Abstract:With the continuous development of the exploration， development and utilization of deep mineral resources， the bottom environment of the hole is more complex. Pregnant diamond bit， as a special tool for geological drilling， the complex deep hard rock geological environment also puts forward higher requirements for the performance of pregnant diamond bit. The efficiency and life of crushed rock of pregnant diamond bit are closely related to the performance of broken rock unit. This paper summarizes the research status of drilling wear response of pregnant diamond bit in deep hard rock drilling. At present， the research is not perfect， so further in-depth analysis is needed to clarify the response mechanism. On this basis， discusses the innovation of broken rock unit in recent years， the emphasis from the internal structure and the analysis of different reinforcement way of the cutting unit strength， wear， drilling efficiency， the results show that it can effectively improve the deep hard rock pregnant drill cutting efficiency and working life. From the perspective of prolonging lifespan and increasing efficiency， this paper discusses the direction of strengthening the broken rock unit of impregnated diamond drill bits suitable for deep hard rock drilling， providing reference for the design and manufacturing of impregnated diamond drill bits for deep geological drilling.

Abstract:Natural gas hydrate is a type of solid clean energy with huge reserve， which is therefore considered as a substitute for traditional fossil fuels and have attracted much attention around the world. Due to its occurrence in low-temperature and high-pressure marine and permafrost environments， the key to achieving commercial exploitation is to find out economical and efficient exploitation methods. Based on the current research status of laboratory research， numerical simulation， and on-site experiments， the exploitation effects of methods such as depressurization， heat injection， chemical inhibitor injection， CO₂ displacement and combination method were analyzed， and the advantages and limitations of each method were discussed. The existing exploitation methods are mainly limited by low reservoir permeability and poor thermal conductivity， and have not been able to achieve long-term continuous gas production. To address the above issues， the in-situ resistance heating method for reservoirs is proposed to improve thermal utilization efficiency， and it is believed that hydraulic fracturing and permeability enhancement technology is an effective measure to increase reservoir permeability and assist in efficient gas production through production methods such as depressurization； Regarding the potential instability of reservoirs caused by hydrate exploitation， it is believed that the use of CO₂ replacement method can strengthen the reservoir， and the use of supercritical CO₂ injection technology can improve the CO₂ replacement rate.

Abstract:With the gradual depletion of shallow underground resources， people gradually seek energy from deeper parts of the earth. In order to coping with the harsh environment of underground formations during drilling， a self-balancing drilling system and a bionic self-propelled drilling tool feeding system are proposed to move the pressure drive unit underground. In this paper. In order to solving the problems of how to increase the efficiency of the support mechanism in the self-propelled feed system， the surface of the drag-enhancing mechanism of the self-propelled feed system is designed bionically by analysing the non-smooth structure of the head surface of the dung beetle. The drag-enhancing performance and the damage to the well wall are simulated， and the friction and wear performance is tested experimentally to study the drag-enhancing and wear-reducing effects of different bionic structures. The results show that the ratio of the spacing of the dung beetle head bumps to the diameter of the dung beetle head is around 1.50， the ratio of the diameter of the middle bumps to the length of the corresponding dung beetle head ranges from 1：142 to 1∶133， with a higher probability near 1∶138， the ratio of the diameter of the two side bumps to the length of the corresponding dung beetle head ranges from 1∶173 to 1∶158， with a higher probability near 1∶167. The proportion of the bumps in the middle part was about 45%， and on both sides was basically the same； the spacing of the bionic structure design had a good drag-enhancing effect when the ratio of the spacing to the diameter of the bionic structure was around 1.50. Under the condition of the same diameter of the convex packs， the larger the spacing was， the greater the damage to the wall of the wells. The orthogonal triangular layout was the best layout for the drag-enhancing effect of bionic units， and a rectangular layout increased the damage to the wall of the wells， at the same time， reduced the drag-enhancing effect； Concentric circular arrangement has the greatest damage to the well wall and the worst drag-enhancing effect.

Abstract:Aiming at the problems of low drilling efficiency and low coring efficiency of hard rock coring tools in ocean drilling， this paper introduces the basic development and land test of ?185mm hollow screw motor bottom hole power rope coring tool developed by the Institute of Exploration Techniques， CAGS. In the development process， through theoretical calculation and Ansys Workbench finite element simulation， the spiral structure of the hollow screw motor is optimized and the dynamic analysis is carried out. The force safety analysis of the universal joint is carried out， and the material is optimized. The key technologies such as multi-head small offset short pitch hollow rotor and flexible hollow universal joint are overcome. The feasibility of the working performance of the prototype of the coring tool is verified by the coring test of granite block on land， which provides the guidance of working parameters and the optimization of matching drill bit for the engineering application of this coring tool. It can provide hard rock coring technical support for ocean drilling and deep scientific drilling in China.

Abstract:Ocean drilling is a major means for the exploration and development of marine energy resources and the study of crustal tectonic evolution， which is often faced with problems such as large disturbances in complex sea state and strong uncertainty in seafloor formation. This paper proposes an online interval prediction method for ROP during the ocean drilling process， and carry out the validation of the method with the indoor simulation experiment of micro drilling ship as an example， so as to lay an important foundation for the engineering application. Firstly， methods such as data resampling， data time-depth matching and data filtering are applied to pre-process the multi-source ocean drilling data. Secondly， methods such as Extreme Learning Machine （ELM） and Particle Swarm Optimization （PSO） are applied to establish a point prediction model of ROP. Furthermore， nonparametric estimation method is utilized to construct confidence intervals， establish ROP interval prediction model， and carry out ROP interval prediction. Finally， the interval prediction model parameters are updated online by moving window to realize online learning and optimization of the model. The comparative results of the indoor simulation experiments on the micro drilling ship verify that the proposed method has strong ROP prediction capability and robustness， and can provide a new engineering solution for the optimization and control of ROP during the ocean drilling process.

Abstract:The deep sea mud lifting system plays a critical role in the Riserless Mud Recovery （RMR） drilling process. In order to enhance the safety redundancy and adaptability of the lifting system， in-depth research on the multi pumps series parallel mechanism was conducted， including the detailed study of the series parallel structure design and working principle of the mud lifting pump， and the relationship between flow rate and lift during series and parallel operation， as well as the mathematical method and graphical method for series parallel operating points of the pump group. Furthermore， by utilizing the measured characteristic curve of the model pump， the Q-H characteristic curve and operating points of the dual pumps series parallel operation were obtained using graphical method. Finally， suggestions for dual pumps collaborative control were proposed.

Abstract:It is of great significance to carry out subglacial bedrock core drilling in polar regions for studying subglacial geology， revealing the evolutionary history of ice sheets and evaluating future climate change. The temperature of the drilling fluid may rise above 0°C after circulating at the bottom of the hole When drilling subglacial bedrock in polar regions， which may cause the wall of the icy hole to be melted during upward return， resulting in the instability of the wall， and even triggering the stuck drilling accident. It is necessary to design a drilling fluid cooling system that cooling the drilling fluid to a lower temperature before injecting it into the borehole， thereby keeping the drilling fluid below 0℃ at all times during circulation. The heat exchanger is the core component of the drilling fluid cooling system. The paper selects plate heat exchanger as the heat exchange component to cool drilling fluid， and uses the average temperature difference method to determine the heat exchange area and basic parameters， then numerical simulation of the heat exchange performance of the plate heat exchanger is using COMSOL Multiphysics 6.0 software. The research results show that the heat exchanger can cool the drilling fluid to -4~-3℃. Further， the simulation results show that the outlet temperature of the drilling fluid decreases with the decrease of the carrier refrigerant injection temperature and the increase of the carrier refrigerant flow rate， the type of drilling fluid has a great influence on the heat transfer performance of the heat exchanger， while the material of the heat exchanger plate has little influence.

Abstract:The fracture leakage channel in fractured formation usually has multi-scale characteristics and uncertainty. The drilling fluid leakage problem is particularly prominent in the construction of geological drilling in fractured formation. Shear Thickening Fluid （STF）， as a new type of intelligent material， has excellent properties such as self-sensing， self-adaptation and self-repair， and has been widely used in many fields. In this study， shear thickening fluid was used as a plugging material， and the plugging characteristics of shear thickening fluid were investigated under different dispersed phase concentrations （56.9vol%， 59.2vol% and 61.7vol%）， slit widths （1，2，3，4，5mm） and pressure conditions through the plugging test of API plugging instrument. The plugging test results show that the amount of leakage increases with the increase of seam width and time. When the concentration of nano silica increases in the range of 56.9%~61.7%， the leakage rate will be reduced and the effect of the gap width on the leakage rate will be weakened. When the leakage pressure is 0 MPa， the shear thickening fluid does not produce thickening effect， but leaks out from the seam in the form of liquid. When the pressure increases slightly， the thickening effect will be stimulated， and agglomeration particles will be generated to seal the seam pipe and reduce the leakage rate. When the pressure further increases beyond the bearing capacity of the sealing layer， the shear-thickening fluid is extruded out of the fracture in a plate form. The application of shear-thickening fluid in plugging field is expected to provide innovative solutions for plugging in fractured formation.

Abstract:Under the dual influence of the extremization of drilling construction conditions and the industrial transformation brought about by the development of new-generation information technologies， the intelligence of drilling technology has become an inevitable trend in the development of drilling technology. Intelligent drilling， in line with the needs of the Fourth Industrial Revolution， utilizes the theories and methods of information technology to transform and enhance traditional drilling models and technical systems， achieving digital empowerment and digital transformation of drilling projects， thereby becoming the core driving force for the development of drilling technology. In this context， this paper focuses on the critical issue of intelligent rock mass recognition based on real-time drilling key parameters， providing a comprehensive overview of non-core sampling in-situ rock mass testing technology based on the drilling process. Finally， it offers an outlook on the intelligent development of drilling engineering. By reviewing the latest technologies and research progress in this field， a new recognition system for deep fusion of process-physical multimodal information during drilling is proposed， aiming to realize intelligent identification of rock and soil masses during the drilling process and improve the quality and efficiency of major infrastructure engineering investigation.

Abstract:Hydraulic fracturing of hot dry rock（HDR） reservoirs to form a complex network of seams is essential for the construction of enhanced geothermal systems （EGS）. In order to deeply understand the mechanism of hydraulic fracture extension in HDR reservoirs and reveal the influence of engineering and geological parameters on hydraulic fracture extension， in this paper， a HDR reservoir in the Gonghe Basin of Qinghai Province is taken as the research object， and based on the extended finite element method （XFEM） numerical simulation software ABAQUS， a field-scale HDR reservoir model is established to realize the thermo-hydro-mechanical coupling and to analyze the extension mechanism of the hydraulic fracture. The results show that： （1） In the normal fracture-type stress state， the crack undergoes a very obvious turning toward the Z-axis， in the strike-slip-type stress state， the crack expands mainly along the horizontal direction with a slight tendency to turn toward the Z-axis， and in the thrust-type stress state， the crack expands along the horizontal direction. （2） With the increase of elastic modulus crack initiation pressure decreases， the injection pressure of crack extension also decreases； the larger the elastic modulus the earlier the crack initiation time； the larger the Poisson ratio the greater the rupture pressure of hydraulic cracks； the rupture pressure as a whole shows a normal fracture-type>strike-slip-type>thrust-type. （3） The hydraulic fracture rupture pressure decreases with the increasing temperature， by about 2~3MPa or so， showing the same trend for all three stress states. This paper inriches the numerical simulation methods of hydraulic fracturing extention for HDR， the relavant research results can also provides technical supports for the prediction of the hydraulic fracturing extention and the influences affected by different perameters for HDR reservoirs.

Abstract:In the process of geothermal well exploitation， the transient high temperature caused by wellbore thermal fluid has a great impact on the mechanical properties of casing. This paper calculates the wellbore temperature and pressure field based on the steady-state heat conduction mathematical model of casing cement sheath formation rock， establishes the mathematical model for the mechanical evaluation of the interaction between middle-deep layer geothermal exploitation heat release and casing， and carries out the finite element calculation and experimental simulation of the influence of geothermal exploitation heat release on casing damage. The following conclusions are obtained： under the action of geothermal exploitation wellbore heat release， the casing has a large ovality， which weakens the collapse strength of the casing. When the internal pressure reaches 90MPa and the temperature in the casing is 30℃， the stress distribution on the inner wall is extremely uneven under the condition of different formation radial pressures， with the maximum difference of 560MPa. The stress is distributed in layers along the circumference， and a large range of stress concentration areas appear on the side subject to the formation radial pressure. With the increase of temperature， the displacement contour of casing changes little， and the maximum displacement increases slightly. When the temperature reaches 120℃， the casing is in a relatively harsh thermal environment. The increase of thermal stress leads to serious plastic deformation of the casing. At the same time， when the internal pressure increases to 120MPa， the inner wall of the casing is in a high stress state as a whole， which is more likely to lead to plastic failure of the wall. The research results can provide guidance for the influence of heat release from geothermal exploitation on casing damage， and for the evaluation of casing stress environment， cement sheath strength， cement sheath micro gap width and other parameters.

Abstract:The new round of strategic action for mineral exploration breakthrough has put forward higher requirements for drilling technology， and the shallow drilling technology is of great important for rapid verification in shallow cover area. Moreover， the multi-technique drilling technology can provide technical supports for green and efficient drilling in complex formations. Based on this requirement， the TGQ-200RC multi-technique automatic drill is developed. The overall schedule of the drill is formulated， and the main components of the drill are designed such as the multi-techniques power head， clamping and unscrewing device， 6-DOF drill rod swinging mechanism， vehicle-mounted integrated hydraulic rod storage， electro-hydraulic control and parameter monitoring system. Furthermore， the process of multi-mechanism collaborative action during automatic adding and removing drill rods was planned. The field test shows that the TGQ-200RC drilli has high drilling efficiency， good sampling quality， and features of multi-technique capability， mobility， automation， and digitization， the average time for a single automatic adding or removing of drill rods is about 90s. With the wireless remote control， it can achieve unmanned operation in the wellhead， effectively reducing labor intensity and improving operational safety. The TGQ-200RC multi-technique automatic drill can provide solid support for building a green， efficient and economical rapid verification drilling technology system， and useful reference for promoting the automated upgrading of domestic shallow drilling equipment.

Abstract:With the increase of mineral resources exploration requirements in resent years， the depth of core drilling is rising and the encountered formations are more and more complex. In order to get the ore body in the target area accurately to realize the geological purposes， the requests to control the drilling trajectory is higher. In some working areas of the Xuefenghu structural belt， the dip angle is large with frequent alternation of the soft and hard layers and broken strata. The stratum deflection is serious during the practical construction. As the hole depth increases， the deviation from the ore body in the target area become larger， which affects the exploration accuracy and quality of the mineral resources. In this paper， through deeply analysing the formation deflection， the primary directional technology and the full-hole drilling tool technology are used in the ZK1001 drilling construction， which greatly improves the quality of the borehole and better controlling the drilling trajectory. Moreover， different core drilling tool combinations in different hole sections are tested， some opinions and suggestions for optimizing drilling tool assemblies are put foward， which provides technical reference of drilling trajectory control for coring hole in the working area.

Abstract:The 3500m extra-deep hole （ZK001 hole） in Xiaoqinling gold mine field is located in Lingbao City， Henan Province. It is the first full-hole continuous coring extra-deep hole in the Xiaoqinling tectonic belt. The formation lithology of this hole is very complicated， with soft， hard and broken strata appearing interactively， and the wall protection is extremely difficult. There are many complicated conditions in drilling， such as hole wall collapse， block loss， hydration decomposition and pulping， high in-situ stress gouge shrinkage and micro-fracture water loss. In this paper， the flushing solution system is adjusted according to the formation changes. The upper part uses low solid phase flushing solution and the lower part uses low solid phase polymer anti-collapsing flushing solution system. The flushing solution formula is constantly optimized， the performance parameters are timely maintained and adjusted， and various problems in the hole are effectively solved. It provides a reliable flushing fluid technology for deep hole core drilling in Xiaoqinling area.

Abstract:Well Chuanmaye 1 is a shale gas parameter well deployed in Mabian， Sichuan. When drilling to 3437.58m， there were drilling complexs and sealed with cement after the first stage of treatment was unsuccessful. This article proposes a three hole open hole section sidetracking technology scheme for the complex situation of Well Chuanmaye 1. Based on the analysis of the factors affecting the sidetracking force near the drill bit position， combined with the actual situation， the sidetracking point， sidetracking method， and sidetracking tool combination were optimized， and the sidetracking technical measures were determined. After two rounds of sidetracking construction， the construction difficulties such as lack of adjacent well data， large sidetracking depth， complex formation prone to collapse， high temperature and formation strength in the sidetracking section， small inclination of the original wellbore， and limited sidetracking direction were overcome. Finally， a new wellbore was drilled and reached the predetermined depth. Provided reference for subsequent drilling construction and complex treatment in the region.

Abstract:The accumulation of cuttings bed in the wellbore is one of the main factors restricting the safe and efficient drilling of horizontal wells. Research has shown that the spiral flow of drilling fluid in the annulus can effectively improve the efficiency of cutting removal. For this purpose， a rock debris removal tool capable of generating annular spiral flow was designed using CFD numerical simulation and experimental methods， and on-site application was also carried out. The results showed that the promoting effect of the V-shaped blade on cutting transport and disturbance ability on the cutting bed is stronger than that of the spiral and straight edged blades， making it the preferred structural form for generating annular spiral flow. There is an optimal range for the length of V-shaped blades， and the higher the blade height， the better the effect， while the number of blades has a weaker impact. The on-site application shows that the cutting removal tool meets the requirements of shale gas horizontal well operation in terms of strength， hardness， and blade wear resistance. The tool can destroy and remove the cutting bed while drilling. Combined with reaming operations on key sections where the cutting bed accumulates during the tripping process， it can effectively remove the stubborn large particle cuttings and improve the borehole cleaning effect.

Abstract:The directional drill pipe in coal mine is subjected to bending， torsion， vibration， tension and other loads in the hole， and the fracture accident often occurs in the construction process. The main reason for the fracture of drill pipe is stress concentration. Based on the resistance strain measurement， this paper builds a full-size physical stress test platform for directional drill pipe， conducts tensile stress tests on drill pipe joints， and plots each experimental data into stress distribution curves. The results show that the stress of drill pipe pin is greater than that of drill pipe box， and the maximum stress of drill pipe pin and box is at the position of tooth 3. The correctness of the simulation model is verified by the stress distribution trend and the stress value of each tooth， and a method to verify the drill pipe simulation model is provided. The experimental data and stress distribution curve in this study provide reliable data support for the finite element simulation of drill pipe.

Abstract:With the deepening of exploration and development of deep geological resources in China， deep mineral deposits have become the focus of geological prospecting work. In the process of deep prospecting and drilling， the problem of maintaining the straightness of the vertical well section in the high steep structure has been a major problem for drilling technicians， which seriously affects the exploration efficiency of deep mineral deposits. In the inclined section， the single bend bistable screw drill is the most commonly used anti-deviation and correction drill assembly. In this paper， a mechanical model of BHA is established based on the crossbar bending beam method and the principle of equilibrium trend. The influence law of each factor on the deviation correction ability is analyzed through the model， and the main control factor is determined by the orthogonal test design method. Finally， based on the theory of multi-objective optimization， a multi-objective optimization method for control parameters of fast drilling is established to obtain the optimal parameter combination. Based on the above research， a set of anti-skew and straightening optimization design method is developed to improve the drilling efficiency of the vertical well section of the high steep structure， and promote the efficient and low-cost drilling and development of deep mineral deposits.

Abstract:The potential for uranium exploration in the Miaoershan area of Guangxi is enormous， but part of the formations are complex， with large thickness of water-sensitive and broken formations. During drilling construction， difficulties such as hole wall collapse and excessively large bore diameter occur frequently， leading to frequent accidents in the hole， which seriously affect the construction progress. Therefore， mineral composition and microscopic characteristics of water sensitive cores in the area were analyzed. The analysis results show that there are a large amount of clay minerals such as montmorillonite， kaolinite， hydromica， etc. in the water-sensitive formations， and the microcracks are developed with serious hydration expansion. To solve above problems， new materials with film forming and wall protecting functions were optimized through indoor evaluation experiments， and a drilling fluid system with good wall protection performance was further developed， which consists of 5% film-forming agent A， 3% film-forming agent B， 1.5% modified asphalt， 1% plugging agent while drilling， 1%sealing agent， 0.6% viscosifier， 0.2% coating agent. The API filtration loss of this drilling fluid is 5~8mL， and the relative expansion reduction rate reaches over 87%. This drilling fluid can effectively inhibit hydration expansion of the water-sensitive formations， and the wall protection effect is significant. This technology has been successfully applied in three boreholes in the Miaoershan area， smoothly drilling through water-sensitive formations without any problems such as core dispersion or hole wall collapse. Good application results have been achieved， and a film forming and wall protection drilling fluid technology has been preliminarily formed for water-sensitive formations in this area.

Abstract:The strata where the receiving end of air shaft shield is located in a subway section of the North China Plain is mainly silty clay， clayey silt and silty fine sand from top to bottom， with high underground water level and strong liquidity. After being reinforced by high-pressure rotary jet grouting at the receiving end， it was found that there is still a risk of water and sand inrush using horizontal exploration holes. The water and sand surging is easy to happen in the gap between the tunnel doors when the cutterhead of the shield tunneling machine break through the tunnel door. To ensure the shield machine smoothly passing out of the tunnel， the method of surface sleeve valve pipe grouting is adopted， and the GX modified silicon grouting material is used to consolidate the fine sand. Targeted reinforcement grouting is carried out in the receiving end of the interval air shaft within the water-rich fine sand formation. After treatment by such technology， the shield machine successfully excavated without any water or sand inrush.

Abstract:Among various drilling methods， hydraulic impact rotary drilling is characterized by its high efficiency， good quality， long cycle times， few accidents， and low costs. The hydraulic down-hole hammer is the technological core of hydraulic impact rotary drilling. This article organizes the structural features of various hydraulic down-hole hammers and explores the various drilling tools which derived from the combination of hydraulic down-hole hammers， wireline coring and downhole motor drilling tools. The typical application cases of this technology are briefly introduced， and the the future development direction and technical challenges are also summarized in order to popularizing the application and promoting the advancement of hydraulic impact rotary drilling technology.