Abstract:According to the construction requirements of myriametric extra-deep well， the BG155V casing with good toughness， high-temperature strength， collapse resistance and delayed fracture resistance is developed on the basis of alloying technology and manufacture process optimization. The test results of batch production showed that the yield strength reaches over 1100 MPa， and the transverse Charpy impact energy at 0 ℃ reached 10% of the nominal yield strength， and the strength and low temperature toughness and microstructure of casing under different service temperatures were analyzed. It was found that the grain size level of the casing with controlled cooling process after hot rolling reaches up to 11. The fine grains ensure good toughness and delayed fracture resistance of the material， which improves the reliability of the casing in the myriametric extra-deep wells for the development of oil and gas resource.

Abstract:In order to help the scientific exploration of ultra-deep formation and oil and gas discovery over 10000m in China， two sets of automatic drilling rig for 12000m extra?-deep wells were developed which is equipped with 15m ultra-high drilling floor base， 4600kW winch with high load ratio， 3000hp five-cylinder drilling pump set， 9000kN AC frequency conversion top drive device， etc.， to meet the needs of drilling operations for myriametric wells with ultra-high pressure complex condition. Ultra-large capacity pipe string automatic processing equipment and integrated control system are accompanied to meet the requirements of automatic storage and discharge of myriametric drilling tool， the full automated process of pipe string from the yard to the wellhead was achieved. Electric drive equipments were comprehensively applied with more accurate control， more environment friendly operation， low temperature environment adaptability and higher safety. Equipements such as top drive device， generator set and domestic inverter are locally made rather than imported. The field application showed that the two sets of automatic drilling rig for 12000m extra?-deep wells has an integrated drilling speed of up to 1.6m/h， and the tripping speed is 24.8columns/h. Through the remote online detection and expert diagnosis system， the average failure rate is reduced by 50% compared with the in-service drilling rig， and the drilling operator can be reduced by 3 people/shift， as a result， the labor intensity of drilling personnel can be greatly reduced. It provides equipment support for China’s oil and gas field development in myriametric formations.

Abstract:Extra-deep scientific drilling is the only technical means to directly obtain the deep information of the earth， which is of great significance to deeply understand the internal structure of the earth and explore the underground resources， which has been risen to the national strategic science and technology issue. In response to the call of the Party Central Committee for “march to the deep earth”， it is necessary to vigorously promote the research and development of extra-deep scientific drilling equipment technology. This paper briefly reviews the development of the extra-deep scientific drilling equipment technology at home and abroad， combined with China’s development needs， the key technical problems faced by top drive， winch， drilling pump in extra-deep scientific drilling are summarized， and on this basis， the development direction and prospect are put forward， which provides reference for the development of extra-deep scientific drilling engineering in China.

Abstract:The structural and performance characteristics of turbodrill are analyzed. In the high-temperature and high-pressure and highly abrasive strata of deep and extra-deep wells， turbodrill has basically become the only alternative downhole dynamic drilling tool to increase speed and reduce costs in composite drilling. In view of the exploration and development requirements of deep resources， the advantages and existing problems of the existing turbodrill core-extraction technology are described. In addition， numerical simulation technology is used to analyze and study the influence of drilling fluid flow state on the coring effect in the process of simultaneous coring with turbodrill. It is recognized that turbodrill can withstand high temperature and is suitable for full drilling and coring in deep and extra-deep wells， but its high rotational speed is also easy to cause core wear and rock column spiral in the process of coring drilling. Improving the high-speed single motion performance of the core-drilling tool， lengthening the spiral stabilizer of the turbodrill and using the reverse spiral spoiler are beneficial to reduce the vortex motion at the bottom of the hole and the axial velocity difference between the inner and outer tubes of the core， so as to improve the core quality of the core-drilling tool.

Abstract:Based on the characteristics of scientific drilling and the situation of the hole configuration of extra-deep wells in China， this paper sets the basic hole configuration and coring sections of China’s myriametric extra-deep scientific well. Combining the SG-3 borehole of the Soviet Union， the main borehole of KTB in Germany and the scientific drilling projects of China， such as the Continental Scientific Drilling Project No.1 and Songke-2 Well， the methods of deviation prediction， measurement as well we the deviation prevention and correction during full-depth drilling and coring for extra-deep well are elaborated. Finally， the overall scheme of the myriametric scientific extra-deep well， including the deviation control method and control index of upper well section and the drilling deviation correction and prevention technology and equipment of coring section are put forward， and the further research seggestions are posed.

Abstract:Polycrystalline diamond bits have the widest application in oil and gas drilling and deep formation drilling. Polycrystalline diamond compact （PDC） consists of a polycrystalline diamond layer and a cemented carbide substrate. Due to the difference in the coefficient of thermal expansion between the polycrystalline diamond layer and the tungsten carbide matrix， there is a huge residual stress inside the PDC after sintering and cooling. To solve the problem of reducing the residual stresses inside the PDC， this paper reports a preparation technology for gradient structure diamond compact. Through the process of fused deposition modelling and sintering （FDMS）， the technical route for the preparation of gradient structure diamond compact was determined； the micro-morphological features of the prepared gradient structure diamond compact and the distribution of the residual stresses were analysed； and the indoor drilling tests were carried out to verify the drilling performance of the gradient structure diamond compact. The results show that the gradient structure diamond compact prepared by the FDMS has a compressive stress of 1.4GPa at the interface between the polycrystalline diamond layer and the gradient layer， which significantly improves the interlayer bonding ability and effectively reduces the internal residual stress， and improves the drilling efficiency by about 36% and the service life is longer compared with that of the conventional compact.

Abstract:The complex drilling conditions of deep drilling put forward higher requirements for the performance of impregnated diamond bits. To improve the application range of electroplated diamond bits， the effects of MnCl₂ and butynediol ethoxylate （BEO） on the surface morphology， microhardness， and thermal stability of the nickel base coating were studied. The drilling performance of pure Ni matrix diamond bit， Ni-Mn matrix diamond bit， and Ni-Mn matrix diamond bit with BEO as an additive after annealing at 300℃ for 1 hr was compared. The results show that the microhardness of pure Ni decreases significantly to 300HV after annealing at 300 ℃ for 1 hr， and the wear resistance of the annealed diamond bit with this matrix is too low， which leads to premature diamond shedding and a short service life to 2.94m. Both Ni-Mn coating and Ni-Mn coating with BEO added have good thermal stability， and the hardness increases to 640HV and 693HV respectively after annealing at 300℃ for 1hr. Ni-Mn matrix diamond bit has both suitable drilling life and drilling efficiency after annealing， and the bit life can reach 4.67m. However， the annealed Ni-Mn matrix diamond bit with BEO as an additive fails due to the matrix’s high microhardness.

Abstract:In the drilling process of deep and extra-deep well， the downhole drilling tools are in a situation of high temperature， high pressure and high corrosion， and the drill pipes are intensely collided and worn with the external rock layers and casing. Therefore， the anti-wear and protection of the drilling tools is a problem that needs to be focused on. At present， welding anti-wear belt on drilling tools is the main method of drilling tool protection for deep wells， which plays an important role in reducing drilling tool wear and prolonging drilling tool life. This paper summarizes the development and research status of anti-wear belt technology at home and abroad， expounds the failure causes of anti-wear belt， the evaluation and test methods of key performance. Moreover， the key points of the development of anti-wear belt technology at present are also analyzed， which are anti-shedding， anti-wear belt repair technology and casing-friendly anti-wear belt material research. Finally， the development trend of anti-wear belt technology in deep and extra-deep wells is prospected.

Abstract:In the field of drilling engineering， silicon-based materials show great potential for application due to their excellent physicochemical properties， especially in deep and extra-deep wells downhole operations under harsh environments such as high temperature， high pressure， and high salinity. This paper reviews the classification of silicon-containing treatments and their current research status in drilling fluid. The specific applications of silicon-based treatments are described， which consist of inorganic silicates， nano-SiO₂， organosilicon， and hybrid silicate as the main components. These applications include strengthening the stability of the well wall， controlling the malignant leakage of the borehole， and improving the comprehensive performance of drilling fluids. This paper also discusses the technical challenges and research directions faced by silicon-based materials in the future application of oil and gas mineral exploration and development. This is of great significance for further optimizing silicon-based material technology and making it applicable to drilling engineering in complex formations.

Abstract:With the implementation of deep oil and gas exploration， high temperature hot dry rock exploration and deep earth exploration strategy， the drilling fluids have been in high temperature and high-pressure environment for a long time， and the stability of water-based drilling fluids under ultra-high temperature and high pressure is a key technology for ultra-high temperature well drilling. In this paper， the technical problems faced by drilling fluids in ultra-high temperature scientific drilling engineering are analyzed， and the design approach for high density water-based drilling fluids formula resistant to 240℃ ultra-high temperature are proposed. The key additives for 240℃ ultra-high temperature and high density water-based drilling fluids were selected by single factor method. Using the synergistic effect of different high temperature additives， a set of ultra-high temperature and high density water-based drilling fluid formula with temperature resistance of 240℃ and density of 2.0g/cm³ was preliminarily developed. The results show that after aging at 240℃ for 16h， the optimal formulation of drilling fluids have good rheology and filtration reduction performance. Its apparent viscosity change rate is less than 30%， and the filtration loss at 180℃ is less than 24mL.

Abstract:Deep drilling is a necessary means of obtaining deep oil and gas resources and accurately detecting the deep earth. As the increase of the depths in deep wells and extra-deep wells， the high-temperature environment poses stricter requirements on drilling fluid systems. In recent years， new progress has been made in anti-temperature drilling fluid systems through continuous research. This paper summarizes the research and application of various high-temperature drilling fluid systems at home and abroad， and highlights the advantages and application scenarios of different systems， including high-temperature resistant water-based drilling fluid systems of high-temperature resistant polysulfide drilling fluid， high-density drilling fluid， low-density drilling fluid； high-temperature resistant oil-based drilling fluid， water-in-oil， oil-in-water and reversible oil-based drilling fluid systems； high-temperature resistant solid-free drilling fluid systems such as offshore deepwater solid-free， formate drilling fluid， foam drilling fluid， and weak gel drilling fluid； organosilicon drilling fluid systems and biomass drilling fluid systems. The future development directions is environment friendly， improved high-temperature resistance perpormance， cost reduction and enhanced multifunctionality， which requires continuous technological innovation and cooperation to promote the development and application of high-temperature drilling fluid systems in the drilling industry towards sustainability and efficiency.

Abstract:In this paper， taking the rock slope of an open-pit mine in Xizang as an example， based on the site investigation and engineering geological characteristics of mine slope， the engineering geological zoning of mine slope is studied， and the slope stability is qualitatively analyzed and quantitatively calculated by combining the stereographic projection method and Sarma method. The research results show that the slope stability evaluation results were consistent with the current slope status. The slope stability of mining area was not good in general， and the slope in local area has poor stability. Both qualitative and quantitative stability evaluation methods confirm each other， which provides an important basis for slope disaster control design and construction in the next stage， and this has a good reference for similar slope projects.

Abstract:Red beds are typically considered as “prone-to-slide strata”， and shallow soil landslides can easily occur under rainy conditions. Therefore， it is of great importance to study the stability of shallow soil slopes in red bed areas under rainfall conditions. In this research，the shallow soil slopes in the red bed areas of Hunan Province is taken as an example， the stability of shallow soil slopes in red bed areas under different slope gradients， rainfall intensities， saturated hydraulic conductivities， and initial water contents is investigated by employing the modified Green-Ampt infiltration model， the specific impact patterns of these factors on slope stability is also analyzed. When the slope gradient is less than 45°， the safety factor decreases as the slope increases； when the slope gradient is greater than 60°， the safety factor increases with the slope. The wetting front depth changes insignificantly with the rainfall intensity， and the safety factor changes insignificantly with the rainfall intensity； the depth of the wetting front increases and the safety factor of the slope decreases as the saturated hydraulic conductivity increases； the safety factor decreases as the initial water content increase. The results can provide a theoretical basis and practical guidance for slope protection engineering in red bed areas.

Abstract:Foam lightweight soil and geogrids play an important role in the treatment of soft soil subgrade diseases in mountainous areas. There are great limitations in the application of foamed lightweight soil alone. As a deepening and supplement to previous research， combining the advantages of foam lightweight soil and geogrids to study the deformation of reinforced foam lightweight soil embankments is of great significance for highway engineering. Full-scale model tests were conducted to study the deformation of foam lightweight soil embankments and reinforced foam lightweight soil embankments. The results show that using reinforced foam lightweight soil embankments can reduce settlement and more effectively decrease subgrade stress and earth pressure， while also helping to spread the base soil pressure and solve the problem of uneven distribution of base stress. Therefore， adopting reinforced foam lightweight soil embankments can improve the bearing capacity of soft soil subgrades and enhance the stability of the subgrade.

Abstract:In order to manage a landslide， a numerical analysis model of the slope was constructed based on the on-site investigation data， taking the inflection point of the displacement of the characteristic point of the slope as the criterion， and adopting the strength discount method to determine the stability coefficient of the natural working condition of the slope to be 1.05， it was determined that the stability level of the slope did not meet the requirements of the engineering specification， and it was in the state of understability. Combined with the numerical analysis results， experts’ on-site analysis opinions and the mechanism of slope reinforcement measures， three kinds of reinforcement and management programs are determined， Program 1 is “Circular anti-slip piles + anchors + intercepting and draining”， Program 2 is “Square anti-slip piles + Circular anti-slip piles + Anchors + intercepting and draining”， and Program 3 is “Square anti-slip piles + Circular anti-slip piles + Intercepting and draining”. Based on the finite element numerical model to analyze the stress field， displacement field and slope stability coefficient changes of the rock and soil body， anti-slip piles and anchors， the stability coefficients of natural working conditions of the slope corresponding to the three reinforcement schemes were calculated to be 1.39， 1.28， and 1.18， which were 32.4% higher than those before reinforcement， and the stability coefficients of the natural working conditions were calculated to be 1.39， 1.28， and 1.18， which were 32.4% higher than those before reinforcement. Before the reinforcement， the stability coefficients of the natural working condition of the slope were 1.39， 1.28 and 1.18， respectively， which were 32.4%， 21.9% and 12.4% higher than those before the reinforcement； after comprehensively comparing the reinforcement measures of the three kinds of reinforcement schemes and the changes in the stress and displacement of the slope， as well as their reinforcement effects and economic levels， Scheme 1 was comprehensively determined as the final reinforcement scheme.

Abstract:The degree of topographic relief is closely related to the spatial distribution of slope geohazards， however， there are few studies that consider the optimal statistical unit， the types of geohazards and the scale of geohazards at the same time. In this paper， the Sichuan Province which has a huge span of geomorphologic units is taken as an example， the mean change-point analysis information method was applied to determine the optimal statistical unit， and the data statistical models， such as the frequency ratio model （FR）， the information value model （IV）， and the certainty factor method （CF） were used to study the impact of topographic relief on the spatial distribution of slope geohazards. The results showed that there was a significant positive correlation between the average topographic relief and the size of the statistical window. The window size of the optimal statistical unit is 20×20， covering an area of 3.24×106 m². The slope geological hazards were mainly distributed in the hills and small undulating mountains， which accounts for 68.9% of the total number. Among them， the susceptible range for landslides was 50~350 m， and for collapses was 50~200 m. The small undulating areas were more favorable for the development of small-scale geohazards， while the large undulating areas were more favorable for the development of medium and large-scale geohazards.

Abstract:The efficiency of pile hole formation for deep and large anti-slide piles in hard rock has always been a highly concerning issue in the industry. This study selected the formation of anti-slide pile holes in typical complex mountainous areas with hard rock landslides in southwestern Sichuan as the research subject. It systematically analyzed the traditional drilling pain points in deep hard basalt formations with weakly developed fractures， and designed nine combined rotary drilling hole formation process schemes for on-site pile testing. An analysis and demonstration were conducted from the aspects of drilling efficiency， technical and economic feasibility. The on-site testing and analysis results showed that the integrated hole formation technology of “large torque cutting tooth barrel drilling rotary drilling and stepwise borehole expansion with optimal cutting diameter difference of 0.4m” has the highest drilling efficiency， lowest tool wear， and lowest cost in hard rock formations. It verified the feasibility and efficiency of the high-efficiency rotary drilling stepwise borehole expansion technology for anti-slide piles in hard rock formations. Compared with existing manual hole formation， impact drilling， and one-time rotary drilling， this technology has greatly improved safety， efficiency， and cost. The technology has been successfully applied to the construction of pile foundations for landslides at the rear edge of the relocated Baihetan Town， with an average time consumption of 1.6 hours per meter， which is three times more efficient and 60% percent less costly than the previous improved one-time rotary drilling efficiency. This technology provides an efficient and feasible construction technical solution for the rapid hole formation of water-sensitive and earthquake-sensitive hard rock landslide anti-slide piles under complex geological conditions.

Abstract:The 3000m scientific drilling project of Dayingezhuang in Zhaoyuan， Shandong Province is the deepest scientific drilling project in the Zhaoping fault zone in Jiaodong area， with a design drilling depth of 3000m. In order to improve the drilling construction efficiency and reduce the probability of accidents in the hole， the project adopts an efficient and stable XY-9DB variable frequency drill rig， self-developed high-efficiency long-life diamond drill bit， CHD76 series high-strength drill pipe and jointly developed LZRT360 drilling fluid centrifuge. The key technologies such as P/H wire-line coring hydraulic percussion drilling technology and wire coring coating drag-reducing inner pipe technology are adopted to carry out deep hole drilling construction， and the rinsing fluid system is optimized for different strata. The final hole depth of the project is 3120.35m， the final hole diameter is 78mm， the average core recovery rate is 95.6%， and the average core recovery rate is 97.9%. This paper summarizes the treatment methods， solutions， and equipment usage of complex formation drilling in the construction process of this project， aiming to provide references for similar deep drilling projects.

Abstract:In response to the technical difficulties in ultra-deep shale gas horizontal well drilling in the Da’an block， such as low mechanical drilling speed in difficult drilling formations， high failure rate of rotary steering instruments at high temperatures， and long drilling cycles. In aim of efficient and rapid development of Da’an shale gas， the characteristics of encountered formations and technical difficulties in drilling were analyzed. Through the technical research and application such as optimization of wellbore configuration， selection of efficient drill bits， rapid identification of “Platinum targets”， density reduction and speed increase in the horizontal section， surface cooling of oil-based drilling fluid， high-temperature resistant white oil-based drilling fluid system， and equal wall thickness screw technology， the optimal and fast drilling technology for ultra-deep shale gas horizontal wells in the Da’an block was formed. This technology was tested on-site in the Da’an 104H ultra deep shale gas horizontal well， where the actual drilling depth was 6789m， with a horizontal section length of 2406.13m and an average mechanical drilling speed of 10.60m/h， which is 30.54% higher than the average value of 8.12m/h in the block. It can provide technical support for the efficient development of shale gas in Da’an.

Abstract:In this paper， the current technical standards and industry status for obtaining undisturbed soil samples is introduced， moreover， the drilling methods， comprehensive analysis of suitability for sampling tool selection， soil sample packaging and transportation methods are studied. The comparative experimental research indicates that the original obtained samples show excellent performance in on-site quality evaluation， indoor sample preparation， and experimental performance under the following two conditions in Wuhan first stage terrace of the Yangtze River. In clay laye， hammer drilling combined with open thin-walled soil samplers is adopted， while in sandy soil layer， the hammer and rotary drilling combined with built-in ring cutter soil sampler is used supplemented by rubber cover and tape sealing. Based on this method， the original structure of the sample is less disturbed， and the original structural force of the soil is also well maintained.

Abstract:The drilling rig， as an important ground equipment in drilling engineering， is undoubtedly a drilling weapon. The full hydraulic core drill is the main developed direction of the coring rig. This article introduces the main functions of core drill in providing pressure and rotational motion during rock breaking from the perspective of popular science. The working principle of hydraulic transmission is analyzed by analogy with lever priciple. The development process from vertical axis handlebar drilling rigs， vertical axis hydraulic drilling rigs to fully hydraulic core drilling rigs is reviewed， the characteristics of lightweight core drill and their advantages in meeting green exploration requirements are elaborated， and the development direction of fully hydraulic core drill is put forward， which is intelligence， efficiency and greening.