Emergency exercise simulation training system developed by Esimtech is a set of virtual simulation solutions for typical well drilling accident emergencies. It can enable relevant operators or learners to receive training on blowouts, explosions, hydrogen sulfide leakage, and other accidents during drilling, and enhance safety awareness and emergency response, handling, and escape capabilities.

Emergency Exercise (VR)

The emergency exercise (VR) is developed based on the emergency drill software platform. The purpose is to train and test drilling emergency drills.

Trainees can have realistic VR interactions and an immersive experience. Through the super simulation system and human-computer interaction, students can get real feedback on the environment during the operation process. Through the training and testing of this system, the trainees can cultivate their own psychological quality and complete the training in emergency response drills and emergency escape.

Drilling Emergency Practice Training Platform

The drilling emergency training platform can make the trainees feel the real situation as much as possible, and make the trainees deeply impressed with the emergency situation handling process in the oil industry. In this way, when students encounter real blowouts, explosions, and hydrogen sulfide leakage accidents, it will help them to calmly take correct emergency measures.

The training items of the training system include the above-mentioned emergency treatment and escape training when blowout is out of control, emergency treatment and escape training in case of fire and explosion, and emergency treatment and escape training in case of hydrogen sulfide leakage and poisoning.

Drilling Emergency Exercise Simulation Training System

The drilling emergency exercise simulation training system can realize emergency treatment and training for typical drilling accidents. The R&D and manufacturing of the simulation training system combine technologies such as 3D simulation, 3D interaction, and network communication. Through 3D technology, the system can simulate the drilling site environment, drilling equipment and facilities, and operators, and show the actual occurrence and progress of accidents. It allows students to perform 3D interactive operations in it to achieve the purpose of training.

The training system not only enables trainees to receive drilling accident training but also evaluates trainees’ completion of training and displays problems and errors in trainees’ operations.

Drilling and well control safety technology directly affects the development of oilfield companies. If the well control safety technology cannot be guaranteed, it will seriously affect the safety of life and property.

Application of well control safety technology in drilling

In drilling work, due to the influence of exploration well depth, long period, complex formation, high formation pressure, and high hydrogen sulfide content, well control safety technology may encounter many difficulties in the drilling process.

First, when drilling in high-sulfur areas, the combination of hydrogen sulfide and well control issues presents a significant safety risk in well control technology. This particular operating environment brings difficulties to materials or tools such as wellhead equipment, casing, and tubing when conducting exploration operations in high-sulfur areas. In the event of a blowout or leakage, it is very easy to cause serious poisoning of hydrogen sulfide.

Second, there is the difficulty of degassing in well control safety technology. When drilling ultra-high pressure oil and gas wells, it is generally necessary to increase the drilling concentration to balance the formation pressure so that the drilling fluid system can develop stably. Degassing in high density and high viscosity drilling fluids is difficult.

Third, the pressure bearing capacity of drilling equipment is limited.

Ways to strengthen well control safety technology

Strictly standardize the design of well control safety technology

Drilling and well control safety technology should be designed in strict accordance with the standards so that the drilling and well control safety technology develops in the direction of standardization and management. In installing equipment, we must adhere to the principles of high standards and strict requirements to eliminate potential safety hazards in the installation of equipment, which is in line with the design of drilling and well control safety technology.

Improve the professional quality of well control personnel

In drilling work, well control safety work is the most basic work. Because employees’ well control safety knowledge is essential, educating and training employees’ safety well control knowledge is a major event in well control work. The company should formulate a practical training plan so as to improve the safety awareness of well control personnel. It is necessary to strengthen emergency drills, and through actual combat drills, employees’ awareness of drilling and well control can be greatly improved.

To strengthen the special inspection of drilling and well control

In daily life, to constantly check the drilling equipment, it is also necessary to carry out special inspections of the drilling and well control equipment. For problems found in the inspection, the company shall arrange technical personnel to deal with the problems in a timely manner.

Improve and perfect well control safety technology

Improve the dynamic control capability of well control equipment

In order to ensure the safety of well control technology, firstly, it is necessary to continuously improve the structure of the choke valve, improve the strength, precise control ability, and anti-erosion ability of the choke valve so that the choke pressure can be easily adjusted, thereby improving the downstream of the choke valve’s impact resistance. Second, to develop a new multi-stage throttling system.

Carry out research on well control technology to solve hidden dangers in well control equipment

Carry out sulfur prevention work and do an excellent job in the protection of hydrogen sulfide

In view of the sulfur content in different regions, each inspection area shall take corresponding measures in terms of sulfur-resistant equipment and technology to ensure the safety of well control technology.

When conducting exploration in high-sulfur areas, artificial ignition should be avoided, and an all-weather remote control ignition device should be installed. In areas with high sulfur content, formulate standards for hydrogen sulfide protection and monitoring equipment.

In the drilling and well control safety work, we can use the drilling and well control simulator to conduct simulation training among the staff in advance to strengthen the safety control. We offer portable drilling well control simulation, cyberchair drilling simulator, top drive simulator, drilling simulation training system, land rig installation simulator, etc. It can highly simulate the real on-site equipment, panel layouts, operation methods, etc. It can produce visual effects similar to the scene, coupled with realistic sound effects of live equipment, giving people a sense of immersion and realism.

This article will discuss various risk factors that may exist in the process of downhole operations. The problems and deficiencies in the safety management of downhole operations are analyzed, and corresponding solutions are proposed for these problems.

Suppose a safety accident occurs in the downhole operation. In that case, it will cause serious economic losses to the enterprise and the country, and the personal safety of the relevant personnel will be affected. Therefore, it is very important to ensure downhole operations’ safety, stability, and efficiency. We need to pay attention to safety management in the drilling and production process.

We should try to avoid the occurrence of unsafe downhole operations and safety accidents and strive to control the occurrence of downhole operation accidents to zero.

Inadequate Safety of Downhole Operations

Downhole operation is a technological method to guarantee the regular manufacturing of oil and also water wells in the process of oilfield expedition and growth. Mainly include oil and water well maintenance, oil and water well overhaul, reservoir reconstruction, and oil testing.

During the long-term production process of oil and water wells, due to the interference of various underground liquids and gases and the action of gas flow, the well conditions will gradually deteriorate, corrode, eccentric wear, and various types of failures will occur, resulting in oil and water wells not producing normally. The downhole repair of oil and water wells with problems and failures to ensure normal oil and water well work, and a series of measures implemented to relieve oil and water well failures, restore or improve their production capacity in the process of repairing various downhole failures. The process is downhole work.

There are many construction points in underground operations involving various constructions, and the hidden dangers of safety are also more complicated. Due to the influence of factors such as humans, environment, equipment, and facilities, underground operations are highly dangerous.

Unsafe underground operation mainly refers to the forcible operation of underground workers without excluding unsafe factors such as unsafe conditions and unsafe behaviors. Unsafe behavior mainly refers to operating errors, ignoring safety, ignoring warnings, using unsafe equipment, venturing into dangerous places, etc.

Unsafe factors caused by machinery, facilities, and humans should be avoided as much as possible. Underground operators must eliminate unsafe operations, master certain safety knowledge, and at the same time strengthen safety awareness, so as to avoid unsafe operations and safety accidents to the greatest extent and ensure safe production.

Problems Existing in the Safety of Downhole Operation

1. Lack of safety awareness of downhole operators

Safety knowledge means that people always keep in mind the importance of safety and know what to do when faced with danger. When working at ordinary times, know how to operate and know what preventive measures, treatment measures, or emergency rescue measures to take in emergencies. However, the safety awareness of underground operators is often weak.

2. Inadequate safety management system

The underground operation sites are often in relatively remote areas, the construction environment is relatively poor, and there are great difficulties in the safety management of the construction site. The production tasks are tight, the construction personnel is many, the workload is large, the work intensity is high, and the production links are many, which leads to the lack of serious implementation of the safety management system.

3. Incomplete standardization scheme for downhole operation safety

A comprehensive safety management system should be established. In addition, a corresponding safety standardization scheme is established for each link in the production process of underground operations to ensure safe production, and the details must be sufficiently standardized.

Actions to be Taken:

1. Strengthen the safety awareness education of underground operators.

2. Improve the safety management system.

3. Improve the safety standardization plan for underground operations.

4. Use simulation systems. The downhole simulators can give students an immersive experience through the 3D animation synchronized with the operating conditions. And it can use mathematical models to simulate various working conditions and parameters in petroleum engineering operations and strive to achieve the same effect as actual drilling operations. In this way, students can intuitively experience and quickly master the relevant knowledge and skills of fracturing and acidizing production.

Oil drilling well control is an essential link in the process of oil and natural gas exploration and development and is the premise and guarantee for the safe production of oil and natural gas. Every effort must be made to ensure the smooth progress of construction and the safety of personnel on-site. Therefore, we must control the oil drilling well control link. From online and offline, both theory and practice need to be learned and mastered in all aspects. This article will introduce two kinds of drilling and well control simulation training systems developed and manufactured by Esimtech.

Full-scale drilling simulation training system

All hardware systems of the full-scale drilling simulation training system highly simulate real equipment on site. Various panel layouts, operation methods, parameter display methods, etc., in the simulation system, are consistent with the production site. The system can produce visual effects similar to the scene by projecting the three-dimensional graphics synchronized with the operating conditions onto the front screen. Combined with realistic sound effects of live equipment, it gives people an immersive sense of immersion and realism.

The system is based on advanced computer industrial control technology, artificial intelligence technology, scientific visualization technology, virtual reality technology, and advanced network technology, combined with strict simulation of the actual process of drilling engineering, using high-reliability classical physical and mathematical models based on real on-site well conditions and well history information provides users with various training operations such as tripping, drilling, well control, equipment fault detection, and handling of drilling accidents and complex situations.

The system highly simulates well conditions and equipment operations, improves the flexibility of trainers’ operations, and greatly improves the training efficiency and effectiveness of trainers.

The operation items involved in the training system include five modules: tripping module, drilling module, downhole accident handling module, well shut-in operation, and well-cementing operation.

Portable Drilling Well Control Simulation Training System

Features of Portable Drilling Well Control Simulation Training System:

The drilling well control simulation training system is easy to carry and has perfect functions.

The system is compliant with IADC and IWCF standards.

Various drilling parameters can be flexibly set, such as drilling tool structure, formation parameters, equipment parameters, etc., making training more flexible and targeted.

The software system adopts an unordered architecture, which can realistically simulate various operations of the drilling rig, making the system closer to reality.

Using virtual reality technology to construct a realistic perception environment, using three-dimensional animation synchronized with the operating conditions, combined with simulated on-site sound effects, gives people an immersive feeling.

The operation items involved in the training system include shut-in operations and well-killing operations.

Due to the limitations of traditional training, we have been paying attention to the development of online training for petroleum occupations and are committed to helping major drilling training centres or petroleum colleges complete training tasks under different conditions. Esimtech has developed an online drilling simulation training system by conducting research on online training. At the same time, through an in-depth understanding of the training needs of IADC and IWCF, we are committed to creating a fully functional online drilling simulation training system.

A drilling simulator is a new training method developed through the concept of virtual manufacturing technology, based on modern computer control technology, computer graphics technology, computer simulation technology, and computer network technology, combined with the actual technology of drilling engineering. It changes the traditional drilling training method and can provide users with the simulation of the operation process of drilling, tripping, well control, drilling accidents and complex situation processing. The training assessment provides a teacher scoring system, which solves the technical problems that cannot be solved objectively in the traditional training process.

The drilling simulator cooperates with three-dimensional interactive equipment through VR virtual reality technology, which can simulate the well site environment, equipment and facilities, and workflow, as well as the formation structure, wellbore trajectory, drilling targets and other objects that are prone to deviations when observed with the naked eye. The display effect is accurate, intuitive and diverse.

Advantages of Drilling Simulator

1. Compared with traditional training methods, it is not limited by time and space.

2. It is convenient for teachers to carry out one-to-many training

3. Support personal practice and review after class

With the support of virtual reality technology, the ideal virtual environment can make the trainees in the realistic environment of the training project objects, and it is difficult to distinguish the true from the false. Moreover, virtual reality technology can carry out personalized education and training according to the foundation and ability of different students. This is not possible with traditional training methods.

EPC is an abbreviation for edge position control. During the high-speed transmission process, the EPC web guiding system is used to manipulate and correct the direction deviation of the coil raw material. It performs real-time testing, active tracking, and active correction.

What Causes Acceleration Offsets In The Process Of The Edge Position Control

One of the most troublesome edge position deviations is known as the acceleration offset. When the machine speed is increased or decreased, the web moves sideways. The rate of movement is usually greatest at the top and bottom of the speed difference rather than on the speed ramp itself. Unfortunately, the term “acceleration offset” misrepresents the true nature of the edge movement. Indeed, the web has no idea how fast it is moving.

The various web tracks through a machine shown in Figure 6 illustrate the cause of most acceleration offsets. We demonstrate how the web moves through a machine with one of the rollers misaligned. When there is absolute traction, the web will follow the Normal Entry law on all rollers, including the misaligned one. Take note of how the web shifts as a result of this misalignment. However, in the case of pure flotation, the web is not steered by the ‘roller’ and thus passes directly through the machine. The case of sliding is intermediate in that there is a small offsetting of the web.

As a result, every roller or element that touches the web also steers it. The path of the web, on the other hand, will remain constant if the roller is stationary and the state of traction is constant. That is not to say it is straightforward. The web will obviously snake through the machine in accordance with web handling laws. What we mean is that the path will, for the most part, remain consistent.

However, if the web switches from full to partial tracking, the web’s path will shift slightly in response. This shift in traction will be subtle and difficult to detect using traditional observations and measurements. Nonetheless, it will move the web in response.

The EPC web guiding system provides edge alignment to avoid deviation of the waterproof coiled material during the entire production and processing process, as well as ensuring accurate and stable performance of the waterproof coiled material during the entire production process with the neatly divided rewinding machine.

The control board can choose the method of tracking the edge or line based on the various raw materials and choose the electric eye test to take into account the requirements of various raw materials.

How Does The EPC Web Guiding System Work

A sensor, an actuator, and a controller comprise a web guiding system. Any detector that can reliably detect the edges of a web can be used as the sensor. Pneumatic (nonporous webs), photoelectric (opaque webs), and paddies are the most common (thick webs). Through the edge sensor, the web must be flat (no curl) and stable (no flutter). The sensor is frequently placed near a roller for this and other reasons. The web could be guided to the front edge, back edge, or center if two sensors are used.

The sensor’s output is routed to a controller, which sends a movement command to the actuator. If the controller’s gain is too low, the guide’s response will be sluggish and slow to correct. If the controller’s gain is too high, the guide will be hot but overshoot, and may even be unstable. For smaller assemblies, the actuator may be a stepper motor and ball-screw, while for larger assemblies, it may be a hydraulic cylinder. For responsive operation, the actuator and framework must be stiff.

Professional EPC Web Guiding System Provider- Arise

Arise is a leading EPC web guide system manufacturer in China. High-accurate Arise web guiding can ensure continuous, precise control of various coil materials in various manufacturing processes, ensuring that the material does not deviate from the correct position and minimizing waste and downtime.

The land rig installation simulation training system is a simulation training system with advanced technology and complete functions in the current industry. It can meet the training needs of oil companies and training institutions.

The simulation system is a training product developed based on computer simulation technology by combining petroleum engineering technology with computer technology and virtual reality technology. It simulates the drilling process of the land drilling rig realistically with reference to the actual operation process of the drilling operation site. The training objects are mainly technical skills training for new employees, drilling rig installers, drillers and assistant drillers, drilling team technicians, drilling team leaders, and other drilling site operators.

Compared with the traditional training method, it enhances the sense of participation and immersion in the training, effectively improves the training effect, and reduces the training cost. The system can train trainees, including the whole process of land drilling rig installation and safety precautions, the lifting and lowering process of land drilling rig derrick base, drilling rig tripping, and drilling operations, and top drive operations.

The Composition of the Land Drilling Rig Installation Simulation Training System

The Training System Mainly Consists of 5 Components:

The animation display module of the whole process of rig installation

Derrick/base lifting and lowering training module

Rig Virtual Assembly Module

Drilling rig simulation operation module

Electronic Atlas

The simulation system adopts high-definition animation to clearly show the whole land drilling rig installation process, and the displayed process is completely consistent with the actual land drilling rig installation process steps. The purpose is to standardize the entire installation process, making the land rig installation process more standard, regulated, and safe.

The simulation system utilizes a large number of mathematical and physical models to simulate and display various parameter changes in engineering operations, such as pressure, torque, drilling speed, and more, by accurately reflecting the relationship between these physical parameters to achieve the same performance as the actual drilling rig.

The land rig installation simulator adopts virtual reality technology and computer simulation technology to construct a realistic perception environment. The three-dimensional animation synchronized with the operating conditions is used to display the scene on a three-channel ring screen or three-channel LCD, combined with high-simulation on-site sound effects, giving people an immersive experience.

Components of a Training System for Land Rig Installation Simulator

Driller’s console

Top drive console

Graphic system

Supporting software

Advantages of a Land Rig Installation Simulation Training System

1. The parameter display, layout, and even operation mode of various equipment panels in the system are completely consistent with the actual products. And the height of each operation console and the real equipment on the drilling site is also the same.

2. The relevant hardware equipment is composed of industrial-grade PLC to ensure the reliability of the equipment to the greatest extent possible.

3. The system’s input cost and maintenance cost is relatively low.

4. The system has no security risk.

The technical operation for the coil materials that must always keep the edge of the coils neat and consistent during the spraying, printing, punching, laminating, slitting, or other coil winding processes is referred to as web guide control. The equipment used in the guiding process is a collection of web guiding control system. A common system consists of a controller, a sensor, a guide mechanism, and a driver.

Webs do not always track down through a machine in the same place. Any offsets in the unwinding roll, for example, will cause the web to start through a machine in a variable CD (cross direction) position on a roll-to-roll operation. Even if a web begins in the position, it may take slightly different paths through the machine depending on a variety of factors.

First, a variably baggy or cambered web will cause the web to track toward the variably tighter side. Second, variations in roller traction or drag can cause web steering. Third, changes in tension will affect how straight the web travels downstream. At zero tension, edge position control is essentially lost. Other edge movement factors include nip roller draw variations, aerodynamics, and so on.

Web guides are used to move the web’s edge or center to a specific CD position. The guide location could be at an unwind to start the web down through a machine in a consistent position, an intermediate location, or the winder to improve roll edge quality. The guide’s accuracy requirements can range from simply keeping the web on the rollers to minimizing trim loss and registering multiple print colors to within a few mils. Guides can be active or passive.

Working Of Web Guiding Control System

The purpose of the web guiding is to direct the sensor to emit infrared or ultrasonic radiation in order to monitor the operation of the coil material and send a signal to the controller. After the controller determines that the web has a positional deviation, the controller controls the drive system to swing to correct the web position using the preset command.

Brushless DC servo motor drive, precision ball screw drive, compact structure, good mechanical rigidity, low inertia, suitable for high-speed and high-precision guide are used in the web guiding system.

A controller, a sensor, an electric driver, and a correction guide mechanism comprise the system. The sensor detects the coil material’s edge position and reads the deviation between the actual and set positions, converting the deviation into a voltage signal proportional to it. The signal is then sent to the controller. After the signal is amplified and calibrated by the controller, the signal is output to the electric driver, and the electric driver drives the guide mechanism to perform correction actions according to the magnitude of the input signal to guide the coil material to the preset position.

Advanced Web Guiding Control System From Arise

Arise is a leading manufacturer in China, offering advanced web guiding control system. It is suitable for paper, non-woven fabric, plastic film, self-adhesive label tape, aluminum platinum, hot-rolled strip steel, and other applications. To ensure the neat division of the rewinding machine, the edge or marking line should be tracked and guided by the control border. The photoelectric correction manipulator uses a universal photoelectric controller for edge and line alignment, as well as imported drive machinery and a high-precision controller to control and maintain the edges or lines in a specific direction. The operation of the web guiding machine is simple, with high precision and reliability.

With the continuous development of 3D animation technology, 3D oil and gas animation also came into being, and oil animation is also a kind of three-dimensional animation.

Esimtech can provide oil drilling and well control animation, land rig installation animation, downhole tool disassembly and working principle animation, diesel engine disassembly, and assembly animation, and so on.

Why do We Need Drilling Animation?

The purpose of drilling animation is mainly to three-dimensional and visualize the equipment and technology in the oil industry and the complex mechanical design drawings. Various working processes, equipment technologies, etc., are made into 3D video demonstrations or interactive multimedia programs in the form of animation for engineering simulation or public display.

Types of Industrial Drilling Animation

Well Control Animation

It mainly shows different types of well control operations in the form of animation, including the installation and use of well control equipment. Let the students understand the real well control process more intuitively.

Well Logging Animation

It includes the appearance, logging principles, and uses of various logging tools such as compensated neutron logging, electrical survey, dual laterolog, spontaneous-potential log, and natural gamma-ray logging. And it contains the operation method of instrument connection.

Oil and Gas Production Animation

The animation of oil production and gas production includes the equipment working principle and production maintenance from the wellhead to the gas gathering station and the oil gathering station in the production process of oil and gas production.

Animation of Disassembly and Working Principle of Drilling and Well Control Equipment

The animation of drilling and well control equipment mainly trains the working principle, internal structure, and disassembly of drilling and well control equipment and tools in the form of animation. The purpose is to understand the components and principles of drilling and well control equipment and tools, to master the inspection and debug of the main working systems of drilling and well control equipment and tools, to analyze and judge the working conditions of drilling and well control equipment and tools, and can check and troubleshoot in time.

Diesel Engine Disassembly Animation

It mainly shows the internal structure and main components of the diesel engine. And it shows the disassembly, inspection, maintenance, and working principle of the diesel engine in the form of animation. At the same time, it is explained with text and dubbing so that the students are familiar with the working principle of the diesel engine and learn and master the inspection and debugging of the main working system.

Downhole Tool Disassembly and Working Principle Animation

The animation shows the internal structure of the tool and the composition of the parts and shows the internal structure of the tool in the form of a half-section or semi-transparent shell. The disassembly and installation steps and working principles of the tools are shown in the animation. At the same time, the text and dubbing are used to explain so that the trainees can master the functions, working principles, precautions, and maintenance methods of various tools.

Land Rig Installation Animation

The animation includes the whole process, from the drawing of the baseline diagram to the installation of each object in the middle, and finally, the whole process of the whole derrick lifting is completed. All processes are completely reproduced according to the actual installation process. Watching the animation can quickly, clearly, and completely understand the whole process of the installation and lifting of the entire land drilling rig.

The virtual simulation platform for drilling emergency exercises in oil and gas fields uses three-dimensional simulation, three-dimensional interaction, network communication, and other technologies to construct and realize the simulation and 3D interaction of drilling scenes, equipment and facilities, personnel conditions, environmental conditions, accident occurrence, and development process and personnel emergency response process. The system can realize the emergency response simulation exercise of typical drilling accident disasters and complete single-person drills and multi-person joint drills for emergency response. And the simulator platform is able to conduct drill evaluations on trainees’ emergency handling operations, emergency handling, task completion, and related knowledge points and point out problems and deficiencies in the process of drills. Therefore, the platform can be used for drilling workers’ emergency response and rescue teaching training.

About the teacher terminal of the virtual simulation platform for emergency drills
The teacher terminal of this virtual simulation platform for drilling emergency drills in oil and gas fields can provide management and editing of student information, emergency plans, and drill programs. The drill content can be adjusted according to the needs, and the one-click plan modification and drill process generation can be completed.

And after the drill, according to the students’ drill process, it can provide individual and team drill results, and then it can inquire about the reasons for the deduction of points.

The platform system can edit the drill program, support the selection of individual and team drill modes, set drill accident parameters, and generate drill process and evaluation criteria according to the parameter settings. It supports multi-point teaching, and the management of computers participating in the exercise can be realized through the teacher’s terminal.

About the student side of the emergency exercise simulation platform system

On the student side of the system, 3D simulation technology can realize emergency response and rescue training for drilling workers when they face dangerous accidents on site. Provides two exercise modes: individual exercise and team collaboration, which can be used to practice and assess the drilling process. The three-dimensional scene is realistic, the equipment is highly operable, and the environmental sound effects are added to make the simulation process close to reality. The training content is to realize emergency process simulation, risk identification, emergency response, rescue, and escape training according to the industry plan.

The system provides a rich knowledge base for trainers to learn and view relevant knowledge in practice mode and supports multi-person collaborative drills. And it provides training for personnel in various roles on the drilling site.

Advanced Technology in the emergency exercise simulation platform System

The system supports the execution of role AI and can automatically cooperate with trainees to complete the exercise project. It has a good user interaction experience. The equipment can be operated through an interactive interface, and the details are rich.

It has a multi-role information broadcast system, broadcasts the drill process in real-time, and judges whether the emergency response process is correct or not.

The simulation system uses CFD technology to realize model calculations such as gas diffusion and flame combustion and to deduce the accident process with real effects.