Research Progress on Recoil Analysis and Control Technology of Deepwater Drilling Risers

Abstract

The deepwater drilling riser is a very important and vulnerable connection between an offshore platform and subsea wellhead. Under some certain complex marine environment and operating conditions, the offshore platform may drift beyond the safe limitations or be driven away rapidly. In order to protect the safety of the platform, personnel and equipment, it is necessary to implement the emergency disconnection of the drilling riser. Since the riser is stretched under a normal connection, the riser will perform a recoil response under the combined effect of elastic potential energy and drilling fluid (mud) discharge frictional resistance after the emergency disconnection. There are complex mechanical mechanisms, influencing factors and difficult safety control problems in the recoil control process. Therefore, effectively controlling the recoil response of the deepwater drilling riser after emergency release has become one of the technical difficulties faced by deepwater drilling. The drilling mud discharge frictional resistance and tensioning force are important factors affecting the recoil response. It is necessary to develop a more general dynamic recoil model for the riser that considers the actual conditions of drilling mud discharge, floating platform motion and nonlinear tensioner factors. This paper introduces the research progress on the recoil analysis and control technology of the deepwater drilling riser, including the discharge, mechanical analysis model, the top tensioner system and control method of the recoil response, which provides a reference for future research on recoil response analyses and design of deepwater drilling risers.

Summary and Prospect of Artillery Recoil Reduction Technology

“…The principle of Electro-Magneto-rheological fluids technology is to use Electro-Magneto-rheological fluids fluid as the buffer liquid, by changing the intensity of the applied electromagnetic field to change the viscosity of the stagnant liquid, to change the recoil resistance. Because this change has the characteristics of instantaneous, continuous and reversible, it can theoretically be adjusted in real time according to the recoil speed of the artillery, so as to realize the recoil resistance curve into a " rectangle", so that the maximum recoil resistance is close to the average recoil resistance [3,12,14]. Test results at home and abroad show that this method has a good recoil reduction effect.…”

“…There are two ways to adjust the liquid flow hole, one is to directly adjust the liquid flow hole of the recoil machine, and the other is to add an additional channel to the recoil machine to adjust the liquid flow hole of the channel. The difficulty of this technology lies in two aspects: on one hand, it is difficult to install the servo valve on the liquid orifice, especially the servo valve directly on the liquid orifice of the recoil machine; on the other hand, the recoil time of the artillery is extremely short (several Milliseconds to ten milliseconds, different guns have differences), real-time adjustment of the servo valve opening in such a short time is difficult to achieve [2,14,11].…”

“…During the recoil of the artillery, the center of mass of the artillery moves upward, and the trajectory is curved. The tandem recoil technology has been applied to the Italian M56 mountain howitzer [2,14,11]. The center of mass of the two-dimensional recoil artillery will produce a turning moment during the curve movement, which will affect the shooting stability of the artillery.…”

“…At present, recoil reduction technology mainly includes: recoil and recuperate technology [20,10], muzzle brake technology [15,16], Electro-Magneto-rheological fluids technology [3,12,14], adaptive control technology, recoilless fire technology [2,14,11], Rarefaction Wave technology [18,1,13,11,19,5,6] and soft recoil technology [11, 3, 4, 7-9, 17, 2]. The maturity of these recoil reduction technologies is quite different, and the applicable conditions for engineering of various technologies are also different.…”

Experimental Study on Key Effectiveness of Bioaerosol Alarm

“…With the rapid development of laser induced fluorescence (LIF) [14] technology, it is widely used. Bioaerosols usually contain (NADH) reducing amide adenine dinucleotides, riboflavin, amino acids [23] and other organic substances, which generate the intrinsic fluorescence of bioaerosols through the excitation of ultraviolet (UV) light [2,18]. By combining with single particle scattering technique, it has made great achievements in various applications.…”