Acid Gas Injection: Days of Future Passed

Prospects of an Acid Gas Re-Injection Process into a Mature Reservoir

“…High-pressure acid gas is transported through pipelines to the well site, where it reaches the wellbore in a dense-fluid state (either liquid or supercritical) before being injected into the reservoir through the well tubing [15]. Depending on the composition and operator specifications, it may also be necessary to dehydrate the acid gas to prevent hydrate formation within the pipeline and wellhead and to mitigate corrosion [11,16,17].…”

“…High-pressure acid gas is transported through pipelines to the well site, where it reaches the wellbore in a dense-fluid state (either liquid or supercritical) before being injected into the reservoir through the well tubing [15]. Depending on the composition and operator specifications, it may also be necessary to dehydrate the acid gas to prevent hydrate formation within the pipeline and wellhead and to mitigate corrosion [11,16,17]. In cases of mature reservoirs containing highly soured resources that have already been produced through primary and secondary recovery, AGI presents a compelling EOR alternative that can potentially circumvent the limitations of waterflooding, as well as provide an eco-friendly option, aligning with global trends towards more sustainable and environmentally friendly industrial practices.…”

“…The first AGI project, although relatively small, was initiated by Chevron near Edmonton, Canada, in 1989 [23]. Subsequently, larger projects emerged, including AGI initiatives at Sleipner West in the North Sea, In-Salah in Algeria, and LaBarge in Wyoming, USA [16]. Beyond these well-established sites where the injection of sour and acid gas mixtures is common practice [24,25], AGI is now applied to numerous sour oil and gas reservoirs worldwide, such as the North Caspian basin's Tengiz field in Kazakhstan [26][27][28] and the Middle East [29][30][31].…”

Rapid Hydrate Formation Conditions Prediction in Acid Gas Streams

“…The high-pressure acid gas flows through pipelines to the well site, arrives at the wellbore in a dense-fluid (liquid or supercritical) state, and finally gets injected into the reservoir through the well tubing [7]. Depending on the composition and the specifications set by the operator, it may also be necessary to dehydrate the acid gas to moderate corrosion [8]. One such alternative is acid gas (re-)injection (AGI) into suitable subsurface reservoirs combining, thus cutting operating costs due to the Claus unit deactivation, reducing sulfur emissions into the atmosphere and increasing oil recovery [2,5].…”

“…The high-pressure acid gas flows through pipelines to the well site, arrives at the wellbore in a dense-fluid (liquid or supercritical) state, and finally gets injected into the reservoir through the well tubing [7]. Depending on the composition and the specifications set by the operator, it may also be necessary to dehydrate the acid gas to moderate corrosion [8]. Gas hydrates are white, solid, ice-like structures of hydrogen-bonded cavities of water molecules, in which gas molecules, H2S and CO2 in the acid gas treatment context (typically smaller than 0.9 nm), are encapsulated in the cavities of the hydrate's crystallized cage-like lattice (Figure 2) under low temperature and elevated pressure conditions.…”