The temperature profile has a decisive influence on the timing of the replacement and blending water of subsea pipeline, as well as smooth restart after shutdown. For a quantitative evaluation on the delay effect resulted from consideration heat storage and dissipation of cover layers, the energy storage capacity of each layer is analyzed theoretically, and the influence of heat storage of steel pipe and soil on the temperature drop of different types of pipelines after shutdown is simulated and calculated. Taking two practical pipelines in Bohai Sea as an example, the transportation scheme is optimized. The results show that the total stored heat by steel is about half of the heat of the crude oil in oil pipeline, 1/4 of the water in water pipeline and 4~16 times of the natural gas in gas pipeline, which depends on the system's pressure. The heat storage and heat dissipation of steel pipe and soil can delay the temperature drop of fluid shutdown. For the insulation pipeline, the stored heat by steel makes a different on temperature drop, while for the non⁃insulation pipeline, the heat by soil has a great impact on temperature profile. Within the crude oil pipeline in Bohai Bay of China, there is about a 3.5~13.5 ℃ temperature increase at the outlet of pipeline when consideration the heat storage and dissipation of cover layers. When the GOR is greater than 10, there is a particularly obvious effect on the temperature drop when shutdown, which is conducive for a safe and smooth transportation. Considering the influence of heat storage and heat dissipation of soil or steel pipe on the temperature drop of shutdown, the water mixing transportation can be delayed or cancelled.

The southern part of Qinhuangdao 331 oil field is a heavy oil field which has not been exploited. The mode of thermal recovery is considered unusually in the early of exploitation. The design of thermal recovery mode depends on mass experimental data. Based on the indoor physical simulation, the influence of different noncondensate gas on high temperature and high pressure property of heavy oil is studied with a set of experiment instrument which support high temperature and high pressure. The results show that the volume ratio of CO ₂ dissolved in heavy oil of the southern part of Qinhuangdao 331 oil field is higher than N ₂ obviously, and the reduction rate of CO ₂ is 30%~90%. The lower temperature and greater pressure make CO ₂ reduce the viscosity of heavy oil more effectively. In different experiment temperature and pressure conditions, the N ₂ viscosity reducing extent is lower than 20%, and the dissolving capacity and viscosity reducing effect of flue gas is between N ₂ and CO ₂.

Oilwater relative permeability curve reflects the law of oil and water flowing in the porous media, and the characteristics of pore structure are important factors which greatly influence the relative permeability curve.The effects of the pore structure characteristics on the permeability and the characteristics of relative permeability in F reservoir was analyzed. It is found that the absolute permeability increases with the radius of pores and sorting coefficient upgoing and decreases with the coefficient of pore structure upgoing .The irreducible water saturation and isotonic point saturation decrease with the pore radius and sorting coefficient increasing, and increase with the coefficient of pore structure increasing.The endpoint permeability of water phase increases with the pore radius and sorting coefficient upgoing, and decreases with the coefficient of pore structure upgoing. The parameters of permeability and relative permeability characteristics in this formation are in power function relationship with the micro pore structure characteristics.

An anti-coking oxide film was prepared by a low oxygen partial pressure method for inner surface of cracking tube in service. The morphologies, composition and structure of the inner surface, the adhesion between the oxide film and the substrate and the anti-coking performance of the specimen were characterized by SEM, EDAX, X-ray diffraction, scratch tester. The results show that Fe and Ni content decreases after the process of low oxygen partial pressure. The oxide film is mainly composed of MnCr ₂O ₄ and Cr ₂O ₃ and the critical load between oxide films and substrates is 9.25 N. The anti-coking ratio reaches 69.92%, it proves that the oxide films can prevent catalytic filament cokes from deposition effectively.