High H2S Gas Field Monetization: A Novel Approach

Abstract

As per EIA, 40% of the world reserves are sour. This has imposed significant challenges and economic burden to monetize ultra-sour gas fields with H2S levels much higher than 5 mol% in the raw gas. Currently most of the ultra-sour gas fields are monetized by using conventional treating technologies like amine solvent process followed a Claus based process to produce sulfur, Sulfur recovery unit and Tail gas treatment unit, SRU-TGTU. This process is extremely capital and operating cost prohibitive as standalone processes. Also, the overall Sulfur production requires a local demand to address overall sulfur disposal cost. With growing number of fields with higher than 5-36% H2S, ultra-sour fields, it’s difficult for operators to maintain healthy production profits while producing such large quantity of sulfur. With ultra-sour gas production, it has many Health Safety and Environmental (HSE) challenges. A new gas treating technology approach is developed to address ultra-sour fields. The approach is using hybrid process by using state of the art H2S removal membranes to do bulk separation of H2S upstream followed by small amine and Claus plant. This is ideal solution where unique membranes have ability to withstand high H2S environment without altering its performance. These membranes will separate H2S enriched stream which is ideal for reinjection or potentially used for Enhanced Oil Recovery (EOR). The membranes retain maximum hydrocarbons in the high-pressure product gas which very valuable in gas production. Low pressure H2S rich stream is water dry and can be reinjected directly. These membranes will also address CO2 capture along with H2S removal. Using combination of unique membrane technology with smaller amine and Claus plant will reduce the overall CAPEX and OPEX requirement for a given project budget. Membranes are much safer and does not have any emission issues. This will allow plants to be much more HSE safe. Having lower CAPEX and overall lower total cost of ownership (TCO) will allow operators to monetize ultra-sour gas fields and provide better return on investment compared to standalone large sulfur plants.