China to Develop MEOR Technology to Enhance Recovery

In an effort to increase oil recovery, China is going to spend more time on developing its MEOR (microbial enhanced oil recovery) technology by using genetically-modified microbes to stimulate higher oil yield rates at the onshore fields near the country's eastern coast.

Research will be carried out at the Daqing field in northeastern China by CNPC and state Key Lab on Virus Genetic Engineering (SKLVGE). The research is expected to take five to eight years to complete. Jin Qi, Deputy Director of SKLVGE, said he was confident the new technology will help recover 6-10% or even more of the total geological reserves in an oilfield. This translates to approximately 600 million to 1 billion tons of reserves that could be recovered from the declining oilfields in eastern China. It was further indicated that several billion tons of recoverable reserves could emerge throughout the country. The measurement of recoverable reserves is usually determined by existing oil-extraction technologies, and the recoverable volume still accounts for only a small fraction of total proven reserves in most of the world's oilfields. In China, it is difficult to overcome the problems of low-quality deposits, high impurity content, excessive viscosity, low permeability and harsh geological conditions using current technology.

The new project will use genetic technology to change the structure of polymers used in MEOR in order to strengthen their ability to break down the long carbon chains of high-density crude oil. Long carbon chains are one of the major barriers in oil extraction. Previous MEOR technologies using polymer and three-nutrient technology in one of the oil layers at Daqing were said to have improved the yield rate by 9 percentage points. 1,428 tons of oil in 13 wells have been successfully retrieved using the technology in Daqing. So far, two strains of microbes have been selected from the pool previously used for oil recovery at Daqing, and researchers there are making activation tests on them under a ground simulated oil-layer environment. Testing results show that the oil-recovery abilities of the two strains are among the best of all known microbes selected for use in EOR technology.

With an improvement in the technology, the research results will be applicable in most geological conditions in China, and could be applied in oilfields in other countries as well, as it is not at all polluting, said Jin. It is estimated that around 60% of the geological crude reserves are unrecoverable using existing technologies. In China, the amount of unrecoverable crude reserves in eastern onshore oilfields now stands at over 10 billion tons.