Season‐based rainfall–runoff modelling using the probability‐distributed model (PDM) for large basins in southeastern Brazil

Southeastern Brazil is characterized by seasonal rainfall variability. This can have a great social, economic, and environmental impact due to both excessive and deficient water availability. During 2014 and 2015, the region experienced one of the most severe droughts since 1960. The resulting water crisis has seriously affected water supply to the metropolitan region of São Paulo and hydroelectric power generation throughout the entire country. This research considered the upstream basins of the southeastern Brazilian reservoirs Cantareira (2,279 km²; water supply) and Emborcação (29,076 km²), Três Marias (51,576 km²), Furnas (52,197 km²), and Mascarenhas (71,649 km²; hydropower) for hydrological modelling. It made the first attempt at configuring a season‐based probability‐distributed model (PDM‐CEMADEN) for simulating different hydrological processes during wet and dry seasons. The model successfully reproduced the intra‐annual and interannual variability of the upstream inflows during 1985–2015. The performance of the model was very satisfactory not only during the wet, dry, and transitional seasons separately but also during the whole period. The best performance was obtained for the upstream basin of Furnas, as it had the highest quality daily precipitation and potential evapotranspiration data. The Nash–Sutcliffe efficiency and logarithmic Nash–Sutcliffe efficiency were 0.92 and 0.93 for the calibration period 1984–2001, 0.87 and 0.88 for the validation period 2001–2010, and 0.93 and 0.90 for the validation period 2010–2015, respectively. Results indicated that during the wet season, the upstream basins have a larger capacity and variation of soil water storage, a larger soil water conductivity, and quicker surface water flow than during the dry season. The added complexity of configuring a season‐based PDM‐CEMADEN relative to the traditional model is well justified by its capacity to better reproduce initial conditions for hydrological forecasting and prediction. The PDM‐CEMADEN is a simple, efficient, and easy‐to‐use model, and it will facilitate early decision making and implement adaptation measures relating to disaster prevention for reservoirs with large‐sized upstream basins.     

螺杆钻侧钻分支绕障技术处理绳索取心钻孔事故

绳索取心钻进施工中常出现卡钻、埋钻和钻具断裂事故。一些孔内事故处理需要很长时间,尤其是深孔事故发生后投入了大量的财力、人力进行处理,最终还不一定能取得成功。在此情况下,采用侧钻绕障而避开孔内事故钻具则是一种理想的选择,可大大缩短事故处理时间,避免钻孔报废带来的损失。重庆北碚龙车勘探区ZK6-2孔运用螺杆定向钻进侧钻分支绕障方法取得成功,并积累了宝贵的经验。     

沁水盆地过采空区煤层气水平井施工技术研究

为了进一步解决山西晋城矿区煤层气的开发利用问题,科学有效地开发和利用3号煤层采空区下部的煤层气,降低煤层中的瓦斯含量,以保障煤层气的高效合理利用,为煤矿开采提供安全保障。本文对该区穿采空区煤层气水平井的施工工艺进行了研究,提出了利用潜孔锤及空气螺杆+氮气施工的钻井工艺,进一步优化了钻井的井身结构,有效地解决了采空区敏感层段的坍塌、掉块、漏失等施工难题。穿采空区煤层气水平井的顺利施工,进一步验证了该钻井技术的可行性,对下一步煤层气的规模性开发具有重要的指导意义。     

SLB56／75型“三合一”取心钻进系统

论述了将绳索取心,螺杆站,不提钻换钻头三项技术结合在一起的新型取心钻进系统,介绍了系统的结构,工作原理及其技术性能参数和操作要点。     

煤矿井下硬岩定向钻进螺杆马达选型及试验

为了提高煤矿井下硬岩定向钻进效率,在分析硬岩定向钻进螺杆马达要求的基础上,选择了4种不同类型的螺杆马达在陕西韩城桑树坪煤矿进行井下硬岩定向钻进试验。试验结果表明,四级7︰8头螺杆马达和五级5︰6头螺杆马达在定向钻进硬岩时,其平均机械钻速分别为2.52 m/h和2.15 m/h,累计纯钻进使用时间可达550 h。这2种类型的螺杆马达表现出长寿命、高效率等特点,适合于定向钻进硬岩地层。