Abstract:China officially implemented the Antarctic deep ice core scientific drilling project within the Dome A area in January 2012， and the drilling depth has reached 803.54m by 2021. It is the first deep ice core drilling project initiated by China， and also the first one of the world in the Dome A area. This paper introduces the implementation process of the deep ice core scientific drilling project at Kunlun Station， and summarizes the drilling activities and experience gained in the past 10 years， so as to provide theoretical and empirical guidance for subsequent drilling.

Abstract:Polar drilling is the most direct method to obtain samples of the polar ice layer or subglacial environment and install scientific observation instruments in ice layer or subglacial environment， and it is a necessary technical method to carry out polar scientific research. The United States is one of the earliest countries that started polar drilling and is also a powerful country in polar drilling technology. Compared with the United States， China’s polar drilling technology is still in its infancy. Based on the Ice Drilling Program long term science plan of America for 2021-2031， and with reference to its official website and related literatures， this article sorts out the scientific goals of polar drilling and the current state of polar drilling technology of the United States， and briefly introduces the polar fieldwork in the past ten years and upcoming fieldwork in the next three years， which are expected to provide some reference for the development of China’s polar drilling.

Abstract:Small-size artificial ice samples are widely used for ice mechanical properties research， and have the advantages of simple preparation procedures， short duration， low cost， and no seasonal and geographic restrictions. In this paper， the snow pressure sintering experiment was carried out under the conditions of -3.5~-17.3℃ and 10~100MPa， and small-size artificial ice samples were prepared by the pressure sintering method. The results reveal the influence of sintering stress and sintering time on the density evolution during the snow pressure sintering process and the final sintered density of the ice sample. It is concluded that with the pressure sintering method， artificial ice samples with a density of 0.917g/cm³ can be prepared under either of the conditions： a long time， low stress， and near melting point temperature， or a short time， high stress， and low temperature. The experimental results have verified the reliability and repeatability of artificial ice sample preparation with the pressure sintering method and provide a practical and feasible small-size artificial ice sample preparation technique for the experiment of ice mechanical properties.

Abstract:Since 1970， the former Soviet Union and Russia have been drilling for nearly 50 years at Vostok Station in Antarctica. It has overcome the drilling problems with complex ice layers including snow layer， ice layer， debris ice， refrozen lake ice； formed a set of deep ice core drilling technology integrating thermal core drilling， electro-mechanical core drilling and offset hole drilling； and created the dry hole drilling depth record （952.4m）， the thermal drilling depth record （2755m） and the ice core drilling depth record （3769.3m）. The cumulative drilling footage was over 13000m， and the refrozen lake ice core with a total length of more than 46m were obtained. The drilling activities at Vostok Station have played a great role in promoting and leading the development of polar ice drilling technology， and accumulated valuable deep ice core drilling experience. This paper conducts a systematic review of deep ice drilling technology at Vostok Station to provide important reference for China’s ongoing deep ice core drilling and the upcoming subglacial lake exploration.

Abstract:The drilling geological environment of Kozasay Oilfield in Kazakhstan is complicated， where the reservoir is located under the salt， multiple formation groups are to be drilled and the stratigraphic properties vary greatly， and there are multiple pressure systems. As a result， complex conditions such as formation leakage， collapse， block loss， creeping of the salt paste layer occurred during the drilling process， which seriously affected drilling efficiency and drilling safety. In response to the above technical problems， analysis and optimization have been carried out on well structure， well quality， speed-up potential， and high-efficiency drill bits with presentation of the pre-bent drill tool high-dip formation well deviation control technology， hybrid bit vibration reduction and speed-up technology， and PDC-impregnated block hybrid drill bit high abrasive formation speed-up technology. The field application has achieved good results with average ROP increased by more than 50%， and the drilling duration shortened by 28%.

Abstract:The complexity of marine broken formation in western Sichuan limits the oil and gas development progress in the western Sichuan， and there is no relevant discussion or research on well collapse in the marine broken formation mainly composed of limestone and dolomite； therefore， it is very necessary to carry out research on the anti-collapse drilling fluid system for the marine broken formation in the Leikoupo formation in western Sichuan. Based on the study of the characteristics of the Leikoupo marine formation in western Sichuan，the film forming agent is added to the existing formula of the temperature-resistant and anti-collapse drilling fluid system to form the anti-collapse drilling fluid system technology for the marine broken formation in western Sichuan. The performance of the system is evaluated with good results obtained in field application.

Abstract:The Shiqianfeng， Shihezi and Shanxi formations in the Yan’an eastern gas field are hard and brittle， with well-developed fractures and high mudstone content. Well collapse and lost circulation often occur during drilling， which greatly increases drilling costs. By analyzing the characteristics of the Upper Paleozoic strata in this area， the mechanism of borehole failure， and the characteristics of the reservoir， a research on a film-forming drilling fluid system with strong inhibition and strong sealing was carried out. With the selection of fluid reducer RHPT-1 and film-forming agent CMJ-2， the formula of film-forming drilling fluid was determined and the system performance evaluation was completed. The results showed that the extreme pressure lubrication coefficient of the system was 0.0659， the cuttings rolling recovery rate was 95.94%， and the 16h linear expansion rate was 8.18%， showing good lubricity and inhibition. It can provide 3% resistance to clay pollution，7% salt resistance， and calcium resistance 2% with stable performance in 100℃ hot rolling drilling fluid， indicating good anti-pollution and thermal stability. It was successfully applied in three horizontal wells， effectively solving well failure in the upper Paleozoic strata in the Yan’an eastern gas field.

Abstract:Coal is still the world’s major source of energy. Geological exploration for coal resources will ultimately go to the deeper earth， and wire-line coring drilling technology has always been the first option for deep exploration due to its high quality and efficiency in deep drilling. Currently， wire-line core drilling technology has not been fully used in the coalfield because of some technical problems with coalfield strata. However， measures can be taken to solve them. Water sensitivity is a common phenomenon in the coalfield’s geological exploration， leading to high sand and mud content in drilling mud and deteriorating performance of drilling mud. There are also problems associated with “water sensitive” and “sand damage” in coalfield wire-line core drilling， such as high pump pressure， high mud flow rate， severe erosion， serious negative effect from flushing fluid dynamics. The low strength and poor capacity of non-coal geological exploration standard drilling tools （drilling stems） cannot cope with the above adverse effects. Therefore， it is necessary to optimize the makeup of drilling mud for water-sensitive formation； more importantly， removal of sand and mud should be solved. In addition， it is necessary to break conventional thought and build a new system， such as enlarging the diameter of the drilling hole， increasing the clearance between the matching bit sizes， improving the power of the equipment so as to overcome the problems with high power.

Abstract:Air reverse circulation sampling drilling technology has not been widely used in mineral exploration for a long time due to the low recognition of rock samples by domestic geologists. In view of the test of air reverse circulation drilling technology in Beiya Gold Mine， Heqing， Yunnan Province， this paper puts forward some findings through comparative analysis of the geological effect in mineral exploration. This paper defines the purpose and contents of the demonstration application test of air reverse circulation sampling technology and conventional core drilling technology； introduces the basis for test hole selection； and compares and analyzes the geological effect of the RC sampling method and the conventional core drilling method in gold exploration from seven aspects： rock sample collection and sampling method， rock sample recovery， missing of strata and ore beds， lithology and primary structure of the sampled strata， accuracy of rock occurrence calculation， core pollution degree， and accuracy of ore grade calculation. The study reveals that the RC sampling method has high efficiency and low cost； and it is superior to conventional core drilling in terms of rock sample representativeness， core pollution and ore grade. Finally， some problems in the application of RC technology in mineral exploration are further pointed out， and the relevant suggestions are put forward.

Abstract:In 2020， 50 boreholes were drilled for limestone exploration in the Yandong Mountain area of Zhongning county by Geology and Mineral Exploration Academy of Ningxia. With presence of well developed fractures in limestone strata in this mining area， serious circulation loss problems were common， and total circulation loss was encountered in most of the boreholes， which resulted in two bit burning accidents in the early stage of drilling and increased drilling cost. In order to complete drilling tasks and save drilling cost， a blind drilling process was explored through addressing the borehole structure， bit selection， drilling parameters and pump rate optimization， where fresh water was used for drilling fluid with strict control of various drilling parameters. As a result， all drilling tasks were successfully completed with average rig-month efficiency of 883m， and average core recovery of 98%. The process has effectively improved drilling efficiency， and reduced drilling cost， providing strong resource support for local development.

Abstract:With the support of a underground diamond drilling project by Guizhou Jinfeng Mining Co.， Ltd.， a series of technical problems encountered in underground drilling， such as equipment selection， inner pipe transportation， hole deviation control， hole cementation， etc. were addressed through adjustment of drilling processes and parameters， leading to good drilling results. Summarization and discussion are conducted on underground drilling technology suitable for Zhenfeng Lannigou gold mine so as to provide reference for underground drilling under similar formation conditions.

Abstract:High strength prestressed concrete pipe piles （PHC） have been widely used in the construction of high-rise buildings in heavy-haze shrouded northern China due to its features of pre-visible quality， high-strength， environmental protection， efficient and flexible construction. In reference to a field case of pipe pile construction for a high-rise residential building in Henan province， this paper introduces the problem of insufficient bearing capacity caused by construction， stratum and other factors in the process of pipe pile construction； underwater photography technology used to accurately determine the problem while the conventional detection methods such as low strain cannot accurately determine the causes； and the treatment process of re-pressing， high-strength grouting and other methods. It provides can some reference for the treatment of similar projects.

Abstract:The proper composition of offshore wind power exploration equipment is very important to offshore wind power geological drilling， whilst the proper composition of an offshore wind power exploration platform with complete functions is the most important. In order to improve offshore wind power exploration efficiency， safety， and accuracy at water depth more than 35 m， with the platform operation and exploration function design as the fundament， functional design research was conducted on offshore wind exploration jack-up platform equipment in terms of the main technical specifications， lift platform control system design， site geotechnical laboratory. A jack-up exploration platform with double-hole exploration capability has been developed， and achieved good field results with greatly improved efficiency and safety since it was put into operation for two years. It meets the research and development objectives， and provides powerful equipment support for offshore wind power exploration.

Abstract:Bozhong 34-9 Oilfield located in Bozhong 34 Embanked Zone is the first large-scale oil field in the offshore igneous rock developed region of China. The target reserviors of Bozhong 34-9 Oilfield are Dongsan Part and Shahejie Formation. In order to strengthen reservoir protection and increase oil and gas production， this paper analyzes the reservoir lithology， porosity and permeability characteristics and fluid characteristics， and evaluates the cores from the reservoir in terms of velocity sensitivity， water sensitivity， salt sensitivity， alkali sensitivity and acid sensitivity. It is intended to evaluate reservoir damage factors intuitively and quantitatively， and put forward proper suggestions to prevent and reduce reservoir damage， which is of great practical significance to reservoir protection for the Bozhong block.

Abstract:Groundwater circulating well technology （GCW） is an in-situ remediation technology that repairs groundwater by creating a three-dimensional circulation for groundwater. This paper describes the development of the technology at home and abroad. It introduces the characteristics， advantages and applicable conditions of UVB， NOVOCs? and DDC as well as their field applications. In view of the problems with groundwater circulation well technology such as limited repair range， long repair time， strict site requirements， unbalanced pumping and injection， it is proposed to improve the technology in terms of large-scale hydraulic control， in-situ biological repair， multi-phase synchronized repair， and integrated intelligent equipment， etc.