Hull Form Development And Performance Analysis Of Deepwater Drillship

With the exploitation of ocean oil and gas switching to deep water and ultra deepwater fields, research on drilling and production system for deepwater has become hot item.Drillship holds definite advantages over other platforms in deepwater exploration drilling project, especially in terms of variable deck load, range of available water fileds, mobility and storage volumes. Drillship is preferred for future development in South China Sea.The primary challenge deepwater drillship faced is that it's more sensitive of wave impact. The better motion characteristics and performance can be achieved through optimizing the shape of the hull , line sleekness and enhanced mooring system deployment. Researches on preliminary design of deepwater drillship for South China Sea are studied and presented in this dissertation, especially in hull form development and performance analysis. This dissertation mainly investigates the following items:1. Characteristics of drillship hull form is introduced based on a survey conducted.Furthermore, the hull form design and general arrangement are carried out based on the survey and primary design target .2. Intact and damage stability for drillship is calculated in the paper. Studies of how the stability responding to different operating conditions,different arrangement of apartment and opening is carried out to find the basic factors effecting drillship' s intact stability and damage stability., appropriate countermeasures to be taken when the stability is found insufficient is proposed based on the analyses.3. The mooring system is designed according to the API RP-2SK rules. The selected mooring system splits the difference of catenary mooring system and taut mooring system. The results of analyses indicate that the project reduces the weight of mooring line and mooring system deployment costs, and it also increases the variable load of drillship.4. Analysis of mooring system with five different kind of deployment is carried out to study the effect of mooring system deployment on restoring force and the tension of lines under design condition. The coupling analysis of the system indicates that the mooring system offers station keeping ability.