Geochemical reactions and their influence on petrophysical properties of ultra-low permeability oil reservoirs during water and CO2 flooding

Cui, Guodong; Yang, Linglu; You, Qing; Qiu, Zhichao; Wang, Yuting; Ren, Shaoran

doi:10.1016/j.petrol.2021.108672

Cited by 50 publications

(36 citation statements)

References 29 publications

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“…It is assumed here that after the rock material is stressed to a certain level, uniform damage occurs, and the change of damage is related to the effective stress acting on the rock structure. Rabonov first introduced the variable corresponding to the continuous variable, namely, the damage variable D [19][20][21],…”

Section: Pore Water Pressure: B-c "Increase-decrease" Transitional Stagementioning

confidence: 99%

Study on the Variation Rule and Characteristics of Pore Water Pressure in the Failure Process of Saturated Rock

Zhang

2021

Shock and Vibration

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With the development of tunnels and other engineering constructions into the deep strata, rock masses are more prone to dynamic damage such as rock bursts under in situ conditions and excavation disturbances. The pore water in the rock mass will produce pressure changes during this process. According to the relationship between the change of pore water pressure and the development of rock mass damage, the variation rule and precursor characteristics of pore water pressure in the process of rock mass failure can be found. In this paper, through mechanical analysis, the evolution law of pore water pressure during the failure process of saturated rock is obtained. The study found that, in the process of rock failure, the pore water pressure presents three stages of linear growth, transition, and decrease. The rise and fall of pore water pressure are closely related to rock damage and influence each other. Through the observation of pore water pressure during coal mining, it is found that the coseismic effect of pore water pressure is significant. It is proved that there is a close correlation between the evolution of the stress field in the surrounding area of the stope and the change of pore water pressure in the surrounding area under the effect of mining disturbance. During the engineering practice, dynamic monitoring can be carried out on the change of pore water pressure inside the rock mass according to the law, and the precursor information of rock mass instability and failure can be explored.

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Section: Pore Water Pressure: B-c "Increase-decrease" Transitional Stagementioning

confidence: 99%

Study on the Variation Rule and Characteristics of Pore Water Pressure in the Failure Process of Saturated Rock

Zhang

2021

Shock and Vibration

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“…CO 2 -water/brine is one of the most important and commonly encountered systems [1][2][3] in CO 2 sequestration [4][5][6][7][8][9][10][11], CO 2 -enhanced oil recovery (EOR) [2,12,13], CO 2enhanced geothermal systems (EGS) [14,15], global CO 2 tracing [16][17][18][19], and so on. In these chemical-, petroleum-, and environment-related technological applications, accurate prediction of the phase-partitioning properties over a wide pressure-temperature-salt composition (P-T-x) range is essential for the understanding of the CO 2 flow and trapping mechanism in subsurface formations [7,11,20,21] and the potential rock-fluid chemical interactions [4,14].…”

Section: Introductionmentioning

confidence: 99%

Modelling of the Phase-Partitioning Behaviors for CO2-Brine System at Geological Conditions

Sun

Wang

et al. 2021

Lithosphere

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An improved phase-partitioning model is proposed for the prediction of the mutual solubility in the CO2-brine system containing Na+, K+, Ca2+, Mg2+, Cl-, and SO42-. The correlations are computationally efficient and reliable, and they are primarily designed for incorporation into a multiphase flow simulator for geology- and energy-related applications including CO2 sequestration, CO2-enhanced geothermal systems, and CO2-enhanced oil recovery. The model relies on the fugacity coefficient in the CO2-rich phase and the activity coefficient in the aqueous phase to estimate the phase-partitioning properties. In the model, (i) the fugacity coefficients are simulated by a modified Peng-Robinson equation of state which incorporates a new alpha function and binary interaction parameter (BIP) correlation; (ii) the activity coefficient is estimated by a unified equilibrium constant model and a modified Margules expression; and (iii) the simultaneous effects of salting-out on the compositions of the CO2-rich phase and the aqueous phase are corrected by a Pizter interaction model. Validation of the model calculations against literature experimental data and traditional models indicates that the proposed model is capable of predicting the phase-partitioning behaviors in the CO2-brine system with a higher accuracy at temperatures of up to 623.15 K and pressures of up to 350 MPa. Using the proposed model, the phase diagram of the CO2+H2O system is generated. An abrupt change in phase compositions is revealed during the transfer of the CO2-rich phase from vapor to liquid or supercritical. Furthermore, the preliminary simulation shows that the salting-out effect can considerably decrease the water content in the CO2-rich phase, which has not been well experimentally studied so far.

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“…e dissolution of CO 2 in water and the dissolution of water in CO 2 occur at the same time in the CO 2 -brine system [5]. Although the solubility of water in CO 2 is low under site conditions, this dehydration process cannot be ignored when a large amount of dry CO 2 fluid is continuously injected into the rock formation [6].…”

Section: Introductionmentioning

confidence: 99%

Sensitivity Analysis Strategy to Assess the Salting‐Out Problem during CO₂ Geological Storage Process

Ren

Feng

2021

Shock and Vibration

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The sensitivity analysis of the salting-out effect on well injectivity is a significant work in the research of geological storage of CO2 in deep saline aquifers, which is helpful in the selection of storage sites and the design of the injection strategy. We conduct a detailed sensitivity analysis about the salting-out process using the local sensitivity method and two global sensitivity methods. Sensitivity coefficients showed that brine salinity (XNaCl) has the highest sensitivity and interaction effect, the CO2 injection rate (QCO2) has a greater influence in the early stage of the salting-out process and a smaller influence in the end stage, and the other three parameters (empirical parameters related to the pore distribution m, the liquid residual saturation in the relative permeability function Splr, and the liquid residual saturation in the capillary pressure function Sclr) have a smaller sensitivity. This paper also analyzes the calculation amount of different sensitivity methods and suitable ways of obtaining the sensitivity coefficient and reveals the following. (1) The sensitivity coefficient changes dynamically with time, if only the sensitivity of the final state is taken into account on a long-time physical process, and some sensitive parameters during the process may be neglected. (2) The selection of the sample size should be based on the convergence of multiple calculations, and the results of the empirical calculation are uncertain. (3) The calculation of Sobol sensitivity is complicated, the results calculated by surrogate model depend on whether the sample is representative enough; on the other hand, it is feasible to use Sti-Si approximation to characterize the second-order sensitivity to reduce the computation. The research results not only reveal the sensitivity of the parameters related to the injection well salting-out problem during CO2 storage in deep saline aquifers but also guide the calculation of global sensitivity analysis with a similar physical process.

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Geochemical reactions and their influence on petrophysical properties of ultra-low permeability oil reservoirs during water and CO2 flooding

Cited by 50 publications

References 29 publications

Study on the Variation Rule and Characteristics of Pore Water Pressure in the Failure Process of Saturated Rock

Study on the Variation Rule and Characteristics of Pore Water Pressure in the Failure Process of Saturated Rock

Modelling of the Phase-Partitioning Behaviors for CO2-Brine System at Geological Conditions

Sensitivity Analysis Strategy to Assess the Salting‐Out Problem during CO₂ Geological Storage Process

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Geochemical reactions and their influence on petrophysical properties of ultra-low permeability oil reservoirs during water and CO2 flooding

Cited by 50 publications

References 29 publications

Study on the Variation Rule and Characteristics of Pore Water Pressure in the Failure Process of Saturated Rock

Study on the Variation Rule and Characteristics of Pore Water Pressure in the Failure Process of Saturated Rock

Modelling of the Phase-Partitioning Behaviors for CO2-Brine System at Geological Conditions

Sensitivity Analysis Strategy to Assess the Salting‐Out Problem during CO2 Geological Storage Process

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Product

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Sensitivity Analysis Strategy to Assess the Salting‐Out Problem during CO₂ Geological Storage Process