钻井隔水管挤毁分析

HYDROSTATIC COLLAPSE ANALYSIS OF MARINE DRILLING RISER

深水、超深水钻井作业时中,隔水管将面临新的风险—挤毁,其必须有足够抗挤毁的能力,以保证作业顺利进行。造成挤毁压差的成因有两种。一种是由于钻井液大量漏失,隔水管被抽空,而使其内外压差增大,也就是"U"形管效应。另一种由于天气或平台漂移造成隔水管紧急脱开时,形成的水击,在极短时间内形成很大的压力差,使隔水管处于被挤毁的危险状态。文章从分析形成内外压差原因入手,主要侧重于由于紧急脱开形成压差的分析,与API标准计算值进行比较,并提出在设计和操作中一些可以减轻、或避免水击影响的建议。

In deep and ultra-deep water drilling operation,the marine riser may face high collapse pressure,so it must have the a-bility to resist collapse pressure. There are two reasons which cause the high collapse differential pressure,one is 'U-Tube' effect,the other is water hammer effect which is caused by marine riser emer-gency disconnect. This paper analyzed mainly the reasons of forming pressure difference when marine riser emergency disconnect,gave one method to calculate the collapse pressure of the marine riser and compared with API standard computed value,and put forward some advice for lightening or avoiding the water hammer.