of permeability and displacement pressure gradient, and decreases with the increase of formation crude oil viscosity. The correlation analysis between oil displacement efficiency and micro⁃pore parameters shows that the correlation coefficient between pore radius and oil displacement efficiency is the smallest, only 0.090. The correlation coefficient between displacement efficiency and throat radius is 0.437. The results show that the effect of pore radius on oil displacement efficiency is small in micro pore structure parameters, and the effect of throat radius and pore throat ratio on oil displacement efficiency is greater.

There is pressure sensitive effect in ultra⁃low permeability reservoirs. It is of great significance for the development of oil fields to study the variation of matrix permeability with pore fluid pressure. Through the core simulation experiment in Chaoyanggou area with changing the fluid pressure to change net pressure, which reflects the real situation of the formation, the curve of the permeability with the change of net pressure is obtained, and the model of the relationship between net pressure and permeability is regressed. The results of the study show that the permeability varies significantly with net pressure, and the percentage of permeability change is about 20% in the stage of decreasing fluid pressure. The permeability does not change significantly with net pressure, and the percentage of permeability change is about 5% in the stage of increasing fluid pressure. At the stage of increase or decrease of fluid pressure, subsection fitting is adopted, and the change rule of permeability with net pressure basically accords with binomial relation with the correlation coefficient more than 0.99.

After the XQ⁃45 block entering the multiple rounds of steam huff and puff, it is affected by edge water, faults, reservoir properties and other factors. The remaining oil distribution is complex, and steam huff and puff effect is getting worse. According to the reservoir dynamic data, the 79 wells in this block are divided into different types of heavy oil wells according to the remaining oil saturation parameters. Among them, the number of remaining oil wells affected by edge water is more than 22. As the edge water proceeds along the high⁃permeability layer to the oil well, the water content rises quickly and easily causes flooding. To further improve the effect of steam huff and puff, aim at the unutilized section in the edge water affected oil well, and take the single⁃layer steam huff and puff mode to study the optimization of steam huff and puff parameters affected by edge water. Through extract single⁃well geological model and compare different steam injection programs, the best program is selected: steam injection volume is 100 t/m, the oil steam ratio maintain at 0.2 t/t or more, obtain the maximum amount of oil production. The results show that cycle steam injection volume is 100 t/m, the oil production is the largest in the third cycle, and the sweep radius of steam reaches the maximum. After 5 rounds of steam huff and puff, cumulative steam injection volume is 3 700 t, cumulative liquid production is 4 500 t, cumulative oil production is 738.65 t, and the program implementation effect is getting better.

In order to study the relationship of oildriving efficiency with microcosmic pore structure in the Changyuan ultralow permeability reservoir of outer edge of Daqing oilfield, the CT technology was used to research dozens of natural cores. Lots of data such as pore radius, throat radius, porethroat ratio, coordination numbers, tortuosity and shape factor were obtained. The waterflood experiment was conduct and each oildriving efficiency was recorded, then the effect of pore structure parameter on oildriving efficiency was studied. After the standard processing, the linear regression equation of pore structure parameters and oildriving was obtained. The results showed that, among all the parameters, the average throat radius was the critical element with a factor of 0.531. While the average pore radius was considered to be insignificant with a factor of 0.045.

Structures of environmental friendly phosphorous flame-retardant polyester were characterized through infrared spectra (IR), the performance of its properties such as intrinsic viscosity, differential scanning calorimeter (DSC), oxygen index (OI) and its spinnability was investigated. The results show that the flexible segments in phosphorous flame-retardant monomer were also introduced into the backbone of the polyester macromolecules, which causes the decrease of the phosphorous flame-retardant polyester glass transition temperature (θ _g) and melting transition temperature(θ _m). The synthesized phosphorous flame-retardant polyester resins have a very good flame retardantability and spinnability; when the mass fraction of phosphorous flame-retardant monomer was 4.5%, the oxygen index of phosphorous flame-retardant polyester reached to 32.8%. The tensile strength and crystallinity decreased owing to the much more space volume of phosphorous flame-retardant polyester. The results indicate that the properties for phosphorous flame-retardant polyester can satisfy the requirements for the manufacture of polyester fibers.