Academic Journal of Science and Technology 
ISSN: 2771-3032 | Vol. 14, No. 3, 2025 

 

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Structural	Design	and	Analysis	of	Hydraulic	
Sandblasting	Perforation	Device	
Qiangqiang Cheng*, Bin Zhao, Chenxi Dong 

School of Mechanical Engineering, Xi’an shiyou University, Xi’an 710065, China 
*Corresponding author: Qiangqiang Cheng (Email: 954895560@qq.com) 

 

Abstract: The coalbed methane reservoirs in China are mostly low-permeability reservoirs, which face many difficulties in 
mining, such as complex fractures, susceptibility to sand blockage, and low support rate. This article designs a new type of 
hydraulic sandblasting perforation device that integrates hydraulic sandblasting and perforation technology. It adopts a modular 
structure and includes guiding, adjusting, fixing, perforation, and stabilizing mechanisms. It is suitable for a well diameter of 
139.7mm, a maximum outer diameter of 110mm, an inner diameter of 45mm, a total length of 450mm, a nozzle outlet diameter 
of 6mm, and a pressure bearing capacity of 90MPa. The fixed mechanism uses threaded rods and other components to achieve 
stable fixation, and the sandblasting perforator of the perforation system consists of a gun body, a protective cover, and a nozzle. 
According to static analysis, the maximum deformation value of the perforator is 0.015602mm, and the maximum stress is 
235.31MPa, which is less than the allowable stress of 715MPa for the material, and the strength meets the requirements. Modal 
characteristic analysis shows that its first six natural frequencies are all above 3377Hz, much higher than the normal operating 
frequency of 100Hz, and it will not resonate during operation. This device can ensure the accuracy of sandblasting perforation, 
reduce the risk of accidents, and provide technical support for efficient exploitation of coalbed methane. 

Keywords: Nozzle; Fracturing; Hydraulic sandblasting perforation device; Static analysis; Modal analysis. 
 

1. Introduction 
The coalbed methane reservoirs in China are mostly low-

permeability reservoirs, and most wells have little production 
without fracturing. Therefore, hydraulic fracturing 
technology is one of the main production increasing 
technologies for coalbed methane development in China[1-3]. 
Hydraulic jet fracturing technology is a new type of 
stimulation and transformation technology that integrates 
perforation, fracturing, and isolation. It is suitable for the 
stimulation and transformation of vertical and horizontal 
wells in low-permeability reservoirs and is an effective 
method for fracturing and increasing production in low-
permeability reservoirs. Due to the low elastic modulus of 
coal and rock, the soft formation, and the development of 
natural cleavage fractures, complex fracture propagation 
patterns are easily formed during coal seam hydraulic 
fracturing. Complex fractures develop in a network shape, 
with limited opening of individual fractures, easy sand 
blockage, and difficulty in improving sand ratio. The ultimate 
effective support rate of fractures is low, and the difficulty of 
extending fracture length is high [4-5]. 

With the huge demand for energy in the development of the 
national economy and the increasingly depleted energy crisis, 
energy exploration technology is forced to constantly 
innovate. It is necessary to increase and target the 
development of low-pressure, low-permeability, and low-
permeability "three low" oil reservoirs and unconventional oil 
and gas resources such as coalbed methane and shale gas. 
Especially as oil and gas fields enter the middle and later 
stages, the utilization of reserves becomes increasingly 
difficult. In order to achieve stable and high yields, the focus 
of development has shifted to the previously overlooked thin 
layers of differential layers[6]. In order to develop these 
complex reservoirs quickly and efficiently, the concept of 
refinement is not only proposed in management, but also 

requires improvements in process technology [7-9]. 

This article designs a new type of hydraulic sandblasting 
perforation device, which is a device used for coalbed 
methane or coal seam water injection mining. It combines 
hydraulic sandblasting and perforation technologies to 
complete sandblasting and perforation operations of coal and 
rock layers in one device. It mainly includes two parts: 
hydraulic sandblasting system and perforation system. The 
hydraulic sandblasting system uses high-pressure water jet to 
wash the coal and rock layers to achieve the effect of 
fragmentation and dissolution, thereby improving the 
permeability of coalbed methane or coal seam water injection. 
The perforation system uses bullet guns or other forms of 
perforation tools to form holes in the washed coal and rock 
layers to facilitate the extraction or injection of coalbed 
methane or water [10-12]. 

In the process of mining coal seams, especially during 
sandblasting and perforation operations, it is usually 
necessary for workers to conduct simulation calculations in 
advance to determine the specific location of sandblasting and 
perforation required for the coal seam. However, in existing 
technologies, there is usually no positioning function for the 
device, which may cause the position of the sandblasting and 
perforation to shift due to its instability when using the device 
for sandblasting and perforation operations, thereby affecting 
the accuracy of sandblasting and perforation of the coal seam. 
In severe cases, it may even lead to coal seam collapse, posing 
a great safety hazard to the lives of workers. 

2. Structural Design and Working 
Principle of a New Hydraulic 
Sandblasting Perforation Device 

2.1. Overall structural design 
Based on the principle of underground erosion and 



 

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combined with the practical application requirements of the 
device, the scheme improvement of the hydraulic 
sandblasting perforation device has been completed, and a 
new type of fixable hydraulic sandblasting perforation device 
is proposed as shown in Figure 1. Then, modular design is 
adopted for the structure of the device, including five parts: 
guiding mechanism, adjusting mechanism, fixing mechanism, 
perforation mechanism, and stabilizing mechanism. 

 

Figure 1. Overall structure of a new hydraulic sandblasting 
perforation device 

2.2. Working principle 
According to Figure 1, the working principle of the 

hydraulic sandblasting perforation device can be observed. 
When the guide head is started and placed inside the coal 
seam, the device can be guided to the designated position 
under the starting action of the guide head. Then, by starting 
the forward and reverse motor 2, the threaded rod 2 can be 
driven to rotate. Under the cooperating restriction of the guide 
rod 2, the adjustment cylinder 2 can be driven to slide inside 
or outside the adjustment cylinder 1. With the movement of 
the adjustment cylinder 2, the position of the electronic 
locator and guide head can be driven to move, thereby 

achieving fine adjustment of the position of the device after 
placement. After the adjustment is completed, when it is 
necessary to fix the device, people only need to start the 
forward and reverse motor 1. With the start of the forward and 
reverse motor 1, Drive the rotation of threaded rod one, and 
with the rotation of threaded rod one, And under the 
restriction of the guiding rod 1, it can drive the threaded block 
to move. With the movement of the threaded block, it can 
drive the movement of the fixed seat. With the movement of 
the fixed seat, it can drive the rotation of the driving rod. 
Through the rotation of the driving rod, under the support of 
the connecting column 2 and the connection of the connecting 
column 1, it can drive the limit claw to expand until it is 
inserted into the coal seam, thereby achieving the positioning 
and fixation of the device after placement. This effectively 
avoids the displacement of the sandblasting perforation 
position caused by its instability, further ensures the accuracy 
of sandblasting perforation of the coal seam, and avoids the 
problem of great safety hazards to the lives of workers caused 
by coal seam collapse in severe cases. 

2.3. Determination of main design parameters 
Based on the optimization results of nozzle structure 

parameters and production materials mentioned earlier, and 
taking into account the actual site conditions, a hydraulic jet 
fracturing downhole tool suitable for 51/2"casing was finally 
calculated. Combined with reference materials, preliminary 
design parameters for a new type of hydraulic sandblasting 
perforation wereproposed, as shown in Table 1. 

 
Table 1. Main technical parameters of the new hydraulic sandblasting perforation device 

Parameter name numerical value 
Applicable well diameter 139.7mm 

Maximum outer diameter of the tool 110mm 
inside diameter 45mm 

Total length of tool 450mm 
Diameter of nozzle outlet 6mm 

pressure-bearing 90MPa 
 

3. Fixed System Design 
The fixed mechanism is the core component for achieving 

accurate positioning and stable fixation of the device in coal 
and rock layers. It consists of threaded rod 1, threaded block, 
fixed seat, driving rod, connecting column 1, limiting claw, 
and connecting column 2, as shown in Figure 2. When the 
threaded rod rotates, according to the principle of threaded 
transmission, the threaded block connected to it will move 
along the axial direction of the threaded rod. The outer surface 
of the threaded block is fixedly connected to a set of fixed 
seats, and as the threaded block moves, the fixed seats also 
move accordingly. The inner wall of each fixed seat is 
rotatably connected to a set of driving rods, and the inner wall 
of the driving rod is fixedly connected to a connecting column. 
When the fixed seat moves, the driving rod will rotate around 
the connecting column. The outer surface of connecting 
column one is rotatably connected to the limiting claw, and 
the inner wall of the limiting claw is fixedly connected to 
connecting column two, which is rotatably connected to the 
inner wall of the positioning cylinder. Through this structural 
design, when the driving rod rotates, under the support of the 
connecting column 2, the limit claw can expand or contract 
around the connecting column 1, achieving the fixation and 

release of the device in the coal rock layer. 
 

 
Figure 2. Schematic diagram of positioning cylinder 

structure 
1-Limit claw; 2- Drive rod; 3-Thread block; 4-Connecting 

pillar two; 5- Fixed seat; 6-Connecting pillar one; 7-Forward 
and reverse motor one; 8-Guiding Rod One 一; 



 

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4. Perforation System Design 
The perforation system is the core operational module of 

the entire hydraulic sandblasting perforation device, and its 
performance directly determines the efficiency and quality of 
coal and rock mining, as shown in Figure 3. 

 

 
Figure 3. Schematic diagram of perforation system 

structure 

4.1. Structure of Sandblasting Perforator 
The spray gun assembly includes the gun body, protective 

cover, and nozzle, as shown in Figure 4, and is one of the key 
components in the entire fracturing pipe string. The high-
pressure sand carrying fracturing fluid pumped into the 
ground will be converted into a high-speed jet through a small 
diameter nozzle, and then impact the inner wall of the casing 
to carry out perforation. The nozzle is installed in the conical 
hole of the body through the nozzle seat and sealed with the 
body using the conical surface; The external design of the 
spray gun body is equipped with a high-quality alloy 
protective layer, which aims to reduce the erosion effect of 
counterattack sand on the spray gun body during high-speed 
sand carrying fluid perforation. 

 

 
Figure 4. Schematic diagram of sandblasting perforator 

structure 
1; Nozzle seat; 2- Nozzle; 3- Spray gun body 

5. Static Analysis of Sandblasting 
Perforator 

5.1. Simulation model establishment 
The hydraulic sandblasting perforating device designed in 

this article is mainly subjected to the effects of high pressure 
zone, low pressure zone, and annular liquid pressure, as well 
as the pressure of the lower drilling tool during the working 
process. Therefore, its model was appropriately simplified 
during static finite element analysis, as shown in Figure 5.  

 

 
Figure 5. Finite Element Model of Hydraulic 

Sandblasting Perforator 

5.2. Grid division and boundary condition 
setting 
The hydraulic sandblasting perforating device was 

meshed with a mesh size of 5mm and a tetrahedral mesh 
type. The number of mesh nodes after partitioning was 

69959, and the number of mesh elements was 40398. The 
mesh partitioning results are shown in Figure 6. Based on 

the actual force situation during the operation of the 
perforating device, a fixed constraint is added on both the 

upper and lower ends of the perforating device, and a normal 
pressure of 30MPa is applied on the outer cylindrical 

surface. The boundary conditions and loading conditions of 
finite element analysis are shown in Figures 4-7 (a) and (b): 

 

 
Figure 6. Grid division results 

 

 
(a)Apply fixed constraints 

 
(b) Apply external pressure 

Figure 7. Application of boundaries and loads 
 

5.3. Simulation result 
According to Figure 8, the maximum deformation value of 

the perforator in actual working conditions is relatively small, 
at 0.015602mm; The maximum stress experienced by the 
perforating device as a whole is 235.31MPa, and the 
maximum strain is 0.001819. The yield stress of 42CrMo 
material is 930Mpa, and assuming the safety factor of the 
hydraulic sandblasting perforator is 1.3, the allowable stress 
of the material is 715MPa. After finite element analysis, the 
maximum stress experienced by the perforating device as a 
whole is 235.31Mpa, which is less than the maximum 
allowable stress max of the material. Therefore, the strength 
of the perforating device can meet the requirements. 
According to the strength verification theory of the hydraulic 
perforator mentioned above, the allowable stress of the 
hydraulic perforator is 715MPa, so its strength is within the 
safe range when in use. 



 

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(a) Total deformation 

 
(b) Equivalent strain 

 
(c) Equivalent stress 

Figure 8. Static analysis of perforating device 

6. Modal Characteristics Analysis of 
Sandblasting Perforators 

In engineering applications, modal analysis is widely used 
to identify the natural frequencies and vibration 
characteristics of components, which are collectively referred 
to as modes. To ensure the safety and reliability of the 
structure, the natural modal frequency of the component is 
usually compared and analyzed with its operating frequency 
to avoid resonance phenomena. When conducting modal 
analysis of perforating equipment, it is necessary to define the 
material performance parameters. In this paper, 42CrMo 
material is selected, with an elastic modulus E of 2.10 × 
1011Pa, Poisson's ratio μ=0.28, and a density p of 7850kg/m3. 

 
Table 2. Frequency table of the first six constrained 

modes of hydraulic injectors 
first mode 1794.5 

Second-order mode 1794.6 
Third order mode 3100.7 

Fourth-order mode 4065.9 
Fifth order mode 4066.0 
Sixth order mode 5444.5 

 
(a) first mode 

 
(b) Second-order mode 

 
(c) Third order mode 

 
(d) Fourth-order mode 

 
(e) Fifth order mode 

 
(f) Sixth order mode 

Figure 9. Analysis cloud map of different modes of 
hydraulic sandblaster 

 
Figure 9 shows the calculated deformation cloud map of 

the first six modes of the hydraulic injector under constrained 
conditions. From the results, it can be seen that the natural 
frequencies of each order of the hydraulic injector are all 
above 3377Hz. Considering that the normal operating 
frequency of the hydraulic injector is about 100Hz, much 
lower than these natural frequencies, the hydraulic injector 
designed in this article will not cause resonance phenomena 
during operation, which will effectively extend the service life 
of the tool and reduce the risk of underground accidents. 

7. Conclusion 
This article proposes a new type of hydraulic sandblasting 

perforation device to address the challenges of extracting low-
permeability coalbed methane reservoirs in China. This 
device integrates hydraulic sandblasting and perforation 
technology, adopts a modular structure design, and the 
various mechanisms work together to achieve precise 



 

140 

positioning, fixation, and efficient perforation operations of 
the device in coal seams. By determining reasonable design 
parameters, the applicability of the device is ensured. The 
fixed system utilizes threaded transmission and special 
structures to achieve stable fixation; The structural design of 
the sandblasting perforator in the perforation system is 
reasonable, effectively reducing the impact of erosion. The 
static analysis results indicate that the strength of the 
perforating device meets the standard, and the modal 
characteristic analysis shows that it will not resonate during 
operation, ensuring the safety and reliability of the device. 
The design of this device provides a new approach for coalbed 
methane mining, which is expected to solve the shortcomings 
of existing mining technologies, improve mining efficiency 
and production, promote the efficient development and 
utilization of coalbed methane resources, and have important 
application value and broad development prospects in the 
field of energy exploration and development. 

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