METHOD AND SYSTEM FOR MONITORING WATERBOTTOM SUBSIDENCE

摘要

A system for monitoring subsidence and/or rising of a waterbottom (3), such as an ultradeep oceanfloor, has a string of pressure sensors (2) along the length of the interior (13) of a sealed pressure resistant protective tube (1) that rests on the waterbottom (3) and is filled with a low pressure liquid, such as water, so that any subsidence and/or rising of the waterbottom (3) can be deduced from subsidence and/or rising of a section of the tube (1) and associated variation of the fluid pressures measured by the pressure sensors due to variation of the hydrostatic fluid pressure of the low pressure liquid in the interior (13) of the tube (1). The tube (1) is equipped with a series of valves (10) which divide its interior (13) into a series of sealed segments during descent to protect the pressure sensors (2) against hydrostatic pressure of the liquid within the tube(l) during installation. The use of a pressure resistant tube (1) filled with a low pressure liquid allows the use of sensitive pressure sensors (2) which are able to monitor pressure variations of -0.001 Bar associated with a waterbottom subsidence of ~1 cm, at a waterdepth of >km where the ambient water pressure may be >100 Bar.