1. Current situation of solar photovoltaic power generation in Daqing Oilfield
Daqing Oilfield is the largest oilfield in China, located in the middle of Songliao Plain and composed of Saltu, Xingshugang and other oil and gas fields. After entering the new era, Daqing Oilfield adheres to the scientific concept of development as the basis, and strives to achieve sustainable development, building solar photovoltaic power generation. Daqing is a second class area of solar energy resources in China, with long sunshine time and clean air. Besides, oil production operations in Daqing Oilfield are located in the field, with flat terrain and no tall shelter, which is very suitable for the erection of solar photovoltaic power generation. At this stage, Daqing Oilfield has built a relatively complete photovoltaic power generation matrix and enterprise power supply network. There are more than 300 substations of different voltage levels in the oilfield, providing very ideal conditions for the power transmission and consumption of photovoltaic power generation. By replacing high energy consuming equipment with photovoltaic power generation system, to achieve the goal of substantial energy conservation and emission reduction, the 1MW photovoltaic power station can save 140 tons of equivalent alternative coal every year, and the emissions of carbon dioxide, sulfur dioxide and nitrogen oxides are reduced to varying degrees.
2. Application of solar photovoltaic power generation in Daqing Oilfield
2.1 Power supply for oil and gas pipeline valve chamber
With the increase of oilfield development, ground construction and equipment are also increasing. Oil and gas fields are widely distributed. The oilfield valve chambers at the periphery are more remote and scattered. Some oil and gas pipeline valve chambers cannot obtain reliable power supply. If the power supply system is built, its cost is not proportional to the power consumption, and the transformer may be damaged in bad weather. Daqing Oilfield chose to use photovoltaic power generation to supply power to the oil and gas pipeline valve chamber for several reasons. First, the photovoltaic modules are small in size and light in weight, simple and flexible in the process of transportation and installation, and the photovoltaic cell array can be added in time in case of power load; Secondly, photovoltaic power generation can directly use the empty area above the valve chamber building, without the need for separate land occupation; Finally, the operation and maintenance cost of photovoltaic power generation is low, the operation is reliable, and there is no need for personnel to be on duty. Normally, only 10 solar panels can be used for stable operation for 5 to 10 years.
2.2 Cathodic protection power supply for oil and gas facilities
The oil and gas facilities in the daily transportation process of oil or natural gas will be affected by electrochemical corrosion. At present, the main methods to solve the electrochemical corrosion of crude oil tanks and oil and gas pipelines are current adding protection (forced cathodic protection) and sacrificial anode protection. Both of them use sufficient polarization current to protect oil and gas facilities. The protected metal becomes the cathode to achieve cathodic polarization, thus completing electrochemical protection. In the past, in order to achieve cathodic protection, it was necessary to occupy part of the land to build power stations, which led to the independence of power supply, some management did not have the conditions for power off potential testing, and the power off potential did not meet the requirements of the protection code. Photovoltaic power generation can not be limited by space. A multi-directional photovoltaic cell array can be built. Power failure protection and potential can be drilled by the solar photovoltaic power generation system, which is easier to provide current for oil and gas facilities and effectively protect the system.
2.3 Electric heating of oil pipeline
Because the traditional steam heating method has great defects in economy and practicality, Daqing oil field oil pipeline currently uses electric heating wire for heating, which is not only convenient but also economical. Electric energy is a form of energy that is easy to be transmitted with long distance in many energy sources. Simple wire connection between power supply and heating element can realize energy transmission, and there is less loss in the process of electric energy transmission. The viscosity of crude oil in Daqing Oilfield is relatively high, the annual average temperature is about 4 ℃, and the winter is relatively long, so higher heating temperature is required. The use of solar photovoltaic power generation can provide auxiliary power for oil pipelines and reduce dependence on thermal power generation.
2.4 Automatic measurement and control system of oil and gas pipeline
The main equipment and oil and gas pipelines of Daqing Oilfield are mostly distributed in the field, and the maintenance and management are complicated. Although oil and natural gas are essential energy for the development of modern society, their flammable, explosive and other characteristics doomed the sloppy safety management of oil and gas pipelines. During the long service life of oil and gas pipelines, they will be affected by weather, corrosion, expansion and contraction and other factors, and no one can monitor the condition of oil and gas pipelines at any time, nor can anyone cover a large number of pipelines. However, with the continuous development of information technology, the monitoring of oil and gas pipelines in the oil field is gradually modernized. The maintenance and inspection of oil and gas pipelines are carried out by means of drones, electronic eyes, etc. These electronic products also need to be charged for use. The solar charging system can be installed for free use in the field. In addition, the oil and gas pipeline automatic measurement and control system is under construction, which combines the oil and gas pipeline, photovoltaic system and automatic measurement and control system to realize the monitoring of oil collection and transportation and other related equipment. It can not guarantee that the oil and gas pipeline can be monitored for a long time, but also save a lot of manpower and material resources.
2.5 Street lighting and road monitoring
The basic application effect of solar photovoltaic power generation is that it does not need to lay power pipelines on street lamps and roads. Solar street lamps have the characteristics of energy conservation, environmental protection, long service life, etc. In addition to street lamps, lighting is needed in the pump station valve chamber of the oilfield and in life. The oilfield itself is a place where living areas and working areas are combined. Solar photovoltaic power generation can provide electricity for work and life, Reduce the cost of thermal power generation or power purchase. Photovoltaic power generation system is also used in road monitoring. Cooperate with time control to monitor and dispatch oilfield roads at the required time, and arrange the cooperation of batteries to further extend the application effect of photovoltaic power generation in real life.
2.6 Remote oil well power supply system
In addition to the valve chambers and oil and gas pipelines mentioned above, remote oil wells are located at the outermost edge of the entire oilfield area. Due to the special nature of the oil wells, large-scale power stations cannot be built nearby, so the selection of power supply systems is particularly important. The use of solar photovoltaic systems with batteries can meet the production requirements of the oil wells, The grid connected or off grid photovoltaic power generation system can be used to supply power to the oil well pumping unit in the daytime, and transmit the surplus power to the grid or battery. At night, the inverter can be used to discharge the battery power to supply power to the oil well. Solar photovoltaic power generation can not only save thermal power generation resources, but also belongs to a system that is put into use for a long time at a time. Unlike coal and stone, it also needs to calculate resource consumption, and the cost saved is simple and clear.
2.7 Equipment anti-theft electric alarm system
Since most of the oil wells are in the field, this gives the opportunity for criminals to steal electric energy, or even oil well equipment. The common means of theft is to bypass the metering and connect the public line privately. In addition, the contact resistance of the wire of the electricity thief is high, which will cause the situation of fire jump and strand breakage or even wire breakage under the thermal effect of the current, bringing serious harm to the power lines and oil well operations. However, the use of solar photovoltaic power generation can avoid this phenomenon. Solar power generation is concentrated in the daytime, and a large number of workers work in the oil well. At night, the power is supplied by the battery. The electricity thieves have no power lines to connect privately. Moreover, the photovoltaic power generation lasts a long time, and the power supply is stable. The occurrence of electricity theft can be immediately reflected in the anti-theft alarm system to improve the safety of the oil well.
3. Application benefits of solar photovoltaic power generation in Daqing Oilfield
3.1 Energy conservation and emission reduction
Solar energy, as a pollution-free, safe and reliable energy with short construction period, has great attraction in all countries. With the instability of political and economic situation in many oil and gas producing regions around the world, China has vigorously promoted the use of solar energy in order to reduce its dependence on foreign energy and solve the increasingly prominent environmental problems and climate change risks related to fossil fuel power generation. In response to the 13th Five Year Plan for Solar Energy Development issued by the National Energy Administration, Daqing Oilfield provides assistance to promote the sustainable and healthy development of the solar energy industry and accelerate the diversified application of solar energy. Taking 2019 as an example, photovoltaic power generation in China reached 224.3 billion kW · h, a year-on-year increase of 26.3%, of which Daqing Oilfield generated about 9 billion kW · h, and the light rejection rate in Daqing was as low as 0.4% To transform traditional fossil energy and coal power into clean power, Daqing Oilfield has added 290000 kW of installed capacity, 22 photovoltaic power stations, and reduced carbon dioxide emissions by 2.79t and sulfur dioxide emissions by 91t In addition, the electricity consumption of Daqing Oilfield in 2019 will be 16.7 billion k W · h, of which 12.2 billion k W · h will be generated by coal mine gas and 2.1 billion k W · h by wind power. The proportion of photovoltaic power generation will be about 11.3%. The rest of the electricity will be used for urban residents. It can be seen that Daqing Oilfield has a huge space to develop new energy and a good prospect. In the future, it will not only reduce the environmental pollution emissions caused by thermal power generation, but also reduce the consumption of limited resources such as coal and oil.
3.2 Resource utilization
Although the scale of the photovoltaic power station does not affect the investment income, the power generation will be affected by the installed capacity, component orientation, conversion efficiency and weather factors. Recently, the National Development and Reform Commission issued the Notice on Matters Related to the 2020 PV Power Generation On grid Pricing Policy, in which the guidance price for centralized PV power generation will continue to be set. The guidance price for new centralized photovoltaic power stations in I-III resource areas, which will be included in the scope of national financial subsidies, is determined as 0.35 yuan, 0.4 yuan and 0.49 yuan per kilowatt hour (tax included). For industrial and commercial distributed photovoltaic power generation projects that are included in the scale of financial subsidies in 2020 and adopt the mode of “self use and surplus online”, the subsidy standard for full power generation is adjusted to 0.05 yuan per kilowatt hour. Daqing Oilfield belongs to Class II resource area, and both centralized and distributed photovoltaic power generation are involved. However, the peak and valley of power consumption of the oilfield itself will be different. Although it can achieve spontaneous self use of resources, it still needs power supply from the grid in some peak power consumption and rainy weather. At 800000 kilowatts per hour, the annual power consumption cost is still more than 600000 yuan, which does not include the power consumption of oilfield development and construction. In terms of resource utilization, although solar photovoltaic power generation can not support the overall development of Daqing Oilfield, it has brought significant results.
