Abstract:Three-dimensional （3D） trajectory measurement technology for underground pipelines plays a vital role in ensuring pipeline construction safety， accident prevention， and emergency response. The 3D trajectory measurement of pipelines encompasses three phases： pre-construction， during construction， and post-construction. This paper systematically reviews the current research progress in 3D trajectory measurement technology for underground pipelines. Pre-construction trajectory measurement primarily employs geophysical detection technologies， such as electromagnetic detection and ground-penetrating radar （GPR）. During construction， handheld guidance devices are widely used for trajectory monitoring， while post-construction measurement relies on dedicated trajectory measurement instruments. This paper analyzes the fundamental principles， technical status， and application challenges of these methods， and discusses the advantages of integrated detection approaches. Future development directions include digital twin systems for real-time drilling monitoring， multi-method fusion， intelligent cloud-based IoT platforms， and 3D trajectory virtual reality visualization technologies， all aimed at improving measurement accuracy， efficiency， and intelligence. This study aims to provide references for further research and applications of 3D trajectory measurement technology for underground pipelines.

Abstract:Russia is a country with a vast territory. There are permafrost rocks underground in the northern part of Russia and in Siberia. In the permafrost rocks there are mineral resources， which are explored and developed urgently and that must be supported and confirmed by drilling engineering. In the engineering construction of these areas， it is necessary to determine the physical and mechanical properties of the underground rocks by drilling engineering. The problem in drilling engineering is the effect of flushing fluid on the ice in the rocks， leading to collapse of the rocks and the borehole wall and the frequent occurrence of accidents. Russian specialists have proposed to use a vortex cooler to make the temperature of the cold compressed air lower than that of the bottom-hole rocks， and sending the cold air to the bottom of the hole in order to guarantee normal drilling and safe construction， increase the penetration rate and raise the bit footage. Good technical and economical results have been obtained. In China， there are also permafrost rocks and seasonal frozen rocks. The drilling technology in permafrost rocks with flushing by cold compressed air in Russia has certain reference value and practical significance for China.

Abstract:Natural gas hydrate muddy siltstone reservoirs are characterized by weak cementation and low strength. Hydrate decomposition reduces the strength of the reservoir and the width of the seepage channel decreases or even closes. The “double-added” reforming slurry is a type of slurry that can enhance the strength and permeability of the reservoir after curing， but the rheological properties of the double-added slurry differ greatly from those of the fracturing fluids and it does not contain sand， and the influence mechanism of the construction parameters of slurry splitting on the expansion of the slurry in the shot-hole clusters is not clear yet. In this paper， a two-dimensional hydrate reservoir fracturing grouting numerical simulation model is established based on the extended finite element method to study the influence of shot hole parameters and fracturing mode on fracture expansion. The results show that： the stress field induced by the cluster spacing of injection holes has a greater influence on the fracture extension when the cluster spacing of injection holes is small， and the slurry extension becomes obvious， and with the increase of the cluster spacing of injection holes， the stress interference between clusters decreases gradually， and the original geostress plays a main role in the direction of the slurry extension； the more the number of injection holes under the same cluster spacing， the stronger the stress interference between clusters is， and the smaller the cluster spacing of injection holes is； the distance of the slurry extension under the synchronous splitting mode is not uniform， and the sequence splitting and intersecting splitting modes are not uniform， and the distance of slurry extension under the simultaneous splitting mode is not uniform. In synchronized fracturing mode， the distance of slurry expansion is not uniform， and when fracturing in sequence and alternating fracturing， the previously formed cracks will be gradually squeezed， and the width of the cracks will gradually become smaller， which increases the fracturing pressure of the subsequent shot hole clusters， and is not conducive to the fracturing of the reservoir. The results of the study provide a reference basis for the design of fracture grouting in natural gas hydrate reservoirs.

Abstract:In the process of cementing mud slurry preparation， ultra-high mixing speed tends to introduce air bubbles， resulting in difficulties in formulating the cement slurry to the correct density， which in turn can adversely affect the slurry properties and the sealing integrity of the cement ring. In this paper， we take the lipid-based defoamer X60L as an example to investigate the effects of different dosages of X60L defoamer （0%， 0.5%， 1%， and 1.5%） on the compressive strength of oil well cement. Combined with thermogravimetric analysis， X-ray diffraction analysis， X-ray micro-computed tomography test and scanning electron microscope test， the changing law of microstructure of cement slurry can be grasped and the mechanism of defoamer’s action on cement slurry can be clarified. The research results show that the compressive strength of cement stone shows a trend of increasing first and then decreasing， while the porosity shows a trend of decreasing first and then increasing. The cement stone has the lowest porosity and the highest compressive strength when the defoamer dosage is 0.5%. The larger the porosity of cement stone， the smaller the compressive strength， and the compressive strength and porosity were obviously negatively correlated and conformed to the Schiller’s Function （R²=0.98）. The incorporation of defoamer does not change the mineral composition and hydration products of oil well cement， and it mainly reduces the surface tension of the bubbles to makes it difficult to maintain the bubbles and thus break them. However， with the increase of defoamer dosage， too much defoamer will hinder the contact between water and cement， inhibit the hydration of cement， and introduce the “defoamer holes”， which will lead to the increases of the cement stone porosity and the decreases of the compressive strength.

Abstract:Leakage prevention and plugging of drilling fluid is a key technical measure to ensure drilling safety， protect reservoirs， reduce economic losses， improve drilling efficiency and environmental protection. Due to the limitations of actual observation and experimental conditions in the field， it is difficult to explore the plugging mechanism of leaky formations. In order to better explain the particle plugging mechanism of fractured leaky formations， this study used COMSOL Multiphysics to establish a plugging model for fractured formations， and analysed the effects of particle concentration， particle size and particle gradation on the plugging efficiency of fractured leaky formations， so as to reveal the specific mechanism of particle plugging. The results show that： （1） The plugging efficiency is positively correlated with the particle size. The larger the particle size， the shorter the plugging time under the same concentration. （2） There is an effective blocking range for particle concentration， and effective blocking cannot be formed when the particle concentration is lower than the lower limit of the range， while the increase in concentration has little effect on the blocking efficiency when the particle concentration is higher than the upper limit of the range. （3） The particle gradation can synergistically improve the blocking efficiency and blocking densification. When the concentration of large-sized particles is the same and the mass fraction of small-sized particles concentration is increased by 1%， the final leakage velocity is reduced by 35%； When the concentration of small-sized particles is the same and the mass fraction of large-sized particles concentration is increased by 4%， the formation time of crack bridge plugging is reduced by 50%. The small particles in the plugging particles mainly affect the densification of the plugging layer， while the large particles mainly affect the plugging efficiency.

Abstract:Azimuth is a key parameter in well trajectory description， but the conventional measurement with MWD usually exists errors because of the complex geomagnetic field and magnetic field interference. To investigate the impact of bottom hole assembly（BHA） magnetic field interference on azimuth measurement， the interference magnetic field of different drilling tools were measured with a portable magnetometer. On the basis of the interference magnetic field experiment measurement， magnetic pole strength of different drilling tools can be acquired through the data fitting method. With the magnetic pole strength， the interference magnetic field strength can be calculated using the superposition principle， and the azimuth error induced by the interference magnetic field was quantitatively analyzed. According to the experiment results， the interference magnetic field strength along the drilling tool axis exponentially decreases with the added distance and finally goes to zero. Compared to the traditional methods， azimuth error correction using the magnetic pole strengths of drilling tools in this study is more direct and convenient.

Abstract:Geothermal energy is a kind of clean， environmentally friendly and sustainable energy. With the proposal of “dual carbon” goals ， geothermal energy is becoming an important force to achieve the goal of net-zero emissions. With the continuous development of geothermal resources， the number of high-temperature and high-pressure deep geothermal wells is increasing， and the domestic geothermal wells have reached a new depth of 5000 meters. High-temperature and high-pressure environment is easy to cause the strength decline of cementing materials， admixture failure and excessive water loss， so the performance of high-temperature cementing materials is increasingly required. Therefore， a new high-temperature cementing material with excellent slurry stability， controllable thickening time， high stone strength and environmental protection is needed. Through analyzing the mechanism of cementing material components， orthogonal test and range analysis， a kind of high-temperature （120℃） resistant cementing material suitable for medium and deep geothermal wells is developed. The test results show that， the properties of cementing material such as density， water extraction rate， stone rate， thickening time， water loss， channeling resistance， stone compressive strength and flexural strength meet the requirements of cementing engineering in middle and deep geothermal wells.

Abstract:To improve the strength of the drill pipe in the large-size hole， the ?168.3mm S135 drill pipe was used for the first time in the extra-deep well， which effectively guarantees the safety of the drill pipe. However， various failure forms are still found in the drill pipe inspection. To study the failure causes of the ?168.3mm S135 drill pipe in the large-size hole， the failure causes were identified through tracing the life cycle of the drill pipe， statistical analysis， drill string mechanics analysis and experimental study. The research shows that the main failure types of ?168.3mm drill pipe in large hole are thread wear， drill pipe bending， drill pipe corrosion and fatigue failure. Thread wear is mainly caused by the long use time of drill pipe and repeated make-and-break operations. Besides， the conventional API thread structure also needs to be optimized to improve the thread resistance to wear. The bending of drill pipe is caused by the plastic deformation of drill pipe which is subjected to large bending stress for a long time under large tensile load. The corrosion of drill pipe is caused by the increase in corrosion rate in the environment of air-water-Cl^- due to the residual drilling fluid on the surface of drill pipe. The fatigue failure of drill pipe is caused by the obvious stress concentration of drill pipe near drill collar and the large bending deformation of drill pipe in large hole. Based on the analysis of the failure causes of drill pipe， the measures to prevent the failure of ?168.3mm drill pipe in large hole are put forward. The research results can provide guidance for the safe application of S135 steel ?168.3mm drill pipe in extra-deep Wells with large size boreholes.

Abstract:The hollow universal joint is one of the vulnerable components in hollow screw coring drill tools， directly affecting their service life. Based on the traditional solid flexible shaft universal joint， a hollow design was implemented. Finite element software was employed to conduct mechanical analysis of the hollow universal joint， investigating the influences of mechanical and geometric parameters on its mechanical performance. Results showed that compared to conventional flexible shaft universal joints， the hollow universal joint with grouting holes exhibited higher stress and strain at the grouting hole locations， making them prone to damage and failure. The stress distribution in other regions remained consistent with hollow universal joints of the same dimensions without grouting holes， indicating that grouting holes did not alter stress conditions in non-hole areas. Stress demonstrated a proportional relationship with torque， while strain increased with torque but exhibited a diminishing growth rate as torque rose， following a nonlinear pattern. When the grouting hole was positioned 250 mm from the end face， both stress and strain reached minimum values， identifying this configuration as the optimal design. These findings establish a foundation for subsequent development of high-performance hollow universal joints.

Abstract:Due to long-term water injection for development adjustment in the Daqing Oilfield， the underground pressure system has become complex， with extensive distribution of abnormally high-pressure zones within the formation. Additionally， the oil reservoirs are characterized by shallow burial depth and low ambient temperatures. These conditions reduce the hydration rate and slow down the structural development of cement slurry during the cementing process， as it is affected by low-temperature environments. Consequently， during the gelling process， the cement slurry is prone to invasion by high-pressure formation fluids， resulting in compromised sealing capacity of the cement sheath. Based on the “crystal nucleus induction” theory， this study synthesized hydrated calcium silicate using a chemical precipitation method to prepare a hydrated calcium silicate sol accelerator （designated as DQZ-1）. Evaluation showed that with a DQZ-1 dosage of 2%~10% ， the 8-hour compressive strength of cement cured at 40°C increased by 39%~153% compared to neat slurry. Microscopic analysis confirmed that DQZ-1 accelerated the formation of cement hydration products， demonstrating excellent early-strength performance in low-temperature environments. To enhance both the low-temperature early strength and anti-channeling properties of the cement slurry system， hydrated calcium silicate and latex components were incorporated. However， issues such as demulsification， settling stratification， and high slurry consistency arose due to their interaction. To address these， polycarboxylate MD was selected， enabling the cement slurry to maintain low initial consistency while achieving significant early strength. Additionally， a polymer colloid X was chosen to impart excellent anti-settling properties to the system. Through rational formulation， a stable early-strength and anti-channeling emulsion composite （designated as DZK） was developed. This composite promotes oil well cement hydration， generating more hydration products. The cement slurry’s performance coefficient （SPN） was lower than 3， and the static gel strength transition time was shortened by 81% compared to the neat slurry. The low-temperature early-strength and anti-channeling emulsion composite was field-tested in 23 adjustment wells in the Daqing Oilfield. It achieved a 100% cementing quality excellence rate， with 96.3% of the oil-bearing sections rated as excellent， demonstrating outstanding field application results.

Abstract:In order to solve the problems of high auxiliary workload， high cost， and great safety hazards in connecting roadways and wells in coal mine areas using the “excavating tunnel to locate well” method， as well as the safety hazards of cutting ground borehole pipelines under fire operation underground， an innovative solution of direct penetrating roadway was proposed. The factors affecting safe roadway penetration were analyzed， two-section casing program was optimized， the technical scheme in the penetration state was studied， and the innovative ground pipeline well penetrating roadways technology was formed， transforming “roadway finding well” into “well finding roadway”. According to different working conditions， two types of processes， one-time borehole completion and two-time borehole completion， were proposed to solve the problem of different borehole sizes being completed at once， and avoiding underground secondary excavation. The field trial and promotion application of the technology in Huaibei mining area drainage pipeline well demonstrated that two-section casing program pipeline well penetration roadway process technology is safe， reliable， cost-effective， and effectively reduces the auxiliary workload in underground coal mine. The research results provide an important reference for implementing ground pipeline roadways in different mining areas.

Abstract:The CGJ series casing oscillators are large-diameter casing driven rock and soil drilling equipment successfully developed by the Institute of Exploration Techniques for urban construction. As a type of electromechanical hydraulic integrated equipment， they adopt a PLC-based electronic control system. This article mainly introduces the research and application of the electrical control system based on PLC. Firstly， the functional requirements of the electrical control system are analyzed. Based on the results， the hardware and program design of the electrical control system are carried out so that the electronic control system design with human-computer interaction function is realized， which integrates wireless remote control， remote wire control and emergency manual operation modes. The functional implementation of PLC program design is emphasized， which has certain application value for the research and design of electrical control systems for casing oscillators and similar equipment.

Abstract:Drilling instead of trenching is a technical method that utilizes shallow drilling to replace trenching engineering and improve the level of green exploration. Previous researchers have mainly demonstrated the practicability of this method from the perspective of drilling equipment and sampling technology， and obtained the occurrence data such as the tendency of the planar structure in the hole through the identification and comparison of marker layers in multiple boreholes. However， multiple drilling holes will inevitably increase the disturbance to the environment. Facing the complex rock formations and tectonic deformation areas， the occurrence cannot be calculated because the marker layers can not be accurately identified and compared. Structural analysis and borehole imaging technology can improve the green exploration effect of drilling instead of trenching. In the Xinjiazui gold exploration area of the Western Qinling Mountains， the proportion characteristics of different axial lengths of quartz lenses related to mineralization were identified using structural analysis methods， providing guidance for drilling deployment； In the drilling process， borehole imaging technology was implemented to identify the lithology of the borehole wall and measure the occurrence of the strata and quartz veins. The data were consistent with the adjacent exposed bedrock. The experimental results show that the new method can obtain more accurate and abundant data with less drilling work，improving the level of green exploration compared with the previous method which relies more on drilling engineering. In addition， portable shallow drilling rigs powered by lithium batteries exhibit green characteristics with lighter， safer and more user-friendly performance， and have the value of promotion and application.

Abstract:The exploration intensity of oil and gas resources in the Qiangtang Basin is not high， and a large number of blank areas need further exploration. Geological survey wells are an important engineering tool for the investigation and research of oil and gas resources in the Qiangtang Basin. Wireline core drilling technology is commonly used to obtain the high quality in-situ cores and logging channels for the entire borehole， which has gradually replaced the conventional core drilling technology over the past decade. The Qiangtang Basin has a unique geographical location and climatic conditions， with complex geological conditions. The application of wireline coring drilling technology in this area has encountered many construction difficulties. This paper combines the lithological testing data and geological stress conditions to analyze and clarify that the wireline coring drilling process and the non-coring oil and gas drilling process are significantly different in terms of well configuration， drilling parameters， drilling fluid， plugging and surging， thus relevant parameter indicators and practical experience cannot be simply copied. At the same time， typical problems of geological survey wells in the Qiangtang Basin over the years were sorted out and analyzed in detail， aspects such as wellbore stability， drilling fluid， drilling leakage， and engineering implementation are elaborated， which can provide important references for the design and operation of geological survey wells in the region.

Abstract:During the drilling construction of a geothermal well in Beijing， numerous technical challenges were encountered， including severe mud-making in mudstone， deterioration of drilling fluid performance， hole-wall collapse， and frequent occurrences of pipe sticking and burying accidents. Aiming at the above problems， this paper systematically expounds the improvement scheme of the original drilling fluid system and the engineering application of the bi-polymer anti-collapse drilling fluid. Through laboratory experiments， the performance indexes of the original drilling fluid such as rheological properties， filtration loss， and inhibition were optimized and improved， and the bi-polymer anti-collapse drilling fluid system was gradually transformed from the original drilling fluid and applied on field drilling. The practice has proved that the improved drilling fluid has achieved significant improvements in hole protection effect， rheological characteristics， lubrication performance， and drilling efficiency. The study also points out the limitation such as insufficient efficiency of solid control equipment in the current drilling technology and puts forward targeted technical suggestions， providing an important reference for the drilling fluid design and construction of the similar geothermal well projects.

Abstract:The construction technology of improving the engineering properties and strengthening the strength of fractured rock mass by grouting reinforcement has been widely used in mining and water conservancy projects. In order to study the related effects of various grouting factors and grouting methods on the strength of fractured rock mass in grouting reinforcement， as well as the effects of freeze-thaw action on the engineering properties of fractured rock mass after grouting reinforcement， cement mortar and other materials are used to make similar materials that can simulate the mechanical properties of fractured original rock according to a certain similarity ratio. By controlling the relative variables of slurry water-cement ratio， grouting velocity （grouting pressure）， grouting temperature and other factors， the fractured rock mass is reinforced by grouting with inorganic materials， inorganic composite materials and organic materials respectively. Through the simulation of the climate and other environmental conditions in this area， the relevant tests of various factors are carried out， and then the influence of various factors on grouting reinforcement is analyzed. Finally， according to the test results， the grouting parameters are optimized， and the grouting reinforcement scheme is designed and monitored according to the engineering geological conditions and geological environment of the slope of Zhonglian Runshi open-pit coal mine in Zhundongxiheishan mining area， Xinjiang， which has certain reference significance for slope disaster prevention and control in this area and other open-pit mines with similar geological characteristics and regional characteristics.

Abstract:The Gaojiabu Mine in the Binchang mining area is located in the middle of the Huanglong Jurassic Coalfield. The main coal seam is overlaid by the Luohe Formation sandstone aquifer， which is characterized by great thickness， low permeability and uneven water abundance. As the mining depth increases， water hazards in the mine seriously threaten safe production. The existing drainage system is unable to meet the demand and needs to be expanded. Therefore， a centralized drainage system was constructed， in which large-diameter drainage boreholes were implemented， with a borehole diameter of ?950mm and a depth of 810m. A novel method was adopted to fabricate the casing cement buoyancy plug using “casing inner diameter reducer+welded threaded steel ring+prefabricated steel hook”， and 378.8t of drainage pipelines were installed. During the construction in this area， complex geological conditions were encountered， and accidents such as borehole collapse， and stuck pipe due to hole shrinkage were prone to occur. The construction passed through the thick Luohe Formation sandstone aquifer with poor rock drillability in some sections， resulting in low drilling efficiency and high overall project difficulty. To address these issues， this paper proposed targeted solutions such as controlling drilling fluid loss， optimizing drilling assembly， and maintaining drilling fluid performance， which achieved good practical application results and provided a feasible solution for water hazard prevention and control in the mining area.

Abstract:Geological disasters in scenic areas not only damage natural landscapes and ecological environments but also pose serious threats to tourists’ safety. This paper introduces the characteristics of collapse geological hazards in Beijing Shimenshan scenic area， systematically analyzes the scale， failure modes， and stability of unstable rock masses. By comparing various treatment methods while considering the scenic area’s location， hazard scale， and internal traffic conditions， comprehensive management measures were proposed including upper-level clearance of loose rocks， bottom retaining walls and hazard avoidance. These integrated solutions aim to maximally protect the scenic area’s natural landscape， ecological resources， and tourist safety while exploring an economically reasonable treatment scheme harmonized with the scenic environment. The research outcomes are expected to provide valuable references for geological hazard management in similar scenic areas.

Abstract:The post-grouting process of bored piles has been widely used in China because it can improve the bearing capacity and reduce deformation. However， due to the large concealment of post-grouting construction， problems have occurred in many engineering applications. A large number of practices show that the bearing capacity of a single bored pile under the same condition often shows quite differences. Simply calculation according to the pile foundation specification will make the calculated value significantly higher than the static load test results， which brings great safety hazards to the construction project. The comprehensive estimation method proposed in this paper analyzed from several aspects， bringing in the increase amplitude of bearing capacity γ， the bearing capacity enhancement coefficient β， and the cmprehensive impact factor λ， covering the influence of various factors. The calculation formula is simple and easy to understand and the method is convenient and feasible. Moreover， the results are close to the actual after the application verification with high safety reliability， and good application effect.