Abstract:Offshore gas hydrates is hosting in the environmental condition of low temperature and high pressure. Drilling in hydrate formation with decomposing inhibition technology, drilling fluid temperature is often lowered to inhibit hydrate dissociation, so low temperature performance of drilling fluid is important. Study was made on the rheology property of formate seawater drilling fluid and polymeric alcohol seawater drilling fluid at different low temperatures; the result showed there was certain degree influence on low temperature rheology property of drilling fluid by both drilling fluid additive and hydrate inhibitor. Reasonable selection on drilling fluid system and additive should be taken into account in the study on drilling fluid for offshore gas hydrate drilling to ensure its good rheology at low temperature.

Abstract:Lost circulation of borehole is one of the complex problems in coal bed drilling process and cement slurry sealing is the most commonly used method on site. However, lost circulation of cement slurry often happens in fissured, cave or high permeability formations. The paper introduced special fiber into the conventional cement slurry systems and made research on its sealing performance, rheopecticity, fluidity and mechanical property of cement stone by laboratory experiments. The paper also analyzed the sealing mechanism of fiber cement slurry and the applications of which were introduced in the drilling and cementing processes. The research results demonstrate that fiber cement slurry has good sealing effect in above-mentioned formations and it has a promising future in coal bed drilling fields.

Abstract:According to the difficulties in well completion in quaternary overburden and silt & fine sand layers, and by the development of gravelfilled filter, the paper tested and discussed the correlation between thickness of filter material and sand-resistance, minimum theoretical thickness value of sand-resistance with different specifications of filter materials was preliminary obtained.

Abstract:As a special drilling fluid, the foam will be affected by temperature in quality, density, stability as well as the flow state in the annular space. Aiming at this problem, the paper studied the foaming ability and stability influenced by temperature based on experiment results. It was found that: the foaming ability of the base fluid had been greatly influenced by foaming formulations and temperature, in a certain limit, the stability of the foam will be increased with the temperature rising, but too high temperature will play reaction to the stability of the foam.

Abstract:In order to cooperate with the further study on stability against sliding in dam foundation of Wudu reservoir, and ascertain the characteristics of the weak structural plane such as fault fracture zone, inter-laminar dislocation band and low-angle fracture, diamond drilling technology was adopted by fitting with SDB double stage and single action diamond drilling tool with two-halves barrel. Coring recovery rate was 100%, the undisturbed rock samples provided reliable basis to the study on stability against sliding.

Abstract:Stratified pumping is necessary for water quality monitoring in different aquifers. A new stratified pumping set was developed with technical improvement; the paper introduced its structural principle in detail.

Abstract:A comprehensive analysis was made on the cause of drilling tool sticking in Kunming Basin geothermal well construction， a set of processing method was excogitated for such incidents to effectively solve drilling technical problems in geothermal well construction in this region.

Abstract:The paper introduced the Baoli ZK3 geothermal well construction with air-lift reverse circulation technology, analyzed the application effect and put forward the improvement suggestion. The conclusion is that air-lift reverse circulation technology has the advantages of high efficiency, clean borehole, high safety, lower construction cost and good drilling quality.

Abstract:According to the practical construction situation in supplementary exploration for coalbed methane in Baiyangling coalmine of Xiyang County in Shanxi Province, the paper briefly discussed the application of wire-ling coring technology in parameter well for coalbed methane with selection methods on sleeve, drilling tool, bit, drilling mud and drilling parameters.

Abstract:In geological drilling of coalfield, the borehole condition is revealed by unsealing the grouted horehole, but because of the long interval between construction and unsealing, sometimes deflection will occur. The paper analyzed the main cause of the deflection with prevention measures put forward, summarized the treatment on borehole unsealing deflection with successful field cases.

Abstract:According to the technical problems in positive circulation construction, a new derived system of reverse circulation DTH was developed, which has been applied in the construction of water well and alluvial exploration with remarkable effect. This new product made DTH more perfect and brought wider application field.

Abstract:Based on the drilling effects of φ75 mm wire-line coring drilling by CS14 fully hydraulic driving head drill in Kangbao copper mine and polymetallic ore in Mongolia, the paper made the analysis on the advantages and disadvantages compared with spindle drilling machine and put forward the opinion that driving head drill was the trend in developing geological coring drill in China.

Abstract:Currently ultimate pile-side friction is determined on the basis of experience and assisted by data analysis on the testing pile， in this case， the result obtained often has some errors. Analysis was made on playing mode of pileside friction by the static load test and the stress test， and corresponding correction factors for pile-side friction calculation were put forward based on the engineering cases.

Abstract:Based on the interaction of pile and soil, this article explored the influence factors of the single pile settlement in pile-soil interaction, and tries to find a theory basis for the design on bearing capacity of pile foundation and settlement control. FEM software ADINA was used to establish the numerical model of pile-soil interaction, which was applied to solve the problem.

Abstract:This paper studies the deformation of deep excavation in mountainous area of Guizhou. The finite element method and large finite element method program ANSYS10.0 are used to simulate and analyze excavation and adjacent buildings interaction. In this model, the study issue has been presumed as plane strain. Seemly, the soil is seemed as ideal elastoplastic model, and four-node equal-parameter element is used abiding by Drucker-Prager yield criteria of soil. At the same time, contact element is set between pile and soil to simulate the interaction. What is more, this paper has analyzed the effect of bracing pile deformation by excavating with different distances between excavation and adjacent buildings, the different stiffness of bracing system and physical mechanics parameter variation of soil at the pile bottom.

Abstract:Based on “Pre-tensioned Pre-stressed Concrete Tubular Pile”（GB 13476-1999）and “Design Structure Standard Alta”（2002 Zhejiang G22）, the length-diameter ratio of frictional pre-stressed tube pile should less than 100, and the length-diameter ratio of end bearing pile or frictional end bearing pile should less than 80 while getting through a certain thickness in hard soil. The paper introduced an engineering case of super-long pre-stressed tubular pile in silty and sandy soil with the longest design pile length of 60m,diameter of 550mm and 600mm, connected by 4 piles of 15m, the length-diameter ratio was more than 100. Beneficial exploration was made on construction of super-long pre-stressed tube pile in sand and silt layer based on this case in Hangzhou City.

Abstract:The foundation of Nanyafengqing Garden was designed of static pressure pre-cast tube pipe; pile floating was detected after construction. Through the cause analysis, repressing treatment scheme was applied with parameters satisfying the design requirement.

Abstract:Two kinds of disassembly and recycling bars were introduced, they were used with lower cost but good effect, and the workload for pile-top removal was reduced with accurate location of steel reinforcement cage and less damage to pile body.

Abstract:With the engineering case of 35kV Xinluodian substation of Shanghai, the paper introduced root pile about its application range, working mechanism, construction technology and matters needing attention; summed up the advantages of foundation reinforcement with root pile technology. It proved that the technology has high practical value in foundation reinforcement and underpinning and is worth to be popularized.

Abstract:Protection measures are very important in foundation pit support around municipal pipeline. Design demonstration and comparative analysis were made to determine the secure supporting structure system, control the construction parameters, ensure the soil stability, and make the excavating order. Technology of late-dismantlement for lateral support was adopted to ensure the safety of water supply pipeline.

Abstract:A pile foundation engineering case for super-large overpass bridge was illustrated; reinforcement was applied to local defects of pile foundation. The paper introduced the technology of composite grouting to reinforce the defect pile and the application effect.

Abstract:Anchor-cable lattice beam is introduced on its design, construction and application effect in treatment of rock landslide by field case.

Abstract:There is serious bias pressure in right line exist of Taoshuling tunnel. The paper introduced the tunneling measure compared to the original design scheme and demonstrated the feasibility of the former with the model provided to bias pressure tunneling.

Abstract:According to the well construction operation, the paper analyzed the well construction project based on the risk control, and put forward the control measures to improve the quality of well construction operation.

Abstract:According to the well construction operation, the paper analyzed the well construction project based on the risk control, and put forward the control measures to improve the quality of well construction operation.