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Lots of gum and asphaltene in heavy oil caused high viscosity, high density and poor fluidity, which makes it very difficult to exploit and transport heavy oil. This paper introduces the mechanism and application of five new viscosity reduction technologies, including microbial viscosity reduction technology, biosurfactant viscosity reduction technology, ultrasonic viscosity reduction technology, magnetic treatment viscosity reduction technology and supercritical carbon dioxide viscosity reduction technology. At present, single viscosity reduction technology is difficult to solve the problem of heavy oil production and transportation. So the development direction of heavy oil viscosity reduction technology is the composite use of various technologies. In the future, it is necessary to develop new viscosity reduction technologies suitable for heavy oil production and transportation from the perspective of studying the structure and performance of heavy oil.

With the increase of crude oil production in the world, the proportion of conventional crude oil is gradually reduced, so the recovery of heavy oil has become the development trend. Due to the characteristics of high viscosity and low fluidity of heavy oil, its exploitation difficulty is much higher than that of conventional heavy oil, which has become the main problem restricting its exploitation and utilization. In this paper, the commonly used chemical viscosity reduction technologies for heavy oil were reviewed, including emulsification viscosity reduction technology, oil-soluble viscosity reduction technology and catalytic modification viscosity reduction technology. Combined with literature and related oilfield experiments, this paper analyzed the mechanisms, advantages and disadvantages of technologies and prospected for future technology development of viscosity reduction technology.

In this paper, the research status of polymer flooding in China and abroad in recent years is reviewed, as well as the mechanism and application of polymer flooding are described. The research progress of several commonly used polymer flooding agents are introduced, including biopolymer, temperature and salt resistant monomer polymer, hydrophobic associating polymer, cross-linked polymer, comb polymer and star polymer. Based on the analysis of the properties, advantages and disadvantages of these flooding polymers, some suggestions are given for the problems existing in the current application of the polymer flooding technology. Also, suggestions of research direction of polymer flooding agent in the future are shared.

Due to the heterogeneity of heavy oil reservoirs and the high viscosity of heavy oil, the recovery rate of heavy oil reservoirs is much lower than that of conventional reservoirs. So increasing the recovery rate of heavy oil reservoirs is of great significance to the goal of improving the technical level of heavy oil development proposed by the National Energy Plan. This paper outlines several commonly used techniques for improving the recovery of heavy oil reservoirs, including steam flooding, hot water flooding, polymer flooding, surfactant flooding, microbial flooding, foam flooding, ultrasonic viscosity reduction technology, etc. And briefly explains the basic principles. The internal causes of the problem are analyzed, and several focal points for improving the recovery of heavy oil that should be paid attention to are put forward.

Oily sludge is one of the most important solid pollutants produced by petroleum industry. Due to the serious pollution and the increasing production of oily sludge year by year, how to effectively treat oily sludge is the focus of worldwide attention. This paper mainly introduces the source, characteristics, environmental impact, as well as traditional and newly developed oily sludge treatment technologies. With the improvement of national environmental protection requirements, oily sludge quality reduction, recyclable and harmless treatment technology will become the most potential technologies in the future.

The production of crude oil has three stages: formation drive, wellbore lifting, and pipeline transportation. This paper summarizes the application effects of flow improvers within several long-distance pipelines in China. The effects of oil- and water-soluble viscosity reducers on lower- and higher-viscosity heavy oils, respectively, and their effects in the wellbore-lifting process are outlined. Further, the technical difficulties and potential solutions associated with driving heavy oil are discussed. This paper has reference value for researchers conducting studies on flow improvers.

Shale gas is a clean and efficient unconventional natural gas energy, which has gradually become a new hotspot in global oil and gas exploration and development. Hydraulic fracturing technology is one of the core technologies in shale gas production, which consumes a lot of water resources and produces a lot of polluted flowback fluid. How to effectively deal with the treatment of flowback fluid is a crucial issue. By analyzing the characteristics of fracturing flowback fluid, this paper lists the treatment technologies of fracturing flowback fluid, which can relieve the worries of shale gas exploitation and wide application.