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Abstract:The warm ice at the bottom of polar ice sheet has small brittleness, high viscoelasticity, high temperature and pressure, and poor drillability. The cutting heat generated during rotary drilling can easily cause the ice chips to be in melting or semi-melting state; as a result, the ice chips will gather together and even freeze again locally over the drilling tool, resulting in frequent accidents in the hole. In order to understand the temperature change law of cutting tools during ice rotary drilling, theoretical study is conducted on the mechanical characteristics and heat transfer law of cutting tools, and then the theoretical model for cutting tool temperature calculation under drilling fluid circulation is established. The result shows that rotation speed of the drilling bit, cutting depth, friction coefficient, cutting edge angle and ice shearing strength et al. are all have important impact on cutting temperature. Although the low-temperature drilling fluid has good cooling and cooling performance, it can still make the cutting tool temperature rise by 2 to 5℃, adversely affecting warm ice drilling. In-depth optimization should also be made for the combination of drilling parameter.

Abstract:Geological drilling engineering is a complicated system engineering and design of diamond bits is a complicated system. Russian Doctor of technical sciences and Professor Skoromnyh V.V. and others have designed surface set diamond drill bits using the system theory approach, where the mechanical penetration rate is taken as the objective function with the cutting depth of the drill bit as a cut-in point to build the mathematical model, and develop the program to perform computer modeling. The modeling results allow the working situation of the diamonds in the bottom hole and rock fragmentation process to be seen more directly, which have some practical significance for in-depth research on the mechanism of rock fragmentation process and assessment of the rationality of the diamond bit design, and their influence on the technical and economical index of drilling.

Abstract:In geothermal well drilling, borehole temperatures increase with depths, making drilling more difficult. Therefore, it is necessary to study the circulation temperature distribution in the well. With analysis of the heat conduction process during drilling fluid circulation, and in view of various thermal well parameters in Xiongan New Area, the wellbore temperature control equation is adopted, and the fully implicit finite difference method is used to solve the equation to find the temperature distribution over each well section during drilling fluid circulation in the well. The influence of the drilling fluid density, viscosity and displacement on the wellbore temperature distribution is studied by equation simulation. Results show that the higher the drilling fluid displacement, density or viscosity is, the lower the wall temperature is; and the more the wellbore wall temperature near the bottom decreases. The displacement change of drilling fluid has the greatest influence on the borehole wall temperature distribution. The results of the simulation study provide some reference for the drilling design.

Abstract:CGSD-01 well is a deep hydrothermal geothermal resource survey well in Tianjin. For complex situations such as downhole circulation loss, active aquifers, selective cementing and long-term high temperature resistance, a set of cementing technology was developed for the well with use of the high-temperature-resistant anti-channeling cement slurry system, the olive-shaped cement basket, cement slurry injection through the liner on top of the screen pipe, and combination of direct injection and top reverse squeeze. Field application indicated there was no leakage and water channeling during the cementing process, and the cementation of the isolation layer was reliable, providing a demonstration for other deep geothermal wells in the area.

Abstract:The LS01 hole for comprehensive geological survey of Lingwu and Ciyaobao has a designed depth of 800.00m. During the drilling process, more than 200 meters of Quaternary unconsolidated loose strata was encountered, mainly gravel (boulder)-coarse sand-medium sand-fine sand were interbeded. It was difficult to drill and protect the borehole wall, and prone to have blockage and collapse incidents which made difficult coring. When entering the Tertiary system, the purple mudstone of Qingshuiying formation was met, and the stratum was slippery and produced mud; when entering the Cretaceous Yijun gravel formation, drilling encountered 365.91m broken conglomerate, loose and broken, prone to leading to sticking, high rotatory resistance, less footage per run, and slow advance. In reference to similar borehole drilling data and formation conditions, the film-forming wall-protecting drilling fluid was finally adopted. During the drilling process, the film-forming wall flushing fluid played a good role in drilling through multi-layers of complex strata and provided good wall protection over the broken conglomerate hole section without falling stones and hole collapse accidents. The overall core recovery rate reached 95.89%, meeting the requirements of geological design, which saved casing material. The final hole depth was 800.00 meters, and the final hole diameter was 124.00mm.

Abstract:In order to solve the problem that common Portland cement (P. O42.5) or concrete can not cure smoothly in low temperature environment, the basic performance test of Portland cement is carried out, and the curing accelerator and the superplasticizer are used to adjust the performance of cement to find out the proper adjustment plan. The strength data of cement slurry and cement paste before and after adjustment are compared, and the results show that the adjustment make-up of 10% LC curing accelerator and 2‰ JSS super plasticizer can improve the fluidity, setting time, release rate of hydration heat, calculus rate and early strength of cement paste. The research results can provide some reference for concrete construction under low temperature conditions.

Abstract:During reconnaissance drilling for polymetallic deposit survey at Qinling Orogenic Belt, different complex strata were encountered, such as collapse, shrinkage, leakage and so on, which seriously affected drilling efficiency. The calcium treated vegetable gum drilling fluid and solid-free polyvinyl alcohol fluid were used for borehole protection, respectively. According to different leakage situations, technical measures such as plugging while drilling, gel plugging were implemented, and good results were achieved.

Abstract:In-situ leaching drilling is a kind of drilling for the mining purpose, where increase in the borehole water yield means increase in the borehole mining volume. Analysis of in-situ leaching drilling experience over many years and its theory found the main factors influencing the borehole water yield were the composition and properties of drilling mud, and permeability difference of artificial filtering layers. Therefore, three technical measures are proposed for in situ leaching drilling: vegetable gel for purification in mud drilling and reaming, gravel filling by jet suction with the gravel tank, well flushing by physical and chemical combination. Comparison of the water yield results before and after the technical measures proved that the technical measures have good effect on increasing the in-situ leaching water yield.

Abstract:The “Tanhai No.1” continental shelf scientific drilling platform is a self-elevating shallow sea geological drilling platform, with a hydraulic lifting system as its core part, which realizes the lifting and lowering of the platform by placing piles, inserting piles, and pulling piles. The system consists of four sets of independent hydraulic lifting devices. When working, each set of hydraulic lifting device is instructed by the operating console, the hydraulic drive system provides power, and the lifting barrel performs the action. The coordination of these three parts ensures the effect of performing the action. In this paper, the performance, structure, working principle, operation and other aspects of the hydraulic lifting system are described in detail. In view of the shortcomings found in practical application, the direction of optimization and improvement is put forward.

Abstract:The geophysical exploration and analysis shows that there is a deep fracture structure 1.0km to the southeast of Nanhaizi Village, Daqinggou Town, Shangyi County, Zhangjiakou, Hebei Province. In order to explore and develop geothermal resources in the Bashang area, it was decided to construct a 2000m deep geothermal well at this location, that is, to explore water conducting channels through the fracture structure and complete the geothermal well. The CMD180T drilling rig was used for drilling, on which the advanced full hydraulic transmission system is adopted, providing high degree of automation and excellent performance. It can greatly reduce the labor intensity of operators and is easy to move and operate. Its advantages have been fully reflected in this geothermal well drilling project.

Abstract:The circular diaphragm wall was adopted for the enclosure structure of the rolling machine room at the Shijiu port area of Rizhao Port. This paper expounds the difficulties on construction of the circular diaphragm wall at the port in the dredger fill formation environment, such as collapse of the thick sand layer, small inner diameter and large radian of the wall, the circular steel cage, trench deviation. Some treatment measures have been adopted, including ground reinforcement, setting up external expansion angle for the guide wall, improvement of the excavation method, fabrication of the special processing platform, deviation rectifying with multiple methods. Good results have been obtained, providing some references for similar projects.

Abstract:This paper introduces the design and implementation of the foundation pit support for the Wangjiaguanzhuang old village reconstruction project in Jimo District of Qingdao City. The project is characterized with complex stratum conditions, rich groundwater, and is close to Shipeng Reservoir with complicate environmental conditions. Through the successful implementation of technical measures such as the soil nailing wall and high pressure jet grouting pile water cut-off curtain, foundation pit dewatering, good foundation support has been achieved, ensuring the safety of foundation pit excavation and foundation construction in the underground garage; and the construction quality meets the relevant technical requirements.

Abstract:The anti-floating anchor bolt is an important technique to control groundwater buoyancy in construction works. The anti-floating anchor bolt project for the underground square foundation pit in north Xingyuhuafu in Qingdao was taken as the research object. The preliminary design was carried out based on the existing anti-floating anchor design theory, and the numerical simulation test was carried out using FLAC3D. The stress and deformation of the foundation pit floor under the combined action of structural loads, underground water buoyancy and anchor bolts were analyzed. The optimization scheme for anti-floating anchor bolts was obtained through trade off of the loading conditions and construction cost.

Abstract:In the construction of pile foundation at the Panzhou Station of the Shanghai-Kunming Railway, the rotary drill rig was used to dry-drill the holes, and dissolved caves were encountered in drilling of nearly 1/3 the foundation piles. Based on the analysis of different adverse situations, and according to the geological conditions of unfilled and semi-filled karst caves encountered, specific technical measures were adopted, including wall construction by backfilling soil and stone and compaction by reverse rotation, sinking boreholes section by section by squeezing plain concrete, protection of borehole walls and retaining of pile concrete with casing, leveling of uneven rock surface and re-drilling, point-backfilling and cementation; as a result, the pile foundation was successfully completed.

Abstract:Based on the background of water surge treatment for the right bank support body of a hydropower station in Yunnan Province, this paper introduces treatment of the special conditions of high-volume, high-pressure and high-flow water inrush encountered during deep hole curtain grouting with high-polymer composite water-blocking slurry (C-GT water-blocking slurry), which provides new material selection and treatment methods for the gushing water treatment in the karst area, and also reference for similar projects.