Oil is closely bound up with us in modern life. One survey shows that everyone would “wear” 290 kg of petroleum, “eat”551 kg of petroleum, “live” 3790 kg of petroleum, “travel” 3838 kg of petroleum.
Is it strange? Not at all. All the colorful, fashionable and beautiful clothes we wear, which is made up of all kinds of fabrics, originate from petroleum. And the plastic wrapping in the beverage and food we get in touch with as well as plastic bags we use when go to food market to buy vegetable are petrochemical products. There is much more in the prospective of living as chemical engineering materials has replaced conventional building materials, and is widely used in national major projects, such as a tube specialty named PE100 bimodal polyethylene has successfully applied to South-North Water Transfer Project, West-East Gas Transmission Project, urban pipe network transformation etc. Besides, many building decoration materials and coating we usually use come from petroleum.
Oil can not only be used as fuel for cars, but also has so wide application that we can't even live without it. But now the oil industry is facing a number of problems that have to be solved, for instance, Our foreign dependence ratio of oil has been close to 60% last year while China has surpassed the United States as the world's largest oil importing country this year., is it because the domestic oil resources are not rich enough? Actually it’s not. Oilfield is faced with the awkward situation that there is oil could not be exploited at present in our country.
There Is Oil Which Could Not Be Exploited
Nowadays in China, developing some mature oilfields taking Daqing Oilfield as the representative is much more difficult. The contradiction of shortage in oilfield reserves is becoming more and more prominent, and pressure in enhance oil recovery is getting increasing. At present, 70% of China's oil production still comes from the mature oilfields. Seven among the first ten oil and gas fields has more than 30 years’ production history. In addition, the average water content in mature oilfields is as high as 90% while the average oil recovery is only 35%. And the mature oilfield has entered the "double high" stage of both high degree of recovery and high water content. So the development of high water cut oilfields will become a major challenge to the petroleum industry.
Much more unacceptably, some oilfields are even close to exhaustion. But in fact, the visible oil has been exploited in lots of oilfields. However, this does not mean that these oilfields have been exhausted or useless. Many places of these fields may also contain abundant oil, where the oil reserves may be two times more than that of traditional method has been exploited.
Oilfields of our country are mainly distributed in continental sedimentary basin, and both changes of reservoir physical properties and the sand distribution are complex, high clay content, with high wax and high viscosity of crude oil, which increase the difficulty in oilfield development in China. And the oil recovery rate in China can only exploit 28% ~ 35% of geological reserves under the current technology level. 65%～78% recoverable reserves still remain under the ground.
In addition, the national onshore oilfield has entered into high water cut stage with water cut as high as 82% in recent years in China. Oil-water separation and sewage recycle greatly increase the energy consumption, which make oil production cost rise to almost no profit and force part of mature oilfields have to reduce production.
Although our country has done a lot of work in the oilfield development, especially in the aspect of enhancing oil recovery, for example, oil recovery of Daqing oilfield and Shengli oilfield has reached to 41.2%. The crude oil production could increase more than 10 Million tons by the polymer flooding technology. However, the average oil recovery rate is still not high in our country. Data shows that China has developed 550 oilfields, the geological reserves used degree is 77%, and the average oil recovery rate is only 30.4% at the end of 2009,
The latest data of Ministry of Land and Resources has shown that China's oil exploitation amount has reached 6.2 Billion tons with the remaining recoverable amount of 20.6 Billion tons at the end of 2014. While our national conventional oil geological resources is 108.5 Billion Tons, that is to say, there are 81.7 Billion tons of oil deep underground which could not be exploited. The remaining conventional oil and gas resources are poor quality, low permeability, deeply buried, deepwater oil and gas and proportion of other low quality resources such as heavy oil, high sulfur gas increase year by year as the difficulty in exploration as well as utilization of these resources is relatively greater.
China sees sustained rapid development of national economy and rapid growth of energy demand, especially the demand for oil and gas, which is also facing severe challenges. It draws general attention of current oil industry in the world to improve the oil recovery in the oilfield, and to make more underground oil and gas resources be transformed into the energy products in actual use.
Oil is the nonrenewable resource. The special group of UK Industry Taskforce on Peak Oil and Energy Security has released a forecast report that Global oil production would reach the peak in 2015 then a rapid decline afterward while the rise in global oil demand is still strong.
Now it becomes the problem in need of urgent solution for the sustainable development of China's oil industry that how to enhance oil recovery in order to increase recoverable reserves and extend production plateau of oil well, which also becomes the world class problem. Over the years, scientists around the world have groped for how to enhance oil recovery, which has become a marathon competition of global energy technology.
Technological Means Emerge Endlessly
At present, most of the oilfields in China have entered the tertiary oil recovery stage. After many years’ transformation, the tertiary oil recovery mainly includes chemical drive, thermal drive, gas injection displacement and MEOR（Microbial enhanced oil recovery）, among which chemical drive is widely used. And other ways have not been widely promoted because the technology is not mature enough or the effect is not obvious.
And the oil recovery has reached to 41.2% in Daqing Oilfields mentioned above, in which chemical recovery plays an important role. But they are exploring new ways to enhance oil recovery. And microbial enhanced oil recovery has received the widespread favor. Many institutions including government have invested much time, human resource as well as technology in MEOR.
Daqing oilfield began to study the technology of microbial enhanced oil recovery since the early 1960s, and now it has become the reserve technology in Daqing oilfield. While there are six fields in Shengli Oilfield has conducted the microbial enhance oil recovery with the increased production of nearly 200,000 tons.
Microbial enhance oil recovery is much more reliable according to the present concept of "profitable, sustainable" in the development of oilfield. Traditional recovery methods cannot meet the demand on the condition that environmental protection requirements gradually increase year by year. And the advantage in MEOR has become prominent.
While the chemical recovery has been widely used, many people neglect a problem, which is that chemical production will pollute the soil and water.
For example, the main component of widely used polymer flooding and alkaline-surfactant-polymer flooding is poly acrylamide, which is non-toxic itself, but the monomer acrylamide it contained is highly toxic as acrylamide is neurotoxicity, genotoxicity, as well as carcinogenicity. When large amount of polyacrylamide accumulates in the soil and water, acrylamide content will be over standard, which would lead to damage of cranial nerves centre and carcinogenesis.
The carcinogenicity of polyacrylamide had been evaluated by International Agency for Research on Cancer (IARC) in 1994, and polyacrylamide is listed as 2 kinds of carcinogen(2A), which is probably carcinogenic to human, on the basis of polyacrylamide would convert into carcinogenic active metabolites-glycidamide on animal and human beings.
But MEOR would not cause such a problem as microorganism is everywhere in nature from water, soil to the air. And both the microorganism and its metabolites are natural organic matter, which will not pollute the environment. And MEOR is the harmless treatment to reservoir without confusion to the soil, formation water or crude oil. Its principle is decided by the biological nature of biological products, which is totally different from chemical reaction. And it directly acts on pollutants and will not change the properties of crude oil or produce any new ramification.
Meanwhile, achievements in MEOR field have been made by some large international corporations such as Schlumberger, Baker Hughes, Halliburton Company etc. While, there’s also a company independently developing a comparatively mature MEOR technology in China, and has made good achievements in foreign markets.
“BERO Biosurfactant”, independently developed by ZFA Technologies Inc., is a technology which uses biosurfactant got by microorganism fermentation to exploit the crude oil contained in the rock stratum. And the effective period could last for more than 12 months with no need to maintain. The technology has a popular promotion in the United States, but it also belongs to a new product.
Compared with other domestic oil recovery technology, the biggest advantage of the “BERO biosurfactant” is stability. As the main component of “BERO™ Biosurfactant” is enzyme, non-active protein, it can adapt to the various formation and wells without influenced by water mineralization degree, pressure and temperature. Besides, it could clean the reservoir of wells to enhance oil recovery.
In the earlier stage of BERO biosurfactant stimulation, the stimulation scheme could be obtained according to the current data of wells rather than plenty of additional experiments and analysis. Besides, the stimulation process is quite simple with no need of lots of human and material resources. And it does not need any follow-up work after stimulation. In addition, strong operability makes it more acceptable for production personnel in oilfields.
And most of the domestic MEOR technology cannot meet the industrial standards, which still belongs to “custom-made”, being effective to this well, not necessarily effective to that one. So each well needs “on-demand production.”.
New Technology Has Promising Prospect
The data provided by ZFA Technologies has shown that with the BERO biosurfactant, the average annual increased production above 100 tons, average annual production increase rate above 120%, effective time above 12 months. While the average annual production increase rate of the similar biological products is only 30%.
If calculated according to input-output ratio, BERO™ biosurfactant is 1:5. BERO biosurfactant could enable the production of crude oil greatly increase while lower production cost, so remarkable economic benefit could be gained.
At present, it takes 3 Million to 5 Million to drill a new well, calculating most conservative production increase as 50%, then the price in removal plugging for two low permeability maturewell could use to drill a new well, that is income increases at least 3 Million. The application of BERO™ biosurfactant applied in stripped wells and wells with reduced production of mature oilfields entering the late stage of development can prolong the duration of return by more than one year, extend development period and gain significant economic benefit.
“Our advantage is to put forward a solution toward the customers’ existing problems in the oil recovery.” says by Hao Duan. At present, ZFA Technologies Inc. has conducted a wide range of technological test as well as stimulation cooperation with Daqing Oilfield, Jilin Oilfield, Karamay Oilfield, Nanyang Oilfield, Zhongyuan Oilfield, Qinghai Oilfield, Yanchang Oilfield etc. in China. Now it has achieved obvious economic benefits and social benefits.
Not long ago, Hao Duan has just came back from Indonesia, and Indonesia's national oil for exchange views in depth, and launched a cooperation.
Even though the world has entered into the adjustment of energy structure, such as renewable energy and more natural gas will replace oil, but there are still limit in the alternative energy applications in many areas, the demand for oil will continue to grow in the short period, which makes it the fundamental issue that how to extract more oil at a lower price.
According to the International Energy Agency’s forecast, China's total energy consumption will continue to grow in the next 30 years, and it is expected to reach 4.834 Billion tons of oil in 2040. China's foreign oil dependence would reach 80% in 2040, which is a serious threat to China's energy security.
China is currently increasing strategic petroleum reserves to avoid the energy crisis. In fact, recoverable reserves can also be counted as strategic reserve, and it’s conducive to ensuring national energy safety to enhance oil recovery in any respect.