Effect of Compaction on Oil Recovery Under Low Salinity Flooding in Homogeneous and Heterogeneous Chalk

Hao, Jiasheng; Shapiro, Alexander

doi:10.2118/195831-ms

Cited by 3 publications

(1 citation statement)

References 52 publications

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“…While dissolution alone is not likely to lead to a large amount of oil production, it may trigger other, probably, more important effects. Consequences such as pH alteration, improved pore connectivity, modified electric double-layer interaction, and compaction of chalk were reported in connection with the calcite dissolution. These mechanisms need a separate investigation.…”

Section: Modeling Of Experimental Datamentioning

confidence: 99%

Kinetics of Calcite Dissolution and Ca–Mg Ion Exchange on the Surfaces of North Sea Chalk Powders

2020

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Calcite dissolution and Ca–Mg ion exchange on carbonate rock surfaces have been proposed as potential mechanisms occurring during smart waterflooding in carbonate reservoirs. However, there is still a lack of fundamental understanding of these reactions to quantitatively evaluate their effects in the reservoir flooding process. Especially, the data on precipitation and dissolution kinetics are insufficient. In this work, the equilibration kinetics of calcite dissolution and Ca–Mg exchange was experimentally studied. The behavior of three powders was compared: pure calcium carbonate, Stevns Klint outcrop chalk, and North Sea reservoir chalk. It was found that the equilibration time for calcite dissolution was of the order of seconds for a given surface-area-to-liquid-volume ratio. The existing theory of calcite dissolution could well reproduce our observations. The Ca–Mg exchange showed two-step kinetics: the first step was fast, and it dominated the process within the first hour of reaction; the second step was slow, and it continued longer than the time of observation (2 weeks). Characteristic times for the two steps were extracted by fitting the experimental curves. A two-layer adsorption model was proposed to characterize the kinetic process and successfully matched with experimental data. The findings were further extended to flow-through scenarios. By comparing with literature data and surface complexation models, it was concluded that calcite dissolution alone was unlikely to be able to explain the additional recovery reported in the literature. The Ca–Mg exchange process could dominate the fluid–rock interactions at a high temperature in pure calcium carbonate rocks, while competitive adsorption of cations appeared to control the process at a lower temperature. Different carbonate rocks possess different properties with regard to the ion-exchange process.

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Section: Modeling Of Experimental Datamentioning

confidence: 99%

Kinetics of Calcite Dissolution and Ca–Mg Ion Exchange on the Surfaces of North Sea Chalk Powders

2020

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Smart water injection

et al. 2022

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Laboratory, numerical and field assessment of the effectiveness of cyclic geomechanical treatment on a tournaisian carbonate reservoir

Indrupskiy

Ibragimov

Tsagan-Mandzhiev

et al. 2023

PMI

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Results are discussed for evaluation of effectiveness of the cyclic geomechanical treatment (CGT) on a Tournaisian carbonate reservoir. Analysis of laboratory experiments performed according to a special program to assess permeability changes for Tournaisian samples under cyclic changes in pore pressure is presented. The main conclusion is the positive selectivity of the CGT: an increase in permeability is observed for samples saturated with hydrocarbons (kerosene) with connate water, and maximal effect is related to the tightest samples. For water-saturated samples, the permeability decreases after the CGT. Thus, the CGT improves the drainage conditions for tight oil-saturated intervals. It is also confirmed that the CGT reduces the fracturing pressure in carbonate reservoirs. Using flow simulations on detailed sector models taking into account the results of laboratory experiments, a possible increase in well productivity index after CGT with different amplitudes of pressure variation was estimated. Results of a pilot CGT study on a well operating a Tournaisian carbonate reservoir are presented, including the interpretation of production logging and well testing. The increase in the well productivity index is estimated at 44-49 % for liquid and at 21-26 % for oil, with a more uniform inflow profile after the treatment. The results of the field experiment confirm the conclusions about the mechanisms and features of the CGT obtained from laboratory studies and flow simulations.

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Effect of Compaction on Oil Recovery Under Low Salinity Flooding in Homogeneous and Heterogeneous Chalk

Cited by 3 publications

References 52 publications

Kinetics of Calcite Dissolution and Ca–Mg Ion Exchange on the Surfaces of North Sea Chalk Powders

Kinetics of Calcite Dissolution and Ca–Mg Ion Exchange on the Surfaces of North Sea Chalk Powders

Smart water injection

Laboratory, numerical and field assessment of the effectiveness of cyclic geomechanical treatment on a tournaisian carbonate reservoir

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