As of December 8, 2021, the annual output of tertiary oil recovery in Daqing Oilfield of PetroChina has exceeded 10 million tons again, and the output has exceeded 10 million tons for 20 consecutive years, with a cumulative production of 286 million tons of crude oil. The world’s largest tertiary oil recovery production base has been built. Tertiary oil recovery technology has become the leading development technology that supports the sustainable development of Daqing Oilfield, and has strongly promoted the development of enhanced oil recovery technologies in the world.
Usually, the self-spraying oil produced by the energy of the oil layer is called primary oil recovery, and the injection of water into the oil layer to supplement the energy is called secondary oil recovery, and the performance of oil, gas, water and rock is improved by injecting chemical substances. The production of more oil is called tertiary oil recovery. Tertiary oil recovery technology is an important technical means for the old oilfields to greatly improve crude oil recovery. At present, tertiary oil recovery has been widely used in Type I and Type II oil layers in Daqing Oilfield. After the application of tertiary oil recovery technology, the recovery rate has increased by 14 to 20 percentage points on the basis of secondary oil recovery technology.
Limited resources, unlimited innovation. Daqing Oilfield always puts innovation at the core of the overall development. Following the idea of ??”application generation, research and development generation, reserve generation”, after continuous research and research, two sets of tertiary oil recovery technology series, polymer flooding and ternary composite flooding, have been established. And always maintain the leading position in the world.
As early as the 1970s, Daqing Oilfield conducted a pilot field test of polymer flooding with a small well spacing, but it only increased the recovery rate by about 4%. In the late 1980s, polymer flooding and other chemical flooding technologies entered a low ebb worldwide, and scientific research on chemical flooding in many countries stagnated.
In the face of many doubts and difficulties, Daqing Oilfield has unswervingly carried out research on polymer flooding technology, finding reasons for failures and finding basis in practice. After more than 20 years of research, scientific and technological research, pilot tests and industrial field tests, it has broken through the existing theoretical framework and technical routes abroad, innovated and developed polymer flooding theory, and formed a mature and complete supporting engineering technology.
Since the industrialization and application of polymer flooding in Type I and II reservoirs began in 1995, the first and second technologies have been achieved through the improvement of polymer flooding scheme design, polymer flooding tracking adjustment, new polymer flooding, and oil production surface supporting technologies. The recovery rate of oil-like layer polymer flooding is at the same level, and it has reached “the target is getting worse and the effect is not reduced.” By the end of 2021, there will be 72 industrialized blocks for polymer flooding in Class I oil reservoirs, with a cumulative oil production of 160 million tons; and 46 industrialized blocks for polymer flooding in Class II oil reservoirs, with a cumulative oil production of 70 million tons.
With the changes in mining targets and the increasing complexity of the underground situation, Daqing Oilfield took precautions and began research on ASP flooding technology in the 1980s. At that time, foreign research results showed that the acid value of Daqing crude oil was too low to be suitable for the application of ASP flooding technology. According to this conclusion, some foreign experts asserted: Let Daqing Oilfield completely forget the ASP flooding technology!
Facing the great responsibility of safeguarding national energy security, Daqing Oilfield will not give up lightly. Since 1983, it has carried out advanced research on ASP flooding technology. After tens of thousands of experiments, it has broken through the traditional theoretical framework and technical route, and revealed the relationship between the ultra-low interfacial tension of the ternary composite system and the structure of surfactants and crude oil composition. Developed Daqing crude oil to form a ternary combination flooding system with ultra-low interfacial tension, breaking the argument that “the low acid value crude oil in Daqing Oilfield is not suitable for ternary combination flooding”, and formed a ternary combination flooding theory with Daqing characteristics. It also tackled world-class problems such as solution design, lifting and produced fluid treatment, and pharmaceutical production. In 2014, it realized the first integration and large-scale application of ASP flooding technology in the world. The recovery rate is better than that of secondary oil recovery. Flooding technology increased by more than 20%. Since 2016, the annual crude oil output has remained above 4 million tons for six consecutive years; by the end of 2021, the ASP flooding technology has been industrialized and applied in 37 blocks of the Daqing Oilfield.
Daqing Oilfield has innovated and formed a complete set of reproducible and exportable chemical flooding integrated supporting technologies, innovated the chemical flooding theory of greatly improving oil recovery, developed a series of flooding chemicals and realized industrialized scale production, forming the industrialization of chemical flooding Integrated supporting technology. The technological innovation of tertiary oil recovery has won 7 national awards and 78 provincial and ministerial awards; 155 authorized core patents have been obtained, including 75 invention patents and 185 enterprise proprietary technologies. Established a chemical flooding technology management standard system, formulated 62 enterprise technical standards and 28 production management systems.
In the process of innovating tertiary oil recovery technology, Daqing Oilfield has built an open national key laboratory for enhanced oil recovery, a national energy continental sandstone old oilfield continuous development center, a CNPC tertiary oil recovery pilot test base, and Heilongjiang Province to improve crude oil recovery. Yield Engineering Technology Research Center. At present, the core patents and proprietary technologies of tertiary oil recovery are not only applied in domestic oilfields, but also successfully provided technical services to Russia, Kazakhstan, Indonesia, Oman and other countries. (Source: People’s Daily Client Heilongjiang Channel Qiu Chengyang Fangyuan)