Experimental Research on Data Synchronous Acquisition Method of Subsidence Monitoring in Submarine Gas Hydrate Mining Area

Abstract

The data synchronous acquisition is crucial to the seafloor subsidence monitoring system for gas hydrate mining areas based on microelectromechanical sensors (MEMS). Because the independent and high-precision time reference sources on land cannot be used on the seafloor, especially in the deep sea, a relative time synchronization method based on input/output (I/O) and controller area network (CAN) bus was proposed to realize the internal time synchronization of the system. To demonstrate the feasibility of the proposed method, tests including the deformation test of the MEMS sensor array under high pressure, synchronous accuracy test, and landslide and collapse simulation tests were carried out. The synchronization method was performed once every 24 h, and the time drift was reduced to 0.38 ms from more than 30 ms, demonstrating that method can achieve consistent internal time of the system. The method does not require additional hardware devices and has adjustable accuracy.

A Review of Subsidence Monitoring Techniques in Offshore Environments

“…Direct measurement techniques Section 3.1 Hydrostatic leveling Section 3.1.1 [24][25][26][27] Casing collar deformation analysis Section 3.1.2 [28,29] Hydrographic techniques Section 3.2 Bathymetry Section 3.2.1 [30][31][32][33] Air gap measurements Section 3.2.2 [33][34][35] Radar water-level measurements Section 3.2.3 [33,36] Radioactive marker technique (RMT) Section 3.3 [8,[37][38][39][40] Well logging Section 3.4 Electric log data Section 3.4.1 [41] Formation-compaction monitoring tool (FCMT) Section 3.4.2 [42] Tiltmeters Section 3.5 [43][44][45][46][47] Fiber optic cables Section 3.6 [48] Fugro-proposed tools Section 3.6.1 [43] Fiber Bragg grating (FBG) strain sensor Section 3.6.2 [43,49] Time-lapse gravimetry and pressure Section 3.7 [43,[50][51][52][53][54][55][56] Agisco compensator Section 3.8 [43] Microelectromechanical systems (MEMSs) Section 3.9 [57][58][59] Remote sensing Section 3.10 InSAR (interferometric synthetic aperture RADAR) Section 3.10.1…”

“…Electric log data Section 3.4.1 [41] Formation-compaction monitoring tool (FCMT) Section 3.4.2 [42] Tiltmeters Section 3.5 [43][44][45][46][47] Fiber optic cables Section 3.6 [48] Fugro-proposed tools Section 3.6.1 [43] Fiber Bragg grating (FBG) strain sensor Section 3.6.2 [43,49] Time-lapse gravimetry and pressure Section 3.7 [43,[50][51][52][53][54][55][56] Agisco compensator Section 3.8 [43] Microelectromechanical systems (MEMSs) Section 3.9 [57][58][59] Remote sensing Section 3.10…”

“…This arrangement effectively covers a square area measuring 30 × 30 square meters. [59]). The array is designed to monitor subsidence by measuring various parameters such as pressure, tilt, and strain.…”

“…SqueeSAR, positioned as the second generation PSInSAR™ by its developer TRE [66], distinguishes itself through the amalgamation of persistent and distributed scatterers in time series analysis. [59]). The array is designed to monitor subsidence by measuring various parameters such as pressure, tilt, and strain.…”

Semi-Empirical Time-Dependent Parameter of Shear Strength for Traction Force between Deep-Sea Sediment and Tracked Miner

“…Many countries shift their attention from the land to the deep sea, which is abundant with mineral resources, due to the gradual lack of non-renewable land resources with the development of social economy. In the deep sea, there are nearly 1500 billion tons of mineral resources, including poly-metallic nodules, cobalt-rich shells, and poly-metallic sulfides [1][2][3]. Therefore, these countries target ocean exploitation as their strategic development direction.…”