Effect of internal wave parametres on drifting quantity of semi-submersible drilling platform

Based on KdV theory and Morison equation, the theoretical calculation is done for the acting force of internal wave. The motion time travel curve of platform under the action of internal wave is figured out. It is discovered that, under the action of internal wave, the platform has the maximum drifting quantity and reverse drifting in the incidence direction of internal wave, and constantly vibrates and finally returns to the balanced position after the internal wave passes. According to effects of 4 factors, namely, upper fluid thickness of internal wave, maximum flow rate, angle of incidence and water depth on the platform drifting quantity, the research on law is conducted, and it is discovered that the changes of upper fluid thickness and water depth do not leave great effects on the platform drifting quantity, the maximum flow rate should be regarded as the primary monitoring factor, and the monitoring scope of angle of incidence of internal wave may be properly adjusted on the basis of determined maximum flow rate. After the strong internal wave current is monitored, the platform operation should be stopped, the operation pipe column should be disconnected, and the anchor chain towards the current direction should be properly loosened.