Session: 01-04-02 Design & Analysis-II

Paper Number: 128126

128126 - A Proposed Operational Technique for Safe and Quick Retrieval of Marine Drilling Riser During Extreme Harsh Environmental Condition 

An operational technique designed for safe and quick retrieval of deepwater drilling risers during an imminent threat from hurricane or typhoon is developed by proposing a new drilling riser model with disjointed sections for easier and faster disconnection as against the conventional practice of retrieving the whole length of the riser which is tedious, time-consuming, and has a huge risk of untimely evacuation of personnel and facilities.The risk implication of the proposed operation has been critically analyzed in terms of the mechanical behaviour of the new drilling riser model before and after the typhoon when reuse for continued drilling operation is needed. A theoretical method is used to model the drilling riser in freestanding disconnected mode and the resulting differential equation is solved numerically. The mechanical behaviour of the drilling riser is analyzed for its survivability in freestanding disconnected mode in order to ascertain its useability when the impending typhoon is over. Parametric studies are carried out on key influencing parameters such as buoyancy can upthrust ration (BCUR), buoyancy can (BC) position, and riser thickness to arrive at an optimum condition that will ensure the survivability of the drilling riser when disconnected in freestanding mode. Fifteen parametric case studies are presented. In the first five cases, with a varying BCUR but a fixed BC position and riser thickness, it resulted to obtaining a suitable BCUR which is used in subsequent cases. The next six case studies gave a suitable BC position and finally, the last four cases for riser thickness. Results obtained from the fifteen cases are used to get the optimum condition for survivability of the riser in freestanding disconnected mode. A deepwater drilling riser designed in conformity to the optimum configurational conditions as presented in the analysis can survive in the event of an emergency situation such as hurricane or typhoon.

Presenting Author: Fatai Abimbola China University of Petroleum(Beijing)

Presenting Author Biography: Dr Fatai Abimbola is a Researcher at China University of Petroleum-Beijing. His current research focuses on design and analysis of freestanding drilling riser systems. Abimbola holds a BSc Degree in Petroleum and Gas Engineering from the University of Lagos, an MSc Degree in Chemical Engineering from Beijing Institute of Technology, and PhD in Oil and Gas Well Drilling Engineering from China University of Petroleum-Beijing.

Authors:

Fatai Abimbola China University of Petroleum(Beijing)
Jin Yang China University of Petroleum(Beijing)