A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Offshore Technology and Management, School of Engineering and Technology

Thesis (M. Eng) - Asian Institute of Technology, 2011

Numbers of EPC (detailed engineering, procurement and construction) revamped offshore platform project, for the purpose of enhancing producing capability and accommodating increasing production, have recently emerged due to sharp increasing demand of energy consumption in Thailand. Changes in scope of work, once they occur during detailed engineering design phase, can lead to a number of change orders which likely results in schedule and budget variations of procurement and construction phase. Thus, by thoroughly studying change orders issued during detailed engineering design phase of historical revamped EPC offshore platform projects, proposed preventive suggestions for minimizing and managing changes during engineering phase for the future projects can be drawn. Records of 58 change orders, from 5 historical projects, were collected from a design firm. A typical detailed engineering design workflow was created by reviewing company design procedure together with interviewing company staffs about practical design sequences. Thirty-two design steps from the typical design workflow were defined as potential causing events of change orders. Ten valid causing events (causes) were investigated by cross-analyzing between history in records of change orders and thirty-two causing events in the typical design workflow. 2Clarification of the Contract Requirement3 was the most frequent cause of change orders while 2Technical Bid Evaluation (TBE)3, first and third 3D model review session ranked the least. Effects of change orders were investigated by summarizing total schedule impact and cost impact for each project. Ten preventive suggestions were eventually drawn from history of change orders and ten valid causing events.