INNOVATIVE GAS-LIQUID SEPARATOR INCREASES GAS PRODUCTION IN THE NORTH SEA

摘要

Innovative gas/liquid separation equipment has increased the throughput to design levels at the Shearwater oil and gas production platform in the central North Sea. The platform is about 150 miles off the east coast of Britain in 300 feet deep water and is operated by Shell UK Exploration and Production and backed by Shell, ExxonMobil and BP. Shearwater was the largest producing high-pressure, high-temperature field in the North Sea when it came on stream in September 2000. Its gas condensate resevoir has wells that are 17,000 feet deep, with pressures up to 14,500 psi and temperatures up to 380°F. The gas is dried and processed on the platform before it is sent directly into the UK network for industrial and domestic use. Gas dehydration plants consist in essence of an inlet scrubber, a contactor and an outlet scrubber, either in separate vessels or integrated in one vessel. Prior to processing the gas through the low-temperature conditioning plant and then into the export pipeline, water vapor is removed in a TEG contactor to avoid condensation in, and corrosion of, the subsea line; however, condensate carryover from the TEG inlet separator restricted the plant capacity to about 75% of the 410 MMscfd design capacity. At the prevailing high operating pressure, the efficiency of the original vane mist eliminator, installed in the bottom of the TEG contactor, was insufficient to capture entrained liquid hydrocarbons in the gas and protect the contactor from contamination.