Abstract:In order to accurately find out the geological conditions along the tunnel， horizontal wireline core drilling technology is usually used； however， it is difficult to run drilling tools and fishing tools in ultra-deep water gushing horizontal holes in wireline core drilling. Research was carried out to solve the problem from several aspects， including developing special horizontal drilling rig， selecting the high-power mud pump， sealing off and diverting water gushing， designing the wireline feeder for the wireline drilling tool， custom-making special inner-flush horizontal drilling wireline coring drill rods. The influence factors such as mud pump pressure， drill rod inner diameter size， drilling depth， drill rod water-tightness， drilling water gushing volume， water gushing pressure， borehole annulus， on the speed of running the drilling tools and lifting the fishing gear are comprehensively analyzed. With careful organization， a horizontal hole with large gushing water at the 1000m depth level was successfully completed with wireline core drilling， and with high efficiency and low cost. It also accurately identified the engineering geological conditions along the tunnel， achieving satisfactory technical results. It can provide safety guarantee for tunnel design and construction， and also provide valuable experience for drilling horizontal holes with ultra-deep water gushing.

Abstract:In the process of harmless treatment of waste geological drilling fluid， the waste solid after solid-liquid separation contains a large amount of ground rock powder and fine sand with high water content， as well as a large number of harmful substances such as organic matter， heavy metal ions. In view of the problems with solidification of the waste solid phase in geological drilling， cement was selected as the main agent from three main curing agents： P.O42.5 ordinary portland cement， fly ash and lime； then the basic formula of the curing agent was determined by orthogonal experiment as 25% P.O42.5 ordinary portland cement + 2% PF-3 accelerator +3% RES-1 composite early strength agent， and verified by range analysis. The adding amount of the proppant was also determined at 7%， which can effectively increase the curing strength without increasing mixing difficulty. The curing agent formula was field tested at YK11-2 well for waste drilling fluid treatment with the compressive strength of solidified body up to 1.41MPa， and the pollution index and heavy metal ions meeting the national secondary discharge standard， achieving good treatment effect.

Abstract:The 3000m deep scientific borehole for the Tibet polymetallic deposit is the first 3000m deep scientific borehole in the field of the investigation of solid mineral resources in the Qinghai-Tibet Plateau， and it has created the latest hole depth record in the field of small-diameter solid mineral exploration in the Qinghai-Tibet Plateau. The project is located in the high mountain and deep cut area at 5200m above the sea level in Jiama， Tibet， with harsh natural climate， strict environmental protection requirements for the drilling project， high temperature in the deep strata， and complicated strata characterized mainly by strong water sensitivity， serious breakage and high in-situ stress which leads to extremely drilling difficulty. In view of the environmental protection and the stratum problem， through the experimental comparison of clay， the environmental protection fluid loss reducer， the environmental protection tackifier， the environmental protection inhibitor and so on， the treatment agents with the best performance were optimized； by using the method of range analysis of orthogonal experiment， the influence of each index corresponding to the level and the value of the optimum level were obtained， the range of the optimum formula of drilling fluid was determined； and a high temperature resistant and environment-friendly drilling fluid system has been successfully developed with good field application effects.

Abstract:In reference to geothermal wells in water-sensitive strata in Xuchang city， Henan province， and based on the analysis of the composition， hydration mechanism and drilling mud performance requirements of water-sensitive strata， drilling mud with small filtration， low density， good rheological property and strong inhibition was specified for the water sensitive formation. Based on the literature and field experience， the components and their concentration for mud preparation were preliminarily selected， mud performance was determined by laboratory test， and component concentration was optimized by orthogonal test range analysis with the final mud make-up optimized. With field verification and adjustment， the mud formula suitable for field use was finally determined. field test has proven that it met the drilling requirements of water sensitive strata with good effect.

Abstract:The formation in the south area of Baijian Iron Mine in Xingtai is broken， containing breccia locally， and with poor cementation and serious leakage； thus， leading to some drilling problems， such as sticking due to falling stones， borehole contraction， collapse， drilling string burial， full circulation loss. By optimizing the drilling structure， using new processes and methods， properly selecting drilling parameters， using wireline core drilling plus pre-set technical casing， collapse of the upper coal measure strata was effectively eliminated. The use of reverse-thread casing greatly reduced the risks in placement of casing and pulling out of casing caused by borehole shrinkage and falling stones. The adoption of conventional wireline coring drill rods instead of casing improved the drilling speed in breccia and loose formation， reduced drilling abandonment， and sped up drilling progress. Notably， the use of the high matrix double nozzle bit improved drilling efficiency， and saved drilling construction cost， allowing the project to be completed on schedule.

Abstract:Sealed coring is a special kind of coring operation. Through the cooperation of the sealed coring tool and the sealed coring bit， the core and drilling fluid can be isolated under the action of sealed fluid， and in-situ oil saturation and oil-water dynamic data can be obtained. The sealed coring bit is designed as a double channel structure， which can meet the requirements of drilling fluid flushing， cooling the bit lip and carrying cuttings. At the same time， the sealed fluid can form an enrichment area at the bottom hole to effectively protect the core from drilling fluid pollution. The channel parameters of the sealed coring bit are the key to the design of the sealed coring bit. Based on the theory of computational fluid dynamics， the k-epsilon turbulence model and continuity equation are used to simulate the two-phase flow field in the bottom hole of KM type sealed coring tool with the sealed coring impregnated diamond bit. The mixed flow state， fluid pressure， flow velocity and shear stress distribution characteristics of the bit lip are studied. The influence of flow characteristics on sealing effect， drilling efficiency and service life of the bit is analyzed， the design parameters of the channel structure of the sealed coring impregnated block diamond bit are verified， and the optimization design suggestions are put forward for the two-phase flow channel of the bit.

Abstract:The Fuyu and Gaotaizi tight oil reservoirs have the characteristic of low porosity with permeability less than 0.01mD， and poor reservoir property. As a result， conventional well completion cannot achieve the effective development， which can only be made possible by volume stimulation. In the past， this kind of reservoir was treated by SRV fracturing with the long horizontal section（1600m） plus the bridge plug， but it was not well targeted and the fracturing operation was inefficiency. In view of the properties of both reservoirs and the problems in fracturing technology， research was conducted on the new intensive cut coiled tubing fracturing technique with the maximization of the crack controlled reserve as the target and the coiled tube carrying the Y211 bottom hole assembly， and separate fracturing of each cluster. Application in four wells in Block 173-86 resulted in effective SRV， and improvement of the fracturing effect with significantly increased output. The well of Q196-P2 has been fractured up to 118 sections， setting a record in the cut section per single well in China. All the wells are producing by natural flows after fracturing measures， indicating obvious effect.

Abstract:To effectively solve the southern Songliao Basin oil and gas reservoir core bit selection difficulties， low rate of penetration and unstable core recovery， the core barrel and the core lifter were compared and matched， the core bit type was selected and the case-dependent core bit was investigated through the analysis of the geological characteristics of the coring interval， the XRD element component proportion， and the formation drillability. The coring assembly and coring parameters were optimized， and the coring process for different reservoirs was improved. The selected coring tool and the new coring bit were used in multiple wells with the average core recovery more than 98.98%， and the highest mechanical drilling speed up to 6.03m/h. The application of the optimized series of coring bits and the complete key technologies has solved the technical difficulties in coring in the southern Songliao Basin reservoir， which can provide reliable reference and technical support for subsequent coring.

Abstract:In order to achieve carbon peak before 2030 and carbon neutrality before 2060， the energy industry of China has proceeded to a new stage of carbon reduction and energy saving from clean and efficient energy development. As a clean， zero-carbon energy source， geothermal energy is facing unprecedented development opportunities. For the scientific， efficient， and high-quality utilization and development of geothermal energy， it is necessary to develop high-efficiency insulation steel pipes for geothermal wells. An insulation pipe has been developed with the thermal conductivity less than 0.02， and the high anti-collapse， high anti-burst， and connection strength up to the design requirements of medium and deep geothermal wells. The product is of independent intellectual property rights， and can be made locally with cost reduction by more than 30%， and excellent economic benefits.

Abstract:Over more than 20 years of development， the well intersection method has been widely used in solution mining， such as salt extraction， soda extraction； however， in the production process of brine extraction well sets， well clogging often occurs due to various causes. Four pairs of brine well sets in Ningjin salt field have been blocked for many times since they were put into production. In view of the frequent blockage， in reference to various accidents encountered in the drilling and workover processes and the relevant data from brine extraction， and with careful analysis and summary， the causes of well clogging and the preventive measures for Ningjinshi salt field are expounded in terms of squeeze-breaking of casing due to salt bed creeping， sedimentation of insolubles and salt crystallization， so as to provide guidance and suggestions for well workover and new brine well construction in the future.

Abstract:In view of the complex downhole conditions of YR1 geothermal well， such as large amount of fault type circulation loss， high water head of the fault water， an openhole interval in the upper part， and taking into account of the application conditions and limitations of the existing plugging technology for malignant circulation loss， it was decided to adopt casing to seal off the fault with analysis of the nature of circulation loss and the borehole environment. The method successfully solved the fault type circulation loss plugging difficulty. In addition， the staged cementing process was adopted to prevent upward channeling and downward seepage of the fault water to ensure the quality of well completion， providing a good reference for dealing with fault or cave type circulation loss in the future. Field practice shows that the casing plugging measure introduced in this paper has the advantages of short operation time， low cost and good effect. The method has facilitated the development and utilization of geothermal resources， and helped to build the “Yuncheng Model”. It has contributed to the local economic and social development and is of great significance to help to campaign against pollution.

Abstract:High voltage electric pulse rock drilling is recognized internationally as a rock breaking method with broad development prospect in deep hole drilling， but research has rarely been done on it in China. This paper describes the design and manufacture of a high voltage electric pulse rock breaking test device， including servo electric cylinder， control cabinet， rock container and other components. The test device is equipped with electric pulse drill bits with diameters of 60mm and 100mm. Manual or automatic downpressure discharge can be used to break rock. At discharge voltage of 120kV and discharge frequency of 1Hz， drilling experiment was carried out in red sandstone and other rocks， and drilling was realized at 60mm diameter. The experimental results show that the device can meet the requirements of electric pulse rock breaking test， and can be used for laboratory research on electric pulse rock breaking.

Abstract:Vibration during drilling can cause fatigue failure and damage to the drilling tool. In order to improve the stability of downhole drilling tool， the author designed a drilling tool structure that relies on the planetary gear system to drive contra rotation of two coaxial bits. The strength verification of its core parts such as gears， seals， bearings， proved that the design strength of the structure can meet the normal working conditions. The vibration effect of the structure has been verified by numerical simulation， where the interaction between the drill bit and rock was simplified as harmonic load to perform harmonic response analysis to solve the vibration of the structure. Compared with the conventional drill structure， the result shows the coaxial contra-rotary drilling tool structure can effectively suppress twisting vibration under the same condition.

Abstract:This article introduces the application of the portable full hydraulic drill in solid mineral geological drilling in the Qinling region， briefly describes the basic data and the drilling process of EP600 series drills， and analyzes the relationship between rock drillability and drilling efficiency with respect to 11 holes in different work areas. In view of drilling efficiency， power loss， drilling capability and the like of the drilling rig， good test results have been initially achieved by the proper selection （improvement） of the drill bit， the reduction of internal friction resistance within the drill string passage， and the adoption of light high-strength drill pipes and other effective measures or suggestions. The applicable conditions and advantages of the portable full hydraulic drill are presented， including high drilling efficiency in shallow holes （hole depth less than 350m） in rock with drillability level Ⅶ， convenient movement， fast assembly， less environmental damage in complex terrain environments， and it meets the requirements of the ecological environment protection policy and green exploration work with the overall economic drilling cost significantly reduced. For the unresolved problems， proper work suggestions are given， which provide positive guidance and reference for further exploiting the performance of the portable full hydraulic drill.

Abstract:The open-cut section of a river-crossing tunnel in Nangjing is a super deep foundation pit with think and high water permeability sand layer， where the aquifer is massively thick with large permeability coefficient， and recharged by the Yangtze River. The hanging type water cut-off curtain was used for the foundation pit due to very large water inflow. During the construction of the dewatering well， it was found that the original dewatering scheme cannot meet the requirements for dewatering through well developemt with high deviation. In order to ensure the safety and smooth construction of the foundation pit， in-situ pumping test was carried out while drilling the dewatering well. Through analysis of the test data， and parameter inversion and dewatering simulation using the three-dimensional numerical method， adjustment was made in time on the diameter， number and pump configuration of the dewatering wells in the JD1 and JD2 sections with large excavation depth . The inverted parameters of the pumping test for the foundation pit were much larger than those of the original scheme. The actual water inflow of the foundation pit was as high as 91000 m³/d， which was 2.2 times of the estimated value of 42000 m³/d of the original dewatering scheme. With the timely and proper adjustment of the dewatering scheme， the water level in the pit was reduced below the base with little increase in the total number of wells， which ensured the smooth implementation of the foundation pit， fully demonstrating the importance of dynamic adjustment of pumping test and the pumping test scheme in dewatering.

Abstract:When vehicle dynamic load is around the foundation pit， it is classified as the general hazard source by the current industry safety standard. The partial collapse of a foundation pit in Hangzhou led to the collapse of the adjacent road， and investigation found that the vehicle dynamic load was the cause of the accident. In reference to the accident， this paper discusses the influence law of vehicle dynamic load on the foundation pit enclosure structure through analysis of the cause and comparison with the current standard code. It is proposed to raise vehicle dynamic load as a major hazard source， and solve the problems from the aspects of cross-industry research， increasing the external load limit of the foundation pit， improving foundation pit monitoring and on-site control. At the same time， it is suggested to take vehicle dynamic load as the research subject to find out the mechanical model， summarize the influence law， give targeted measures， and add them to the current standard and specification.

Abstract:According to the characteristics of deep and thick soft soil ground and the requirements of ground treatment， combined with the comprehensive treatment technology advantages of the four foundation treatment methods of gravel cushion， light well point precipitation， dynamic compaction， and vibration-replacement stone column， experimental research on comprehensive foundation treatment technology was conducted. The treatment process index such as groundwater， pore water pressure were carefully monitored， and the foundation bearing capacity before and after treatment was compared and analyzed. The results show that the comprehensive ground treatment method can make up for the shortcomings of a single ground treatment method， and can effectively improve the bearing capacity of ground. The article can provide a reference for subsequent construction of similar ground treatment projects.

Abstract:This article introduces the design and construction process of demolishing the reinforced concrete elevator test tower with directional controlled blasting technology in complex environment， analyzes and summarizes the blasting results. In view of the characteristics of the shear wall structure of the elevator shaft， pre-demolition of the non-load-bearing shear wall， the column beam and part of the load-bearing shear wall was carried out to determine the proper blasting height， the cut form and the tilting angle； a proper half-second delay time was adopted to increase the structure material action time to ensure that the elevator test tower lose stability and collapsed as designed. The safety protection design was checked， and the surrounding environment and facilities were not affected after blasting， and the expected blasting demolition effect was achieved.