【作者】 吴海彬；

【导师】 陈鹰； 朱世强；

【作者基本信息】 浙江大学 ， 机械电子工程， 2002， 博士

【摘要】 海洋平台是海上钻井采油的必备设施之一。为了适应各种不同的油田地质状况和海况条件，开发了各种不同结构形式的海洋平台，如导管架式平台、重力式平台、自升式平台以及张力腿平台等。随着各国对石油需求的日益增加，以及现有大型油田开采的日益衰竭，人们已经逐渐把目光转向储量小、地址条件恶劣、但数量庞大的边际油田。边际油田由于特殊的地质条件，其开采设施与开采方法也有其特殊性。一个共同的要求就是开采边际油田的海洋平台要有可移动性、结构形式简单、最好有储油功能等。 为了满足边际油田开采的需要，目前国际上研制成功一种新形式的海洋平台，即桶形基础海洋平台。这种平台是依据负压桩原理，通过调节桶形基础内的压力实现平台的沉贯与拔出，国内外已对桶形基础的工作机理有了很深入的研究。随着此类平台逐渐被各国重视并投入使用，有一个越来越突出的问题摆在面前，那就是，由于桶形基础平台的可移动性，其从水底上浮到水面和从水面下沉到水底以及拖航这一系列环节应该以怎样的方式来进行?传统的方法是通过浮吊等大型海上施工机具来实现平台的沉浮和拖航，这对于需要经常移动的平台来说，无疑是大幅度的增加了施工成本，从而造成边际油田开发总体效益的下降。更主要的是，在浅水区域，大型施工机具根本无法进入。为了解决这一难题，本课题提出了通过抽注水的方法实现平台的自主沉浮，为桶形基础平台沉浮过程的实现提供了一个切实可行的技术方案，从而达到简化平台施工过程，降低平台施工成本的目的。平台自主沉浮是通过向各容腔(桶形立柱或经过密封处理的桶形基础)中注水或抽水的方法得以实现，即通过调节注水或抽水的总体流量实现平台的下沉或上浮，通过把总体流量适当分配给平台各容腔(即调节平台的质量分布)，实现平台的平稳沉浮。 为了验证这一策略的可行性，本文提出应用半物理仿真技术研究海上平台的沉浮过程。为了验证半物理仿真试验结果的可信度，本文以实验室一平台物理模型为研究实例，通过半物理仿真试验与物理模型试验结果的对比，充分证明了海上平台沉浮运动研究中应用半物理仿真技术是切实可行的，以抽注水的方法实现平台自主沉浮的控制策略是可以实现的，并且达到了纵向运动控制精度在±2°以内。 本文总体目标是构筑海上平台沉浮过程半物理仿真试验系统，然后进行试验，并对试验结果进行深入分析研究，得出相应的结论。为了实现这一半物理仿真试验系统，需要建立平台沉浮过程的数学模型、研究沉浮过程的实时控制方法以及半物理仿真系统中其它各环节的实现。所以，总体上，本文分为三大块，即平台沉浮过程数学建模(第二摘要章)、半物理仿真系统设计与试验(第三章)，以及试验结果比较分析与结论(第四、第五章以及结论部分)。具体各章研究重点如下: 本文的第一章通过分析目前边际油田开发的技术现状、平台沉浮过程的研究进展，以及半物理仿真技术应用状况与前景，提出了本文的研究内容。 第二章论述了半物理仿真试验系统中最重要的一环:平台沉浮过程的数学建模。首先是根据海洋平台沉浮过程的机理，给出了具有一定普遍意义的参数计算思路和方法，其中主要包括平台浮心、重心计算，稳心高以及回复力矩等参数。然后把平台的沉浮运动过程分解为横向运动和纵向运动，并对纵向运动按静力学原理进行建模与仿真，横向运动按动力学原理进行建模与仿真，并建立相应的数学模型，在横向运动建模中同时考虑了相关模态的祸合与非线性情况。 第三章提出了应用半物理仿真方法对平台沉浮过程进行系统仿真的总体构想，并进一步分析平台半物理仿真系统各个环节之间的接口关系，通过适当简化使整个半物理仿真系统达到可实际操作的程度。根据仿真运算的具体情况，提出了在平台半物理仿真系统中，把平台纵向运动数学模型进行实时仿真，而对横向运动数学模型进行间歇仿真策略，有效解决了半物理仿真系统的实时性问题。较详细的论述了平台半物理仿真系统的控制软件与仿真软件，并给出了二者的通讯方法。并对平台半物理仿真系统中的一些关键环节进行了概述，包括水路设计、传感器布置以及虚拟仪器技术的应用状况。为了对平台半物理仿真结果进行校验，在进行半物理仿真试验的同时，也同时进行了模型试验，根据模型试验的结果可以用来进一步修改数学仿真模型。 第四章对平台沉浮过程中的稳性进行研究。通过分析平台的初稳性和大倾角稳性，得出了平台初稳性在沉浮过程中的变化规律，并依据大倾角稳性分析，提出了平台施工前稳性校核的具体方法。 第五章对平台沉浮过程中横向运动和纵向运动半物理仿真结果进行了分析研究，并与模型试验的结构进行了比较。给出了平台横倾角、纵倾角随吃水涤度变化关系，并得出相应的结论。对平台半物理仿真结果的可信度进行分析，并提出对模型进一步修改的意见。 第六章对全文进行了总结，并给出本文的研究结论、创新之处以及对未来的展望。更多还原

【Abstract】 Offshore platform is one of the most necessary equipments for oil extraction in the ocean. Many series of platforms have been developed in recent years, such as gravity platform, jacket platform, self-elevation platform and tension leg platform, etc., to meet different geologic and marine conditions. As the increase of the world oil demand and decrease of the large oil field reserves , people have to give their attentions to the thousands of small oil fields whose geologic conditions are generally bad. The extraction method and equipments needed in these kinds of oil fields are distinctive from those in normal oil field. Most basic requirements are that the platform can be used repeatedly, has the ability to store oil and has simple structure.For the need of extracting more marginal oil fields, a new-style platform has been developed, which is called bucket foundation offshore platform. This kind of platform has the pull-out and suction capability based on principle of suction pile. Much research work on bucket foundation mechanism has been done recently. As the recognition and use of this kind of platform, a question must be emphasized, that is how to make platform lower from marine surface to bed and raise from marine bed to surface. The raising and lowering procedures should be considered because of the platform’s mobility. Traditional method is to depend on floating crane, On one hand, which increases the installation expenses, so that the total benefits of the oil exploitation decrease, on the other hand, which can not be carried out in shallow sea because of no way to offer enough sea gauge. In order to resolve this difficult problem, a new feasible method for the raising and lowering procedures of the platform is presented in this dissertation. This method is called pumping-out-and-pumping-in method which means that self-raising or self-lowering of the platform is implemented by pumping water into the cavity or pumping water out of the cavity. The cavity is the bucket columns and/or sealed bucket foundations. That is to say, die raising or lowering procedure of the platform is controlled by regulating the total flow pumped in or pumped out of the cavity, and the platform stability is controlled by regulating every cavity flow.In fact, the platform is very large. If the test is performed in field, the cost must be high, and the test period is also very long, at the same time, there is danger in the test. In order to testify the feasibility of the method, hardware-in-the-loop simulation is used for analyzing the raising and lowering procedures of the platform in this dissertation. To validate the reliabilityof the hardware-in-the-loop simulation results, a platform model is bulit as the research example, and furthermore, model test and hardware-in-the-loop simulation test are performed synchronously. By this means, feasibility of the hardware-in-the-loop simulation applied in the research on the raising and lowering procedure of the bucket foundation platform, and the pumping-out-and-pumping-in method can be realized. Precision of the controlled longitudinal motion is less than ±2 degree.The final goal of this paper is to build hardware-in-the-loop simulation test system for the raising and lowering procedures of the platform, and to do the experimentation, then carefully to study the experimentation results so that conclusions are drawn at last. To build this system, the mathematic model during raising and lowering should be established firstly, then real-time control arithmetic must be carried out during test secondly, and the other part of the system also should be studied at last. So, there are three parts in this paper, which are establishment of the mathematic model(the second chapter), design and test of the hardware-in-the-loop simulation system(the third chapter), and analysis and conclusions of the experimentation results(the fourth, fifth and sixth chapter).The first chapter: based on the development of technology of the marginal oil fields, studies on the procedure of th更多还原