High-pressure Pump Research Articles

Flow characteristics of asymmetric plunger pairs in high-pressure plunger pumps

Abstract The deep-sea submersible is an essential piece of equipment for deep-sea development, serving as a crucial tool for conducting exploration and operations in the deep ocean. As the core component of the hydraulic system, the plunger pump is vital for ensuring the smooth lifting and lowering of the submersible. The plunger pair, which constitutes the most significant friction pair in plunger pumps, plays a pivotal role in determining both the service life and volumetric efficiency of the pump through its friction, lubrication, and sealing performance. This article proposes a flow model for the plunger pair in eccentric and inclined positions, considering its various orientations and placements. It elucidates the deformation and leakage characteristics of the plunger pair under different configurations, including various postures, material properties, and design parameters. The findings not only provide a theoretical foundation for the design of reciprocating seals and the evaluation of sealing performance but also contribute to the broader field of parameter design and performance assessment for other types of gap seals.

On Leakage Flows In A Liquid Hydrogen Multi-Stage Pump for Aircraft Engine Applications

Abstract A comprehensive operational characterisation of a representative, Liquid Hydrogen (LH2) aircraft engine pump is presented in this work. The implications of leakage flows are investigated in a 2-stage, high-pressure pump for a wide range of flow rates and rotational speeds, through 3D (U)RANS simulations. Two configurations are compared: a baseline model comprising the primary flow path components - inducers, impellers and volutes and a realisable pump hardware that includes hub, shroud and power unit cavities. Performance metrics, including head changes and efficiencies, are extracted both at a component and system level. Leakage flow rates of 27.6% and up to 92.9% of the overall pump flow rate are recorded at design and lowest flow points respectively. The head loss in the mid to low flow rates does not exceed 4.5%, but the efficiency diminishes by up to 13.5% at off-design operation. The component analysis indicates significant penalties in impeller efficiency. At high flow rates, the presence of leakage flows improves the overall pump performance by 43% and 27% in head rise and efficiency, due to reduced losses in volutes and connecting ducts. The characterisation of pump behaviour described in this work is crucial for developing and designing safe and predictable LH2 aircraft pumps. Contrary to LH2 pumps utilized in rocketry and for cooling in nuclear industry, aircraft pumps are required to operate with wider turn-down ratios and often at low specific speeds. Therefore, this study addresses design considerations for this enabling technology.

Blood trauma in veno-venous extracorporeal membrane oxygenation: low pump pressures and low circuit resistance matter

BackgroundVeno-venous extracorporeal membrane oxygenation (VV ECMO) has become standard of care in patients with the most severe forms of acute respiratory distress syndrome. However, hemolysis and bleeding are one of the most frequent side effects, affecting mortality. Despite the widespread use of VV ECMO, current protocols lack detailed, in-vivo data-based recommendations for safe ECMO pump operating conditions. This study aims to comprehensively analyze the impact of VV ECMO pump operating conditions on hemolysis by combining in-silico modeling and clinical data analysis.MethodsWe combined data from 580 patients treated with VV ECMO in conjunction with numerical predictions of hemolysis using computational fluid dynamics and reduced order modeling of the Rotaflow (Getinge) and DP3 (Xenios) pumps. Blood trauma parameters across 94,779 pump operating points were associated with numerical predictions of shear induced hemolysis.ResultsMinimal hemolysis was observed at low pump pressures and low circuit resistance across all flow rates, whereas high pump pressures and circuit resistance consistently precipitated substantial hemolysis, irrespective of flow rate. However, the lower the flow rate, the more pronounced the influence of circuit resistance on hemolysis became. Numerical models validated against clinical data demonstrated a strong association (Spearman’s r = 0.8) between simulated and observed hemolysis, irrespective of the pump type.ConclusionsIntegrating in-silico predictions with clinical data provided a novel approach in understanding and potentially reducing blood trauma in VV ECMO. This study further demonstrated that a key factor in lowering side effects of ECMO support is the maintenance of low circuit resistance, including oxygenators with the lowest possible resistance, the shortest feasible circuit tubing, and cannulae with an optimal diameter.

Drill bit hydraulic system for oil and gas boreholes

We set out to improve the existing design of a polycrystalline diamond bit with a steel or matrix body with the purpose of creating a hydro-monitoring effect. The research object was the hydraulic system of a diamond bit with a near-bit jet pump. The near-bit ejector system was studied by a theoretical analysis of the operation of the bit hydraulic system by means of canonical dependencies and hypotheses. A hydraulic system for a polycrystalline diamond bit is proposed. This system includes a high-pressure jet pump, which enhances the hydro-monitoring effect at the bottomhole. The main hydraulic characteristics of the bit flushing system with a jet pump are as follows: at a drilling pump feed of 18.4 l/s and a drilling fluid density of 1180 kg/m3, the working coefficient of jet pump injection equals 0.34; the working nozzle diameter equals 10.3 mm; the mixing chamber is 11.9 mm, bit hydromonitor nozzles are 11.1 mm; the number of hydromonitor nozzles is 3; the velocity at the exit of hydromonitor nozzles is 85.0 m/s; the pressure drop at the bit is 15.7 MPa. The possibility of using the hydro-monitoring effect enhanced by a near-bit jet pump was substantiated, since the velocity at the exit from the hydro-monitoring nozzles is sufficient to destroy most rocks (sandstone, limestone, dolomites, rock salt, gypsum stone, basalt, marble, granite). The jet pump in the proposed design of a polycrystalline diamond bit creates an additional circulation circuit above the bottomhole, injects cuttings from the annular space and feeds them to the hydro-monitor nozzles. This enables a more efficient destruction of the bottomhole rock. The power of hydro-monitor jets is sufficient to improve drilling performance.

Effects of distribution valve spring stiffness and opening pressure on the volumetric efficiency of micro high-pressure plunger pump

With the rapid development of material science and manufacturing capabilities, hydraulic technology is increasingly high-pressure, lightweight and miniaturizing. Micro plunger pump is widely used in the field of deep-sea hydraulic equipment and advanced intelligent hydraulic equipment, owing to its high-power density, high output pressure and many other advantages. Its broad application aims to examine the inlet and outlet distribution valve spring parameters change on the micro high-pressure plunger pump volumetric efficiency, by changing the inlet and outlet distribution valve. This paper is based on the simulation of AMESim engineering software to derive multiple sets of data. It compared and analysed the specific effect of different spring stiffness and opening pressure on the volumetric efficiency of the micro high-pressure plunger pump which was then verified through experiment. Results of this study have certain reference significance for the design of the spring of the inlet and outlet distribution valve of the micro high-pressure plunger pump, which facilitates the optimization and improvement of the dynamic performance of the micro high-pressure plunger pump.

Transient numerical simulation and characteristic study of flow field in high-pressure piston pump

Transient numerical simulation and characteristic study of flow field in high-pressure piston pump

The prospects for the use of alternative gel formers for hydraulic fracturing

The article discusses the relevance of using alternative gel-forming agents in the preparation of fracturing fluids for hydraulic fracturing (HF). Besides the obvious tasks, such as increasing the residual conductivity of the fractures created during stimulation, it also addresses the impact of alternative gelforming agents on the treatment process. The author, supported by field data, concludes that under otherwise equal conditions, replacing traditional fracturing fluids with alternative ones significantly reduces frictional pressure losses in the pipes, which is particularly important when treating deep and extensive horizontal wells with limited internal pipe diameters. Moreover, the aforementioned impact of gel-forming agents on frictional pressure losses allows for a reserve of power in the hydraulic fracturing fleet equipment. Consequently, the treatment can be performed with higher flow rates under otherwise equal conditions, without the need for additional high-pressure pumps or the deployment of more expensive, stronger, larger-diameter tubing. Another important conclusion reached by the author is that due to the specific properties of alternative fracturing fluids, their ability to transport and retain proppant is significantly increased. This property of fracturing fluids is especially important when treating low-permeability, fractured formations and during the stimulation of long horizontal wells. On the other hand, the use of alternative gel-forming agents raises the requirements for the controlled breakdown of fracturing fluids, complicating the task of selecting a rational formulation and necessitating additional research.

A system-level CFD simulation model for investigating the energy dissipation mechanism of seawater pump and rotary energy recovery device in SWRO desalination system

Seawater reverse osmosis (SWRO) technology has been universally adopted because of its high efficiency, economic benefits, easy maintenance, and high-pressure seawater pump (HPSP) and energy recovery device (ERD) are essential components, which determine the specific energy consumption of SWRO system. However, it is still unclear about energy dissipation mechanism and mixing characteristics from the perspective of system. For that, this thesis proposes a novel system-level Computational Fluid Dynamics (CFD) model considering all interfaces in HPSP and integrated energy recovery and pressure boost device (IERPBD). To profoundly investigate the system performance under various operating conditions, the pressure and composition distribution, power loss of each interface and mixing rate are numerically calculated and analyzed. Additionally, experiment of the effect of temperature on SWRO system performance is conducted to practically verify the proposed model, which indicates that the presented model could precisely reflect the energy dissipation and mixing characteristics. Besides, it is advised that the rotating speed of HPSP and IERPBD should not be set too high which could increase the mixing rate and energy consumption, and higher temperature might lower the quality of produced freshwater. This study offers a feasible way to reveal the energy dissipation mechanism of SWRO desalination system.

Intrarenal pressure and flow rate profile using LithoVue™ elite: impact of different irrigation systems and working channel instruments.

To report real-time IRP and FR while performing flexible ureteroscopy in porcine kidney model utilizing LithoVue™ Elite (Boston Scientific®) with different irrigation systems, including automated pumps. Using an ex-vivo model of porcine kidney, IRPs were measured with LithoVue Elite. Ureteroscopic settings (US) were tested with all permutations of irrigation methods (IM), working channel occupant (WCO), and ureteral access sheaths (UAS). IMs included: Single Action Pumping System (SAPS™, Boston Scientific), Thermedx FluidSmart™ (Stryker®), and ENDOMAT™ (Karl Storz®). Pumps were tested at 50, 100, and 150mmHg. WCOs included a 1.9Fr zero-tip basket, 200µm, and 365µm laser fibers. UASs utilized 11/13Fr and 12/14Fr 36cm. 84 different US were tested (252 experiments). ENDOMAT had higher IRP but the same FR as Thermedx at the same US for 50 and 100mmHg (p < 0.01). SAPS had higher IRP and FR than pumps in all US studies (p < 0.01). There was positive correlation between pressure set by the pump and both IRP and FR (rho > 0.9). As the diameter of the WCO increased, lower IRP and FR were observed with the pumps (p < 0.01). With SAPS, IRP was similar regardless of WCO, but FR was decreased with the increased diameter of WCO (p = 0.81 and p < 0.01, respectively). There was significantly higher IRP when using 11/13Fr UAS than 12/14Fr (p < 0.01). IRP was higher with SAPS than automated pumps. ENDOMAT showed higher IRP than Thermedx when under 150mmHg. IRP and FR increase with higher pump pressure and decrease with larger diameter WCO. Likewise, a larger UAS significantly reduced IRP.

USAGE OF TECHNICAL MEANS FOR ANNULAR GAS EXTRACTION TO INCREASE OIL WELL PRODUCTION

In recent years, the technology of annular gas extraction from wells has become increasingly widespread in the fields in order to improve the working conditions of the submersible pump due to increasing its filling and supply coefficients, as well as increasing depression on the formation. Some types of compressor designs have been developed and put into production, allowing the annular gas extraction from wells and forced injection into the pressure line of the well. One of the most well-known types of compressors is a piston pair driven by a piston from a rocking machine balancer. They were used at oil production facilities in the Orenburg, Ulyanovsk Regions, the Republics of Tatarstan and Bashkortostan, Udmurtia and other regions of the Russian Federation.In the fields of Sheshmaoil LLC, a complex for pumping gas from the annulus of a well and pumping it into the COGS product collection system has found mass usage, allowing gas to be taken from a group of wells and reducing pressure in the annulus to values close to 0.1 MPa. Hydraulic piston compressors, in which gas compression occurs using a high-pressure pump that drives the piston group of the compressor, have been tested.One of the main disadvantages of the developed types of compressors is the insufficient volume and pressure of the compressed gas. The article provides an analysis of the technological parameters of the compressors. As a result of research possible solutions to the problem are worked out.To achieve the largest pumping volumes of separated annular gas, the maximum permissible diameter of the compressor cylinder should not exceed 0.07 m in order to prevent significant resistance exerted by the piston rod on the balancer of the pumping machine.The most suitable region for the effective use of suspended compressors is the Ural-Volga Region at fairly depleted oil fields with at least 60–65 % water cut, oil well flow rate of no more than 10–15 tons/day and a gas factor of no more than 15–20 m3/t . At the fields of Western Siberia, suspended compressors cannot be used due to high flow rates and gas factors. Exceptions may be wells with a water cut of at least 80 % and flow rates of no more than 20–25 tons/day.The KOGS compressor unit, developed and widely implemented at Sheshmaoil Management Company LLC, showed positive results, consisting of an increase in flow rate and additional oil production. For further use of the unit in fields, especially for high-viscosity oil production, as well as operation in winter conditions, it is necessary to increase the maximum gas injection pressure.

Study on the Transient Flow Characteristics of Multistage Centrifugal Pumps during the Startup Process before System Operation

Multistage pumps are essential in emergency water supply, irrigation, and other systems undergoing unavoidable hydraulic transitions like pump startup and valve operations. These transitions cause rapid changes in impeller speed, flow rate, and pressure, destabilizing the internal flow field and impacting system reliability. To study transient flow characteristics, a numerical analysis of a three-stage pump was conducted, focusing on vortex identification, entropy production, and time–frequency pressure pulsation. Using the SST turbulence model, the simulation analyzed different start times and flow rate variations. Findings revealed that shorter startup times intensified transient effects, with the head increasing rapidly initially and then stabilizing. Vortex structures showed periodic development and dissipation. Entropy production rose with impeller speed, peaking higher with shorter startups. Blade passing frequency dominated pressure pulsations, with increased low-frequency pulsations as speed rose. During valve opening, flow stabilization accelerated with increasing flow rates, reducing amplitude and eliminating low-frequency components. This research aids the reliable operation of high-pressure pumping systems in energy storage.

Internal flow field changes and cavitation characteristics research of the high-pressure axial plunger pump

High pressure axial piston pumps have the characteristics of high power density, small volume and high integration degree and are used in coal machinery, construction machinery and other industrial fields. However, the cavitation impact of the oil flow field inside the pump directly affects the performance and stability of the plunger pump. Once the fault occurs, it will cause the equipment to stop, threatening the life of the current personnel. Taking the axial piston pump as the research object, this paper conducts a numerical simulation analysis of part of the basin model in the piston pump, discusses the fluid characteristics and cavitation mechanism in the piston pump, and provides a theoretical reference for the design and application of high pressure pumps.

Effect of fracturing on transient pressure fluctuation of tubing in ultra-deep well

The tubing is prone to failure during the fracturing process because of the high pressure and massive flow of the fracturing fluid. The fast change in pressure and velocity inside the tubing caused by an instantaneous shift in the flow boundary of the fracturing fluid can lead to tubing failure or possibly fracture, which poses a major risk to the integrity of the wellbore. In the process of high pump pressure and large displacement fracturing in ultra-deep wells, the calculation model of fluid hammer in the fracturing string is constructed in this article in accordance with the instantaneous pump stop condition. The quasi-dynamic boundary conditions of fracturing fluid are also considered. It is discovered how wellhead pressure is affected by pump stop time and fracturing fluid displacement. In this paper, the model is verified based on the field fracturing data of an ultra-deep well and the error between the calculated value and the field value is 1.04%. The simulation results show that the wellhead pressure declines once the pump is turned off, fluctuates close to the equilibrium pressure value, and the magnitude of the fluctuation steadily shrinks until it reaches the equilibrium pressure. The difference between the peak pressure and the stable value is within 5 MPa, and the difference is 2.61 MPa under the fracturing condition of the example well in this paper. The shorter the pump shutdown time, the earlier the inflection point appears, and the greater the pressure mutation value. In the five groups of pump stop time set in this paper, when the stop time is 2.5 s, the peak pressure can reach 80.35 MPa, which is 24.77 MPa higher than the peak pressure when the pump stops for 12.5 s. Proppant content combined with appropriate wellhead pump pressure can reduce the wellhead pump stop pressure under the premise of supporting the formation fracture is not closed. In addition, when the proppant content in the fracturing fluid is high, the additional axial force on the tubing is large and the fluctuation is advanced.

HPLC analysis of synthetic dyes in wastewater

The analysis of synthetic dyes in wastewater is an urgent task of modern analytical chemistry since an increased content of dyes in wastewater can have an adverse effect on the environment. Reverse phase high performance liquid chromatography (RP HPLC) is often used to control the content of dyes in various objects, which makes it possible to reliably determine the content of specified substances. The purpose of this work was to create and evaluate the metrological characteristics for the method of analysis of synthetic dyes in the industrial wastewater with a high content of inorganic salts. The chromatographic system used in this work was a Knauer high-pressure pump. The separation was performed on a Kromasil 100-5-C18 (w) reverse phase column (4.6 × 250 mm) in the gradient elution mode. Acetonitrile and ammonium acetate solution were used as the mobile phase. Synthetic dyes were detected on an Azura diode array detector. The paper presents the results of concentrating 10 synthetic dyes on commercially available solid phase extraction cartridges that were suitable for working with aqueous solutions with a high content of inorganic salts. For each substance, the degree of concentration from distilled and model wastewater was calculated, which varied from 2 to 98%. Among the analysed cartridges, the highest degree of concentration during operation in conditions close to real wastewater was shown by the Diapak P cartridge, at a pH of the concentrated solution equal to 4. The results of this study were used to develop and validate a method for a simultaneous detection of 10 synthetic food dyes (SFD) (E102, E104, E110, E122, E124, E129, E131, E133, E142, E151) in aqueous and organic solutions. The results of the study can be used to provide analytical control of the content of synthetic dyes in the industrial wastewater. The limit of intermediate precision of the method did not exceed 5%, and the expanded uncertainty of the measurements was less than 10%.

An Investigation in the Control Effectiveness of the Driving Wheel Slip Prevention System of a Diesel Engine Dump Truck

&lt;div&gt;This article proposes the structure and algorithm to design a PID controller for the driving wheel slip prevention system (DWSPs) of a dump truck using a diesel engine, which is equipped just only with a traditional high-pressure pump (HPP) under low-adhesion coefficient conditions. First, a longitudinal dynamic model, and a dynamic model of the wheel and powertrain of a dump truck are, respectively, established, and an experiment in the torque determination of a diesel engine is set up to investigate longitudinal vehicle dynamics as well. Then, a control system structure of the DWSPs for a dump truck using a diesel engine with a high-pressure inline fuel pump is proposed. Finally, based on performance analysis of other types of controllers, a PID controller is selected to control actual load level of a diesel engine. The criteria representing the vehicle’s acceleration such as the vehicle speed, vehicle acceleration, total slip time, and time to reach vehicle speed are selected to examine the effectiveness of the proposed controller when vehicles are being operated under the road surface conditions with low values of adhesion coefficient. The obtained results show that the proposed controller has greatly limited the driving wheel slipping phenomenon and increased the acceleration of the original dump truck. In addition, these findings can be used as a theoretical basis for the improvement of the wheel slip controllers in trucks using diesel engines.&lt;/div&gt;

Influence of structural parameters of distributor disk on flow pulsation in axial piston pumps

Firstly, a virtual prototype of axial piston pump AMESim is used to observe the effects of outlet pressure, swashplate inclination, bulk modulus (compressibility), density, dynamic viscosity, air viscosity, air content, dead space volume, leakage of mating clearance of the moving parts, plunger cylinder clearance, eccentricity, contact length of the copper bushing of the high-pressure piston pump, and the over-flow area of the flow distributing disk on the swashplate torque, the pressure in the plunger chamber, the pulsation in the flow rate, and the backing-up. To explore the influence of fluid noise, mechanical noise and air noise. After comparison, the overflow area of the disk, which has the greatest influence on the noise, is selected as the research object, in which the structural parameters of the disk are the most important influencing factors. Finally, it is found that too large or too small overflow area will aggravate the fluid noise and mechanical noise of the piston pump. Therefore, the optimized design of the structure of piston pump flow distribution plate is of great significance to reduce the vibration and noise of the hydraulic system. This study catches the optimization method of axial piston pump flow distribution shock, which can provide a reference for the design and optimization of axial piston pumps.

Fracture propagation and evaluation of dual wells, multi-fracturing, and split-time in Fuyu oil shale

Reservoir stimulation is crucial for in-situ exploitation, it can promote a fracture network and increase the heat transfer area. Therefore, it directly affects heat injection and products transportation efficiencies. Conventional reservoir stimulation techniques, such as hydraulic fracturing are widely used. However, hydraulic fracturing in a vertical well tends to generate simple fractures that are unfavorable for heat transfer, and real-time fracture propagation is difficult to monitor, thus failing to precisely control the hydraulic fracturing scale. In addition, there are few qualitative and quantitative criteria in reservoir-scale fracture evaluations for interpreting the overall hydraulic fracturing effect. Consequently, in this study, dual wells, multi-fracturing, and split-time technology (DMS) were designed and conducted based on microseismic monitoring in field experiment to find real-time fracture propagation. Furthermore, based on Hugot's research on connecting microseismic events by spatiotemporal sequences, we proposed a step index and path intensity considering microseismic event intensities to evaluate the effect on hydraulic fracturing. The results showed that a three-dimensional fracturing zone with a 60 × 30 × 8 m length, width, and height was generated at a 476–484 m depth, which corresponded to the designed hydraulic fracturing and facilitated heat transfer and product migration. Higher pump pressure and rate harmed hydraulic fracturing, blocking proppant migration during which the FK1-4 coefficient of viscosity reached 70 N⋅s/m2, 1.4 times greater than that of FK1-2 and FK1-5 according to Poiseuille's law. The hydraulic fracturing effect in FK1-4 was superior than that in FK1-2 and FK1-5. This study serves as a reference for monitoring oil shale exploitation via in-situ pyrolysis.

The Development Cycle of Machining Operations on an Educational CNC Machine

The paper presents a technological analysis, the phases and working methods, as well as the parameters of the processing cycle of a flange for a high-pressure hydraulic gear pump, which has the code FHP-05-12-24, made of polymeric material of ERTALON 66 SA type. The processing was made by cutting with the help of an educational milling and drilling machine with numerical control called EMCO MILL 55 CNC. The commands were programmed through a computer interface, using a conventional numerical code that commands the same kinematic chains, defining specific elements such as the geometric structure of the part, the technological conditions, the structure of the CNC kinematics, the calculation of the programmable coordinates, the parameters of the cutting tools and the parameters of the cutting regime. Based on the characteristics of the polymer material, but also on the identification of programmable functions and routines, the complete development cycle of the complex part processing operations was defined using special functions dedicated to the drilling and milling processes of the profiled surfaces. The part program structure contains program blocks associated with each stage and machining tools. The purpose of the study is to highlight, at an early stage, how students and young researchers can use computer numerical control (CNC) machines, which can be used as a support for the physical processing of complex surfaces, possibly obtained by digitizing and measuring data through a digital correlation based on specialized software products (e.g. GOM Scan, GOM Inspect, FEM analysis, etc.).

Tribological behavior of alumina (Al2O3) and zirconia (ZrO2) plungers used in high pressure pumps

Ceramic materials are commonly used in plungers due to high resistance to wear, abrasion, and low coefficient of thermal expansion. Also, they are commonly used in dry conditions without permanent damage, ceasing of pump head and better corrosion resistance than metals due to their inert characteristics. Zirconia (ZrO2) ceramic is used due to its high strength whereas, alumina (Al2O3) is commonly used in industries for high pressure pumps. The toughness of zirconia ceramics is higher than alumina ceramics as it overcomes the inherent brittleness of ceramic materials. It also has higher wear resistance and extends the life of the product. Whereas alumina has better mechanical characteristics such as hardness compared to Zirconia. In this research work tribological behavior of Alumina and Zirconia ceramics used in high pressure pumps have been studied. The wear test using end face wear testing apparatus has been conducted under flat contact for both alumina and ceramic material considering a mean contact pressure of 10 N, 20 N, 30 N and 40 N and sliding velocity of 40 mm/s. The wear test was conducted for 30 min considering a total sliding distance of 1500 m and 3000 m. The wear test results indicate that both alumina and ceramic exhibit lower wear factors and superior mechanical properties. The findings also reveal that the wear rates of Al2O3 and ZrO2 are influenced by friction forces, subsequently impacting the overall wear rate. Also, as the load increases the surface contact area also increases which in turn increases the wear rate. However, zirconia could be a potential substitute for alumina due to its high strength and fracture toughness.

Research and application of small-diameter hydraulic fracturing in situ stress measurement system

Abstract. Observation and estimation of the stress state in the deep crust is a crucial challenge in in situ stress measurement work. The hydraulic fracturing method is an important borehole-based technique for absolute in situ stress measurement. The small-diameter hydraulic fracturing in situ stress measurement system described in this article consists mainly of underground measurement components (serial small-diameter packers and dual-circuit connecting installation rods) and surface control components (hydraulic fluid control system, data acquisition system, and high-pressure oil pump with controllable flow). It enables series measurement of small-sized boreholes for in situ stress and provides a maximum measurement range of 30–45 MPa. The subsequent calculation of in situ stress data adopts a uniform design method to discuss the influence of various external factors on rock fracturing values. The small-diameter hydraulic fracturing in situ stress measurement system has the advantages of simple and lightweight structure, short testing time, high success rate, and low requirements for rock integrity and pressurization equipment. It has formed a series of small-diameter in situ stress measurement equipment which has been innovatively promoted to the field of underground tunnel safety assessment in coal mines and metal mining areas. It has an important practical value and economic significance in accurately determining the in situ stress state of deep development areas.