Microseismic monitoring technology
Science
What is a micro-earthquake ?
Microseismics are weak seismic waves produced by rock ruptures caused by changes in stress fields in rock bodies, that is, weak seismic signals.
Micro-seismic is different from artificial earthquakes in seismic exploration, it occurs naturally in the production process, with small energy and short duration. The acoustic emission phenomenon produced by the rupture of underground rock masses is called a microseismic event.
What does microseismic monitoring technology monitor?
Microseismic monitoring technology is a kind of geophysical detection technology, the main means is to collect data on the small seismic events generated in production activities, and observe and analyze them, and record the data and conclusions obtained, and predict the interference, effectiveness and stability of rock mass of small earthquake events on production activities. Its basis is acoustic emission and seismology.
There are many technical methods used in micro-seismic monitoring technology, but the basic process is roughly the same, mainly including several key steps such as data acquisition, processing and inversion positioning. The three elements of systematic monitoring of microseismics are the primary tasks of monitoring activities, including the location of the source, the moment of occurrence, and the depth and intensity of the source. The basic practice is to arrange the detectors in the well and on the ground to receive or induce the small seismic events generated or induced by the production activities, and to obtain parameters such as the location of the microseismic source through the inversion of these events, and then apply these parameters to monitor or guide the production activities.
What is the principle of microseismic monitoring technology?
Microseismic events occur in the fracture section of the rock mass or the deformed surface, which is due to the phenomenon of stress concentration, which will destroy the original stress balance of the rock mass in the production activities, then the stress concentration will appear around the cracks in the rock mass, these cracks can be their own existence or newly generated, and their strain energy is improved. There are original cracks in the rock mass, the original cracks will be affected by external forces, when subjected to a large force will occur local reverse yield and deformation, resulting in cracks will continue to extend to the inside of the object, at this time stress relaxation is accompanied by outward radiation energy to the outside in the form of elastic waves, this phenomenon is a micro-seismic phenomenon. The frequency of these waves is generally in the range of 200 to 1500 Hz, and the general duration is shorter than 15s.
Microseismic monitoring instruments
The monitoring system collects and analyzes and records the signal of the original crack defect part and the newly generated crack area, and determines the deformation location of the newly occurring crack as well as the specific form and size with the help of information such as the increase of external forces. After continuously accumulating data and forming a database, it can be known from experience that when the frequency is higher, the shorter the time, the smaller the energy of the radiation wave, that is to say, the weaker the micro-seismic event, the shorter the corresponding known rupture length.
Using statistical principle analysis, the time and space related information of microseismic events can be obtained, and through these experiences, a reasonable comprehensive evaluation of the stability of the rock mass area can be given.
What are the applications of microseismic monitoring technology?
Small seismic events often occur in production activities, such as rock ruptures and seismic activity during the mining of deep underground mines, which are often unavoidable. By monitoring rock rupture and seismic activity through microseismic monitoring technology, the impact of small seismic events on production activities can be assessed, and the stable state of the surrounding rock in the underground cavern can also be monitored due to its physical monitoring technology.
With the continuous evolution of production needs, as well as the in-depth study of shale gas, unconventional oil and gas exploitation and various emerging energy extraction, micro-seismic monitoring technology, as the core of its dependence, has become an important guarantee for ensuring efficiency and safety of personnel and equipment, and it is mostly used to judge the formation of fracturing fractures and the basis for judging the development trend.
Mine micro-seismic monitoring software system
It is inevitable to study the development direction of microseismic monitoring technology and the technical field. After several years of unremitting efforts and continuous exploration, the mainland has made great progress in this technology.
Since 2019, the microseismic monitoring team of the Institute of Geomechanics of the Chinese Academy of Geological Sciences has deployed an advanced high-precision microseismic monitoring system in the Republican hot dry rock field area of Qinghai, china, which proves that microseismic monitoring also has a very good application prospect in hot dry rock development.
Now
Microseismic monitoring technology has become one
Geophysical exploration techniques are widely used.
This technology gives engineers a "clairvoyant eye",
The rock mass rupture process can be closely monitored at all times,
Safe mining for mines, tunneling,
Safe development of emerging energy sources such as shale gas
Escort.
END
References:
"Development Direction and Application of Microseismic Monitoring Technology" Xu Jin
"Overview of Microseismic Monitoring Technology", Shao Xiaoguang, Dong Hongli, Dai Liyan
Source: Jizhen WeChat