The calculation models for crude oil viscosityare complex because of the determination of physical data,the limited calculation accuracy and application scope. Consequently, some representative straight chain alkanes were taken as model compounds of crude oil, and their viscosity and sound velocity were measured under different temperatures and pressures in this work. The influences of temperature and pressure on the sound velocity of straight chain alkanes were investigated, and the correlation model between viscosity and sound velocity was built on the base of experimental results. The experimental results indicated that the sound velocity of straight chain alkaneslinearly decreased with the increase of temperature and the decrease of pressure. The relationship between viscosity and sound velocity of alkanes was exponential type, and the viscosity sound velocity correlation model was applied to three different oils in Jidong Oilfield. The calculation results demonstrated a satisfactory applicability of the model. So, a feasible method was provided to reduce the dependence of conventional viscosity models on the physical property parameters.

Considering the geological features of the tight sandstone reservoir of Fuyu oil layer, Northern Songliao Basin, some key techniques of horizontal well design platform were developed based on the geological studies in the pilot development projects. These techniques attached importance to the key controls in geological design of horizontal wells by using such techniques as accurate delineation of the structural features in depth domain, fine characterization of “sweet spot” sandstone distribution, quantitatively fine description of channel sandstone geometry and optimum horizontal well design based on refine 3D geological model, which laid the solid foundation for locating the horizontal wells. The successful results were attained in horizontal well drilling in the primary stage of pilot project. The availability of the reservoir of tight channel sandstone within Fuyu oil layer was raised, the production of individual well and single well controlled reserves were greatly enhanced combining with volumetric fracturing stimulation, and support for economically tapping the tight oil in Daqing oilfield was securing.

Water channeling is a serious problem during the water flooding of naturally fractured low permeability reservoir. To solve the problem, nitrogen foam profile control and displacement technology were researched applying both experimental and simulation methods. The sealing capacity and oil displacement capacity of nitrogen foam were the main research objects. The results showed that nitrogen foam could reduce water cut and increase oil recovery significantly. After plugging the interconnected fracture, the swept volume of flooding liquid and oil recovery would be increased obviously. In the experimental research, oil recovery efficiency was increased by more than 10% after injection of nitrogen foam. The injection of nitrogen foam was flexile and convenient when applied in field construction, and the nitrogen foam profile control and displacement technology were suitable for EOR of naturally fractured low permeability reservoirs.

A method which applies step perforation to improve the effect of polymer flooding is presented against the problems of poor producing degree of low permeability, remaining oil in the inner thick oil layer abounds, and uneven vertical producing degree. After water flooding, the thick layers are perforated selectively followed by water flooding potential tapping, and the polymer flooding is performed ultimately. By carrying out laboratory physical oil displacement experiment of three tube parallel cores and applying theoretical formulas, reasonable polymer injection parameters are determined and the impacts of polymer flooding after step perforation on development effectiveness are also studied. The results showed that the better effect of polymer flooding was obtained by using big pre slug, high molecular weight polymer, and echelon descending concentration slug combinations. And projects which had adopted step perforation showed a bigger producing degree on low permeability layers and a better effectiveness on polymer flooding compared to the ones not adopted step perforation. The ultimate recovery was increased by 1.28%.

In order to further explore the mechanism of “increasing oil and decreasing viscosity” of heavy oil emulsification and viscosity reducer, experimental studies on oil displacement of heavy oil emulsification and viscosity reducer and its influencing factors have been carried out. Viscosity reducer was screened and related performance was evaluated.The viscosity and recovery efficiency were used as evaluation indexaccording to the geological characteristics and fluid properties in Bohai reservoir. The results showed that, the mechanism of decreasing viscosity of three kinds of viscosity reducer was forming oil in water emulsion, and the viscosity reduction effect of “viscosity reducer 2” was best among three kinds of viscosity reducer. Oil water emulsion gradually changed from oil in water (O/W) into water in oil(W/O) type and the viscosity was increased when the water content in emulsion decreased, eventually exceeding that of crude oil. Besides, with the heavy oil reservoir hetergeneity increasing, oil displacement of viscosity reducer got better. Oil displacement of viscosity reducer got worse with the increasing of curde oil viscosity, so the recovery amplification can be increased through preprocessing on viscosity reduction before similarty viscosity reducer was used.

Oil bearing sewage containing polymer in GD Oilfield has the properties of high viscosity, high oil content and more suspended particles, and the conventional single flocculating agent has the disadvantages of high dosage, loose coagulation and high cost. Oil removal rate and removal of turbidity were chosen as the evaluation values in this test, and flask experiment was used to evaluate the sewage processing effect of three inorganic flocculants and two organic polymer flocculants. Inorganic flocculant of poly (aluminium ferric chloride) with the concentration of 100 mg/L and organic polymer flocculant of PAM 4 with the concentration of 40 mg/L were respectively selected as the best flocculant. The oil removal rate and removal of turbidity of waste water were 92.3% and 90.7% respectively when poly (aluminium ferric chloride) and PAM 4 were used to dispose oilfield waste water. Some influencing factors such as temperature, pH value and settling time were investigated. The experimental results showed that the oil removal rate and removal of turbidity of oilfield waste water which was disposed by using compound flocculant system were the best when temperature of waste water was 40~60 ℃, pH value of waste water was 6~9 and the settling time was longer．The compound flocculant system has strong prospect in the processing of oil bearing sewage containing polymer.

The wettability and microstructure characteristics can be changed by molecular film technology through injecting molecular film reagent into the reservoir micro pores, and the purpose of reducing injection pressure and improving water injection total is achieved. The adsorption capacity comparison between molecular films to rock surface with water molecular to rock surface was studied, and it was revealed that the molecular film took advantage in competition, then adsorbed in rock surface and formed molecule layer. Based on it, the application conditions and its change rules were explored then the molecular drag reduction mechanism from reducing the boundary layer effect and friction was revealed. At the last the property of the molecules film drag reduction was studied.

Aiming at non standard octagonal gasket used in hydrotreating reactor. Ansys was used to calculate the contact stress on the sealing surface during the hydrostatic pressure test, and the causes of the different contact stress on each sealing surface were analyzed. The results showed that the contact stress down to the trough when the test pressure was the highest, the maximum stress on the inner side of gasket was away from the center of gasket, and the outer situation was in contrast to it. Variation of gasket sealing surface contact stress provides a reference to the analysis and evaluation of other non standard seal structure.

Current card is the main basis of electric submersible pump well fault diagnosis. At present, the diagnosis of electric pumping wells is mainly completed by technical workers. It is difficult to achieve rapid mass diagnosis, and the diagnosis results are greatly influenced by engineer technology level. Therefore the application of BP neural network for fault diagnosis of electric submersible pump is put forward. First of all, different pump current cards are collected, and sample library is established. The eigenvalues of the different pump current card are gathered and trained according to certain principles. After completion of training a weight matrix is got, and the current card characteristic values and weights matrix of similarity is calculated. Through computer programming application, the method can be proved to make electric pump diagnosis accurately and rapidly.

Sand deposit will be formedinside of subsea multiphase pipeline after operating for a period of time, which will lead to diminution of passable area, reduction of inhibitor efficiency, acceleration of corrosion, and even cause the PIG block accidents. In this article, the geometrical model and physical model with field dataare set up building upon the subsea multiphase pipeline from platform A to B in a group of offshore oil and gas fields.Numerical simulations by FLUENT are performed in order to study the sand depositional rule of straight section and bend section according to the variation of parameters such as sand content, particle size, density and flow rate. The research shows that sand depositional amount is positive correlative with and content, particle size, density and negative with flow rate, and the rule of sand depositional maximum position is opposite. The sensitivity of parameters to average sand depositional amount is sand content, flow rate, particle size and density from high to low.

Rapid and efficient desorption of CO2 from produced liquid has become a key issue which is addressed urgently in the gathering and transporting system of CO2 drive oilfield in China. Main theories of gas desorption are introduced and the features of traditional desorption technology, membrane desorption technology and ultrasonic desorption technology are analyzed in this paper.On the basis of which, defects of all kinds of desorption technologies are pointed out, and the direction of the gas desorption research is proposed. In addition, research progress of ultrasonic desorption, based on the self built experimental device of ultrasound promoting the gas desorption from the CO2 drive produced liquid, is introduced. Then, the combination of the new desorption technology and the traditional desorption is suggested to be applied to the CO2 desorption of produced liquid.