Numerical Simulation Technology Research Articles

Numerical simulation and field application of biological nano-technology in the low- and medium-permeability reservoirs of an offshore oilfield

As a result of deep burial depth, small pore throat, poor connectivity between pores, different clay mineral contents in reservoirs, and strong reservoir sensitivity, injection wells often have problems such as rapidly increasing water-injection pressure and insufficient water-injection quantity in the process of water-injection development. The main measures used to solve the difficulties of water injection in low-permeability reservoirs include fracturing, acidizing, and surfactant depressurization and injection increase, all of which have some disadvantages of high cost and environmental damage. In recent years, depressurization and injection-increase environment-safe bio-nano-materials have been introduced into low-permeability reservoirs and have achieved good application results in China. On the other hand, although there have been many researches on EOR (enhanced oil recovery) of nano-materials, the numerical simulation field of nano-depressurization and injection-augmenting technology is still a blank that the wettability mechanism of nano-materials and EOR nano-materials used in bio-nano-depressurization and injection-augmenting technology are almost completely opposite, and the influence of adsorption on formation is almost completely opposite. The adsorption of nanoparticles in other EOR studies will reduce the porosity and make the reservoir more hydrophilic. Nanoparticles used in biological nano-technology will produce hydrophobic film near the well, which will reduce the seepage resistance through the slip of water phase. In this study, a set of water flooding model of numerical simulation technology for depressurization and injection-augmenting of biological nano-materials considering adsorption characteristics and reservoir physical properties was established, the sensitivity analysis of key injection parameters was carried out, and the application effect prediction chart of biological nano-technology was drawn, and the model and prediction chart were verified by real oilfield data. As far as we know, this is the first numerical simulation study on biological nano-technology that has been applied in oil fields.

ARKADIA—For the Innovation of Advanced Nuclear Reactor Design

Abstract This paper describes the outline and development plan for “Advanced Reactor Knowledge- and Artificial Intelligence (AI)-aided design integration approach through the whole plant lifecycle (ARKADIA),” which the Japan Atomic Energy Agency has begun developing to transform advanced nuclear reactor design to meet expectations of a safe, economic, and sustainable carbon-free energy source. ARKADIA will realize AI-aided integrated numerical analysis to offer the best possible solutions for any challenge that could arise in the design and operation of a nuclear plant, including optimization of safety equipment as well as structures, systems, and components. State-of-the-art numerical simulation technologies and a knowledge base that stores data and insights from past nuclear reactor development projects and R&D are integrated with AI. In the first phase of development, ARKADIA-design and ARKADIA-safety will be constructed individually, with the first target of a sodium-cooled reactor. In a subsequent phase, everything will be integrated into a single entity that is technology inclusive and applicable not only to advanced rectors with a variety of concepts, coolants, configurations, and output levels but also to existing light-water reactors.

Study on prediction in far-field aerodynamic noise of long-marshalling high-speed train.

It is still difficult to conduct numerical calculation of the aerodynamic noise of full-scale, long-marshalling, high-speed trains. Based on the Lighthill acoustic analogy theory, the aerodynamic sound source of the high-speed train is equivalent to countless micro-vibrating sound sources. An acoustic radiation model of the dipole sound source of high-speed trains is established, and a method to predict the aerodynamic noise in the far field of long-marshalling high-speed trains is proposed. By this method, combined with numerical simulation technology, the flow field, noise source, and far-field noise characteristics of high-speed trains with different marshalling numbers are studied. The improved delayed detached eddy simulation method is used for flow field calculation, to obtain aerodynamic noise source information regarding the surface of high-speed trains. The numerical calculation method is verified by wind tunnel testing. The results show that the flow field and noise source characteristics of high-speed trains with different marshalling numbers are similar. The greater the length of the train body, the longer the trailing distance of the train wake, and the stronger of a surface noise source the tail car becomes. The spatial distribution characteristics of aerodynamic noise in the far field of high-speed trains do not change significantly with the length of the train body, but the magnitude of the sound pressure level will increase with the increase in length of the train body. The middle car body parts of high-speed trains with different marshalling numbers have similar noise distributions and sound pressure levels. Based on the noise calculation results of the 3-marshalling high-speed train, the far-field noise of the 5-marshalling and 8-marshalling train models is predicted and found to be in good agreement with the far-field noise of the actual train model. The differences in average sound pressure level are 1.01 dBA and 1.74 dBA, respectively.

Numerical simulation of in-situ stress field characteristics about the dam site area of Baihetan Hydropower Station

In order to study the geological history of the rock mass in the Baihetan dam site area, this paper carries out a numerical simulation study on the in-situ stress field in the dam site area of Baihetan Hydropower Station. With the help of numerical simulation technology, the macro distribution law of the in-situ stress field is discussed. The results show that the in-situ stress value in the dam site area belongs to medium ∼ high stress level. The large principal stress value of the powerhouse on the left and right bank will be close to or even greater than 25 MPa, furthermore the stress state are not good. The horizontal large principal stress is close to the horizontal small principal stress. The results of the paper reproduce the load action history of the rock mass in the dam site area, which provides a preventive theory for the safety of the dam construction of Baihetan Hydropower Station.

Simulation of Internal Flow Characteristics of an Axial Flow Pump with Variable Tip Clearance

This study investigated the influence of the change in blade tip clearance on the internal flow characteristics of a vertical axial flow pump. Taking the actual running vertical axial flow pump of a pumping station as the research object, based on the SST k-ω turbulent flow model, the numerical simulation technology was used to study the effects of different tip clearances on the pressure, turbulent kinetic energy, Z–X section pressure and flow state of the impeller at the middle section. Furthermore, the impact of clearance layer tip leakage was also analyzed. Unsteady calculations of flow characteristics under the design conditions were performed. The research results showed that the variation trend of the pressure in the impeller was basically the same under different tip clearance values. With the increase in the clearance value, the pressure gradient along the water inlet direction of the blade decreased and the leakage vorticity increased. Observing the leakage vorticity distribution of the gap layer under the flow condition of 0.6Q0, it was found that when the tip clearance was smaller than 1 mm, the leakage flow was small and easily assimilated by the mainstream, and the leakage flow and mainstream had a certain ability to compete, which caused adverse effects on the performance of the pump device. The pressure pulsation characteristics showed that the leakage flow caused by the tip clearance caused a high-frequency distribution, and the clearance obviously influenced the pressure pulsation characteristics.

Interwell connectivity inversion method of steam flooding: Based on an analytical model and genetic algorithm

The steam channeling between wells of steam flooding in heavy oil reservoirs is an important factor impacting the development effect. Interwell connectivity is a key indicator for analyzing and predicting steam channeling. At present, only the correlation between injection and production is used to analyze the interwell connectivity, and the variation characteristics of liquid production and bottom hole temperature are not comprehensively considered to achieve the quantitative prediction of interwell connectivity in steam flooding. In this paper, based on the mass-conservation equation and energy-conservation equation, the analytical-calculation model of liquid production and bottom hole temperature of steam flooding in one injection well and one production well model is established. The ‘interwell connectivity coefficients’ are used as the splitting parameter of injected steam to each production well, and the analytical-calculation model of multiwell injection-production is extended. Taking the minimum mean square deviation of the error between the liquid production and bottom hole temperature as the objective function, the genetic algorithm is used to fit the liquid production and bottom hole temperature, and the ‘interwell connectivity coefficients’ of steam flooding are inverted. The innovation of this method lies in the establishment of analytical models of multiwell injection-production fluid production and bottom hole temperature and the establishment of a variable weight function in the objective function, which improves the accuracy of interwell connectivity inversion of steam flooding. Utilizing reservoir numerical simulation technology, the accuracy of the method is verified by synthetic models of homogeneous and high-permeability channels. The method is applied to the steam flooding reservoir of the Ng5 unit in Zhongerbei, Shengli Oilfield, China. The interwell connectivity of the two steam flooding well groups is inverted, and the results are consistent with the tracer analysis results. The findings of this study can help for better understanding of the geological conditions of the steam flooding reservoirs, and provide guidance for the selection of the next development plan.

Construction of aluminum alloy constitutive model based on BP neural network and the study of non-isothermal hydroforming

With the continuous development of high-end technology in aerospace and automotive, the materials used are lightweight and strong to meet the needs of high performance, high precision, and lightweight of parts; however, they are too difficult to deform, which means that it is difficult to obtain high-quality and high-precision parts. In order to improve the forming quality and precision of parts, taking Aluminum Alloy 6061-T6l cylindrical cup with spherical bottom as the research object, the non-isothermal hydroforming process is studied by combining numerical simulation with experiment. The key of numerical simulation technology lies in the accuracy of simulation, which depends on the establishment of a suitable rheological stress relationship. For this reason, a constitutive model that can truly reflect the thermoforming characteristics of Aluminum Alloy 6061-T6l materials is established through a uniaxial tensile test and BP neural network. Applying the constitutive model to the study of numerical simulation of non-isothermal hydroforming, the cylindrical cup with spherical bottom with high quality is obtained through the optimization of non-isothermal process parameters. After experimental verification, the results of numerical simulation are highly compatible with the actual forming results of parts, and have high reliability.

Springback inhibition of Ti-6Al-4V sheet with impact hydroforming at room temperature

Springback is a tough issue in sheet forming, and always leads to dimensional inaccuracy of formed parts. Titanium alloy selected as desired light-weight alloy has been playing significant roles in aerospace industry because of its good comprehensive performance. Whereas, titanium alloy components manufactured always exhibit severe springback at room temperature, which greatly restrict their application. To explore the possibility of reducing springback, rectangular lath-shaped parts with Ti-6Al-4V alloy sheet were fabricated by impact hydroforming (IHF) with self-designed equipment. Consequently, much lower springback is obtained using IHF with high strain rate than that formed by conventional stretch-bending with low strain rate. Great efforts are paid to clarify the mechanism of springback restriction under IHF. Different from traditional forming methods, more complex and high-speed interaction behavior between liquid and Ti-6Al-4V alloy sheet occurs. It considerably increases the difficulty for analyzing the deformation process of sheet under IHF. Thus, a novel solid-liquid coupling numerical simulation technology for IHF was developed. To validate the simulation accuracy, experiments with different forming processes and parameters were performed. Given the combined analysis of experimental and simulation results, it is found that distinctive forming paths are introduced between stretch-bending and IHF. Specifically, the preferred deformation region of sheet transfers from middle region for conventional stretch-bending to end regions under IHF, which mainly attributes to the unique loading behavior of liquid at high strain rate.

Application and Optimization of the Rheological Model for a Hydrophobically Associating Dendrimer Polymer.

Polymer flooding is one of the most important enhancing oil recovery (EOR) technologies in the world. With the optimization of polymer synthesis, the performance of polymer solutions has been greatly improved, which can adapt to more complex oil and gas reservoirs. However, with the continuous improvement of the properties of polymer solutions, the elastic property of polymer solutions is significantly improved, and the rheological law has also changed. This series of changes affects the application of polymer flooding reservoir numerical simulation technology. Therefore, constructing an accurate description model and precise limitation conditions is particularly important. The rheological curve with a wide shear range (0.1~10,000 s−1) and the viscoelasticity of the two polymers (partially hydrolysed polyacrylamide (HPAM) and dendritic hydrophobic association polymer (DHAP)) were analyzed and tested by a rotating rheometer. The results showed that under the experimental conditions, the rheological curve of both polymers can be described by the Carreau rheological model. Meanwhile, the structural viscosity of the hydrophobically associating polymer solution (DHAP) greatly improved the elasticity of the solution and led to the change of elastic modulus. Considering the influence of elastic characteristics on the rheological curve, the relaxation time spectrum derived from small vibration experimental data was used to limit the characteristic relaxation time, that is, the value range of λ. It was observed that the experimental data were highly matched with the nonlinear regression fitting curve of the Carreau rheological model. Therefore, the relationship between different test parameters should be fully considered while studying the rheological constitutive equation of viscoelastic fluid, so as to optimize and improve the equation of it.

Groundwater circulation patterns in bedrock aquifers from a pre-selected area of high-level radioactive waste repository based on two-dimensional numerical simulation

Deep geological disposal is internationally accepted as a feasible and safe way to dispose the high-level radioactive waste (HLW) in low permeability fractured bedrocks. It is essential to understand the regimes of groundwater flow, circulation, and predict the characteristics of long-term flow systems for site selection and safety assessment of deep geological HLW disposal by using numerical simulation technology. In this study, TOUGH3/EOS9 software with an improved evaporation module is used to develop a two-dimensional variably saturated numerical model of a typical profile at Xinchang site, which is considered as a potential deep geological repository for spent HLW in China. Results reveal that almost 99% of the precipitation is discharged through evaporation, and less than 1% infiltrates into shallow groundwater. The groundwater flow pattern is closely related to topography and lithological distribution, and the groundwater flow in Xinchang rock mass cannot discharge to the south Hexi Corridor. Groundwater in the typical profile is divided into three types of groundwater flow system, namely local, intermediate and regional flow system, and each has its own characteristics based on aspects of flow path, cycle amount, cycle path, residence time and discharge position. The circulation flux of these three systems accounts for 79.25%, 13.24% and 7.51% of the total groundwater quantity of Xinchang site, respectively. Meanwhile, different-depth models were constructed to validate the influence of bottom boundary depths on groundwater characteristics. Increasing the bottom boundary depth has limited influence on the maximum circulation depth of regional flow system, but negligible impact on circulation flux. This study can enhance the understanding of groundwater circulation and evolution in fractured bedrock aquifers with low permeability, and provide the feasibility of geological repository for spent HLW for the view point of groundwater flow.

Experimental and Numerical Study on Uniaxial Compression Failure of Concrete Confined by Nylon Ties

The developments in the cisvil engineering fields have led to an increased demand for structural reinforcements. Therefore, designing an effective, green, convenient, and low-cost reinforcement method is considerably important. Nylon ties have high strength and good heat resistance, and they can retain good tensile properties after high-temperature cooling. Further, they are inexpensive and can be recycled. Thus, they are considered suitable for structural reinforcement engineering. In this study, the core concrete was reinforced by the active confinement of prestressed nylon ties. A uniaxial compression test was performed to evaluate the reinforcement effect of the preload generated by the high-temperature cooling of the tie rod on the core concrete. The results show that nylon ties can effectively improve the mechanical properties of the core concrete. Combined with numerical simulation technology, a damage model of a confined concrete column (CC) was established, and the damage evolution law of CC under uniaxial axial compression was analyzed. Combined with numerical simulation and experimental research, the effectiveness of nylon tie reinforced concrete and the reliability of the damage model were verified, providing a reference for research on engineering reinforcement.

Application of Artificial Intelligence Extrusion Die Model Based on Finite Element Simulation in Decorative Material Aluminum Alloy

At this stage, the varieties and specifications of aluminum profiles continue to increase, and the scope of application continues to expand. The extrusion forming process is the key technology to realize the production of aluminum profiles, and its technological level determines the quality of the profile products and the service life of the mold. However, in actual production, the quality of the die is difficult to guarantee, and it takes multiple die trials and die repairs to produce qualified products. The numerical simulation technology is used to simulate the actual extrusion process, which can track and describe the flow behavior of the metal in real time, reveal the real flow law of the metal, predict the possible defects of the profile during the extrusion process, and adjust the mold structure and process parameters in time. It can not only improve the quality of extruded profiles, but also reduce production costs and shorten the mold production cycle. Based on this, this paper established an extrusion die optimization design model integrating finite element simulation technology and artificial intelligence algorithm. The prediction models were established with the mean square deviation of the section velocity, the maximum extrusion force and the maximum temperature of the section, respectively, and the optimal design of the structure was realized by using the particle swarm algorithm. The experimental results show that the model in this paper can realize the function well, which verifies the validity of the model.

Discussion on erosion and accumulation behaviours in the process of soil-rock flow migration with deep learning experimental analysis method and numerical simulation

The frequency of debris flows occurring has increased in Taiwan and mitigation strategies are important to protect property and save lives. Dr Shih-Hao Chou is a research scholar based in the Department of Mechanical Engineering, National Central University, Taiwan, is exploring how AI and deep learning can be applied to the mitigation of debris flow. He is investigating the physical mechanisms of debris flow, as well as migration behaviour and the potential scale of future disasters, which includes analysing flow behaviour and comparing it with an occurrence model. In their work, Chou and his collaborators are using a deep learning experimental analysis method to observe the current situation of debris flow in real time, and further predict the downstream debris flow behaviour. The researchers are also utilising numerical simulation in order to observe the internal movement behaviour in the earth-rock flow field and the damage caused to engineering facilities. Chou is conducting this research in collaboration with Professor Hsiau Shusan from the Department of Mechanical Engineering, National Central University. Chou is also looking at erosion transport or sedimentation behaviour in the process of collapse and flow, responding to a knowledge gap in this area. This involves studying the erosion and sedimentation behaviour of an artificial dam-break particle flow field on the bottom bed and, following the dam break, studying the particles in the collapse process using image and particle tracking technology and numerical simulation technology, looking at avalanche speed, avalanche time, erosion and sedimentation phenomena.

Simulation Study on Interactive Propagation of Hydraulic Fractures and Natural Fractures in Shale Oil Reservoir

Natural fractures are developed in the shale oil reservoir, and the hydraulic fracture (HF) morphology is complex. The fracture shape can be inverted by using fracture propagation numerical simulation technology, which provides guidance for fracturing parameter design and fracturing process optimization. However, the existing models still have many deficiencies in the interactive propagation mechanism of HF and natural fracture (NF). Based on the three interactive modes of HF and NF (HF propagation without NF, HF propagation with full NF, and HF propagation with half NF), this work establishes the fracture propagation model and puts forward the simulation calculation method. The Brinkman equation is used to modify the leakage model based on Darcy’s law, and G1701H well is taken as an example to simulate the fracture propagation law under different interaction modes. The research shows that there is a transition region between the HF wall and rock matrix. The greater the porosity and permeability of the rock matrix, the more significant the influence of the transition region on leakage. The NF zone will change the propagation direction of the main fracture. When there are multiple clusters of fractures in the same fracturing section, only some HFs meet with natural fractures, and it is easy to form a “T”-shaped fracture network. The results improve the existing hydraulic fracturing model and provide help for fracturing parameter design and fracture parameter inversion of the shale oil reservoir.

Research on steam flow excited vibration of nuclear power condenser based on full three-dimensional numerical simulation technology

Numerical calculation is regarded as the most effective research method for studying problems about a condenser due to the experimental difficulty caused by the huge size. However, almost all numerical research studies about condensers are two-dimensional, which severely reduce the reliability of the research about a three-dimensional problem. In this case, a full three-dimensional computational fluid dynamics (CFD) method based on a porous medium model was first used to study the seawater leakage event in a condenser. The steam flow field of the condenser under a series of operation conditions was obtained. The distribution of a risk coefficient of steam flow excited vibration (SFEV) was obtained as well. The results show that the sweep velocity of steam across a titanium tube was the primary factor determining the risk coefficient of SFEV. The risk of SFEV of the outer layer in the upper finger joint region is relatively high. It is necessary to install anti-abrasive strips or implement preventive tube plugging. According to the calculated results, the recommended values of electric power limits for a nuclear power unit were given, which was 840 MW under half-side condenser operation conditions in summer. Through comparing the simulated flow field before and after tube plugging, it is found that local tube plugging in the high-risk area will transfer the position of the high-risk point of SFEV.

Design Method of Laboratory-Scale MMC Physical Simulation System Considering Multiharmonic Simulation Accuracy

Besides real-time numerical simulation technology, the laboratory-scale physical simulation technology is an alternative for simulation analysis and hardware testing of modular multilevel converter (MMC). It can realize full-scale connection with complicated control and protection hardware with no need for extra interface devices, which is necessary in real-time simulation. However, due to the limitations on size and investment, the power loss rate of the MMC physical simulation system is inevitably higher than that of the real MMC project, which obviously will have a negative effect on the simulation accuracy. To solve the problem, an improved parameter design method of the MMC physical simulation system is proposed in this article. The similarity criteria of MMC with explicit expressions are first derived. On this basis, the relationship between multiharmonic simulation accuracy and power loss nonsimilarity is theoretically analyzed. Furthermore, the range of the power loss nonsimilarity is determined, which facilitates the selections of passive elements in the MMC physical simulation system with appropriate quality factors. The proposed design method can guarantee the simulation accuracy while reducing the whole system investment. Finally, the effectiveness of the proposed design method is validated by both the simulation and experimental results.

Study on Three-Dimensional Dynamic Stability of Open-Pit High Slope under Blasting Vibration

AbstractThe propagation process of blasting vibration has always been a difficult problem affecting the stability of high slopes in open-pit mines. Taking the Jianshan Phosphorus Mine as the research background, combined with engineering geological investigation, field blasting test, blasting vibration monitoring, numerical simulation technology, and theoretical analysis, the three-dimensional dynamic stability of the adjacent high slope after blasting vibration was systematically studied. In our study, a small-diameter buffer shock-absorbing blasting technology near the slope was proposed, which greatly improved the production efficiency. Through regression analysis of a large amount of vibration test data, the law of blasting vibration propagation in Jianshan stope and Haifeng stope was obtained. In addition, by establishing four three-dimensional geomechanical numerical models, the slope’s own frequency, damping characteristics, and dynamic response acceleration distribution after detonation were studied, respectively. On the other hand, under the action of Ei Centro wave with 8-degree seismic intensity, the maximum total acceleration and maximum total displacement of the slope were calculated and analyzed. Both the explosion unloading of the 8-degree earthquake and the Ei Centro wave simulation results showed that the high slope near the Jianshan Phosphorus Mine was generally in a stable state. Thus, this study can provide technical support and theoretical guidance for mine blasting.

Mine Slope Stability Based on Fusion Technology of InSAR Monitoring and Numerical Simulation

In this paper, the slope of the open pit of Dahongshan iron ore mine in Yunnan is taken as the research object, the safety coefficient and settlement values of the slope under natural and rainfall conditions are derived by the finite element software Midas/GTS, and the surface settlement versus time is produced by fusing the InSAR monitoring results of the study area for a whole year to judge the stability of the open pit slope. The results show that the settlement and deformation areas shown by numerical simulation and InSAR monitoring results are consistent; the comparison between InSAR monitoring results and rainfall intensity shows that the cumulative value of slope settlement has a high correlation with heavy rainfall. The safety coefficients of the slopes of the open pit under natural conditions and rainfall conditions are 1.50 and 1.21, the cumulative value of settlement in InSAR monitoring data for one year is 18.4 mm, and no obvious large deformation area is found. The use of numerical simulation combined with InSAR monitoring can realize the analysis of the stability of the slope of the open pit mine.

A multi-indicator orthogonal investigation into the dust suppression effect of a shearer-mounted negative-pressure spraying device

The actual production situation of a coal face with a large mining height of 6.5 m was taken as the research object, and factors investigated included spray pressure (P), nozzle retraction distance (L), and nozzle quantity (N) as the key research factors to solve the problem of dust pollution. Our analysis demonstrated the order of importance of the influence on the size of the droplets is P > L = N; the order of importance of the influence on the number of droplets is P > N > L; and the order of importance of the influence on the strength of the negative pressure is P > N > L. It was concluded through comprehensive analysis that when P = 8 MPa, L = 94 mm, and N = 6, the dust suppression efficiency of the device could reach more than 86%. The optimal spray dust reduction parameters were obtained by combining numerical simulation technology with an orthogonal experiment, and dust concentration was effectively reduced.

Prediction and Analysis of PDC Bit Wear in Conglomerate Layer with Machine Learning and Finite-Element Method

Polycrystalline diamond compact (PDC) bits experience a serious wear problem in drilling tight gravel layers. To achieve efficient drilling and prolong the bit service life, a simplified model of a PDC bit with double cutting teeth was established by using finite-element numerical simulation technology, and the rock-breaking process of PDC bit cutting teeth was simulated using the Archard wear principle. The numerical simulation results of the wear loss of the PDC bit cutting teeth, such as the caster angle, temperature, linear velocity, and bit pressure, as well as previous experimental research results, were combined into a training dataset. Then, machine learning methods for equal-probability gene expression programming (EP-GEP) were used. Based on the accuracy of the training set, the effectiveness of this method in predicting the wear of PDC bits was demonstrated by verifying the dataset. Finally, a prediction dataset was established by a Latin hypercube experiment and finite-element numerical simulation. Through comparison with the EP-GEP prediction results, it was verified that the prediction accuracy of this method meets actual engineering needs. The results of the sensitivity analysis method for the gray correlation degree show that the degree of influence of bit wear is in the order of temperature, back dip angle of the PDC cutter, linear speed, and bit pressure. These results demonstrate that when an actual PDC bit is drilling hard strata such as a conglomerate layer, after the local high temperature is generated in the formation cut by the bit, appropriate cooling measures should be taken to increase the bit pressure and reduce the rotating speed appropriately. Doing so can effectively reduce the wear of the bit and prolong its service life. This study provides guidance for predicting the wear of a PDC bit when drilling in conglomerate, adjusting drilling parameters reasonably, and prolonging the service life of the bit.