Binnan Oil Production Plant Test Site. Tianding Lianchuang Company / Courtesy photo
In the process of heavy oil extraction, it is necessary to inject high temperature and high pressure steam, and whether these steam can be well sealed underground is related to the efficiency of heavy oil extraction and the efficiency of the oil field, which is also a world-class unsolved problem. So, can the experience in the field of nuclear power sealing be applied to China's heavy oil extraction?
Since 2015, after three years of scientific research, Tianding Lianchuang Sealing Technology (Beijing) Co., Ltd. has innovatively opened up a new way to overcome the world-class problem of heavy oil mining high temperature and high pressure annular air seals. In view of this technological innovation, recently, the reporter of this newspaper interviewed Song Wei, chairman of Tianding Lianchuang Sealing Technology (Beijing) Co., Ltd.
Wen 丨 Tong Xiaobo
Reporter of China Energy News
Song Wei
Song Wei, whose clothes are not outstanding and his appearance is not amazing, is a well-known "capable person" in the field of sealing - for more than 20 years, he has won more than ten first and second prizes of national and provincial and ministerial science and technology awards in the field of sealing. In 2010, as the third person to complete the project, the project of "New Technology, New Product and Application of Nuclear Power Plant Sealing Technology" also won the second prize of the National Science and Technology Progress Award.
China Energy News: Is your research experience in the field of nuclear sealing helpful in overcoming this technical difficulty?
Song Wei: Although sealing is different in different fields, the technology is the same. In this research on sealing materials in the field of heavy oil mining, we have indeed borrowed the basic content of nuclear industry materials and nuclear sealing fields, such as the selection of nuclear grade graphite as one of the three main raw materials, and the sealing design of the main nuclear power pump is also borrowed in the design of the sealing cylinder.
However, TD350 is a material that we have independently developed and is unique in the world, and from the material to the sealing cylinder equipment, we have applied for more than 70 patents, including more than 20 invention patents. At present, there are 7 invention patents and 25 utility model patents. He was evaluated by Professor Weng Duan of the Department of Materials Science of Tsinghua University as "this is absolutely subversive and original in the world field".
China Energy News: How do you see the application prospects of this technology?
Song Wei: Since its establishment in 2015, Tianding Lianchuang Company has spent tens of millions of yuan on the research and development of heavy oil exploitation in high-temperature and high-pressure annular sealed oilfield. Because we are optimistic about its development prospects, from the very beginning we have won the opportunity to cooperate with Tsinghua University and Shengli Oilfield. The Beijing Fengtai Science and Technology Commission has also given us strong support on scientific research land.
As one of the innovation projects in Beijing in 2016, TD350 sealing cylinder has also received financial support for technological innovation of beijing science and technology SMEs. In 2017, we also completed the first round of financing of 30 million yuan, led by Yunhui Capital, founded by several former executives and senior bankers of Goldman Sachs Group.
China Energy News: What are the priorities of recent work?
Song Wei: At present, we already have two major R&D bases in Beijing Fengtai and Ningbo, Zhejiang, and it is expected that 5-10 new production lines will be added in the next year, and automated production can be realized within two years, and we already have a certain R&D and production foundation.
We are committed to solving practical problems for customers, the future need to summarize the existing experience, further expand the scope of the test, at present, we have carried out preliminary cooperation with CNOOC Offshore Heavy Oil Project Team, Xinjiang Oilfield. We will further strengthen the cooperation between industry, education and research, and together with petroleum engineering experts, continue to strengthen scientific research on related supporting products and supporting facilities, and solve specific practical problems in combination with practical applications.
China Energy News: What are the R&D or promotion plans for the future?
Song Wei: As far as solving the problem of annular sealing of heavy oil mining is concerned, we are only now mainly in the key link of materials to make a breakthrough, the progress of a generation of materials will inevitably lead to the improvement of a generation of equipment, specific to heavy oil mining, and even to improve the recovery rate, there are other shortcomings in the equipment and oil production process programs that need to be made up.
In the long run, our goal is to build a long-term sealed oil recovery process solution that serves heavy oil thermal recovery, and to promote the technological progress of heavy oil thermal recovery and the improvement of heavy oil recovery as a whole.
In addition, through this oilfield test, TD350 composite materials have withstood the test from normal temperature to high temperature to normal temperature. I hope to continue to study and practice, expand it to other fields of machinery and equipment manufacturing, and contribute to the technological progress of basic parts of China's machinery industry.
Small seals help solve the world-class challenges of heavy oil extraction
Wen 丨 This newspaper reporter Tong Xiaobo
High temperature and high pressure annular sealing technology is recognized by the industry as a world-class problem restricting heavy oil production in oilfields. However, this technology has recently made breakthroughs thanks to the efforts of Chinese researchers.
The reporter learned that from November 2017 to the day before, the core components independently developed by Tianding Lianchuang Sealing Technology (Beijing) Co., Ltd. (hereinafter referred to as Tianding Lianchuang) - the world's first seal cylinder made of 350 °C resistant and 20Mpa sealing material TD350, have been successfully carried out for 40 days in two on-site production wells of Binnan Oil Production Plant in Sinopec Shengli Oilfield.
In 40 days, what tests have the sealed cylinders of the packers undergone? From normal temperature to high temperature, after 15 days of continuous steam injection (steam injection temperature 330-355 °C, steam injection pressure 12-19.7Mpa, steam dryness of more than 70%), the stewing well natural cooling, and then reverse pressure sealing, the test results proved that the high temperature packer sealing cylinder has maintained excellent sealing performance, greatly exceeding the performance of the original sealing cylinder in the oilfield.
Industry experts believe that this marks a major breakthrough in China's ultra-high temperature underground sealing technology in the world, which will provide strong technical support for the improvement of recovery of heavy oil reservoirs. Weng Duan, professor of the Department of Materials Science and Engineering of Tsinghua University and director and deputy secretary-general of the Chinese Society for Materials Research, commented: "It is expected to fill the gap between high temperature and high pressure sealing materials and products in the process of heavy oil mining, which is of great significance to reducing the cost of oil production and improving the efficiency and efficiency of heavy oil extraction. ”
The development potential is enormous
Heavy oil is crude oil with a relative density greater than 0.92 and an oil layer viscosity greater than 50 centipoise at 20 °C, also known as heavy oil. At 50 °C, the heavy oil with a viscosity of more than 100,000 centipoise is a super heavy oil, which is basically solid under ground conditions after extraction, and the foot is not deformed.
According to public reports, the global recoverable reserves of heavy oil are currently about 400 billion tons, which is 2.7 times that of conventional crude oil recoverable reserves (150 billion tons). Of the world's approximately 10 trillion barrels of surplus oil resources, more than 70% are heavy oil resources. Heavy oil is expected to become an important strategic successor resource.
Relevant data show that China is the fourth largest heavy oil resource country after the United States, Canada, and Venezuela, with proven and controlled reserves of about 4 billion tons, focusing on Liaohe Oilfield, Shengli Oilfield, Karamay Oilfield and Henan Oilfield. Offshore heavy oil is concentrated in the Bohai Sea region, where 62% of the proven geological reserves of crude oil are heavy oil.
However, heavy oil reservoirs are low-grade petroleum resources, because of their high viscosity, difficult to flow, difficult to extract, the current global annual output is only nearly 100 million tons. Since the end of the last century, China's annual production of heavy oil has been stable at more than 10 million tons, and the average recovery of heavy oil in the oil fields being exploited in China is less than 20%, and the development potential is huge.
Steam leakage restricts thermal recovery efficiency
According to Song Wei, chairman of Tianding Lianchuang, the outstanding feature of heavy oil is that it is very sensitive to temperature, and every time the temperature rises by 8-10 ° C, its viscosity is reduced by 1 times, so the high-pressure saturated steam is injected into the oil layer for thermal recovery, and the production increase effect is very significant. "When the formation is injected with 250-350 ° C of high-temperature and high-pressure steam, the oil reservoir and crude oil in the near-well zone are heated, the viscosity of crude oil can be greatly reduced to a few centipoises, the resistance of crude oil flow is greatly reduced, and the production of oil wells will inevitably increase significantly."
Over the years, steam thermal flooding has become the world's mainstream heavy oil mining direction. In China, since the 1980s, steam heat recovery technology has also been the main technology of heavy oil extraction. However, the development of ultra-heavy oil requires large steam injection pressure and high temperature, and the general heavy oil extraction method is simply not feasible, and there is almost no experience at home and abroad.
Industry experts pointed out that the key to the thermal recovery of heavy oil is the quality of the injection steam. According to the research of the American Society of Mechanical Engineers (ASME), when the steam injection temperature reaches 350 °C and the dry gas saturation (steam dryness) reaches 100%, it is the best solution for heavy oil to reduce viscosity.
"In recent years, with the successful development of equipment such as critical/supercritical boilers, oilfields have been able to fully guarantee the quality of steam injection at the wellhead when extracting heavy oil. However, due to the fact that the problem of annular sealing has not been well solved, which greatly affects the steam quality of the wellbore below the thermal recovery packer in the well, and leakage often occurs when the oilfield injects steam into the heavy oil extraction, which has become the key bottleneck restricting the thermal recovery of heavy oil in the oilfield. Song Wei told reporters.
The reporter learned that over the years, many companies at home and abroad have participated in the research of large annular sealing technology in the field of heavy oil thermal recovery, the core of which is to solve the material problem, that is, to find a high temperature resistance, high pressure, and long-term high elasticity of the sealing material, but the effect is not satisfactory.
Among them, the perfluoroether material developed by DuPont in the United States has become a leader in this field because of its high temperature resistance of 315 °C, but it still cannot meet the actual working conditions required for heavy oil extraction. The Removable Packer, designed for uh-uh-uh-high pressure wells launched by Baker Hughes in the United States in early 2016, can withstand only 204 ° C.
The world's first sealing technology was successfully tested
In order to overcome this problem, since 2015, the R&D team of Tianding Lianchuang Company has cooperated with the School of Mechanical Engineering of Tsinghua University, Shengli Oilfield Petroleum Engineering Research Institute and other units, with the help of Yunhui Capital, after three years of scientific research, successfully developed the world's first high elastic composite material that can withstand 350 °C and 20Mpa supersa supersaturated water vapor pressure - TD350, and obtained 7 invention patents and 25 utility model patents.
According to reports, TD350 is a composite polymer material with high temperature resistance, high pressure resistance, oil resistance, water resistance characteristics, especially in high temperature conditions can still maintain similar to the elasticity of rubber, at 350 °C, 20Mpa pressure can continue to seal the oil sleeve annular, the highest withstand temperature up to 361 °C, the highest withstand pressure up to 25Mpa.
Sealed barrel. Tianding Lianchuang Company / Courtesy photo
Tianding Lianchuang Company cooperated with Shengli Oilfield Petroleum Engineering and Technology Research Institute, using its self-developed TD350 sealing cylinder to carry out 11 tests on the ground for three years in Shengli Oilfield Petroleum Engineering Institute, realizing the large annular air sealing of heavy oil thermal recovery simulation device, providing a solid foundation for the on-site promotion of heavy oil mining underground sealing control.
"Since November 2017, Binnan Oil Production Plant in Shengli Oilfield has taken the lead in boldly trying to select two on-site production wells, equipped with dozens of professional technicians divided into three shifts, and experts from the Petroleum Engineering Institute have carried out experiments day and night to verify the sealing performance of new materials under different practical working conditions." Song Wei said.
Field test report shows that the whole set of experimental temperature from room temperature to high temperature, and then to the high temperature after the stewing well, the quality of steam injection is significantly improved, for 30 consecutive days the packer sealing cylinder has always been leak-free, because the annular pressure is zero, can not wash the well, without pressure operation, saving a lot of water resources at the same time, but also greatly improve the construction safety.
"For the first time, the TD350 high-temperature sealing cylinder has achieved sealing under the alternating working conditions of ultra-high temperature and normal temperature, breaking through the bottleneck that the heavy oil thermal recovery process in the oilfield has long been unable to be further effectively implemented due to sealing problems, and laying the foundation for the next improvement of the high-temperature heavy oil heat recovery process and the realization of efficient oil production." Wang Lushan, vice president of the Shengli Oilfield Petroleum Engineering Technology Research Institute, commented.
It is understood that at present, shengli oilfield has more than 5,000 heavy oil thermal production wells, due to the heavy oil well bottom seal is not strict, resulting in large steam losses, low unit steam oil production, and high oil production costs. This, combined with the current low oil prices, has left more than half of the wells in a state of hovering. If this technology is promoted, a large number of hovering wells are expected to restore economic mining value.
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Produced by | China Energy News (ID:cnenergy)
Editor-in-charge | Yan Zhiqiang