Lin-lin Wang

Research on design scheme and hydrodynamic performance of floating body based on sandglass-type FDPSO

In order to solve the limitations of the hydrodynamic performance of traditional ship-type and cylindrical FDPSO (floating, drilling, production, storage and offloading unit), this paper proposes a new concept of sandglass-type FDPSO. For the new floating model, by using classic boundary element method, the characteristic of its heave motion response can be studied. Then based on the wave potential theory, engineering estimation expressions of heave motion performance are theoretically and mathematically deduced to summarise the design guidelines and schemes for sandglass-type floating body. Furthermore, according to the information of a ship-type FDPSO named as MPF, a sandglass-type floating body of new FDPSO with the same basic function has been designed. Finally, compared with ship-type, cylindrical and semi-submersible floating body, the design guideline in this paper can be validated to be effective and rational. New sandglass-type design can significantly improve the hydrodynamic performance of FDPSO. Therefore this paper can provide an innovative engineering platform and design proposal for the development of deep-water oil and gas.

Experimental analysis on behaviour in waves for sandglass-type floating body

abstract In order to solve the performance limitations of traditional ship-type and cylindrical FPSO, this paper describes a new concept of sandglass-type floating body. In order to verify the performance advantages of the new concept of design, a series of tests with the sandglass-type and cylindrical floating models were carried out, which include free decay, regular and irregular wave experiments. Finally, the characteristic of natural period, viscous damping and motion response for the new sandglass-type model was studied. By comparing the experimental results of the two floating models, some useful conclusions can be made as follows: the design of sandglass-type shape floating body can significantly improve the heave motion performance of FPSO and can be considered as an attractive alternative system in deep water for offshore petroleum exploration.

Wave-free characteristic of heave motion response for new sandglass-type model

ABSTRACT This paper mainly studies the wave-free characteristic of heave motion of a sandglass-type floating body to overcome the limitations of traditional ship-type and cylindrical floating, production, storage and offloading units. In the first instance, the theoretical and numerical methods are used to determine the added mass and damping wherein the heave motion can be decoupled. The existence of wave-free characteristic of heave motion is theoretically and numerically verified. Moreover, the heaving quadratic transfer function of second-order wave drift force is calculated and its performance has been discussed. Finally, the relationship between wave-free frequency and wave spectrum is selected as the design principle of the shape parameters. On this basis, some experiments of new sandglass-type and cylindrical models are carried out, which coincide with the numerical predictions very well and show that the new design based on wave-free frequency can significantly improve the heave motion performance.

Second-Order Slowly Varying and Mean Value of Pitch Motion of the Sandglass-Type Floating Body With Dynamic Positioning System

This paper takes the presented concept of sandglass-type floating body as the research object. The shape of new sandglass-type floating body has extended oblique characteristic, which may result in special performance and the problem of pitch (or roll) motion. From the experimental tests, it can be found that its pitch natural frequency is small and the second order slowly varying pitch motion in irregular wave is significant, which may cause an unintentional interaction between the pitch and surge motions. Additionally, the floating body with small-waterplane-area and low metacentric height may have obvious mean pitch angle with wind moment under harsh sea condition. To solve the above two problems, numerical simulations have been conducted with two sea conditions. Lastly, based on the existing technique, the problems are solved and the positioning accuracy can be satisfied well for the harsher sea condition.Copyright