The gelling oil with high wax content can be used to simulate the wax deposit inside the pipelines. In this paper, a new yield stress measurement method for gelling oil with high wax content was presented. It has a wider measurement range compared to regular measurements. Thus, the yielding behavior of oilwax mixture in low temperatures was further studied. In particular, the effects of melting temperature, standing time in melting and measurement temperatures on yielding behavior were presented for oilwax mixture. It is found that high melting temperature contribute to a low yield stress. The yield stress of gelling oil increases with the increase in standing time in melting temperature. Within 5 h standing time, the yield stress is kept constant. In addition, the effect of standing time in measurement temperature on yielding behavior can be ignored. The yield stress remains basically unchanged while standing time in measurement temperature is more than 30 min. These conclusions are of great significance in preparing gelling oil with high wax content. It forms the basis for exploring the wax breakage and removal mechanisms during pipeline pigging.

A number of crude oils is transported by Tangyan crude oil pipeline with frequent switch and thus wax deposition prediction is difficult. In this paper, wax deposition rates of different transported crudes along Tangyan pipeline in different seasons are predicted by using the unified wax deposition model based on crude properties. The thickness and distribution of wax deposition are forecasted, which provide a theoretical basis for the pigging operation securely. The results show that the wax deposition rates of different crudes in different seasons are various. Wax deposition along Tangyan pipeline mostly happens in winter and seldom happens in summer. Wax deposition of Aisipo and Maxila crude oil is less than that of Jienuo and Shazhong crude oil. The distribution of wax deposition along the pipelineis uneven. Wax deposition mainly accumulates in the inlets of the pump stations. When there is little variation of pipeline operation stress, the pressure drop in the unit length increases rapidly in the position where wax deposition is serious. Pressure effect may cause potential security risks in the pipeline. It is suggested that the pigging operation should be conducted in each autumn.

According to the characteristics of the water in low permeability oilfield, an integrated filter skid device is designed for wastewater treatment. Microfiltration membrane technology andauxiliary process of flocculation sedimentation are applied in this device. After using this device, the indexes including the content of suspended solids, the diameter of the suspended median particle and the content of oil meet the requirements of sewage reinjection in that oilfield. Then based on results of the microfiltration process, the factors which influence this process are analyzed. The effect of operating temperature and pressure is studied, and the optimum operating temperature and pressure of the metal membrane filter are obtained.

By setting up numerical models of pipeline normal operation, temperature drop along the pipeline after shutdown and restart procedure, the normal and opposite direction transportation pipeline shutdown and restart procedure were described. The relative errors of the results calculated using the numerical models were less than 2%, so thermal variation along the pipeline can be simulated accurately. Based on the numerical models, maximum safe time after shutdown in different seasons, temperature drop along the pipeline after shutdown and flow recovery after restart in winter were calculated, respectively. The results can provide evidence for production management, safe and highly efficient operation of hotoil pipeline.

The gas diffusion coefficient and therefore gasmixing section length was studied by using onedimension mathematical model in combination with three different methods for calculating gas diffusion coefficient (Taylor, TaylorCW and G.R.I). In addition, the predominant factors in affecting the gasmixing section length were also investigated, including pipeline length, diameter and velocity of the flow. And the comparison between the calculation results and field data show that TaylorCW method can reflect the field practice better. The relative errors of the results for three domestic pipelines are 397%, 23.4% and 22.0%, respectively.

At present, the operating inlet oil temperature to the pump station along Asai pipeline is much higher than the gel point of the crude oil. And the pigging frequency is much higher. There is much waxes removed from the pipeline during the pigging operation. It not only blocks the inlets of heating furnace, but also consumes more thermal energies. In this paper, the wax deposition profiles of the crude oil along Asai pipeline at different inlet temperatures under normal conditions were predicted by using the unified wax deposition model, and also the wax deposition distribution under the condition from damaging thermal insulation was also examined. The prediction results show that the wax deposit mainly accumulated in the inlets of the pump stations. On this basis, a new pigging program involving pigging frequency was proposed, and the same time the inlet oil temperature was also optimized to be a lower value. In winter, the inlet oil temperature is advised to be 40 ℃.While in other seasons, the temperature is 35 ℃. The prediction results were compared with the field data, the relative average error is 9.49%.

The nonuniform solution exhibited as waterinoil suspension or emulsion produce for the admixture of oil and waterbased viscosity depressant, which brings some potential difficulties to the measurement of viscosity and thus evaluation of viscosity depressants. Agitating method is employed to solve this problem at present. However, this method can't well mimic the effect of pipe flow shearing on rheological behavior of wateroil blend due to the difference in agitating strength from limitation of experimental design. As a result, the evaluation result from this method is generally too far optimistic. For this reason, an improved evaluation method for the performance of waterbased viscosity depressant was proposed, which can simulate the shear and thermal conditions tightly as in a real field. The experiment results reveal that the method has a better performance and provide a solid basis for evaluation for waterbased viscosity depressants. 