天然气水合物诱因的深水油气开发工程灾害风险——以墨西哥湾深水钻井油气泄漏事故为例

Geohazards and risk of deepwater engineering induced by gas hydrate——A case study from oil leakage of deepwater drilling well in GOM

随着深水油气资源的大力开发,与水合物有关的海洋工程安全问题日益增多.天然气水合物分解使得海底地层产生超孔隙压力,同时导致沉积物结构强度下降,容易引发气体泄漏、海底滑塌等工程事故,增加了海洋深水工程的灾害风险.2010年4月20日在美国墨西哥湾海域作业的BP公司"深水地平线"钻井平台爆炸并沉没,这一事故引发了墨西哥湾海域有史以来最大规模的原油泄漏灾害.初步分析结果表明,天然气水合物分解产生的甲烷气泡成为油井爆炸的直接肇因,而在漏油井口的封堵过程中,水合物的意外出现使得利用"控油钢筋水泥罩"封堵漏油井口的方案失效.文中分析了深水工程的水合物风险以及墨西哥湾钻井爆炸事故的触发过程,并提出了相应的解决方案.

With the development of deepwater hydrocarbon resources, more and more safety complications of deepwater engineering evoked by gas hydrate are confronted. Pore pressure of bed stratum raised and structural strength of sediments declined due to gas hydrate dissociation, which declines to evoking stratum slumping and other engineering accidents. On April 20, 2010, the Deepwater Horizon rig leased by the oil company BP exploded and sank in Gulf of Mexico, the accident initiated the serious oil leakage disaster of this sea area. The Preliminary analysis of the accident shows that much methane bubbles generated by gas hydrate dissociation is the direct cause of explosion. During the plug to the leaking wellhead, gas hydrate formed surprisingly and the plan to shut off the leaking wellhead by using steel and concrete containment dome failed. This paper analyzed the risk of deepwater engineering caused by gas hydrate and the processes of the explosion, and proposed the solution to the similar problem.