深水钻探面临的挑战:浅水流灾害问题

浅水流(shallow water flow,简称SWF)灾害被看作深水钻探中面临的重要挑战之一,它是指深水钻探中,钻头钻过一超压砂层时,孔隙压力太大以致砂和水激烈流进到井眼里,导致了井和钻井平台损坏的事件.SWF问题仅发生在深水区,位于海底泥线下几百米以下,主要出现在一种原位超压的未固结的斜状砂体中,这种砂体一般被低渗透的泥覆盖.超压的形成常认为是快速沉积压实所致,也可能与构造因素或水合物分解有关.SWF砂体具有低密度、低速度和高Vp/Vs的性质,是可能被地震勘探方法所检测的.我国即将进入深水钻探领域,为了避免或减轻深水钻探中可能面对的SWF灾害,我们建议开展有关SWF灾害问题的前期研究.

Shallow water flow hazard: a challenge in deepwater drilling

One of challenges in deepwater drilling is shallow water flow(SWF)hazard,which is referred to that sand and water eject into drill hole shrewdly,when drilling into poorly consolidated overpressured layer,and cause damage to drill platform.SWF hazards are only met in deep water regions and occurred in hundreds meters below sea floor.They locate in the sloppy loosen sands with overpressure,covered with shale with low permeability.The origin of overpressure is often related to rapid deposit compression,or to geological structure and gas hydrate.SWF sands have the properties of low density,low velocity and high Vp/Vs,and hence can be identified by the seismic exploration techniques.Deepwater drilling will be proceeded in our country,and the studies of SWF hazards should be carried out in order to avoid and lessen the potent hazards in the deepwater drilling works.