Climate change of the last millennium inferred from borehole temperatures: regional patterns of climatic changes in the Czech Republic — Part III

Accurate temperature–depth profiles may help to assess the temperature variations associated with the climate changes in the past. Ninety-eight ground surface temperature histories inverted from the temperature–depth borehole logs drilled on the territory of the Czech Republic [Bodri, L., ermák, V., 1995. Climate changes of the last millennium inferred from borehole temperatures: results from the Czech Republic — Part I. Global Planet. Change 11, pp. 111–125; Bodri, L., ermák, V., 1997. Climate changes of the last two millennia inferred from borehole temperatures: results from the Czech Republic — Part II. Global Planet. Change 14, pp. 163–173.] are used to reconstruct the regional patterns of the respective climate change. The climate was mapped for the following periods: 1100–1300 A.D. (Little Climatic Optimum), 1400–1500 A.D., 1600–1700 A.D. (main phase of the Little Ice Age), and for the most recent climate trend after year 1960. Comparison of the obtained maps with the meteorological observations and proxy climatic reconstructions confirmed good applicability of the “geothermal” paleoclimatic reconstructions for the regional studies.     

Determination of Porosity and Permeability out of Dispersion Analyses of Borehole Wall Displacements

Waves carried in the borehole can be measured by the use of controlled sources inside the borehole and receivers located in the same borehole as well. This article gives the theoretical background and develops a new method to determine rock-physical parameters out of such controlled measurements of waves carried inside the borehole. Theoretical dispersion curves of the group velocities are matched to dispersion analyses of registrations obtained in the borehole. This inversion process intends to determine the in situ porosity and permeability of the rock.     

A comparative study of geothermal and meteorological records of climate change in Kamchatka

To reconstruct the recent climate history in Kamchatka, a series of repeated precise temperature logs were performed in a number of boreholes located in a broad east-west strip (between 52 and 54°N) in the central part of Kamchatka west of Petropavlovsk-Kamchatski. Within three years more than 30 temperature logs were performed in 10 holes (one up to six logs per hole) to the depth of up to 400 metres. Measured temperature gradients varied in a broad interval 0 to 60 mK/m and in some holes a sizeable variation in the subsurface temperatures due to advective heat transport by underground water was observed. Measured data were compared with older temperature profiles obtained in the early eighties by Sugrobov and Yanovsky (1993). Even when older data are of poorer precision (accuracy of about 0.1 K), they presented valuable information of the subsurface temperature conditions existing 20–25 years ago. Borehole observations and the inverted ground surface temperature histories (GSTHs) used for the paleoclimate reconstruction were complemented with a detailed survey of meteorological data. Namely, the long-term surface air temperature (SAT) and precipitation records from Petropavlovsk station (in operation since 1890) were used together with similar data from a number of local subsidiary meteo-stations operating in Central Kamchatka since 1950. Regardless of extreme complexity of the local meteorological/climate conditions, diversity of borehole sites and calibration of measuring devices used during the whole campaign, the results of the climate reconstruction supported a general warming of about 1 K characteristic for the 20th century, which followed an inexpressive cooler period typical for the most of the 19th century. In the last three to four decades the warming rate has been locally increasing up to 0.02 K/year. It was also shown that the snow cover played a dominant role in the penetration of the climate “signal” to depth and could considerably smooth down the subsurface response to the changes occurred on the surface.     

煤矿1号大口径瓦斯抽排井施工实践

宣东二号矿布设施工的大口径瓦斯抽放井以小口径导向钻进,后逐级扩孔成井。总结了该孔施工过程中的主要技术经验,如导向孔粗径钻具组合、钻压控制、钻井液使用以及下管和固井等,提出了其中存在的问题以及下一步改进的建议。     

CL植物胶复合无固相冲洗液在复杂地层绳索取心钻进中的应用与研究

为满足复杂地层绳索取心钻探技术的需要,寻找、配制了既能代替泥浆具有良好的护壁堵漏性能,又能满足绳索取心钻进技术要求的CL植物胶复合无固相冲洗液。详细介绍了CL植物胶复合无固相冲洗液的配方和配制工艺、性能指标测试与评价、护壁机理认识及应用效果。     

温州世贸中心大厦超深大直径钻孔灌注桩施工技术

介绍了温州世贸中心大厦120m超深大直径钻孔灌注桩的施工技术，针对超深大直径钻孔灌注桩施工中极易引起的钻进孔斜、卡钻、垮孔、堵管等问题，提出了相应的处理措施。     

复合钻进工艺在云驾岭复杂地层钻孔中的应用

云驾岭矿区上部黄土中夹杂大量卵砾石,下部地层则因岩浆岩侵入具有岩硬、破碎、漏水、掉块等特性,严重影响钻进效率。为克服卵砾石及硬岩钻进难题,选用多工艺液压钻机YHJ-2000及性能参数比较稳定1150-XH空压机等钻探设备。采用牙轮钻头钻进、气动潜孔锤以及金刚石复合片等复合钻进工艺,并根据地层岩性确定钻孔结构、钻具组合及钻进参数。施工中注意调整泥浆性能,保证泥浆携带岩粉能力。经实践验证,该区采用的钻进工艺和方法,有效地提高了钻效,达到500m/月。     

Fracture plane control in rock blasting

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高位钻场长钻孔在淮南刘庄煤矿瓦斯抽采中的应用

刘庄煤矿东二采区121102工作面所开采的11-2煤层为非突出煤层,但在工作面回采期间,存在瓦斯突出的可能。为防止工作回风巷尤其是上隅角瓦斯超限,确保工作面的正常生产,同时兼顾瓦斯资源的抽采利用,施工了最大长度496m,钻孔直径133mm的瓦斯抽采孔。实际应用表明,该孔投入使用后,整个工作面回采过程中均未发生过瓦斯超限现象,说明利用大口径长距离钻孔取代巷道抽放瓦斯是完全可行的。本文介绍的高位钻场长钻孔的设计、施工和瓦斯抽采情况,可以为今后同类工作面中长钻孔的施工提供借鉴。     

3 D inversion of borehole gravity data using cokriging

Borehole gravity has been used in mineral exPloration recently with the advent of slim-hole gravime-ters. It is logical to Perform inversion to utilize the information in the newly acquired data. The i...