墨西哥湾油泄漏续——前所未有的深度

发表在我在Nature Blogs上的博客（英文）

Rheology is indeed involved in oil drilling engineering, including enhanced recovery method and spill control. Therefore I thought I could tell quite a lot about the disater in the Gulf of Mexico, until I found that the problem is mainly mechanics — the spill occurs because of the unexpected failure of blow out preventer (BOP). From asking “what is a BOP” I have to extend my knowledge to the whole mechanic aspect of oil drilling engineering. The following texts are the result of my books and webpages ad hoc reading and are not meant to be expert opinions.

Semi-submersed platform

Ocean has the amount of energy and resources that probably define how long in the future can human race last on this planet, energy and resources on the land approaching to the end. However the courage to built positioned bases in the ocean — a huge brave trial — is finally granted by high profits behind the abundance of oil under the seabed (among many other e.g. wind, tidal, etc.).

US was the first of the world to design and practice offshore drilling rigs. As the drilling depth increases, different designs appeared in the history. Deepwater Horizon is a semi-submersed rig, a design known to support the deepest oil well offshore ever known. Allegedly DH has the ability to drill the worlds’s deepest oil well, without using a newer design. No design, however, can be a final one and support an infinite drilling depth. DH may be a sign that the old design, not only the rig but the whole drilling design, after more than a decade of application if not misinformation, has now reached its limit. Or put it in another word, it was the unexplored depth that causes the failure. To answer against my ill-disposed, arbitrary conclusion one should know clearly what cause this event actually and is it unpreventable under the same rig design? or is it unrelated to the rig design?

Dynamic positioning

We all know that first the rig caught fire and then sank. Although up till now I don’t know how the fire started but it could hardly be related to the design of the rig of anything to do with the hardware. because the same design is used elsewhere. However the fire was really a big one. It causes the rig to sink and, catastrophically, offset from its original position. As you can see from the structure of a offshore drilling system, considering the length of the oil pipe submersed in the sea water, the rig must be precisely positioned above the oil well holding the pipe perpendicular to the sea horizon, otherwise the oil pipe must be broken. Before the accident DH was drilling a new main well. That means once broken the oil well has well extra pressure to push the oil out by itself, causing an oil spill accident. Historically offshore rigs were positioned by anchors. With the development of powerful propellers, GPS, and signal processing technology, dynamic positioning — positioning without anchors — played its role in newer drilling rigs including the DH. Under dynamic positioning the real time position of the rig is continuously analysed and fed back to the propeller system with proper commands of new strengths and directions. Because this feedback cycle is delicately maintained by AI rather than physically by anchors, once the signal/control system fail (e.g. in a fire) the rig will be suddenly turned back to a simple unchained flowing boat on the sea. The design of dynamic positioning, although hi-tech, adds risks of oil spilling accident to the system.

The blow out preventer (BOP)

The Wall Street Journal did an excellent explanation about the BOP. The blow out preventer is located at the oil well on the sea bed. As the oil pipe broke at somewhere, it leaves to the blow out preventer to stop the oil from the exit of the well (triggering it perhaps by a dropping signal of flow pressure). According exclusively to BP, however, the BOP ceased to work as expected by unknown reason. News reporters also found from the safety evaluation of DH 10 years ago evidence that BP planned not to implement emergent manual “stop” button for the BOP, i.e. a remote acoustic trigger. It seems that the producer of the BOP was very confident with their product at that time, and successfully convinced its customer BP not to implement additional remote trigger for DH due to economic reasons. All these information represent an atmosphere of over-confidence around the construction of this platform which is to drill the deepest seabed ever.

Historically when the offshore drilling task did not involved very deep sea, people use BOPs with the same design as those used on dry land oil wells. As we drill from deeper and deeper the seabed this simple copying started to cause problems. Under increased hydrodynamic pressure the hydraulic transmission system used for the BOP become more inefficient, limited by the diameter of hydraulic tubes. Thus the deeper the BOP goes down the sea, the slower for the hydraulic transmission system to response, and in the worst condition, the system just fails. Although this has been history and now these problems must have been overcome, the experience tells us that drilling from new depth poses new unexpected factors and challenges. Confidence on the BOP component base on previous success in shallower constructions is faint.

The rescue

Underestimation extended to the rescue phase of this event. As I wrote this post news that the containment domes plan has failed come to my eyes. The idea of using domes is not the first idea, but after the earlier failure of remotely operated underwater vehicles (ROVs). However, the speed of spilling was already warned of by many source of information before these failures, while BP kept assuring us of the effectiveness of the ROVs, then the containment domes by previous success of these methods, despite public questions whether these would also work under the depth we never have explore.

The ocean is no more accessible than the moon

Offshore projects, although started more than 50 years ago in USA and later in other countries (including China), are still kind of adventures. The most important obstacles — ocean currents, winds and environmental impacts, are currently still out of mankind’s prediction and control. We are proud to say that a small step deeper of the drilling rig is a large step of the mankind, just like what we call about the moon landing project. However, as BP described earlier, although it took full response of the accident but it is not BP’s own fault (from Chinese news sources). In other words, any small fault in this adventure may also be a big one of the mankind, just like what we have in the space shuttle Columbia disaster.

Does the US government treat their offshore exploration projects equally well as their moon or Mars exploration projects?

墨西哥湾油灾续三——《新知客》：早就知道的事。

拿到5月份《新知客》后，看到一个之前没见过的栏目——“观察”。题目恰为：《奥巴马为何要吃窝边油》。

《新知客》5月“观察”

《新知客》5月“观察”

5月份的杂志，应该是4月中旬就组版了。因此此文应该是四月初写就的。美国墨西哥湾油灾事件是四月底开始引起广泛关注的。成为新闻热点应该是刚刚5月前后。因此我实在惊异于行内人的预言能力。我这个行外人在博客里写的东西，仅能作为自己学习了解此事的个人笔记罢了。所幸我发现我了解了一番之后，所形成的基本见解跟行内人的看法类似；更庆幸的是我在此次事件关注系列的第一篇文章开头就清醒地认识到：

人人IQ都高，你的价值不在于你比别人聪明多少，而在于你的职业，你的生存环境和阅历的个人性、独家性。想要“独家”，就“独家”在此。如果人人都最大程度地利用自己的IQ，就能在最少的时间里把事情推进到最前沿的程度，任何发展都会因此加速；放在有IQ不用，做那种看译文的懒事，很可耻，跟听信谣言的不明真相群众无异。……

我打的文字，主要是补充这些资料所没有的内容，同时把这些零碎的资料连接成一起。哪怕是这项工作，我价值也是为零的……

所以，可以认为，以下引用于原文的话，其实是行内人早就知道的事情了。站在这些话的高度之上去看待此次油泄露事件（这是起码的），就能感觉到它不仅仅是不堪设想的生态灾难，而且还是不堪设想的政治灾难。好像有个什么名言说人类的政治全都是非理性的胡言乱语，因此人类的愚蠢是注定的。

目前，美国一半以上的石油依赖进口，……（陆地）油田不再像以前那样大量产出……

随着美国人的石油胃口越来越大，以及石油峰值的来临（我注：什么是Peak Oil），事情越来越不如人意。……

……在声称石油储量大约在700亿桶、能满足美国数年（注意，仅仅是数年！）（我注：现在该处某油井正以每天25000桶的速度消散）石油消耗量的墨西哥湾，其中400亿桶储存在没有发现的超深水域，相当于美国石油储备的最后疆界……

……超深水域的绘图和钻探难度无异于石油科技上的珠穆朗玛峰，每一个探索都须付出巨大代价。状如阿尔卑斯山的盐层让地质学家至今还示能准确描绘这里的地质构型，墨西哥湾的暖流和9000多米深的沉积层让精密的钻机随时可能折断，还不必说因为超深水域带来的高温高压危险，以及飓风的袭击，种种因素让墨西哥湾石油的开采成本极高，平均一艘钻船每日营运成本高达50万美元，而一个小小的意外，都可能带来上亿美元的损失。

（要看全文请购买5月份的《新知客》。）

关于从此次事件引申出的消费高度发达的资本主义社会弊端的思考，我在高度在国外一个很活跃的石油话题论坛网站The Oil Drum看到这样的回复：

一人说：Why are BP drilling in GOM (我注：即Gulf of Mexico) anyway? Because Americans like to live 50 miles from work and like to live a consumerist lifestyle too. All of which needs oil, and a bloody shed load too.

So perhaps Obama and all you other Americans should take the plank out of your own eyes before trying to criticize and damn BP. Y’all want the friggin oil… live with it.

另一人回复上文：Because they failed to create low cost, high efficiency photovoltaic panels when governments paid oil companies to create them.

Because industry refuses to provide options for consumers and prefers to use methods like General Motors used to destroy the EV-1.

British Petroleum is run by oil men who know no other product. Since they have no interest in adapting to something else, they seek to extract oil where ever they can still find it, even though it lies in ever more difficult locations. At the fuel pump American consumers do not give a hoot whether their fuel came from BP or Saudi Aramco.

Where’s the electric car that would put oil men out of business?

我又联想到我们国家。《新知客》“观察”文章说美国多少多少比例的石油主要靠进口，说陆上的石油要采光了，看着就好像是在描述中国的国情。大庆等老牌大陆油天正在拼命地研究三次采油复合驱，关心石油的国人一直都在把眼睛瞄准我国的南海，难道那里不正就是我国“石油储备的最后疆界”么？我国其实面临着跟美国同样的问题。

今年2月份，由中国海油投资、我国自行建造的深水半潜式钻井平台“海洋石油981”在上海外高桥造船有限公司顺利出坞，这个东西就是跟现在墨西哥湾出事的Deepwater Horizon同一级别的东西（严格来说更高级，Deepwater Horizon是第5代，海洋石油981据称是第6代，具体什么差别恕我外行）。而此前中海油荣获2008年度国家科技进步二等奖的“中国南海西部海域复杂构造安全快速钻井技术”介绍中也明确提到：

针对中国南海西部海域所存在的高温超压并存、井壁失稳严重等世界级重大钻井技术难题，通过技术引进……使钻井井眼复杂事故率从40%～72%降至5%以下……

而（不知道是不是我犯概念混淆）据媒体报道此次出事的Deepwater Horizon平台，当初正是因为BP评估事故风险为5%，觉得够低了，所以在方方面面免去了价格昂贵但能大大降低此次灾难等级的应急保险措施（包括但不仅限于现在曝露出来的远程触发开关缺如、深海求急技术方案可行性演练等）。5%是一个什么概念？就是每二十次会发生一次！这如此高的风险竟被业界公认为“很低”，背后到底是何等巨大利益驱使如此胆大的冒险成为业界公认？让人更关心的简单问题是：如何避免海洋石油981成为人类下一个Deepwater Horizon？近海工程可借鉴经验极少，这就是此次Deepwater Horizon之灾的唯一宝贵之处。

落后商品检测的出路何在？

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影响深远的毒奶粉事件的一个直接原因是，凯氏定氮法的落后。这种检测方法只是笼统地通过氮元素的含量来确定样品的蛋白质含量。要把检测结果等同于蛋白质含量，前提必须保证样品里边只有蛋白质含氮。天然牛奶确实是符合这一前提的，但是随着食品工业的发展，现在已经没有什么食品是全天然的了。无害的食品添加剂都五花八门，牛奶里添加三聚氰胺这样的有毒物质，有意蒙骗执法的行为消费者也不少见了。最终，还是通过叫做液相色谱的检测方法，才能检出牛奶里的三聚氰胺。这种检测仪器比凯氏定氮法昂贵多了，一台仪器价格就要几十上百万，而且平时经常要更换色谱柱一条就要几万。

平时仔细阅读新闻就会发现，检测落后导致卫生安全危机的例子不止这一个。今年1月份农夫山泉、统一“砒霜门事件”的新闻发布会上，海口市工商局解释为何初检结构有误。简单地说，一是仪器太老了，二是检测人员员不按规范操作。2月份，海南“毒豇豆事件”，之所以“一次次逃过例行的快速检测，最终在实验室的色谱检测中才查出了违禁高毒农药的具体品种和残留量”，原因就是快速检测的范围太窄，导致出事的那种农药光用快速检测法检不出来。放眼国外，闹得沸沸扬扬的塑料瓶双酚A残留，归根结底也是因为检测上的落后。广泛用于“太空壶”和桶装水的聚碳酸酯含有双酚A是早就清楚的了。以前一直认为它没毒。最近发现有毒，是来自实验室研究的结果。双酚A跟人体的荷尔蒙“长得很像”，混入人体会导至各种荷尔蒙失调。这样的毒性是慢性的，而且要依赖于最前沿的实验室技术才能发现和证实。事情曝光之后反思不少，但是无论如何难以要求监管部门承担发现新物质、新毒性的科研探索任务，确实难怪以往监管部门没办法注意到双酚A之毒。

商品检测部门的实验室，跟高校和研究所是有区别的。研究型实验室走在科学研究的前沿，在研究手段上也必须尽量更新，因此需要购置大型检测设备。商品监管部门的检测实验室的任务则是面对大量常规的检测任务，而且检测项目是全方位的，涉及化学、物理和生物。如果全部都用大型检测设备，不仅经济上不现实，而且也满足不了如此大量的日常工作任务。两种实验室另一重要的区别——也是导致如此多漏检误检事故的根本原因——在于科学思维的重视程度。政府部门的检测实验室，长期处于任务式的工作性质，而且检测结果总是大比数过关，因此容易让人掉以轻心，工作流程也流于刻板教条，缺乏研究型实验室所强调的科学素养。孰不知检测分析本应是一项严肃的、对未知物性质的科学探索。以科学的态度进行检测，应该以样品为敌，以检测仪器为武器，做一名战士。合格的战士首先就应该谨记自己的武器的局限性，并长期检查武器的服役状态，同时必须研究敌人的新动向、新伎俩，正所谓知己知彼才能百战不殆。现在的检测部门之所以“几战一殆”，原因自不待言。

如何走出目前商品监管部门在检测上存在以上困境？长期备受唾骂的“国家免检产品”就是以减轻监管负担而提出的。其实，免检并不是我国政府发明的，国外也有一些类似免检的做法。但是“免检”原本的思想并不是“信誉”谎言下的放任自流，而是“免检=民间来检”，把监督的权力放开给潜力巨大的民间力量。打开美国农业部、食监局等网页上公布的免检规定网页，就会发现它们实际上是一张张社会检测资源的列表，指导大家除了政府部门外，还能把东西拿到什么可靠的地方进行检测。国外的第三方检测市场已经非常成熟，但直到本世纪初，我国的第三方检测力量仍然近似于零。2003年检测行业向民间资本开放，目前国内已经有像华测、普尼、胜邦等具有科研实力的民营检测公司。但是为何一次又一次的食品卫生事故仍在持续发生？质疑的视线为何仍然二元式地投向政府和生产企业？如何积极引入民间监督力量，踏开商品检测的第三条路？在不断加长的大量受害者名单面前，我们难道还要继续原地踏步不前？