Determining the total price of construction projects and effective control of investment are not only important components of construction project management, but also directly related to the economic benefits of investment institutions. Taking 4 different construction schemes of an oil depot as examples, the project cost evaluation index system is constructed. On this basis, technical and economic analysis was introduced through cloud model, classification standard was established, and entropy weight method was used to determine the weight of all grass⁃roots indicators. Finally, four construction schemes were evaluated based on cloud model generator. The results show that the order of membership of the schemes is M1＞M3＞M2≈M4. The peak point of M1 appears earliest, between 2.0 and 2.5, and the peak point of M4 appears later. The influential basic indexes are fire protection engineering, foundation engineering, heat insulation engineering and project measure cost, of which the measure cost accounts for more than 1/10 of the total project cost. Therefore, on the premise of ensuring the construction requirements, we should strengthen the control of the project cost in such aspects as fire engineering, foundation engineering, thermal insulation engineering and project measure cost, so as to achieve the purpose of the optimal design and the most economical investment in the construction of the best project.

Construction standardization and civilization are not only the minimum requirements of the construction site, but also the innovation of the construction field in the new era, which are related to the social and economic development and the process of national modernization.Based on the recruitment and bidding information of an oil depot and taking four different construction schemes as the basic data, a standardized construction management evaluation index system was firstly constructed. On this basis, the standardized construction scheme evaluation system was constructed by entropy weight method and comprehensive evaluation method. The results show that the degree of standardization and civilization of the four schemes is ranked as M3＞M4＞M1＞M2. The first⁃level index weight ranking is environment＞safety＞energy saving＞cost＞quality＞progress. Among them, the weight proportion of environment factor is the largest, about 0.193, and the weight proportion of project progress factor is the smallest, about 0.128. Therefore, during the construction of oil depot, the emphasis should be placed on construction environment and safety construction, and the road of green, standardized and sustainable development should be taken.

Collapsible loess is prone to self weight collapse after soaking. The strength of loess will be greatly reduced, and it will threaten the safe operation of buried pipelines along the way. In order to study the stability of buried pipelines in collapsible loess regions, the displacements, stresses and strains of different pipe outer diameters and wall thicknesses during collapsing were analyzed based on the finite element method. The limit length that the buried pipeline could withstand in the loess disaster under certain conditions was obtained by the eigenvalue buckling theory. The results show that: increasing the outer diameter and wall thickness of the pipeline and reducing the buried depth of the pipeline in the loess can effectively reduce the displacement of the pipeline in the collapsible loess; and increasing the outer diameter and wall thickness of the pipeline can also effectively avoid the phenomenon that the local stress of the pipeline is too high; the maximum stress and strain of the pipeline occur at the center of the collapsing zone and the fixed ends on both sides; according to the buckling eigenvalue theory, the ultimate length of the collapsible area of the pipeline is about 65 m when the soil mass has self weight collapsible, and increasing the outer diameter and wall thickness of the pipeline can enhance the buckling resistance of buried pipelines when self weight collapse after soaking.

In the gas pipeline, the gas⁃solid two⁃phase flow causes erosion and wear on the inner wall of the pipeline, and the erosion wear in the tapered tube is particularly serious. Using the knowledge of computational fluid dynamics, the model was established by CFD simulation software, the fluid⁃solid two⁃way coupling equation was used, and standard k⁃ε model and discrete⁃phase model (DPM) were used for analysis. Investigating the influence of inlet flow velocity, solid particle size and particle mass flow rate on the wear and tear of reducing pipe, and predicting the location of the tapered tube where erosion wear is likely to occur and the optimum flow rate of natural gas. The results show that the inlet flow rate increased from 5 m/s to 25 m/s, the maximum erosion rate of the tapered tube increased first, then decreased and then increased. When the inlet flow rate is 15 m/s, the erosion rate reached the minimum, which is 1.76×10-6 kg/（m2•s）. The particle size increases from 0.5 mm to 4.5 mm, and the maximum erosion rate increases from 4.23×10-6 kg/（m2•s）to 7.56×10-6 kg/（m2•s）, and then gradually decreases to 2.68×10-6 kg/（m2•s）. The particle mass flow rate increases from 0.1 kg/s to 0.6 kg/s, when the inlet flow rate is 15 m/s, the maximum erosion rate increases from 1.76×10-6 kg/（m2•s） to 1.00×10-5 kg/（m2•s）. The erosion wear area is mainly located on the lower wall surface of the tapered tube throat, the lower wall of the tapered tube segment from the 2D region of the throat and the upper wall of the tapered tube segment outside the 2D region, and the erosion wear area of the upper wall surface is approximated by "U" type symmetrical distribution. During gas transfer, the optimum inlet flow rate of gas through the reducing pipeline should be 15 m/s. In order to prevent erosion and wear, it should also be noted that the particle size should not be too small, and the mass flow rate should be controlled within a reasonable range.

In view of the fact that the buried pipeline design does not fully consider the stress changes during the operation process of the pipeline subjected to frost heaving and corrosion, considering the complex working conditions of the buried pipeline containing corrosion in the frozen soil area, the deformation and damage of the buried pipeline in the frozen soil area are analyzed. Factors, the establishment of a finite element model suitable for buried pipelines in frozen soil areas, study the impact of environmental temperature, corrosion depth and length on pipeline stress changes. The results show that the effect of frozen soil on corroded pipelines is mainly divided into elevation and end tensile stress. The elevation and stress increase the stress and strain of the corrosion pipeline linearly, but the effect of end tensile stress is opposite; the stress strain of the pipeline is directly proportional to the square of the corrosion depth. The increase of the corrosion length leads to a sharp increase in the stress and strain of the pipeline. When the length is greater than 150 mm, the mechanical properties of the pipeline fluctuate within a certain range. It provides a new idea and method for the design of buried pipelines in permafrost areas.

The stability of heavy crude oil emulsion is very important in the heavy crude oil transportation. However, in the pipeline transportation process, the oil⁃water volume ratio, water content (water quality fraction) and other factors have a certain influence on the stability of the heavy crude oil emulsion. The microstructure, stability mechanism of emulsion and the role of focused beam reflection measurement (FBRM) technology in the study of stability of emulsion were introduced. The comprehensive effects of different factors such as oil⁃water ratio, water content and additives on emulsion stability were comprehensively analyzed. Finally, the research status of dynamic stability of emulsions was introduced. The main factors affecting the stability of heavy crude oil emulsions are oil⁃water volume ratio, water content, emulsification temperature and salinity, surfactants, alkaline agents. High molecular polymer used to enhance recovery of heavy crude oil also have effect on the stability of emulsion. The dynamic stability of the emulsion was studied by different simulation methods, and the results were similar. Among them, the loop simulation method had the most reference value

Taking the heavy oil production liquid in a block of Liaohe oilfield as the research object, a compound viscosity reducer was formulated according to the current situation, and the effect of the ratio and amount of such viscosity reducer on the viscosity of heavy oil emulsion was studied. The emulsified viscosity reducing agent is composed of non⁃ionic surfactant Triton X⁃100 and zwitterionic surfactant dodecyldimethyl betaine (BS⁃12).The experimental results show that when the mass fraction of 1.6% Triton X⁃100 is added into the heavy oil alone, the viscosity reduction rate of the heavy oil can reach 75.93%; BS⁃12 with a mass fraction of 0.6% and Triton with a mass fraction of 1.6%. Triton X⁃100 is compounded by a volume ratio of 1∶1, and the viscosity reduction rate of heavy oil can be increased to 92.63%. In addition, when the complex system is added in a volume ratio of 1∶1∶1, weak alkali sodium carbonate with a mass fraction of 0.4% is added. After the aqueous solution, the viscosity reducing rate of heavy oil can be further increased to 93.14%, and the stability of the compounding system is also improved.

Using the OP⁃10 and L61 emulsifiers to configure different hydrophilic equilibrium values (referred to as the HLB),the viscosity test of heavy oil in the second area of the oil production plant of liaohe oilfield was carried out to find out the optimal HLB of the heavy oil.At the same time, FBRM was used to measure the viscosity of heavy oil, and the effect of droplet quantity and particle size on viscous oil viscosity was analyzed.For further study on the viscosity change mechanism of heavy oil emulsion, it can be used to provide reference for the process of heavy oil reduction.Test results show that:the HLB of the emulsifying agent added to the heavy oil emulsion was 9.0,the effect of viscosity is best.At this time, the number of droplet drops to stable, compared with other HLB emulsifiers, the quantity of emulsifier is obviously low, the droplet is evenly distributed and the emulsion is stable.

In order to achieve the emulsification viscosity reduction of heavy oil in Huanxiling oil production plant of Liaohe oilfield, the emulsifier solution with the mass fraction of 30%, emulsifying temperature of 50 ℃, emulsifying time of 1 h, stirring speed of 200 r/min, stirring time of 5 min, under the shear rate of 16.9 s－1, the effect of single emulsifier and compounding emulsifier on the stability and viscosity⁃reducing rate of emulsion is investigated. The results show that the optimal compounding mode of the compounding emulsifier is as follow: 0.7% OP⁃12 and 0.8% sodium oleate; the best compound emulsifier and heavy oil could form a stable emulsion, and the viscosity can be reduced from 1 020.9 mPa•s to 72.0 mPa•s, and the viscosity reduction rate reachs 92.95%. The emulsion with the best compound emulsifier and heavy oil has better stability than the single agent OP⁃12 and heavy oil emulsion.

For the problem of erosion-corrosion in oil pipeline system, used ANSYS FLUENT software, by changed the inlet velocity, the particle mass flow rate and the particle diameter, conducted numerical simulation for flow field distribution and severe erosion area of 90° elbow pipe. The results show that: with the increase of inlet velocity, the pipe erosion rate increases gradually; with the increase of particle diameter, the pipe erosion rate decreases; with the increase of particle mass flow rate, the pipe erosion rate increases linearly; and there have interaction between the three erosion factors of inlet velocity, particle mass flow rate and particle diameter.

      The ice blocking could happen during the process of conveying products oil in the pipeline, because of the low temperature in north China in winter. The pipeline occurred ice blocking, not only oil transport was affected but also unnecessary damage of production was caused, and the potential safety hazard could exist when it became serious. Based on thenumerical simulation software FLUENT, the flow field distribution was calculated around the single and multiple ice blocks in products pipeline which were in different height. The research results showed that increasing with the height of the ice wall, the pressure difference of front and back produced nonlinear changes, the pressure distribution regularities of multiple ice also produced nonlinear changes. In the aspect of velocity, the velocity variation degree of front and back the ice block was relatively stable, but the velocity change process around the ice block was more obviously and layered effect was better, the speed distribution regularities of multiple ice blocks were similar to that of the single ice blocks.

In order to optimize the transportation pipeline of heavy oil and provide baseline data for the study of energysaving technology, the experimental study on the viscosity-temperature characteristics and rheological properties of heavy oil in Huanxiling was carried out. The viscosity-temperature curve and the rheological characteristic curve were drawn, the viscosity-temperature equations and the rheological equations were fitted, and the viscosity-temperature index was calculated at each temperature interval. Through the viscosity-temperature curve and rheological characteristic curve fitting, the results showed that the correlation coefficient was close to 1 which indicated a higher degree of fitting and the small error. The rheological index was less than 1, which indicated that the heavy oil used in the experiment was pseudo plastic fluid. At the test temperature of 70 ℃,the heavy oil showed Newtonian behavior.

The moisture content of soil will change when the ambient temperature changes in permafrost, and by this time the internal friction angle, cohesion and severe of permafrost will change accordingly. And for slope segments of buried pipelines, the soil will produce friction on the pipeline along the slope direction with the thawing of permafrost occurrence, to make the pipeline generate the additional tensile stress. Understanding the impact of frozen soil parameters on the pipeline stress correctly was convenient to the analysis of pipeline stress, and it had practical significance for the development of scientific and effective method of preventing damage. When the frozen soil around the buried pipeline of slope section thaws, the degree of influence on pipeline stress with different soil parameter was investigated, and yields the conclusion by the numerical simulation. The results show: when thaw landslide occurs, with the increasing of soil cohesion and weight of soil, the pipeline stress increased; and with the increasing of internal friction angle, the pipeline stress decreased. Moreover, the friction angle of the frozen soil was the most sensitive to the pipeline stress, weight of soil followed, and the influence of permafrost cohesion on pipeline stress was minimal.