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1.
During the drilling of ultra-deep-water subsea petroleum wells, a blow-out preventer (BOP), a piece of safety equipment, must be assembled on the wellhead. The BOP is suspended using the drilling riser during the wellhead approach operation, and the riser's top end is connected to the floating platform rig. This article presents a feedback control system for the automatic approach of the BOP to the wellhead. Compared to state-of-the-art controls, ours does not require ancillary thrusters installed alongside the riser nor inclination sensors atop of the drilling riser. Additionally, our proposed control embeds a closed-loop dynamic positioning system, thus retaining the characteristics of the original control system and adding an extra closed-loop. This eases implementation of the BOP approach control to an existing platform. To calculate the optimal gains for the BOP controller, we assume a linear system for the riser, including only the pendulum-shape. The simulation is carried out using nonlinear models for both riser and floating platform. We assume an International Towing Tank Conference standard semi-submersible platform, coupled with a 3000-m free-hanging vertical riser for the time-domain simulation. The results show the BOP tracking to be a step-shaped input signal under current and wave loads. A discussion of the performance of feedback control under different environmental loads is also included. 相似文献
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Stephen A. Bowden Abdalla Y. Mohamed Ayad N. F. Edilbi Yu-Shih Lin Yuki Morono Kai-Uwe Hinrichs Fumio Inagaki 《Basin Research》2020,32(5):804-829
Basin models can simulate geological, geochemical and geophysical processes and potentially also the deep biosphere, starting from a burial curve, assuming a thermal history and utilizing other experimentally obtained data. Here, we apply basin modelling techniques to model cell abundances within the deep coalbed biosphere off Shimokita Peninsula, Japan, drilled during Integrated Ocean Drilling Program Expedition 337. Two approaches were used to simulate the deep coalbed biosphere: (a) In the first approach, the deep biosphere was modelled using a material balance approach that treats the deep biosphere as a carbon reservoir, in which fluxes are governed by temperature-controlled metabolic processes that retain carbon via cell-growth and cell-repair and pass it back via cell-damaging reactions. (b) In the second approach, the deep biosphere was modelled as a microbial community with a temperature-controlled growth ratio and carrying capacity (a limit on the size of the deep biosphere) modulated by diagenetic-processes. In all cases, the biosphere in the coalbeds and adjacent habitat are best modelled as a carbon-limited community undergoing starvation because labile sedimentary organic matter is no longer present and petroleum generation is yet to occur. This state of starvation was represented by the conversion of organic carbon to authigenic carbonate and the formation of kerogen. The potential for the biosphere to be stimulated by the generation of carbon-dioxide from the coal during its transition from brown to sub-bituminous coal was evaluated and a net thickness of 20 m of lignite was found sufficient to support an order of magnitude greater number of cells within a low-total organic carbon (TOC) horizon. By comparison, the stimulation of microbial populations in a coalbed or high-TOC horizon would be harder to detect because the increase in population size would be proportionally very small. 相似文献
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正2018年5月26日,自然资源部中国地质调查局在黑龙江省安达市松科二井工程现场召开大陆科学钻探工程(松科二井)完井暨学术研讨现场会。中国地质学会常务副理事长兼秘书长、自然资源部中国地质调查局副局长、松科二井工程领导小组组长李金发宣布松辽盆地大陆深部科学钻探工 相似文献
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地应力监测孔作为地应力测量与监测的基础场所,钻探施工的质量直接影响到地应力测量试验的效果,扩孔的质量更是决定地应力监测仪器能否顺利安装以及后期监测仪器能否正常工作的关键因素。本文以京津冀协同发展区地应力监测孔钻探施工为例,详细介绍了地应力监测孔的施工工艺,包括取心钻具组合、金刚石钻头选择、组装式扩孔钻头分级扩孔钻进等,对保证钻孔垂直度和同心度、降低钻孔孔径误差、保证岩心采取率,以及提高监测孔扩孔效率和质量等关键技术提出了一些具体措施,并取得了良好的钻探效果,对今后地应力监测孔的钻探施工具有重要的指导作用。 相似文献
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本人在借鉴前人成果并结合施工经验的基础上,系统总结了砂卵石地层与非开挖钻进施工的适应性,对非开挖钻进施工中出现的问题进行了归纳和分类,并对其原因进行了分析和探讨。同时,为了解决非开挖导向钻进在复杂地层特别是砂卵石层中的施工难题,考虑采用注浆预加固技术对砂卵石层进行预先加固,以提高其强度,保证非开挖导向钻进的顺利进行。更进一步地,对水平孔中注浆预加固的三种方法(垂直注浆法、导管注浆法、随钻注浆法)在导向钻进工程中的概念、适用范围、优缺点以及实施控制要点等进行了对比和研究。 相似文献
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作为非开挖施工的一个分支,定向钻穿越技术得到了越来越广泛的应用。本文以DN630供水管道定向钻穿越淮河工程为例,介绍了定向钻穿越的技术特点,指出了设计基本原则及设计要素如管道钻进的入土角、出土角、曲率半径和穿越深度等确定方法,并阐述了定向钻穿越施工工艺流程及泥浆配制、钻导向孔、扩孔及管道回拖等主要施工工艺。 相似文献