Implementation Study for Miscible Water Alternating Gas (WAG) EOR in a Giant, Offshore Field

Shehhi, Budoor Al; Patel, Harshad; Jani, Zankar; Khan, Sameer A.

doi:10.2118/172787-ms

Cited by 4 publications

(2 citation statements)

References 4 publications

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“…Throughout the literature review sourcing process it became clear that many papers related to WAG serve as case studies of particular offshore fields [11] or very specific simulation studies aimed at evaluating WAG recovery as an EOR technique [12]. The novelty of this study comes from its evaluation of WAG as a secondary recovery method, compared against water flooding and gas flooding in a sensitivity analysis format.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Oil Recovery Methods for Reservoirs in the Flemish Pass Basin

LaFitte¹

2022

Day 2 Thu, March 17, 2022

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Summary In recent years, the Flemish Pass Basin has been gaining momentum as an area of potential high-volume resources on the frontier of remote, deep-water offshore oil development. This simulation study utilizes three sector models representing regional, discovered reservoirs, and two tuned fluid models representing oil sampled from wells in the Flemish Pass Basin. Generally speaking, WAG is considered a late-life enhanced oil recovery (EOR) technique, while implementing WAG immediately upon first oil for secondary recovery is less common; however, may be equally or more valuable. This study aims to evaluate three secondary oil recovery methods, water flooding, gas flooding, and water-alternating-gas (WAG) flooding. Each recovery method is simulated with Schlumberger’s ECLIPSE reservoir simulator and uses a combination of three distinct reservoir geo-models and two fluid models. This study is a sensitivity analysis using geo-models that represent three discovered regions and two sampled fluids from the Flemish Pass Basin. The study is aimed at evaluating the effects of the various recovery methods over a duration of either five- or twenty-year forecast periods. Results from this study capture an inherent uncertainty by drawing from eighteen simulation cases to quantify the relative benefit of each recovery method. These results indicate that using WAG as a secondary recovery method can yield a 4% to 10% increase in recovery over water or gas flood, and that secondary WAG can extend a well pair’s production plateau by up to 80% in specific circumstances. Further observations indicate that secondary WAG in light oil reservoirs yield a ∼10% increase in recovery over secondary water or gas flooding. Using WAG in a medium oil reservoir yields a 4% to 9% increase in recovery over water flood, and a 2% to 16% increase in recovery over gas flood. In terms of geology, WAG is observed to be most valuable in ultra-high-quality reservoirs. The better the reservoir quality, the more recovery improvement. In terms of fluids, the medium oil responds best to the gas injection phase of WAG while the light oil appears to respond well to both phases. During development optimization, these trends can be accounted for in the injection cycle timing and duration for each phase. In terms of using WAG as a tertiary recovery method after a period of water or gas flooding, tertiary WAG is observed to be most beneficial in the low to medium quality reservoirs. Tertiary WAG extends the production duration and results in a ∼4% increase in recovery beyond water flooding. Study results go on to quantify the differences in water and gas breakthrough as a factor of pore volume injected (PVI) and conclusions further indicate which reservoirs are best suited for each recovery method.

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Section: Introductionmentioning

confidence: 99%

Assessment of Oil Recovery Methods for Reservoirs in the Flemish Pass Basin

LaFitte¹

2022

Day 2 Thu, March 17, 2022

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“…Because primary recovery processes only cover 5-10% original oil in place,this oil rate production is plummeted regarding depletion of fluids on the rock matrixes and pressure drop by passing the production time. (Al Shehhi et al, 2015;Campbell, 2002;Djuraev et al, 2017;Hascakir, 2017). This oil rate production is plummeted regarding depletion of fluids on the rock matrixes and pressure drop by passing the production time.…”

Section: Introductionmentioning

confidence: 99%

An experimental study of alternative hot water alternating gas injection in a fractured model

Ebadati

Akbari

Davarpanah

2018

Energy Exploration & Exploitation

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Alternative injection of gas as slugs with water slugs, or alternative water gas injection, is the conventional technique for improving the recovery factor due to its high potential for mobilizing the residual oil in place in the reservoirs and to control gas mobility. The water alternating gas methodology is a combination of two oil recovery procedures: gas injection and waterflooding. The principal parameters that must be evaluated in water alternating gas injection in laboratory scale are reservoir heterogeneity, rock type, and fluid properties. In the current investigation, a feasibility study has been performed to analyze the five various scenarios of enhanced oil recovery techniques and compare them experimentally. The laboratory experiments are done for one of the Iranian reservoirs which have been subjected to waterflooding for several years, and the amount of recovery factor for water flooding is about 42%. The results of this study illustrate that water alternating gas injection and hot water alternating gas injection exert a profound impact on the amount of recovery factor. Moreover, the primary purpose of this study is to assess the application of alternative hot water and hot carbon dioxide gas injections in the conventional and fractured reservoir model.

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Improving Oil Recovery Using Miscible Selective Simultaneous Water Alternating Gas (MSSWAG) Injection in One of the Iranian Reservoirs

Farahani

Movaghar

2017

Arab J Sci Eng

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Implementation Study for Miscible Water Alternating Gas (WAG) EOR in a Giant, Offshore Field

Cited by 4 publications

References 4 publications

Assessment of Oil Recovery Methods for Reservoirs in the Flemish Pass Basin

Assessment of Oil Recovery Methods for Reservoirs in the Flemish Pass Basin

An experimental study of alternative hot water alternating gas injection in a fractured model

Improving Oil Recovery Using Miscible Selective Simultaneous Water Alternating Gas (MSSWAG) Injection in One of the Iranian Reservoirs

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