Macondo matters
Sir, OE's article by Ian Fitzsimmons on preventing future Macondo spills [‘Macondo and other titanic struggles', OE July] was excellent and I distributed a copy to my colleagues both in EIA and DOE. The recommendations made regarding developing better cements and longer curing times, BOP/riser modularity, and BOP ram spacing are indisputable.
Articles I have read in the various media lead me to believe that the BOP might have been nearing the end or past its useful life, given the operating problems that were experienced. Consequently, the industry might also need to embrace a more conservative/aggressive preventative maintenance and retirement policy regarding offshore BOPs.
Ian Fitzsimmons' comments regarding the oil containment problems being more severe if the riser pipe had collapsed on the wellhead made me wonder how much worse the oil containment problem would have been if the drilling semisubmersible had come to rest on the wellhead after sinking.
I am glad to see that the oil industry is putting together a consortium to deal with deepwater oil spills in the future. Philip Budzik (by email)
Sir, Excellent article by Ian Fitzsimmons in OE July. It hit the nail on the head. Robert Margolis (by email)
Sir, Ian Fitzsimmons' opinion piece on the Macondo blowout states: ‘Those who are familiar with BOPs know that they can slice through a drill pipe collar with ease and seal – time after time.' According to a 2004 report, standard blind-shear (BS) rams can only cut through drill pipe, and will not cut through the threaded joints in a drill string, (http://www.mms.gov/tarprojects/463.htm, attachment AA). As far as I can determine, no supplier is yet able to offer BS rams that will cut through a drill pipe joint and then seal off. Cameron offers Super Shear Rams, which can cut through a drill collar, large diameter casing, heavy wall drill pipe and threaded joints, but will not seal. Keith Shotbolt (by email)
Ian Fitzsimmons responds: Mr Shotbolt acknowledges that qualified shear rams exist that can shear drill collars. However, it may well be that not all current operational BOPs have that capability. That may be a matter for a separate debate. As far as Macondo is concerned, it is irrelevant. There was no drill pipe inside the well at the time of the blowout.
The BOP strategy that I laid out in OE July presumes at the outset that a single pair of shear rams will fail to do their job, whatever the cause, and whatever their claimed capability, and that the BOP and LMRP should be configured accordingly. My strategy is based on the presumption of failure of a single pair of shear rams from the outset, regardless of cause. When an internal obstruction of any description prevents a pair of shear rams from doing its job, my proposal provides for another two pairs of shear rams to be called up, which have a high probability of being clear of the internal obstruction.
A revised BOP configuration is required, which will help to avoid another Macondo, and which can be applied equally to both old and new BOPs. The smug paradigm that a BOP is too big to fail, and that only one pair of shear rams is required, is fundamentally flawed.
Chinese puzzle
Sir, I loved Michael Economides' piece on China (‘Ebb and Flow', OE July). It seems hard to think that he was really tongue-tied, just unable to understand and explain the ravings of our current C-i-C.
If the Chinese really want the world to notice, they probably should invest more in USA, though the Saudis have all but purchased Colorado, and no-one takes any notice. Perhaps if they buy a few good oil shale fields, then install a nice LPG export facility, someone would raise an eyebrow! Pickard Mirfak (by email)
Sir, Please convey my gratitude to Professor Michael J Economides for his lucid, eloquent, and meaningful account (OE July) as to how and why the US is seemingly destined, by its own actions, to become a third world power, while China sees the relationships between energy and economic growth quite clearly and is taking the necessary steps to continue its amazing economic development. I will be sending copies of this dissertation to President Obama, Secretary of Energy Chu, and to my senators and my US representative. Arlie M Skov (by email) OE
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