Experimental and numerical investigation of tertiary-CO2 flooding in a fractured chalk reservoir

Ghasemi, Mohammad; Astutik, W.; Alavian, Sayyed Ahmad; Whitson, Curtis Hays; Sigalas, L.; Olsen, Dan; Suiçmez, Vural Sander

doi:10.1016/j.petrol.2018.01.058

Cited by 9 publications

(1 citation statement)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In previous experimental studies, indirect methods are mainly carried out to determinate the CO 2 effective diffusion coefficient in laboratory. The process of CO 2 diffusion in bulk liquid or in porous media is indirectly reflected by measuring and recording experimental data, including pressure decay, volume change, gas-liquid interface location (Trivedi and Babadagli, 2009;Ghasemi et al, 2018;Zhou et al, 2020b).…”

Section: Introductionmentioning

confidence: 99%

CO2 Mass Transfer and Oil Replacement Capacity in Fractured Shale Oil Reservoirs: From Laboratory to Field

Qiao

Zhang

et al. 2022

Front. Earth Sci.

View full text Add to dashboard Cite

CO2-based fracturing is widely introduced to stimulate shale oil reservoirs for its multiple advantages. However, the range of CO2 entering the matrix around fractures and CO2-oil replacement capacity between matrix and fractures cannot be fully explained. To address this issue, a radial constant volume diffusion experiment on shale cores was designed in this study, and the pressure drop curve history was matched through numerical model to determine the composition effective diffusion coefficient. A field-scale numerical model was established, in which a series of certain grids were used to explicitly characterize fracture and quantify the prosess of CO2 mass transfer and oil replacement. Based on the field-scale numerical model, the process of shut-in, flow back, and oil production was simulated. The distribution of CO2 in fractured shale oil formation and its impact on crude oil during shut-in stage and flow back stage were investigated. This study concludes that CO2 gradually exchanges the oil in matrix into fractures and improve the fluidity of oil in matrix until the component concentrations of the whole reservoir reaches equilibrium during the shut-in process. Finally, about 30∼35 mole % of CO2 in fractures exchanges for oil in matrix. The range of CO2 entering the matrix around fractures is only 1.5 m, and oil in matrix beyond this distance will not be affected by CO2. During the process of flow back and production, the CO2 in fracture flows back quickly, but the CO2 in matrix is keeping dissolved in oil and will not be quickly produced. It is conclued that the longest possible shut-in time is conducive to making full use of the CO2-EOR mechanism in fractured shale oil reservoirs. However, due to the pursuit of economic value, a shut-in time of 10 days is the more suitable choice. This work can provide a better understanding of CO2 mass transfer mechanism in fractured shale oil reservoirs. It also provides a reference for the evaluation of the shut-in time and production management after CO2 fracturing.

show abstract

Section: Introductionmentioning

confidence: 99%