埕岛海域悬跨海底管线仿生草处理方法适宜性研究

发布时间：2018-05-14 16:38

本文选题：埕岛海域 + 悬跨管线　；参考：《中国海洋大学》2014年硕士论文

【摘要】：埕岛海域胜利油田是我国第一家海上油田，自1993年建成投产之后，海上石油平台林立，海底管线纵横交错，至今已有海底输油管线和注水管线共计一百余条。海底管线是海上油气运输的主要方式，对油田的安全和高效生产发挥着越来越重要的作用。近几年来的勘测资料显示，石油平台周围冲刷严重，管线裸露、悬跨问题突出，亟需合理有效的处理。埕岛海域海底管线裸露、悬跨的原因有很多，主要有以下两个方面：一、波浪、潮流等水动力对海床的冲刷、侵蚀，使埋藏之下的海底管线出现裸露、悬跨；石油平台、海底管线等人工海上构筑物的存在，引起差异冲蚀，加剧了海底管线周围海床的冲刷，使之更容易出现裸露、悬跨；二、海底滑坡、塌陷凹坑、侵蚀残留体、水下斜坡等不稳定地质因素的存在，容易引起海底地形的变化，导致海底管线的裸露、悬跨。其中，石油平台桩柱周围差异冲蚀引起的管线裸露、悬跨在所勘查管线中占了大多数。传统的处理海底管线的方法主要有桩基支撑、抛填沙袋和碎石、挖沟埋设等，这些方法虽然可以暂时性起到一定的保护作用，但是无一例外的都会引起海床的二次冲刷，不是长久之计。单一的实施其中一种方法处理海底悬跨管线，在埕岛海域并不适宜。胜利油田从2006年开始，引进仿生草技术对海底裸露、悬跨管线进行处理，取得了很好的效果。仿生草技术是基于海洋仿生学原理开发研制的一种新型海底防冲刷技术。仿生草采用耐海水浸泡、抗长期冲刷的新型高分子材料加工而成，由安装基垫和特殊设计的海底锚固装置铺设于海底。其主要作用机理是：水流流经仿生草时，波能被吸收、减弱，水流流速降低，对海床的冲刷能力减弱；同时，由于流速的降低和仿生草的阻碍，促使水流中携带的泥沙在自身重力作用下不断地沉积到仿生草安装基垫上，起到固沙促淤的作用。仿生草铺设后，可以起到明显的防止海床冲刷、降低水流流速和促进泥沙淤积的作用。通过实际测量和计算发现，仿生草至少可以降低水流流速15%-20%，10米x30米范围的仿生草，一天之内的泥沙淤积量可以达到160kg。胜利油田曾于2008年至2013年间对埕岛海域的海底地形地貌及仿生草处理效果进行了多次勘查。本论文在对这些资料收集、整理和分析的基础上，对仿生草技术处理海底悬跨管线的效果及适宜性进行了研究。一、大量的调查资料显示，在埕岛海域利用仿生草技术处理海底悬跨管线问题，取得的整体效果不错。黄河入海泥沙含量大，，悬沙浓度高，沉积物主要由粗粉砂和粘土质粉砂组成，仿生草技术在这一海域可以很好的发挥其促进泥沙淤积的作用，适宜性很好。二、最近几年的仿生草监测资料显示，埕岛海域的采油井组平台端附近，冲刷坑普遍存在，管线裸露、悬跨问题仍然很严重，采用抛填沙袋或碎石与铺设仿生草相结合的方法来处理，效果不是很理想。受石油平台桩柱周围强烈冲刷作用的制约，仿生草技术对平台桩脚附近裸露、悬跨海底管线的处理并不适宜，这一问题还有待今后进一步的研究和改进。
[Abstract]:The Shengli oil field in Chengdao sea area is the first offshore oil field in China . After the construction and production in 1993 , there are more than 100 offshore oil pipelines and submarine pipelines . The submarine pipeline is the main way of offshore oil and gas transportation . The submarine pipeline plays a more and more important role in the safety and efficient production of the oil field . The survey data in recent years show that the erosion in the oil platform is severe , the pipeline is exposed , and the suspension span problem is outstanding .

There are many reasons why the submarine pipeline is exposed and suspended in Chengdao sea area . There are two main aspects : 1 , wave , tidal current and other hydrodynamic forces on the scouring and erosion of the seabed , and expose the submarine pipeline under the buried ;
The existence of artificial marine structures , such as petroleum platform and submarine pipeline , causes differential erosion , which increases the erosion of seabed around the submarine pipeline , making it easier to expose and suspend ;
Second , the existence of unstable geological factors , such as submarine landslide , collapse pit , erosion residual body and underwater slope , can easily cause the change of seabed topography , which leads to the bare and suspended span of submarine pipeline .

The traditional method of processing submarine pipeline mainly includes pile foundation support , throwing sand bag and gravel , digging ditch burying , etc . , these methods can temporarily play a certain protection role , but without exception , it can cause secondary scouring of seabed , not a long time . The single implementation of one of the methods of treating submarine suspension line is not suitable . In Shengli Oilfield , from 2006 , the introduction of bionic grass technology to treat submarine exposed and suspended pipelines has achieved good effect .

The bionic grass technology is developed by the principle of marine bionic principle . The bionic grass is made up of a novel high molecular material resistant to seawater immersion and long - term scouring .
At the same time , due to the reduction of the flow rate and the obstruction of the bionic grass , the silt carried in the water flow is continuously deposited on the bionic grass mounting base mat under the action of self - gravity to play the role of sand - fixing and silt - promoting .

On the basis of the collection , sorting and analysis of these data , the paper studied the effect and suitability of bionic grass technology on submarine suspension cross - line .

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P756.2

【参考文献】