Editor's note: As the world economy continues to develop, energy issues are becoming more and more important. Growing world energy demand is forcing countries to solve their own energy problems through various channels. One of the most important means is to find supplementary and alternative energy . As a clean and efficient energy, natural gas occupies a large proportion in the world's energy demand. Unconventional natural gas has been valued by governments, scientific research departments, and energy companies because of its huge resource potential and economic benefits.
Unconventional natural gas refers to natural gas reservoirs with large reserves that are difficult to develop and must rely on large-scale production stimulation measures or special development methods and advanced exploration and development technologies to produce economically valuable production. Commonly used unconventional natural gas includes tight sandstone gas, coal bed gas, shale gas, natural gas hydrate (combustible ice) and so on.
As the proportion of unconventional natural gas in the world's energy structure has gradually increased, energy scientists from various countries have begun to work hard on their exploration and development technologies. Professor Ju Yiwen, a doctoral supervisor at the University of Chinese Academy of Sciences, has been focusing on exploration in this field and has always been Walk at the forefront of the discipline.
Develop and use coalbed methane in one fell swoop
Coal-bed methane, commonly known as gas, also known as coal-bed methane, is a gas resource associated with and coexisting with coal. Its main component is methane (CH4), with a relative content of about 80% to 99%, followed by a small amount of CO2, N2, H2, SO2, C2H6 and other gases. The frequent occurrence of gas disasters brings serious problems to the safe mining of coal mines in China, but at the same time, gas is also a very precious natural gas resource. Therefore, experts pointed out that the development and utilization of coal-bed methane can both control gas, increase energy supply, and reduce greenhouse gas emissions.
China is rich in coalbed methane resources, and its reserves rank third in the world. Coal geologists gradually realized that China's deep coalbed methane resources are much larger than shallow ones, and coalbed methane resources deeper than 1000 meters account for 61% of total coalbed methane resources. Even in the most developed Qinshui Basin and Ordos Basin, coalbed methane geological resources with a burial depth greater than 1,000 meters account for 47% and 72% of the entire basin, respectively. However, unlike shallow coal seams, deep coal seams are characterized by high ground pressure, high ground temperature, low permeability, and complex structural deformation, which have caused great difficulties in coal and coalbed methane mining.
In this regard, on November 6, 2012, at the Xiangshan Scientific Conference on the theme of "Deep Coal Mine Gas Disasters and CBM Development Major Issues", Zhu Yiwen was entitled "Important Scientific Issues in Deep CBM Exploration and Development in China's Structural Deformation Areas" 》 The central issue review report pointed out that it is an urgent need to find new coalbed methane development favorable selection and breakthrough in deep coal seam of structural deformation area in China, and further finely detect and enrich high permeability area to improve its production capacity and exploitation Efficiency is also a difficult problem to be solved urgently in coalbed methane development.
The important scientific issues of deep coalbed methane development in structural deformation areas mainly include four aspects: the superimposition of extrusion and extension structures during the evolution of the basin; the metamorphic deformation of coal reservoirs and the superimposition and conversion of brittleness and toughness; the micro-nano of coal rock deformation In terms of structure and physical property mutation; in the reservoir reconstruction, the reservoir space conduction transformation and multi-field dynamic changes. The first two aspects are mainly related to the search for favorable areas for coalbed methane development from a macro perspective, and the latter two aspects are based on microscopic perspectives to study the mechanism and technical development of coalbed methane enrichment and high permeability.
Ju Yiwen pointed out that in order to truly realize the large-scale and industrial development of coalbed methane, in addition to deep-buried coalbed methane that can only be mined on the ground, joint development of coalbed methane ground mining and underground coal mine extraction must be implemented. This is China ’s coalbed methane The mode of industrial development and the only way.
It is imperative to change the concept of shale gas exploitation
As a clean energy source, shale gas has received increasing attention in recent years. At the end of 2011, shale gas was classified as an independent mineral, and then in April 2012, "Shale Gas Development Plan (2011-2015)" (hereinafter referred to as "Planning") was introduced. On July 13 of the same year, the Ministry of Land and Resources issued the Technical Requirements for Shale Gas Resources / Reserve Calculation and Evaluation (Trial) (Draft for Comments), hoping to pave the way for the actual development of shale gas in the next step.
"Planning" proposed that during the "Twelfth Five-Year Plan" period, basically complete the national shale gas resource potential survey and evaluation, preliminary grasp the national shale gas resources and their distribution, preferably 30-50 shale gas prospects and 50 ~ 80 favorable target areas; proven shale gas geological reserves of 600 billion cubic meters, recoverable reserves of 200 billion cubic meters. In 2015, shale gas output reached 6.5 billion cubic meters and other targets.
"Compared with conventional oil and gas reservoirs, shale layers have extremely low permeability. Prior to this, we used them as caprocks of source rocks and oil and gas resources, not as reservoirs," said Ju Yiwen.
Shale gas is natural gas located in organic-rich shale layers and its interlayers, and exists in the shale matrix or organic pores in an adsorbed and free state. According to reports, although shale gas development has low production capacity, it has the advantages of long mining life and long production cycle. At the same time, due to the wide distribution range and large thickness of gas-bearing shale, shale gas resources are huge. It is for this reason that shale gas wells can produce gas at a stable rate for a long time, and the production life can usually reach 30 to 50 years, or even last for 80 years.
Ju Yiwen said that to date, basic research on shale gas in China has not become a theoretical system. He introduced that the current research concept of shale in China needs to be changed: the study of shale as a source rock and cap rock as a reservoir, from single unconventional gas production to co-production of multiple unconventional gas, very Cooperate with conventional gas and conventional gas for multi-gas co-production; the shale gas enrichment mechanism research has not been carried out: the domestic early stage mainly focuses on the study of shale fractured oil and gas reservoirs, the shale gas research foundation is weak, and the enrichment mechanism and enrichment conditions ( Main control factors), enrichment mode and enrichment unit (system) division principles have not been systematically studied; lack of technical innovation research: shale gas reservoir nanopore system conduction technology, reservoir fracture reconstruction technology, temperature pressure and seepage, etc. No breakthroughs have been made in the multi-field transformation technology. On the basis of domestic and foreign research results, Ju Yiwen et al. Carried out research on shale gas source rock, generation and evolution characteristics, storage and distribution characteristics, seepage and migration characteristics, and summarized the shale gas enrichment conditions, Enrichment characteristics and commonality and difference with CBM.
Ju Yiwen also pointed out that the shale gas reservoirs in China are quite different from those in the United States. They are mainly manifested in different sedimentary environments and have experienced more complicated structural deformation. Some technologies and methods that have been successful in the development of shale gas in the United States need to be modified before they can be applied in China.
Explore the evolution of Penshan and the occurrence of unconventional natural gas
Significance
The formation, migration, accumulation and accumulation of unconventional natural gas in the basin are closely related to the basin-mountain unified evolution dynamics process and the deep lithospheric effect. The basin-mountain evolution process and the basin-developed tectonic-thermodynamic force Science is the premise and key to study the enrichment and distribution of unconventional natural gas. By studying the dynamics of basin-mountain evolution within the North China Block and its periphery, it is found that the basin tectonic dynamics directly restrict the conditions, characteristics and distribution of unconventional natural gas (including coalbed methane and shale gas) formation and other hydrocarbon accumulations law.
The research results of Ju Yiwen indicate that the structural-thermodynamic conditions of the Qinshui Basin and Lianghuai Coalfield in the North China Block are favorable dynamic conditions for CBM enrichment, and the structural transition zone between the squeezing / extension conversion and superposition is CBM. Favorable structural units enriched in high permeability. The Qinshui Basin and Lianghuai Coalfield are in different structural-thermodynamic environments, and their dynamic mechanisms are clearly different: the occurrence characteristics of coalbed methane in the Qinshui Basin are high coal metamorphism and weak deformation, which is beneficial to coalbed methane enrichment However, it is not conducive to the penetration of coalbed methane, and the subsequent transformation of the compressive tectonic stress field increases the structural fissures of the coal reservoir, which is conducive to the seepage and exploitation of coalbed methane. It is conducive to the enrichment of coalbed methane, and the later compressive stress field is converted into a tensile stress field, which is conducive to the permeability enhancement of coalbed methane. Therefore, it is possible to find favorable areas for the exploration and development of coalbed methane in structural coal development areas.
Ju Yiwen's exploration of basin-mountain evolution and unconventional natural gas not only fully reveals the characteristics of CBM enrichment, but also clarifies the relationship between basin structure-thermodynamic evolution and the occurrence of unconventional natural gas, and can guide coalbed methane and shale gas under complex geological conditions. Exploration and development has important theoretical value and application significance.
Sipimo Hair Essence
Key ingredients: Polygonum
multiflorum, angelica, aloe,
ginseng, tea polyphenols,
flaxseed and other extracts
Capacity: 100ml
Regular Edition: Daily scalp care
for older or white haired people
-HERBAL EXTRACT-
Sipimo Hair Essence
Hair Essence Spray,Best Hair Treatment,Best Hair Serum For Men,Best Hair Growth Products
Shenzhen Sipimo Technology Co., Ltd , https://www.sipimotech.com