EVALUATION OF HYDRATE FORMATION IN A PEPELINE SYSTEM AND THE MITIGATION TO PREVENT COMPRESSOR REPETITIVE SHUTDOWN

• Main Author: GESMATUL - NIM: 23016018 , SEMUEL
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/30867
• Institution: Institut Teknologi Bandung

<p align="justify">Oil and gas production from an existing field will decraesed naturally, thus exploration is requiring to discover oil and gas reserve. Currently Indonesian oil and gas reserves are estimated located mostly in offshore, specially in the deepwater area. Exploration and exploitation of oil and gas in deepwater field require high end technology, high cost and also with relatively high risk. <br /> <br /> <br /> Hydrate formation is one of typical challenge related to oil and gas productin from the deepwater field due to low environmental temprature, where the hydrate formation may lead to serious operational problems either in term of potential loss of production opportunity or related to safety of the facility, since hydrate formation may cause blockage of the pipeline or other equipment, as has been experienced in a deepwater production facility operated by PT ABC located at Makassar strait, producing oil and gas from field A and field B, where repetitive shutdown compressor suspected caused by the hydrate formation and blockage. <br /> <br /> <br /> The purpose of this study is to evaluate hydrate formation and determine the prevention strategy as well to prevent repetitive compressor shutdown. From the simulation result, it was confirmed that the repetitive compressor shutdown caused by the hydrate formation which blocked gas flow in the suction line (suspectedly in the suction filter) of the compressors. <br /> <br /> <br /> The simulation also indicated that at gas flow rate from field A is 23.5 MMSCFD, if gas flow rate from field B higher then 75 MMSCFD, hydrate will form along the suction line from outlet of slug catcher until compressor inlet. On the other hand, if the gas flow rate from field B less then 75 MMSCFD, no hydrate formation observed at suction header but still formed at the outlet of slug catcher. Based on operational data that the repetitive compressor shutdown will occurs when the gas flow rate from field B were increased over 75 MMSCFD until 110 MSCFD. Refer to this data, it was assumed that since the hydrate just formed in the outlet of slug carcher, the hydrate will be flowing and melting when reaching suction header, but when the hydrate will remain formed until suction filter, the hydrate tends to accumulate in the suction at suction filter and blocked gas flow into compressor. <br /> <br /> To prevent hydrate formation and blockage three scenarios were evaluated in this study: By increasing gas flow rate from field A to maintain gas flowing temperature at suction header above the hydrate formation temperature, in this case the gas flworate from field A need to be incresed until 37.9 MMSCFD at gas flow rate from field B is 110 MMSCFD. Another method is to install heater at gas outlet line from slug catcher, where the gas temperature need to be increased to 39.9oF (heater duty = 4.427e+6 btu/hr) at gas fow rate from field A is 23.5 MMSCFD and field B is 110 MMSCFD. For hydrate prevention with methanol, the require injection rate is 600 USGPD to prevent hydrate formation at suction header at gas flow rate from field B is 110 MMSCFD and from field A is 23.5 MMSCFD. <p align="justify">