Injection Point Research Articles

Comprehensive numerical study of sequential injection of SiO2-nanofluids for enhanced oil recovery

Improving the efficiency of oil production is an important element in reducing the carbon footprint of the oil industry. One of the methods for increasing the efficiency of oil recovery is the use of oil flooding using solutions of various chemical reagents. The paper presents a computational investigation of the oil recovery from a porous micromodel using a nanofluid during sequential injection of water-SiO2 nanofluid-water. The effect of the nanosuspension concentration, duration of injection of the nanosuspension, the starting time point of nanosuspension injection, as well as the influence of oil viscosity on the oil recovery during sequential injection of main displacement fluid and nanosuspensions was investigated. Such a systematic study was performed for the first time. It was found that injection of three pore volumes of nanosuspension increases oil recovery factor by 1.5 times compared to injection of three pore volumes of water. It has been established that, from a practical point of view, it is most effective to increase oil recovery by starting the injection of nanosuspension after injecting two pore volumes of water. This case leads to an increase in recovery factor by 1.35 times compared to the injection of three pore volumes of water. As a result, it was shown that employing sequential injection allows obtaining an oil recovery factor comparable to that corresponding to oil recovery by nanosuspension. Thus, sequential injection makes it possible to significantly reduce the amount of nanoparticles during injection of nanosuspensions, while maintaining a high beneficial effect on the ORF. This is an important positive fact for the further development of this method of increasing oil recovery.

Flow regime evolution mechanism and falling flux prediction model for bypass injection of viscous liquid in vertical T-junction

The gas–liquid two-phase flow in T-junction serves as a fundamental theoretical foundation for studying mass and heat transfer laws in industrial applications, including oil and gas resource development and material mixing in the chemical industry. We designed a T-junction pipeline consisting of a vertical gas flow pipe and a horizontal liquid injection pipe and conducted experiments to investigate gas–liquid two-phase flow with liquid bypass injection. The experimental results indicate that there are two critical states for the downward flow of liquid at the injection point at different gas velocities: Critical Downward Flow(CDF) and All Downward Flow(ADF). Based on liquid falling state and response law of falling flux, the liquid falling conditions were categorized into three regions: region without liquid falling (flux ratio = 0), region of all liquid falling (flux ratio = 1) and transition region(flux ratio from 0 to 1). Through analyzing the dynamic characteristics of gas–liquid two-phase flow at the connection point and considering the zero shear stress state of the pipe wall and flow pattern transition, a CDF criterion for the liquid was established. The flooding state of gas–liquid countercurrent was used as the limit condition for ADF, and a criterion for ADF was developed based on experimental data. Under varying liquid viscosity conditions, compared with experimental data, the error of the CDF criterion model is less than 5 %, and the error of ADF criterion model is less than 15 %. A liquid falling flux prediction model was established based on the two extreme states of liquid falling, and its accuracy was verified through experimental results, challenging the existing theoretical criterion of liquid falling flux ratio being limited to “either 0 or 1”.

Experimental Simulation on the Stress Disturbance Mechanism Caused by Hydraulic Fracturing on the Mechanical Properties of Shale Formation

Hydraulic fracturing is an indispensable technology for the development of shale oil and shale gas. Knowing the changes in the rock mechanical properties and failure modes during hydraulic fracturing is the key to improving the efficiency of hydraulic fracturing. Based on experiments and simulations, it can be concluded that the injection of fracturing fluid in the hydraulic fracturing caused deformation of the fracture surface, and the rock mechanical properties experienced degradation with a maximum reduction in the rock mechanical properties of 44.24%. As indicated in the experiments, the displacement of the measurement point was decreased with the distance increase between the injection point and the measurement point. According to the numerical simulations, tensile failure is the main failure mode in hydraulic fracturing, but the percentage of shear failure had an obvious increase with the increase in distance between the injection point and the measurement point. Comparing DDS #1 and DDS #5, the DDS #5 measurement point was farther away from the injection point, and the average percentage of shear failure increased from 21.94 to 52.72%. Meanwhile, the increase in the branch fractures also caused shear failure to occur. Comparing Sample 1 and Sample 3, in Sample 3, which had more branch fractures, the average percentage of shear failure increased from 33.12 to 37.58%. Due to the porous medium of the reservoir rock, the enormous pressure generated during the injection of fracturing fluid caused significant deformation of the fracture surface, leading to the tensile failure of the rock. The displacement of the fracture surface caused by the fracturing fluid injection also led to the deformation of the pore throat structure; thus, the shear failure increased when the measurement point was away from the injection point.

Cloud microphysical response to entrainment and mixing is locally inhomogeneous and globally homogeneous: Evidence from the lab

Entrainment of dry air into clouds strongly influences cloud optical and precipitation properties and the response of clouds to aerosol perturbations. The response of cloud droplet size distributions to entrainment-mixing is examined in the Pi convection-cloud chamber that creates a turbulent, steady-state cloud. The experiments are conducted by injecting dry air with temperature (Te) and flow rate (Qe) through a flange in the top boundary, into the otherwise well-mixed cloud, to mimic the entrainment-mixing process. Due to the large-scale circulation, the downwind region is directly affected by entrained dry air, whereas the upwind region is representative of the background conditions. Droplet concentration (Cn) and liquid water content (L) decrease in the downwind region, but the difference in the mean diameter of droplets (Dm) is small. The shape of cloud droplet size distributions relative to the injection point is unchanged, to within statistical uncertainty, resulting in a signature of inhomogeneous mixing, as expected for droplet evaporation times small compared to mixing time scales. As Te and Qe of entrained air increase, however, Cn, L, and Dm of the whole cloud system decrease, resulting in a signature of homogeneous mixing. The apparent contradiction is understood as the cloud microphysical responses to entrainment and mixing differing on local and global scales: locally inhomogeneous and globally homogeneous. This implies that global versus local sampling of clouds can lead to seemingly contradictory results for mixing, which informs the long-standing debate about the microphysical response to entrainment and the parameterization of this process for coarse-resolution models.

The Importance of Mixing Time in Intensely Stirred Metallurgical Reactors: Applied on Decarburization Reactions

In metallurgical converter processes, numerical modeling is a useful tool for understanding the complexity of the systems. In this paper, we present a practical model that couples fluid dynamics and chemical reactions to explore the impact of mixing time on decarburization. Using computational fluid dynamics (CFD), in this study, we investigate an arbitrary metallurgical reactor with continuous oxygen supply, focusing on the Fe–C–O system. The model employs local equilibrium, a turbulence limiter, and finite volume method for mass, momentum, and energy transfer. Tracer injection points in the gas plume’s rising region exhibit faster mixing, and a comparison of reaction cases reveals distinct decarburization rates based on oxygen injection distribution and the influence of turbulence on reactions. Overall, while mixing time matters, the results show that this system is primarily governed by thermodynamics and oxygen supply, and a 270% increase in mixing time increase had a small impact on the end carbon content.

Development of bio-grout injection strategy and design guide using reactive transport model for field-scale soil improvement based on microbially induced calcium carbonate precipitation (MICP)

Microbially induced calcium carbonate precipitation (MICP) has garnered huge interest for its potential as an alternative and sustainable ground improvement method as it exploits natural microbiological processes. To this date, there is little or no guidance on the injection strategy to achieve a uniform calcium carbonate distribution at a field scale and most of the MICP method is still limited to lab-scale or meter-scale experimentation. Therefore, this study investigates effect of biochemical factors on spatial distribution of calcium carbonate precipitation at a field scale by using a reactive transport model, and suggests a guide to field-scale MICP treatment strategies for ground improvement. The reactive transport model couples microbial, chemical, hydrological processes associated with MICP, in which the key model parameters are validated with half-meter column experiments. The parametric case study primarily examines the effects of bacterial density in biological solutions, chemical concentration in cementation solutions, and bacterial attachment rate on spatial distribution of precipitated carbonate. The results reveal that the density of attached bacteria has a profound effect on the uniformity in calcium carbonate content around the injection point. Bio-augmentation with low bacterial density facilitates in achieving a homogeneous precipitation due to the slow reactions of urea hydrolysis. The findings in the parametric study leads to the development of preliminary design guide to achieve the uniform distribution of calcium carbonate with the minimal heterogeneity and the minimal over-precipitation and to account for the calcium loss due to the diffusion and solution mixing.

BCH modelling studies on biocementation process in mitigating leaks from a CO2 sequestrated aquifer

BCH modelling studies on biocementation process in mitigating leaks from a CO2 sequestrated aquifer

Downsizing, Use of Dummy and Venturi Valves Enhance Gas Lift Performance

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 213975, “Gas Lift Performance Enhancement Strategies by Downsizing and Using Dummy and Venturi Valves: A Paradigm Shift in Gas Lift Systems Management Philosophy,” by Wael F. Akeil, Ahmed M. El-Bohoty, and El-Sayed I. Abd El-Mawla, Gulf of Suez Petroleum Company, et al. The paper has not been peer reviewed. _ A mature offshore Egyptian field has entered a depletion phase. Most of its gas lift design bases were initiated during production startup and feature standardized sets of large gas lift valve port sizes with narrow spacing. Inconsistent well flow during reservoir depletion adds complications to the system. Therefore, a screenout model was created to select candidate wells for downsizing and for changing out with dummy and Venturi valves. After screening, 70 wells were selected for application of the new strategy. The complete paper discusses the effectiveness of smaller port sizes and the use of dummy and Venturi valves in enhancing gas lift performance and maximizing recovery. Field Background The field is divided into four main geographical quadrants, each with its own facilities. Total production currently is approximately 60,000 BOPD with an average water cut of 85%. Exploration and development of the field saw the drilling of more than 460 wells; half of these currently are experiencing reservoir pressure decline, drained reserves, or operational problems. Most wells are gas lifted, and the remainder either use electric submersible pump (ESP) installation or flow naturally. The facility consists of 73 offshore satellite platforms containing the wells—both oil producers and water injectors—connected to nine offshore complex platforms. As a part of continuous improvement trials, the operator reviewed the process of gas lift system management to introduce necessary improvements and recommend changes for long-term plans. The proposed amended management system was the result of monitoring, troubleshooting, and optimization activities outlined in the complete paper. Amended Gas Lift Management System Using Dummy Valves in Gas Lift System. Conceptual Phase. A dummy valve is a special gas lift valve shaped like solid metallic bar with upper and lower packings. They are installed to replace unloading valves that are no longer needed. Installing dummy valves instead of the unloading valves can reduce problems such as valve interference and deepens the point of gas injection. Redesign Procedure Based on the New Production Profile. This practice can be applied in two main cases: First, if reservoir pressure has declined and the well is producing with a lower rate but the surface injection pressure is still high enough to reach deeper valves; and, second, if the well is planned to be recompleted from one formation to another that has a higher reservoir pressure but with lower formation feed as the result of lower productivity. The main steps for redesign are provided in the complete paper.

Design and application of a B-ultrasound-guided deep vein puncture precise positioning device

Deep venipuncture catheterization is a routine and basic operation in the treatment of critically ill patients, and it is the most effective way to quickly correct the shock. Clinical B-ultrasound guided deep vein catheters can improve the success rate of puncture, but in the process of operation, the short axis needs to be replaced by the long axis. In the replacement process, the stability of the novice is insufficient, the positioning is difficult, and the operation time is too long. If only short axis puncture is used, it is impossible to know whether the current position of the puncture needle, and the puncture may be too deep and stray into the artery. The accuracy of the 45 degree angle of the injection point requires a very experienced operator. In view of the above shortcomings, doctors in the department of critical care medicine of Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine designed a B-ultrasound puncture equipment, which has obtained the National Invention Patent of China (ZL 2016 1 0571557.X). The device is composed of B-ultrasound probe fixing frame, sliding scale plate, simulation slide rule, puncture needle, sliding device. By sliding device the angle of the pinhole channel, it is conducive to the accurate positioning of the puncture target, optimizing the operation procedure, improving the puncture speed and accuracy, effectively reducing the occurrence of puncture complications, ensuring patient safety, reducing unnecessary waste of human and material resources. It can reduce the workload of medical staff and is worthy of clinical practice.

Analysis of Well Performance Based on Bottom Hole Pressure Calculations for Gas Lift Application

This paper focuses on optimizing gas lift techniques in four wells located in the North Sea to overcome the common issue of low reservoir pressure. Gas lift is a common artificial lift technique used in wells with low reservoir pressure where the natural pressure of the reservoir is insufficient to bring the oil to the surface. The success of gas lift optimization depends on identifying the deepest injection point, gas injection rate, and pressure of the gas injected. The paper proposes the deepest injection points for wells A-03, A-09A, A-10T2, and A-12BT2 as 3809.38 ft, 6649.7 ft, 3559.88 ft, and 3979.04 ft, respectively. The injection rates analyzed in this paper range from 1-10 mmscf/day, and injection pressures of 500 psia, 1000 psia, and 1500 psia were used. The response of each well to gas lift was analyzed, and increasing injection rate and pressure were found to increase oil production rate. The optimal gas injection rate and pressure for wells A-03, A-09A, and A-12BT2 were found to be 10 mmscf/day and 1500 psia, while for well A-12BT2, the best oil recovery was obtained at an injection rate of 3 mmcsf/day and injection pressure of 1500 psia. Tubing size within the range of 1-5.5 inch was examined, and it was found that increasing tubing size enhances oil flow rate. The optimal tubing size for the wells was found to be 5.5 inch, taking into consideration factors such as flow rate, pressure, temperature requirements, and fluid type.

Analysis of the Hydrodynamics Behavior Inside a Stirred Reactor for Lead Recycling

This work focuses on an analysis of hydrodynamics to improve the efficiency in a batch reactor for lead recycling. The study is based on computational fluid dynamics (CFD) methods, which are used to solve Navier–Stokes and Fick’s equations (continuity and momentum equations for understanding hydrodynamics and concentration for understanding distribution). The reactor analyzed is a tank with a dual geometry with a cylindrical body and a hemisphere for the bottom. This reactor is symmetrical vertically, and a shaft with four blades is used as an impeller for providing motion to the resident fluid. The initial resident fluid is static, and a tracer is defined in a volume inside to measure mixing efficiency, as is conducted in laboratory and industrial practices. Then, an evaluation of the mixing is performed by studying the tracer concentration curves at different evolution times. In order to understand the fluid flow hydrodynamics behavior with the purpose of identifying zones with rich and poor tracer concentrations, the tracer’s concentration was measured at monitoring points placed all around in a defined control plane of the tank. Moreover, this study is repeated independently to evaluate different injection points to determine the best one. Finally, it is proved that the selection of an appropriate injection point can reduce working times for mixing, which is an economically attractive motivation to provide proposals for improving industrial practices.

The effects of heterogeneity on solute transport in porous media: anomalous dispersion

Mixing of solute in sub-surface flows, for example in the leakage of contaminants into groundwater, is quantified by a dispersion coefficient that depends on the dispersivity of the medium and the transport velocity. Many previous models of solute transport data have assumed Fickian behaviour with constant dispersivity, but found that the inferred dispersivity increases with the distance from the point of injection. This approach assumes that the dispersion on either side of the advective front is symmetric and that the concentration there is close to half of the injected value. However, field data show consistent asymmetry about the advective front. Here, motivated by experimental data and a fractal interpretation of porous media, we consider a simplified heterogeneous medium described by a dispersivity with a power-law dependence on the downstream distance from the source and explore the nature of the asymmetry obtained in the solute transport. In a heterogeneous medium of this type, we show that asymmetry in solute transport gradually increases with the increase in heterogeneity or fractal dimension, and the concentration at the advective front becomes increasingly different from 50% of that at the inlet. In particular, for a sufficiently heterogeneous medium, the concentration profiles at late-time approach a non-trivial steady solution and, as a result, the concentration at a downstream location will never reach that at the inlet. By fitting the Fickian solution to our results, we are able to connect the parameters from our model to those found from experimental data, providing a more physically grounded approach for interpreting them.

Hydraulic-based fixed spray delivery system: Homogeneity distribution among emitters and internal cleaning performances evaluation

Fixed spray systems, an alternative to conventional pesticide application equipment, are under investigation in perennial fruit crops for improving spray applications. A prototype of a hydraulic fixed delivery spray system (31 m length) was evaluated for its suitability to be adopted as crop protection technology. In this research, two emitter densities selected from previous studies were used. Field trials were conducted to evaluate the performances of the system for spray mixture delivery, and to this extent, homogeneity distribution and cleaning performances were tested. Results showed that the emitter nearest to the injection point will deliver, the spray mixture first and water second, sooner than those further down the line. This delivery delay balanced the amount of spray mixture delivered by the fixed spray system along the line. Thus, the system delivered a similar amount (CV = 6.91%) of mixture from every sampled location in both emitter densities tested. Cleaning the line with water reduced the residue concentration by a factor greater than 300 in both emitter densities. In addition, the optimal time for cleaning that also reduced the water volume was identified as 2:30 and 4:30 min for high and low emitter densities, respectively. Linear regression models were built to estimate water volume consumption and cleaning step timing according to the fixed spray system's flow rate. In conclusion, emitter flow rate, emitter number, and spray mixture volume injected resulted the three key factors affecting dose applied, homogeneity of distribution among emitters, and cleaning performance.

Simulation of grout diffusion in fractured rock mass by equivalent seepage lattice elements

There are a large number of discontinuities in underground rock masses with different geometric properties, inducing complex grout diffusion processes. Classical discrete models commonly necessitate fine meshes to explicitly model these discontinuities and result into great computing efforts. In this work, a seepage lattice element model is proposed, which models the fissure seepage by pore seepage in equivalent pipes. We use the new model to study the horizontal grouting cases, considering diffusion as well as solidification processes of Bingham fluid. Some patterns are found: (i) The lattice elements do not need complex discretization which properly capture the grout diffusions processes; (ii) The diffusion of grout will become steady after reaching a specific distance from the injection point where the rock domain full of grout is the diffusion range; (iii) Crack openings, injection pressure and shear strength significantly influence this diffusion range. The proposed method and revealed rules can assist engineers to control the diffusion range and optimize the designs.

Vulnerability Detection in Computer Networks using Virtual Reality Technology

This paper challenges the time-related challenges inherent in conventional network security detection methodologies. It is achieved by incorporating virtual reality technology into the domain of computer network security detection. The research methodology employs optimization calculations to extract attributes that characterize network security vulnerabilities. Concurrently, the weighting of diverse vulnerability attributes is adjusted using a web crawler, a comprehensive list of injection points, and meticulous analyses of the attacks’ genetic characteristics. This collective approach facilitates the exploration of automated network security vulnerability detection within a virtual reality framework. The study’s empirical results demonstrate that the detection method proposed within this investigation exhibits a notably reduced delay of 75.33 milliseconds. The respective delays observed in the two conventional methods stand at 290.11 milliseconds and 337.30 milliseconds. The substantial decrease in detection delay validates the effectiveness and efficiency of the devised automated network vulnerability detection approach grounded in virtual reality technology.

A framework to model the hydraulic fracturing with thermo-hydro-mechanical coupling based on the variational phase-field approach

In this research, a numerical framework for hydraulic fracturing has been formulated, incorporating thermo-hydro-mechanical (THM) coupled effects. While previous studies have reported various hydraulic fracturing models based on the phase-field method, a THM coupling scheme grounded in the variational phase-field approach remains unexplored. The THM coupling is of paramount importance for understanding underground fracture propagation. This study’s principal innovation lies in its extension of the variational phase field model, introducing it to a thermoporoelastic medium, thereby integrating fluid flow and heat transfer elements in fractured materials. In our advanced model, the fluid flow and heat transfer in the matrix and fracture are modeled independently. Subsequently, employing a set of reasonable assumptions, we introduce unified flow and heat transfer equations derived from phase-field calculus. A pivotal contribution of our work is the development of an iterative solution algorithm based on the fixed stress method, pivotal for tackling the THM coupled system. The proposed equations are discretized employing the FEM. Additionally, to address the numerical oscillations in advection-dominant issues that manifest in the heat transfer model, we have applied a generalized Streamline Upwind Petrov Galerkin method for 8-node elements. The accuracy of fracture propagation was assessed by comparing the numerical results of the evolution of fracture length, fracture width at the injection point, and the injection pressure under the K regime with the corresponding analytical solution. Furthermore, the process of heat transfer within a fractured domain, often referred to as the Barends problem, has been studied by proposed model. Additionally, some numerical experiments were conducted to gain insights into the intricate interplay between the thermal–hydraulic–mechanical system during hydraulic fracturing, thereby further emphasizing the significance of our advanced model.

Predicting sample injection profiles in liquid chromatography: A modelling approach based on residence time distributions

The pharmaceutical and bio-pharmaceutical industries rely on simulations of liquid chromatographic processes for method development and to reduce experimental cost. The use of incorrect injection profiles as inlet boundary condition for these simulations may, however, lead to inaccurate results. This study presents a novel modelling approach for accurate prediction of injection profiles for liquid chromatographic columns. The model uses the residence time distribution theory and accounts for the residence time of the sample through the injection loop, connecting tubes and heat exchangers that exist upstream of the actual chromatographic column, between the injection point and the column inlet. To validate the model, we compare simulation results with experimental injection profiles taken from the literature for 20 operating conditions. The average errors in the predictions of the mean and variance of the injection profiles result to be 8.98% and 8.52%, respectively. The model, which is based on fundamental equations and actual hardware details, accurately predicts the injection profile for a range of sample volumes and sample loop-filling levels without the need of calibration. The proposed modelling approach can help to improve the quality of in-silico simulation and optimization for analytical chromatography.

How to improve infraorbital hollows with neuromodulators-A clinical prospective interventional study about the application of facial biomechanics.

A previous injection algorithm termed the "Toxin Lift" was recently introduced and described volume increases in the midface following neuromodulator treatments of the jawline. Increase in midfacial volume due to soft tissue repositioning could also affect the severity of infraorbital hollows. The objective is therefore to evaluate whether the severity of infraorbital hollows can be improved by injecting neuromodulators in the supra-mandibular segment of the platysma. A total of 35 volunteers (11 males/24 females) with a mean age of 39.8 (9.6) years and a mean BMI of 25.2 (5.2) kg/m2 were investigated. Bilateral infraorbital regions were evaluated via clinical assessment and semi-quantitative 3D imaging. The applied injection technique targeted the platysma via four injection points administering 5 I.U. per injection point resulting in a total of 20 I.U. per facial side. Volume increase of the infraorbital region was 0.13 cc at 15 days (p = 0.001) and was 0.02 cc at 30 days (p = 0.452) whereas the skin displacement in cranial direction was 0.54 mm at 15 days (p < 0.001) and was 0.31 mm at 30 days (p < 0.001). Clinical evaluation revealed a highly statistically significant improvement of the tear trough, palpaebromalar groove, and of the lid-cheek junction when compared to baseline with all p < 0.001. The results of this clinical prospective interventional analysis revealed that the "Toxin Lift" injection technique is capable to improve the clinical appearance of infraorbital hollows. The effects can be explained by the concepts of facial biomechanics.

State-Sensitive Black-Box Web Application Scanning for Cross-Site Scripting Vulnerability Detection

Black-box web application scanning has been a popular technique to detect Cross-Site Scripting (XSS) vulnerabilities without prior knowledge of the application. However, several limitations lead to low efficiency of current black-box scanners, including (1) the scanners waste time by repetitively visiting similar states, such as similar HTML forms of two different products, and (2) using a First-In-First-Out (FIFO) fuzzing order for the collected forms has led to low efficiency in detecting XSS vulnerabilities, as different forms have different potential possibilities of XSS vulnerability. In this paper, we present a state-sensitive black-box web application scanning method, including a filtering method for excluding similar states and a heuristic ranking method for optimizing the fuzzing order of forms. The filtering method excludes similar states by comparing readily available characteristic information that does not require visiting the states. The ranking method sorts forms based on the number of injection points since it is commonly observed that forms with a greater number of injection points have a higher probability of containing XSS vulnerabilities. To demonstrate the effectiveness of our scanning method, we implement it in our black-box web scanner and conduct experimental evaluations on eight real-world web applications within a limited scanning time. Experimental results demonstrate that the filtering method improves the code coverage about 17% on average and the ranking method helps detect 53 more XSS vulnerabilities. The combination of the filtering and ranking methods helps detect 81 more XSS vulnerabilities.

Study on Nitrogen Injection Fire Prevention and Extinguishing Technology in Spontaneous Combustion Gob Based on Gob-Side Entry Retaining.

Under the gob-side entry retaining mining mode with roof cutting and pressure relief (GERRC), the gob and retained roadway section are interconnected to create an open area. Owing to the increased airflow, the coal remnants in the gob are more prone to spontaneous combustion. This study aimed to investigate the distribution of oxygen concentration within a gob and identify optimal parameters for nitrogen injection. The engineering context was the "110 method" introduced in the 1201 working face of the South Five mining area at Daxing. Computational fluid dynamics simulation software was used to analyze the effects of various nitrogen injection treatment parameters on the overall performance of the gob, including their impact on oxygen distribution. The simulation results showed that air leakage within the gob primarily originates from the working face adjacent to the intake roadway, as well as gaps within the retained roadway. The increased air leakage causes the high O2 concentration range in the gob to expand, and the retained roadway section is connected to an area with a high concentration of oxygen near the working face, which increases the risk of residual coal spontaneous combustion. The results show that the optimal nitrogen injection conditions for inerting and reducing the risk of spontaneous combustion within the gob require an injection quantity of 500 m3/h, with the injection point located at a depth of 60 m. With these parameters, the range of the oxidation zone was significantly reduced. To monitor the O2 concentration and temperature change curves in the gob during the project implementation, a bundle tube monitoring system was used, considering the actual mining situation. By varying the nitrogen injection spacing and quantity, we found that injecting nitrogen at a spacing of 30 m and at a quantity of 500 m3/h effectively placed most areas of the gob in the suffocation zone, reducing the risk of spontaneous combustion of residual coal. The accuracy of the simulation was verified. The study offers valuable insights into improving safety in coal mines and reducing spontaneous combustion incidents, providing important reference significance for fire prevention and control.