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Flaring of associated gas at hydrocarbon production facilities contributes to Scope 1 of GHG emissions and is a wastage of a valuable energy resource. A wide range of technical and technological solutions have been proposed to address this issue. However, the volumes of flared associated gas are rarely large enough to capture and monetize economically at a single location hence the struggle to achieve ZRF, especially at offshore locations. This paper presents the practical solutions to monetize this small-volume associated gas and the resulting techno-economic assessments of these options at five different offshore locations. A thorough state-of-the-art review has been conducted categorizing external outlooks on process improvement initiatives and/or technologies that can be applied for flaring and venting management. The study focuses on solutions for offshore facilities where the volume of associated gas is small, within the range of 5MMSCFD or less. Five fields in offshore Malaysia were considered for this purpose. A two-steps techno-economic assessment with a case study field was carried out to firm up IRR, NPV, CAPEX, OPEX, variable cost and revenue for each technology solutions. The four leading solutions were: 1. recovering the flare gas and utilizing it as fuel gas to generate electric power using small-scale generators, 2. recovering the flare gas and utilizing it for gas reinjection through existing idle reinjection facilities, 3. installing in-situ small-scale gas-to-liquids conversion process, and 4. improving the efficiency of the existing processing system using data analytics to further reduce or eliminate the gas volumes. Except for the fourth option, additional equipment are required with their respective footprints. The existing processing system and platform size played a major role in determining the right solution for a given location. For the identified offshore field case studies, the vent gas reduction is achieved through Solution 1 at two fields, Solution 2 at one field, and Solution 3 at two fields. The techno-economics assessment shows that power generation (Solution 1) requires the lowest CAPEX and provides the highest IRR 21% with an NPV of USD4.2 million. The gas reinjection (Solution 2) also has lower CAPEX but the production increment is not significant and hence lowest IRR. In conclusion, there is no single standard or generic solution to help recover associated flare and vent gases and monetize it. Operators need to consider several factors especially on flare or vent volume variation, low pressure, and limited space at brownfield facilities. |
