OPTIMUM TEMPLATE SELECTION AT MARGINAL FIELD

• Main Author: Gangaraj, Anantram
• Format: Thesis
• Language: English
• Published: 2014
• Subjects: T Technology (General)
• Online Access: http://utpedia.utp.edu.my/13966/1/AnantramIPthesis2014.pdf; http://utpedia.utp.edu.my/13966/

Template selection is significant in saving time and money in the oil and gas industry. The problem of selecting an optimum template is mainly the type of vessel to be deployed for template operations and also the operational risk present. The objective of this project is to determine the suitable type of vessel to transport and install the suitable type of template. Other than that it is important to calculate the time and cost in relation to the template selection. Weather conditions of the open sea needs to be considered as well. Marine operations at South China Sea are companied along with the presence of typhoon, giant waves or even monsoon wind and these risks besides other common hazards may jeopardize the overall project by wasting precious time and cost. Literature studies have showed that two common types of template utilized in marginal fields are Integrated Template Structure (ITS) and Stacked Template Structure (STS). These templates are different in mass, design and installation method. In this project, several analyses have been done to compare both types of templates mentioned. These analyses shown in methodology chapter emphasize the usage of mechanical knowledge in particular vessel dynamics formula and also petroleum economics during time and cost calculations. First, template selection based on type of vessel is done by calculating and comparing the heave period of each vessel in relation to the type of template structure. It is known that the lower this heave response, the worse the performance of the vessel in waves. For this project, it is found that the Semi-Submersible Crane Vessel (SSCV) to be the most stable vessel to be operated at South China Sea boasting a heave period value of 19.3 seconds therefore recommending SSCV preferable for ITS and monohull vessel suitable for STS. Once vessel selection is complete, the next step is to calculate the transportation and installation time and consequently cost. For this project purpose, the Sepat field is chosen as the marginal field located at South China Sea. Cost calculation is done by multiplying vessel daily rate and vessel total operation time. Vessel transportation time is the product of vessel average speed and the distance from Sepat field to its nearest port which is 130 Km. From literature studies, I’ve also leart that weather-critical operation is one of the important element in template selection therefore cost calculations considering the weather effect on operations is done by introducing waiting on weather (WOW) factor in the cost calculation formula. The results show that ITS transportation and installation carries a higher cost than STS and more templates also increases installation cost due to the complexity. It is also proven that weather conditions significantly increases cost as well. Next, Hazard identification (HAZID) studies will be conducted. Hazards identified in this project are based on historical information and past experiences of other field operations in South China Sea. Risk rating is determined by the product of severity and probability of occurrence. Results show that the ITS which is heavier than STS consumes more installation time due to its complexity, thus presenting more risks and hazards which needs more mitigation measures. The project concludes STS is better compared to ITS in marginal fields and also future recommendations to improve the project are included.